WO2023028918A1 - 电化学装置及包含该电化学装置的电子装置 - Google Patents

电化学装置及包含该电化学装置的电子装置 Download PDF

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Publication number
WO2023028918A1
WO2023028918A1 PCT/CN2021/115967 CN2021115967W WO2023028918A1 WO 2023028918 A1 WO2023028918 A1 WO 2023028918A1 CN 2021115967 W CN2021115967 W CN 2021115967W WO 2023028918 A1 WO2023028918 A1 WO 2023028918A1
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Prior art keywords
separator
electrochemical device
electrode assembly
packaging
present application
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PCT/CN2021/115967
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English (en)
French (fr)
Inventor
李晨晨
盛阳平
丁宇
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宁德新能源科技有限公司
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Priority to PCT/CN2021/115967 priority Critical patent/WO2023028918A1/zh
Priority to CN202180006224.1A priority patent/CN114730963A/zh
Publication of WO2023028918A1 publication Critical patent/WO2023028918A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/193—Organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/463—Separators, membranes or diaphragms characterised by their shape
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of electrochemistry, in particular to an electrochemical device and an electronic device including the electrochemical device.
  • Lithium-ion batteries are used in electrical appliances. As the remaining space for lithium-ion batteries in electrical appliances is getting smaller and smaller, the back cover of the electrical appliance is close to the outer wall of the lithium-ion battery, and the lithium-ion battery is slightly bulging and deformed. The cover cannot be closed and it cannot be used normally. In addition, lithium-ion batteries packed with aluminum-plastic film cannot withstand the strong pressure inside them, and the expansion and deformation of lithium-ion batteries will increase the risk of leakage. Therefore, the expansion phenomenon has become an important factor affecting the pass rate and safety performance of lithium-ion batteries.
  • the present application provides an electrochemical device and an electronic device including the electrochemical device, so as to improve the energy density of the electrochemical device.
  • the first aspect of the present application provides an electrochemical device, which includes a packaging case; a partition, the partition includes a packaging part and a main body, the packaging part is connected to the packaging case and the packaging case is respectively defined on both sides of the partition
  • the electrochemical device by using a separator with a stretching ratio ⁇ ⁇ 10%, the electrochemical device can face the differential expansion of the first electrode assembly and the second electrode assembly during the cycle.
  • the first electrode assembly with a larger expansion rate can be squeezed to one side of the second electrode assembly with a smaller expansion rate, occupying the space originally used to accommodate the second electrode assembly with a smaller expansion rate cavity space. Therefore, on the one hand, the cavity space of the packaging case can be flexibly used by the expanded electrode assembly without excessively increasing the volume of the entire electrochemical device, so that the energy density of the electrochemical device can be improved.
  • the ductile separator can buffer the electrode assembly, prevent the sealed connection between the separator and the packaging shell from being damaged by force, and improve the drop pass rate of the electrochemical device.
  • the main body is provided with a pre-deformation structure
  • the pre-deformation structure includes at least one of an arc-shaped structure, a wave-shaped structure or a groove-shaped structure.
  • the setting of the above-mentioned pre-deformation structure can increase the stretching rate of the separator, which is beneficial to the first electrode assembly with a larger expansion rate to make full use of the cavity space of the packaging case without increasing the volume of the electrochemical device, thereby increasing its energy density .
  • the electrochemical device further includes an encapsulation layer disposed at the edge of the surface of the separator or on the entire surface of the separator.
  • the separator can be sealed and connected to the sealing edge of the first package body and the sealing edge of the second package body, so that the overall sealing performance of the electrochemical device is better, thereby further improving the packaging reliability of the electrochemical device.
  • the encapsulation layer is disposed on the encapsulation portion of the spacer.
  • the packaging part is sealed and connected to the packaging case through the packaging layer, and the thickness of the main part is thinner because there is no packaging layer, which provides more accommodation space for the electrode assembly and electrolyte, and can increase the energy density of the electrochemical device.
  • the material of the separator includes at least one of a polymer material or a metal material
  • the polymer material includes polyethylene terephthalate, polybutylene terephthalate ester, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, poly Vinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene difluoride) Difluoroethylene-co-trifluoroethylene), silicone, vinylon, polypropylene, anhydride modified polypropylene, polyethylene, ethylene and its copolymers, polyvinyl chloride, polystyrene, polyetheretherketone, polyimide,
  • the separator made of the above polymer materials and metal materials not only has the characteristics of ionic insulation, can avoid high-pressure decomposition of the electrolyte and short circuit in the electrode assembly, but also has good ductility, and can be stretched and deformed according to the expansion of the electrode assembly , so that it is possible for the electrode assembly to use the cavity space flexibly, and it can prevent the sealing connection between the separator and the packaging shell from being damaged, and improve the reliability of the packaging.
