Patent Application
20230261206
This application relates to the field of battery technologies, and particularly to an electrochemical apparatus and an electric device including the same.
It is well known that use of lithium-ion batteries is greatly affected by temperature. Generally, in a low-temperature environment, the batteries suffer from degradation of charging capability, their capacities cannot be fully utilized, electron conductivity and ion conductivity are reduced, and kinetic performance drops dramatically. This causes the lithium-ion batteries to undergo lithium precipitation during high-rate charging, which deteriorates the battery’s interface and results in safety risks. In addition, in a low-temperature environment, extractable capacity of battery active materials is reduced, and the voltage platform is reduced, resulting in a loss of battery’s energy density.
Existing methods for improving the low-temperature performance of lithium-ion batteries mainly include heating the battery, and the commonly used heating schemes include external heating and internal heating. In external heating, battery performance in low temperature is improved by adding a heating apparatus outside a battery or battery module. Such a solution has low heating efficiency and limited improvement. During the heating, temperature differences between various parts of the battery are large, which has a greater impact on electrode materials, resulting in deterioration of battery’s cycle performance and safety risks. In internal heating, battery temperature increase is achieved by embedding heating sheets inside the battery to heat the battery inside, improving battery’s kinetics, and further improving charge and discharge capabilities of the battery in a low-temperature environment. During the internal heating, the heating rate is fast and the temperature differences between the parts of the battery are small, which can realize rapid heating of the battery while causing less damage to the battery.
However, the embedding of the heating sheets may cause some problems, for example, the heating sheets occupy a given space, which affects energy density of the battery; the heating sheets deteriorates interface contact inside the battery, which causes problems such as accelerated cycle attenuation and local lithium precipitation; corners of the heating sheets may penetrate a separator, causing serious self-discharge problems; and the heating sheets are not firmly fixed to battery body so that they are prone to fall off when the battery is dropped, then causing battery failure or the like.
In view of this, this application is intended to provide an electrochemical apparatus with a self-heating function and an electric device, to resolve at least one of the problems in the foregoing internal heating.
According to a first aspect of this application, an electrochemical apparatus is provided, including a first electrode plate, a first terminal, and a second terminal; the first electrode plate includes a composite current collector; and the composite current collector includes: a base layer, where the base layer has a first surface and a second surface that are opposite to each other, a first conductive layer, where the first conductive layer is disposed on the first surface; and a second conductive layer, where the second conductive layer is disposed on the second surface, where the first conductive layer includes a first zone and a second zone, and the first terminal and the second terminal are electrically connected to the first zone. The first zone serves as a heating zone configured to heat the electrochemical apparatus.
In some embodiments, a first resistance R1 is provided between the first terminal and the second terminal, satisfying R1≥5 mΩ. Further, R1≥20 mΩ.
In some embodiments, the electrochemical apparatus further includes a positive tab and a negative tab, and an internal resistance R is provided between the positive tab and the negative tab, satisfying 0.05≤R1/R≤5000. Futher, 1≤R1/R≤1000.
When a temperature of the electrochemical apparatus is lower than a nonnal operating temperature (for example, lower than about 5° C.), the first terminal and the second terminal will be connected to a heating circuit and heat the electrochemical apparatus. Because the resistance R1 is much greater than the internal resistance of the electrochemical apparatus in normal operation, and a current of the heating circuit can be conveniently increased during charging, the internal temperature of the electrochemical apparatus may rise rapidly, so that electrochemical performance of the electrochemical apparatus can be quickly improved.
In some embodiments, the first zone is formed integrally by extending from the second zone.
In some embodiments, the first zone is located at an end of the composite current collector in a length direction.
In some embodiments, the first zone includes a pattern.
In some embodiments, the second conductive layer includes a third zone and a fourth zone, the electrochemical apparatus further includes a third terminal and a fourth terminal, the third terminal and the fourth terminal are electrically connected to the third zone, and a second resistance R2 is provided between the third teminal and the fourth terminal, satisfying R2≥5 mΩ. Further, R2≥20 mΩ. The third zone serves as a heating zone configured to heat the electrochemical apparatus.