  • the material of the encapsulation layer includes polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-ethylene At least one of alcohol copolymer, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyamide, polyester, amorphous ⁇ -olefin copolymer and derivatives thereof.
  • the above materials are easily heat-sealed and bonded to the inner surface of the packaging case, thereby effectively improving the sealing performance of the separator and the packaging case, thereby improving the packaging reliability of the electrochemical device.
  • the elongation ratio ⁇ of the separator satisfies 10% ⁇ 40%, and the elongation ratio of the separator is within the above range, which can improve the energy density and safety of the electrochemical device at the same time , without affecting the structural stability of the electrochemical device.
  • the separator has a thickness of 10 ⁇ m to 100 ⁇ m.
  • the thickness of the separator is within the above range, the energy density and safety performance of the electrochemical device can be improved.
  • the separator has a thickness of 10 ⁇ m to 30 ⁇ m
  • the packaging layer has a thickness of 20 ⁇ m to 40 ⁇ m.
  • the ratio of the expansion rate of the first electrode assembly to the expansion rate of the second electrode assembly is k, 1 ⁇ k ⁇ 5.
  • the expansion rate of the two electrode assemblies is limited within a specific ratio range, so as to avoid the expansion rate of the first electrode assembly being too large, which will cause the first electrode assembly to be over-extruded into the second cavity and exceed the extensibility of the separator, resulting in The sealing connection of the bulkhead is broken.
  • the second aspect of the present application provides an electronic device, which includes the electrochemical device provided in the first aspect of the present application. Therefore, the electronic device has good expansion performance and energy density.
  • Figure 1 is a schematic diagram of the decomposition structure of an electrochemical device in some embodiments of the present application.
  • Fig. 2 is a top view of the partition structure of some embodiments of the present application.
  • Fig. 3 is the front view of the partition structure of some embodiments of the present application.
  • Fig. 4 is a top view of the partition structure of some embodiments of the present application.
  • Fig. 5 is the front view of the partition structure of some embodiments of the present application.
  • Fig. 6 is a top view of the partition structure of some embodiments of the present application.
  • Fig. 7 is the front view of the partition structure of some embodiments of the present application.
  • Fig. 8 is a schematic structural diagram of a separator in some embodiments of the present application.
  • the lithium-ion battery is used as an example of the electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to the lithium-ion battery.
  • the specific technical scheme is as follows:
  • the embodiment of the first aspect of the present application provides an electrochemical device 001, which includes a packaging case 40, a separator 20, a first electrode assembly 11 and a second electrode assembly 12; the separator 20 includes a packaging part 21 and a main body part 22.
  • the packaging part 21 is connected to the packaging case 40 so that the packaging case 40 defines a first cavity (not shown in the figure) and a second cavity (not shown) on both sides of the partition 20, respectively. not shown in the figure), the first electrode assembly 11 is arranged in the first cavity, and the second electrode assembly 12 is arranged in the second cavity.
  • the elongation rate ⁇ of the separator 20 is greater than or equal to 10%.
  • the expansion rate of the electrode assembly 12 is high, the first electrode assembly 11 with a larger expansion rate can be squeezed to the side of the second electrode assembly 12 with a smaller expansion rate, occupying the second electrode assembly originally used to accommodate the smaller expansion rate. Therefore, on the one hand, the cavity space of the packaging shell 40 can be flexibly used by the expanded electrode assembly without excessively increasing the volume of the entire electrochemical device 001, so that the energy density of the electrochemical device 001 can be improved. improve.
  • the expansion of the first electrode assembly 11 and/or the second electrode assembly 12 will not adversely affect the sealing connection between the separator 20 and the packaging case 40, ensuring the reliability of the sealing and improving the safety of the electrochemical device 001 performance.
  • the ductile separator 20 can buffer the electrode assembly, preventing the sealed connection between the separator 20 and the packaging case 40 from being damaged by force, and improving the drop resistance of the electrochemical device 001. Passing rate.
  • the present application does not impose a special limit on the upper limit of the elongation rate of the separator 20, as long as the elongation rate of the separator 20 ⁇ 10 %, the purpose of this application can be met.
  • the elongation ratio ⁇ of the separator is less than or equal to 40%, so as to avoid that the electrode assembly shakes back and forth in the packaging case during the use of the electrochemical device due to an excessive elongation ratio, thereby affecting the structural stability.
  • the material of the separator 20 includes at least one of a polymer material or a metal material.
  • the material of the separator 20 includes a polymer material, and the density of the polymer material is low, so that the weight of the separator 20 can be reduced, thereby increasing the energy density of the electrochemical device 001 .
  • the probability of polymer materials producing debris is smaller, and the wrapping effect on the mechanically damaged surface is better, which can improve the safety of the above-mentioned mechanical abuse. Performance, so that the pass rate of the safety test is improved, and the safety performance of the electrochemical device 001 is further improved.
  • polymer materials may include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polyether ether ketone, polyimide, poly Amide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, poly Ethylene naphthalate, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene (PP ), anhydride-modified polypropylene, polyethylene, ethylene and its copolymers, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polyester,
  • the material of the separator 20 includes a metal material.
  • the metal material has strong isolation reliability, good toughness and compactness, and the processing thickness can be made thinner, which can increase the energy density of the electrochemical device 001 .
  • metallic materials may include Ni, Ti, Cu, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, At least one of In, Zn, stainless steel (SUS), alloys thereof, and the like.
  • the material of the separator 20 includes a composite material of a polymer material and a metal material.
  • the composite material may include Ni metal composite PP, Ag metal composite PET, and the like.
  • the structure of the separator 20 may be flat, and the above-mentioned polymer materials and metal materials will be able to realize the ductility of the separator 20 .
  • the extensibility of the separator 20 is realized by changing the shape of the separator 20 .
  • the separator 20 includes an encapsulation part 21 and a main body part 22, and the encapsulation part 21 and the encapsulation shell 40 are sealed and connected.
  • the package shell 40 is closely connected, and the main body 22 realizes the extensibility of the separator 20 by setting a pre-deformation structure.
  • the pre-deformation structure is used to provide an additional accommodation space for the expansion of the electrode assembly, thereby preventing the expansion of the electrode assembly from the packaging part 21. The pulling of the seal will cause the failure of the seal.
  • the pre-deformation structure includes an arc-shaped structure shown in Figure 3, a wave-shaped structure shown in Figure 5, or a groove-shaped structure shown in Figure 7, etc. at least one of the Those skilled in the art can understand that the above-mentioned pre-deformed structure may also include other shapes, as long as it is beneficial to increase the elongation ⁇ of the separator, all are within the protection scope of the present application.
  • the setting of the above-mentioned pre-deformed structure can increase the elongation ⁇ of the separator 20 and provide additional space for the expansion of the electrode assembly, thereby effectively alleviating the expansion of the electrochemical device 001 and improving the expansion performance of the electrochemical device 001 .
  • the present application has no particular limitation on the method for preparing the pre-deformed structure, as long as the purpose of the present application can be achieved.
  • an arc-shaped structure, a wave-shaped structure, or a groove-shaped structure can be formed on the main body 22 by hot pressing with a mold.
  • the electrochemical device 001 further includes an encapsulation layer 30 disposed on the peripheral edges of the surface of the separator 20 or on the entire surface of the separator 20 .
  • the separator 20 can be sealed and connected to the sealing edge of the first packaging body 41 and the sealing edge of the second packaging body 42, so that the overall sealing performance of the electrochemical device 001 is better, thereby further improving the packaging of the electrochemical device 001. reliability.
  • the encapsulation layer 30 is disposed on the encapsulation portion 21 of the separator 20 .
  • the packaging part 21 is sealed and connected to the sealing edge of the upper packaging body 41 and the sealing edge of the lower packaging body 42 respectively through the packaging layer 30 , so that the overall sealing performance of the electrochemical device 001 is improved.
  • the thickness of the separator 20 can be set thinner, providing more accommodation space for the electrode assembly, so that the volume of the electrochemical device 001 is reduced, thereby improving the electrochemical performance. Energy density of device 001.
  • the material of the encapsulation layer 30 includes polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene- At least one of vinyl alcohol copolymer, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyamide, polyester, amorphous ⁇ -olefin copolymer and derivatives thereof.
  • the packaging material is polypropylene
  • the packaging temperature is 180°C to 195°C
  • the packaging time is 2s to 4s
  • the packaging pressure is 0.2MPa to 0.5MPa.