In some embodiments, the third zone is formed integrally by extending from the fourth zone.
In some embodiments, the third zone is located at an end of the composite current collector in a length direction.
In some embodiments, the third zone includes a pattern.
In some embodiments, materials of the first zone, the second zone, the third zone, or the fourth zone each independently include at least one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, silicon, germanium, antimony, lead, indium, or zinc.
In some embodiments, a porosity of the first conductive layer ranges from 0% to 60%, and a porosity of the second conductive layer ranges from 0% to 60%.
In some embodiments, a thickness of the first conductive layer ranges from 0.1 µm to 10 µm, and a thickness of the second conductive layer ranges from 0.1 µm to 10 µm.
In some embodiments, a material of the base layer includes a polymer. In some embodiments, the polymer includes an insulative polymer. In some embodiments, the insulative polymer includes at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyether-ether-ketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polysulfone, and their derivatives.
In some embodiments, a porosity of the base layer ranges from 0% to 50%.
In some embodiments, a thickness of the base layer ranges from 1 µm to 20 µm.
In some embodiments, the first electrode plate further includes a first active material layer, and the first active material layer is disposed on a surface of the second zone.
In some embodiments, the first electrode plate further includes a second active material layer, and the second active material layer is disposed on a surface of the fourth zone.
In some embodiments, a bonding layer is provided between the base layer and the first conductive layer, and the bonding layer includes a binder.
In some embodiments, a bonding layer is provided between the base layer and the second conductive layer, and the bonding layer includes a binder.
In some embodiments, the binder includes at least one of polyamide, polyurethane, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylic acid ester polymer, sodium alginate, polyacrylic acid, polyvinyl alcohol, carboxymethyl chitosan, gelatin, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride, polyacrylonitrile, polyphenylene ether, polypropylene carbonate, polyethylene oxide, silicone resin, ethylene acrylic acid copolymer, and their derivatives.
In some embodiments, the bonding layer further includes a conductive agent. The conductive agent includes at least one of carbon nanotubes, conductive carbon, or graphene.
This application further provides an electric device, including the electrochemical apparatus according to any one of the foregoing embodiments.
In some embodiments, the electric device further includes a switch. The switch closes when a temperature of the electrochemical apparatus is lower than T1, so that a current passes through the first zone to heat the electrochemical apparatus.
In some embodiments, the electric device further includes a switch. The switch closes when a temperature of the electrochemical apparatus is lower than T1, so that a current passes through the third zone to heat the electrochemical apparatus.
In some embodiments, T1≤5° C.
In the electrochemical apparatus and the electric device provided in this application, a heating zone is provided on the composite current collector to connect a heating circuit, the self-heating function of the electrochemical apparatus is realized, and a method to introduce a heating structure is optimized, thereby effectively alleviating problems caused by existing heating methods, such as energy density reduction, interface contact deterioration, serious self-discharge, and reliability risks in drop tests.
The following fluther describes this application in detail with reference to the accompanying drawings and specific embodiments.
Reference signs of main components:
Embodiments of this application will be further described with reference to the accompanying drawings in the following specific embodiments.
Unless otherwise defined, all technical and scientific terms used herein shall have the same meanings as commonly understood by those skilled in the art to which embodiments of this application belong. The terms used in this specification are merely intended to describe specific embodiments but not intended to constitute any limitation on the embodiments of this application.
Spatial related terms such as “above” may be used herein for ease of description to describe the relationship between one element or feature and another element (a plurality of elements) or feature (a plurality of features) as illustrated in the figure. It should be understood that in addition to the directions described in the figures, the spatial related terms are intended to include different directions in the use or operation of devices or apparatuses. For example, if a device in the figure is turned over, an element described as “on” or “above” another element or feature should be oriented “below” or “under” the another element or feature. Therefore, the example term “above” may include directions of above and below.
It should be understood that although the terms first, second, third, or the like may be used herein to describe various elements, components, zones, layers, and/or portions, these elements, components, zones, layers, and/or portions should not be limited by these terms. These terms are used to distinguish one element, component, zone, layer, or portion from another element, component, zone, layer, or portion. Therefore, the first element, component, zone, layer, or portion discussed below may be referred to as the second element, component, zone, layer, or portion without departing from the teachings of the example embodiments.
Some embodiments of this application are described in detail below. In absence of conflicts, the following embodiments and features in the embodiments can be combined.
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The projections of the first zone 1051 and the third zone 1071 in the thickness direction of the composite current collector 101 may be completely overlapped, partially overlapped, or not overlapped at all. It can be understood that the second conductive layer 107 may only include the fourth zone 1072 but not the third zone 1071. In this case, the metal layer on the second conductive layer 107 corresponding to the first zone 1051 may be removed, as shown in
In some embodiments, materials of the first zone 1051, the second zone 1052, the third zone 1071, or the fourth zone 1072 each independently include at least one of nickel (Ni), titanium (Ti), copper (Cu), silver (Ag), gold (Au), platinum (Pt), iron (Fe), cobalt (Co), chromium (Cr), tungsten (W), molybdenum (Mo), aluminum (Al), magnesium (Mg), potassium (K), sodium (Na), calcium (Ca), strontium (Sr), barium (Ba), silicon (Si), germanium (Ge), antimony (Sb), lead (Pb), indium (In), or zinc (Zn).
In some embodiments, a porosity of the first conductive layer 105 ranges from 0% to 60%, and a porosity of the second conductive layer 107 ranges from 0% to 60%. The first conductive layer 105 and the second conductive layer 107 each have a porosity, which helps reduce weight and increase a loading amount of the active material. However, too large porosity causes too many pores in the first conductive layer 105 and the second conductive layer 107, which lengthens a transmission path of internal electrons along the first conductive layer 105 or the second conductive layer 107, and reduces the electron conductivity, affecting electrical properties of the electrochemical apparatus.
In some embodiments, a thickness of the first conductive layer 105 ranges from 0.1 µm to 10 µm, and a thickness of the second conductive layer 107 ranges from 0.1 µm to 10 µm. The thickness of the first conductive layer 105 or the second conductive layer 107 being within the foregoing ranges helps ensure that the first conductive layer 105 or the second conductive layer 107 has high electron conductivity and ensure the electrochemical performance, while ensuring that the electrochemical apparatus has a high energy density.
In some embodiments, a material of the base layer 103 includes a polymer. The polymer includes an insulative polymer. The insulative polymer includes at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyether-ether-ketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polysulfone, and their derivatives.
In some embodiments, a porosity of the base layer 103 ranges from 0% to 50%. The base layer 103 has a porosity, which helps reduce weight and increase a loading amount of the active material, and increases a surface area of the composite current collector 101 to improve the electron transmission path. The principle of increasing the surface area to improve the electron transmission path is: with a larger porosity, a larger surface area of the base layer 103 may be covered by a metal layer when the first conductive layer 105 or the second conductive layer 107 is being prepared, that is, inner walls of pores close to the surface may also be vapor-deposited with a layer of metal, which become part of the first conductive layer 105 or the second conductive layer 107 in a practical sense.
In some embodiments, a thickness of the base layer 103 ranges from 1 µm to 20 µm. The thickness of the base layer 103 being within the foregoing range helps ensure that the base layer 103 has a high mechanical strength, and that the first conductive layer 105 and the second conductive layer 107 on two sides of the base layer 103 are not connected to each other to cause failure, while ensuring that the electrochemical apparatus has a high energy density.
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In some embodiments, a bonding layer is provided between the base layer 103 and the first conductive layer 105. In some embodiments, a bonding layer is provided between the base layer 103 and the second conductive layer 107. It can be understood that a bonding layer may be provided on each of two sides of the base layer 103, or on only one of the two sides. The bonding layer is configured to improve interface bonding force between the base layer 103 and the first conductive layer 105 and between the base layer 103 and the second conductive layer 107, and improve reliability of the composite current collector 101.