  • the thickness of the separator 20 is at least 10 ⁇ m, preferably 10 ⁇ m to 30 ⁇ m, and in some embodiments, the thickness of the separator 20 is preferably 30 ⁇ m to 60 ⁇ m. In some embodiments, the thickness of the separator 20 may include any one of the following values: 10 ⁇ m, 20 ⁇ m, 30 ⁇ m, 40 ⁇ m, 50 ⁇ m, 60 ⁇ m, 70 ⁇ m, 80 ⁇ m, 90 ⁇ m or 100 ⁇ m, etc.; when the thickness of the separator 20 is too thin (for example, less than 10 ⁇ m), it will affect the barrier properties of the separator 20 to the electrolyte, and the electrolyte in the first cavity and the second cavity on both sides of the separator 20 will easily penetrate the separator 20, thus affecting the electrochemical performance of the electrochemical device 001. Performance; when the thickness of the separator 20 is too thick (for example greater than 100 ⁇ m), the volume of the electrochemical device 001 increases,
  • the thickness of the encapsulation layer 30 is 20 ⁇ m to 40 ⁇ m.
  • the lower limit of the thickness of the encapsulation layer 30 may include any one of the following values: 20 ⁇ m, 25 ⁇ m or 30 ⁇ m, etc.
  • the upper limit of the thickness of the encapsulation layer 30 may include any one of the following values: 32 ⁇ m, 36 ⁇ m or 40 ⁇ m wait.
  • the thickness of the packaging layer 30 When the thickness of the packaging layer 30 is too thin (for example, less than 20 ⁇ m), it will affect the sealing effect between the separator 20 and the packaging shell 40, thereby affecting the packaging reliability of the electrochemical device 001; when the thickness of the packaging layer 30 is too thick (for example, when it is greater than 40 ⁇ m), the sealing edge of the electrochemical device 001 is too thick, which is not conducive to the folding process of the sealing edge, thereby affecting the packaging reliability of the electrochemical device 001, and the sealing edge is too thick, making the volume of the electrochemical device 001 An increase will cause a decrease in the energy density of the electrochemical device 001.
  • the thickness of the encapsulation layer in this application refers to the thickness of the encapsulation layer located on one side of the separator.
  • the thickness of the separator refers to the thickness of the separator when it is in the form of a flat plate.
  • the thickness of the separator refers to the thickness of the separator when it is flat before the pre-deformation structure is provided.
  • the ratio of the expansion rate of the first electrode assembly 11 to the expansion rate of the second electrode assembly 12 is k, 1 ⁇ k ⁇ 5.
  • the first electrode assembly 11 and the second electrode assembly 12 expand to different degrees due to reasons such as electrode piece rebound or gas release, and the expansion rate of the second electrode assembly 12 is smaller than that of the first electrode assembly.
  • the expansion rate of the electrode assembly 11, the first electrode assembly 11 with a large expansion rate can be squeezed to the side of the second electrode assembly 12 with a small expansion rate, occupying the second electrode assembly originally used to accommodate the small expansion rate
  • the cavity space of 12 can prevent the overall expansion rate of the electrochemical device 001 from increasing, and effectively improve the expansion performance of the electrochemical device 001 . In this way, the volume increase of the electrochemical device 001 can also be avoided, thereby improving the energy density of the electrochemical device 001 .
  • the present application has no special limitation on the respective expansion ratios of the first electrode assembly 11 and the second electrode assembly 12 , as long as it is less than 10%, the purpose of the present application can be achieved.
  • the expansion rate of the first electrode assembly 11 may be 5% to 10%
  • the expansion rate of the second electrode assembly 12 may be 1% to 5%.
  • the expansion rate is greater than 10%, the expanded electrode assembly will exceed the packaging strength of the separator and the packaging case, resulting in damage to the sealing of the separator and the packaging case, which will adversely affect the safety of the electrochemical device.
  • the structure of the electrode assembly may include at least one of a wound structure or a laminated structure.
  • the electrochemical device 001 of the present application may also include other devices that undergo electrochemical reactions, such as lithium metal secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
  • the present application has no special limitation on the preparation process of the electrochemical device 001, as long as the purpose of the present application can be achieved.
  • the electrochemical device 001 can be prepared through the following process: overlap the positive pole piece and the negative pole piece through a separator, and put them into the packaging case 40 after winding or folding as required, and inject the electrolyte into the packaging case 40 Inside and seal.
  • anti-overcurrent elements, guide plates, etc. can also be placed in the housing as needed, so as to prevent pressure rise and overcharge and discharge inside the electrochemical device 001 .
  • the second aspect of the present application provides an electronic device, including the electrochemical device 001 provided in the first aspect of the present application.