Further, the bonding layer includes a binder. The binder includes at least one of polyamide (PA), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), acrylic polymer, sodium alginate (SA)), polyacrylic acid (PAA), polyvinyl alcohol (PVA), carboxymethyl chitosan (CMCS), gelatin, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyphenylene ether (PPO), polypropylene carbonate (PPC), polyethylene oxide (PEO), silicone resin, ethylene acrylic acid copolymer (EAA), and their derivatives. Materials of the bonding layers on two sides of the base layer 103 may be the same or different.
Further, the bonding layer further includes a conductive agent. The conductive agent includes at least one of carbon nanotubes, conductive carbon, or graphene. Addition of the conductive agent may further increase an electron conduction path and improve the electrical properties.
This application further provides an electric device, including the electrochemical apparatus according to any one of the foregoing embodiments.
Further, the electric device further includes a switch, which satisfies at least one of the following conditions:
When a temperature of the electrochemical apparatus is lower than a normal operating temperature (for example, lower than about 5° C.), the first terminal 30 and the second terminal 50 will be connected to a heating circuit, and/or the third terminal 70 and the fourth terminal 90 will be connected to a heating circuit. Because the resistances R1 and R2 are much greater than the internal resistance of the electrochemical apparatus in normal operation, generated heat is positively correlated with the resistance, and a current of the heating circuit can be conveniently increased during charging, the internal temperature of the electrochemical apparatus may rise rapidly, so that electrochemical performance of the electrochemical apparatus can be quickly improved.
Specific examples and comparative examples below are used to describe this application.
Preparation of a composite current collector: On surfaces of a 10 µm thick polyethylene terephthalate (PET) film, a 0.3 µm thick metal Al plating layer was prepared respectively on two sides by a vacuum deposition method as a first conductive layer and a second conductive layer. At an end of the composite current collector in a length direction, a pattern shown in
Preparation of a positive electrode plate: Lithium cobalt oxide (LiCoO2) as a positive electrode active material, conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) was added to prepare a slurry with a solid content of 0.75, and the slurry was well stirred. The slurry was applied evenly on a surface of a coated zone of the metal Al plating layer on one side of the composite current collector, and dried at 90° C., so that single side coating of the positive electrode plate was completed. Subsequently, the above process was repeated, and the slurry was applied on the other side of the composite current collector and dried. After the above process was completed, active substance layers of the electrode plate were cold pressed to a compacted density of 4.0 g/cm3. Then, auxiliary processes such as tab welding and tape sticking were carried out to complete the preparation of the positive electrode plate.
Preparation of a negative electrode plate: Graphite as a negative electrode active material, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) were mixed in a weight ratio of 96:1.5:2.5, and deionized water was added to prepare a slurry with a solid content of 0.7, and the slurry was well stirred. The slurry was applied evenly on one side of a metal Cu current collector, and dried at 110° C., so that single side coating of the negative electrode plate was completed. Subsequently, the above process was repeated, and the slurry was applied on a surface of the other side of the metal Cu current collector and dried. After the above process was completed, active substance layers of the electrode plate were cold pressed to a compacted density of 1.7 g/cm3. Then, auxiliary processes such as tab welding and tape sticking were carried out to complete the preparation of the negative electrode plate.
Preparation of an electrolyte: In an atmosphere of dry argon, first, organic solvent ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a mass ratio of EC:EMC:DEC = 30:50:20, and then lithium hexafluorophosphate (LiPF6) was added to the organic solvent for dissolution and mixed evenly, to obtain an electrolyte with a lithium salt concentration of 1.15 M.
Preparation of a lithium-ion battery: A polyethylene (PE) with a thickness of 15 µm was selected as the separator. The positive electrode plate, the separator, and the negative electrode plate were stacked in sequence, and the stacked electrode plates and separator were wound to form a wound type electrode assembly, where the first zone is located at a single side zone in the innermost circle. The electrode assembly was placed into an outer packaging aluminum-plastic film, and the top edge and the side edge were sealed. Then, processes such as liquid injection and chemical conversion were performed to obtain a lithium-ion battery.
The difference from Example 1 was that: the thickness of the PET film was 20 µm.
The difference from Example 1 was that: the thickness of the PET film was 1 µm.
The difference from Example 1 was that: the thickness of the metal Al plating layer was 1 µm.
The difference from Example 2 was that: the thickness of the metal Al plating layer was 10 µm.
The difference from Example 1 was that: the thickness of the metal Al plating layer was 0.1 µm.
The difference from Example 1 was that: the material of the base layer was polyimide (PI).
The difference from Example 4 was that: the material of the base layer was polybutylene terephthalate (PBT).
The difference from Example 4 was that: the material of the metal plating layer was Ni.
The difference from Example 4 was that: the material of the metal plating layer was Cu.
The difference from Example 4 was that: the material of the first conductive layer was Al, and the material of the second conductive layer was Cu.
The difference from Example 4 was that: the porosity of the metal plating layer was 30%.
The difference from Example 4 was that: the porosity of the base layer was 30%.
The difference from Example 4 was that: a bonding layer was provided between the base layer and each of the metal plating layers on two sides, and the material of the bonding layer was polyurethane.
The difference from Example 4 was that: a bonding layer was provided between the base layer and each of the metal plating layers on two sides, and the material of the bonding layer was ethylene-vinyl acetate copolymer (EVA).
The difference from Example 4 was that: a bonding layer was provided between the base layer and the metal plating layer on one side, and the material of the bonding layer was polyurethane.
The difference from Example 4 was that: a bonding layer was provided between the base layer and each of the metal plating layers on two sides, and the material of the bonding layer was polyurethane on one side, and ethylene-vinyl alcohol copolymer (EVOH) on the other side.
The difference from Example 4 was that: before preparation of a positive electrode plate, a primer layer was prepared on the surface of the composite current collector by the following method: Conductive carbon black (Super P), and styrene-butadiene rubber (SBR) were mixed in a weight ratio of 97:3, and deionized water was added to prepare a slurry with a solid content of 0.85, and the slurry was well stirred. The slurry was applied evenly on surfaces of coated zones of the metal Al plating layer of the composite current collector, and dried at 110° C. to obtain the primer layer.
The difference from Example 4 was that: a spacing of the pattern lines was arranged such that the resistance R1 between the first terminal and the second terminal that were connected to the first zone was 1.27 Ω.
The difference from Example 4 was that: a spacing of the pattern lines was arranged such that the resistance R1 between the first terminal and the second terminal that were connected to the first zone was 28.07 Ω.
The difference from Example 4 was that: a spacing of the pattern lines was arranged such that the resistance R1 between the first terminal and the second terminal that were connected to the first zone was 6.25 Ω.
The difference from Example 4 was that: a spacing of the pattern lines was arranged such that the resistance R1 between the first terminal and the second terminal that were connected to the first zone was 0.2 Ω.
The difference from Example 4 was that: no pattern was arranged in the first zone such that the resistance R1 between the first terminal and the second terminal that were connected to the first zone was 0.05 Ω.
The difference from Example 4 was that: the second conductive layer in the composite current collector opposite the first zone was removed.
The difference from Example 4 was that: the third zone was arranged in the second conductive layer, and no pattern was disposed in the third zone, where the resistance R2 between the third terminal and the fourth terminal that were connected to the third zone was 0.09 Ω.
The difference from Example 4 was that: the third zone was arranged in the second conductive layer, and the pattern in the third zone was different from that in the first zone, where the resistance R2 between the third terminal and the fourth terminal that were connected to the third zone was 1.24 Ω.
The difference from Example 4 was that: the composite current collector was used only in the negative electrode plate, and the material of the metal plating layer in the composite current collector was Cu.
The difference from Example 4 was that: the composite current collector was also used in the negative electrode, and the material of the metal plating layer in the composite current collector was Cu.
The difference from Example 4 was that: the first zone was located in the middle of the composite current collector in a length direction.
The difference from Example 4 was that: the first zone was located at a singled side zone in the outermost circle of a wound structure.