  • the electronic device has good energy density and safety performance.
  • the electronic devices of the present application are not particularly limited, and may include, but are not limited to: notebook computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo earphones , VCR, LCD TV, Portable Cleaner, Portable CD Player, Mini Disc, Transceiver, Electronic Notepad, Calculator, Memory Card, Portable Recorder, Radio, Backup Power, Motor, Automobile, motorcycle, Assisted Bicycle, Bicycle , Lighting appliances, toys, game consoles, clocks, electric tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • the tension rod can be up and down normally, and the speed of the tensile machine is controlled at 50mm/min; use a cutter to cut samples with a width of 15mm and a length of 100mm, and each separator type Prepare at least 2 parallel samples of the sample, adjust the upper and lower fixing clips to align on the same vertical plane; open the upper fixing clip, clamp one end of the sample to the upper fixing clip, and clamp the other end of the sample to the lower fixing clip, and make sure that the sample is installed on the fixing clip It cannot slip, and the sample is fixed after it is placed upright; click the reset and run buttons to start the test, and the final tensile force judgment result is as follows: after the tensile test is completed, the machine will automatically stop, and the tensile machine will output force, displacement and time;
  • SEM scanning electron microscope
  • Expansion rate (T500-T1)/T1 ⁇ 100%.
  • the expansion rate of the first battery is considered as the expansion rate of the first electrode assembly, the size is 10%
  • the expansion rate of the second battery is considered as the expansion rate of the second electrode assembly, the size is 2% .
  • the second packaging body (aluminum-plastic film with a thickness of 88 ⁇ m) formed by punching the pit into the assembly jig, with the pit facing up, and place the second electrode assembly (with an expansion rate of 2%) in the pit, from the second electrode assembly Lead out a positive pole lug and a negative pole pole lug.
  • the second electrode assembly is of the same batch as the electrode assembly in the second battery tested.
  • the separator was placed on the second electrode assembly, the first electrode assembly (expansion rate: 10%) was placed on the separator, and a positive electrode tab and a negative electrode tab were drawn out from the first electrode assembly.
  • the first electrode assembly is of the same batch as the electrode assembly in the first battery tested.
  • put the first packaging body (aluminum-plastic film with a thickness of 88 ⁇ m) pit face down on the first electrode assembly, leaving the area where the liquid injection port and the tab protrude, and heat seal the other positions of the packaging shell, Therefore, independent first cavities and second cavities are formed on both sides of the separator, and an assembled electrode assembly is obtained.
  • the heat-sealing temperature is 180° C.
  • the heat-sealing pressure is 0.5 MPa.
  • the negative electrode tab of the second electrode assembly and the positive electrode tab of the first electrode assembly are welded together by laser welding, so that the two are connected in series.
  • the charging and discharging process only needs to connect the positive tab of the second electrode assembly with the negative tab of the first electrode assembly.
  • the separator prepared in Example 1 was placed in an arc-shaped mold and hot-pressed to obtain a separator with an arc-shaped main body, and the elongation ratio ⁇ of the separator was 14%.
  • the thickness of the separator was 15 ⁇ m, and the elongation ratio ⁇ of the separator was 22%, and the rest was the same as that of Example 11.
  • Example 2 From Example 1, Example 2 and Comparative Example 1, it can be seen that the expansion performance of the electrochemical device can be effectively improved by selecting a separator with a stretching ratio ⁇ within the scope of the application, thereby increasing the energy density of the electrochemical device .
  • Example 3 From Example 3 to Example 12 and Comparative Example 2 and Comparative Example 3, it can be seen that the present application makes the elongation rate ⁇ of the separator within the scope of the application through the setting of the separator material and the pre-deformation structure on the main part of the separator Inside, the expansion performance of the electrochemical device can be significantly improved, thereby increasing the energy density of the electrochemical device.
  • the electrochemical device has a difference in the face of the first electrode assembly and the second electrode assembly during the cycle.
  • the first electrode assembly with a larger expansion rate can be squeezed to one side of the second electrode assembly with a smaller expansion rate, occupying the cavity space originally used to accommodate the second electrode assembly with a smaller expansion rate , which effectively improves the expansion performance of the electrochemical device, prevents the volume of the electrochemical device from excessively increasing, and improves the energy density of the electrochemical device. It can also improve the sealing reliability of the separator and the packaging shell, thereby improving the safety performance of the electrochemical device.

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  • Electrochemistry (AREA)
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  • Engineering & Computer Science (AREA)
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Abstract

本申请提供了一种电化学装置及包含该电化学装置的电子装置，该电化学装置包括包装壳、隔板、第一电极组件和第二电极组件；隔板包括封装部和主体部，封装部与包装壳连接并将包装壳在隔板的两侧分别限定出第一腔体和第二腔体；隔板的拉伸率δ≥10％；第一电极组件和第二电极组件对应地设置在第一腔体和第二腔体中。该电化学装置和电子装置具有良好的膨胀性能、能量密度和安全性能。

Description

电化学装置及包含该电化学装置的电子装置 技术领域
本申请涉及电化学领域，具体涉及一种电化学装置及包含该电化学装置的电子装置。
背景技术
锂离子电池在用电器中使用，由于用电器中可容纳锂离子电池的余量空间越来越小，用电器后盖紧贴锂离子电池的外壁，锂离子电池稍有鼓胀变形，用电器后盖便无法合上，继而无法正常使用。另外，以铝塑膜为包装壳的锂离子电池经不起其内部产生强大气压，锂离子电池的膨胀变形将导致漏液风险加大。因此，膨胀现象成为影响锂离子电池合格率和使用安全性能的重要因素。
为了克服该问题，现有的锂离子电池通常使用具有相对较大尺寸的包装壳以适应电极组件的膨胀，这种死体积(为容纳膨胀所预留的体积)通常为锂离子电池总体积的约15％至约20％，这种死体积的存在会降低锂离子电池的体积能量密度。
发明内容
本申请提供了一种电化学装置及包含该电化学装置的电子装置，以改善电化学装置的能量密度。
本申请第一方面提供了一种电化学装置，其包括包装壳；隔板，该隔板包括封装部和主体部，封装部与包装壳连接并将包装壳在隔板的两侧分别限定出第一腔体和第二腔体；隔板的拉伸率δ≥10％；第一电极组件和第二电极组件，该第一电极组件设置在第一腔体中，该第二电极组件设置在第二腔体中。
本申请实施例的电化学装置，通过使用拉伸率δ≥10％的隔板，使得该电化学装置在循环过程中，在面对第一电极组件和第二电极组件出现差异膨胀的情况下，由于隔板的延展性，膨胀率较大的第一电极组件能够向膨胀率较小的第二电极组件的一侧进行挤压，占用原本用于容纳膨胀率较小的第二电极组件的腔体空间。因此，一方面，包装壳的腔体空间可以被膨胀后的电极组件灵活使用，而不过分增加整个电化学装置的体积，使得电化学装置的能量密度得以改善。另一方面，由于隔板的延展性，电极组件的膨胀不会对隔板与包装壳的密封连接产生不利影响，保证密封的可靠性，提高了电化学装置 的安全性能。此外，在面临电化学装置跌落时，具有延展性的隔板可以对电极组件产生缓冲作用，防止隔板与包装壳的密封连接会受力破坏，提高了电化学装置的跌落通过率。
在本申请的一些实施例中，主体部设置有预变形结构，该预变形结构包括弧形结构、波浪形结构或凹槽状结构中的至少一种。上述预变形结构的设置，能够增加隔板的拉伸率，有利于膨胀率更大的第一电极组件充分利用包装壳的腔体空间，而无需增加电化学装置的体积，从而提高其能量密度。
在本申请的一些实施例中，电化学装置还包括封装层，封装层设置在隔板表面的边缘处或隔板的整个表面上。由此，隔板能够与第一包装体的封印边和第二包装体的封印边实现密封连接，以使电化学装置整体密封性更好，从而进一步提高电化学装置的封装可靠性。
在本申请的一些实施例中，封装层设置在隔板的封装部。这样，封装部通过封装层与包装壳密封连接，而主体部上因为没有设置封装层而厚度变薄，为电极组件和电解液提供了更多的容纳空间，能够提升电化学装置的能量密度。
在本申请的一些实施例中，隔板的材料包括高分子材料或金属材料中的至少一种，所述高分子材料包括聚对苯二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯、聚萘二甲酸乙二醇酯、聚醚醚酮、聚酰亚胺、聚酰胺、聚乙二醇、聚酰胺酰亚胺、聚碳酸酯、环状聚烯烃、聚苯硫醚、聚乙酸乙烯酯、聚四氟乙烯，聚亚甲基萘、聚偏二氟乙烯，聚萘二甲酸亚乙酯、聚碳酸亚丙酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)、有机硅、维尼纶、聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚苯醚、聚