The difference from Example 4 was that: the first zone was located at a vacancy foil zone in the outermost circle of a wound structure.
The difference from Example 4 was that: the electrode assembly was in a laminated structure, and the first zone was located at an outermost single side zone of the electrode assembly.
The difference from Example 32 was that: the first zone was located in the middle of the electrode assembly.
The difference from Example 4 was that: one side of the composite current collector was a metal Cu plating layer, the other side was a metal Al plating layer, the first zone was arranged on the metal Al plating layer, an positive electrode active material layer was disposed on a coating zone of the metal Al plating layer, and an negative electrode active material layer was disposed on the metal Cu plating layer. The composite electrode plate and the separator were stacked and wound to form a wound electrode assembly.
The difference from Example 1 was that: a conventional Al current collector was used in the preparation of a positive electrode plate.
The difference from Comparative Example 1 was that: a heating sheet of Ni was disposed in the wound electrode assembly.
The difference from Comparative Example 1 was that: no first zone was arranged on the composite current collector, and a heating sheet of Ni was disposed in the wound type electrode assembly. Temperature rise test: When the lithium ion battery was heated with a power of 50 W from minus 10° C. to 25° C. at the highest temperature point of the battery surface, the maximum temperature difference (°C) on the battery surface was tested.
Nail penetration test: Ten lithium-ion batteries were taken for nail penetration test, and the battery passed the test if there was no fire or smoke. Nail penetration test pass rate = number of lithium-ion batteries that passed the test/10.
Drop test: Ten lithium-ion batteries ware taken for drop test and freely fell at a height of 1.5 m, and those lithium-ion batteries that have not failed passed the test. Drop test pass rate = number of lithium-ion batteries that passed the test/10.
Energy density test: In an environment at 25° C., the lithium-ion battery was charged from 3.0 V to 4.4 V at a charging rate of 1 C, and then discharged to 3.0 V at a discharge rate of 0.1 C, and the discharge capacity at 0.1 C was measured. Discharge energy density at 0.1 C = discharge capacity at 0.1 C/volume of lithium-ion battery.
Cycle capacity retention rate: In an environment at 25° C., the lithium-ion battery was charged from 3.0 V to 4.4 V at a charging rate of 2 C, then discharged to 3.0 V at a discharge rate of 0.2 C. A discharge capacity in this case was determined as the initial discharge capacity. The foregoing charge-discharge cycle was repeated for 50 times, and the discharge capacity of the 50-th discharge was measured. Cycle capacity retention rate = 50-th discharge capacity/initial discharge capacity.
For compositions and performance test results of lithium-ion batteries prepared in Examples and Comparative Examples, refer to Table 1 and Table 2.
As can be learned from Table 1 and Table 2 that compared with Comparative Examples 1 to 3, the lithium-ion batteries in Examples 1 to 34 improved the temperature rise performance, and can significantly improve the nail penetration and drop test safety performance of the lithium-ion battery. In addition, compared with the way of separately disposing heating sheets of Ni in the electrode assembly, by arranging a heating zone in the composite current collector, interface contact deterioration was improved, and therefore the cycle performance of the lithium-ion battery was improved. Moreover, by controlling the thicknesses of the base layer, the first conductive layer and the second conductive layer, the energy density of the lithium-ion battery can be further improved.
In the electrochemical apparatus and the electric device provided in this application, a heating zone is provided on the composite current collector to connect a heating circuit, the self-heating function of the electrochemical apparatus is realized, and a method to introduce a heating structure is optimized, thereby effectively alleviating problems caused by existing heating methods, such as energy density reduction, interface contact deterioration, serious self-discharge, and reliability risks in drop tests.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110694180.8 | Jun 2021 | CN | national |
This application is the Continuation application of PCT international application: PCT/CN2021/128780 filed on Nov. 4, 2021, which claims priority of the Chinese Patent Application No. 202110694180.8 filed on Jun. 22, 2021, the disclosure of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2021/128780 | Nov 2021 | WO |
| Child | 18128729 | US |
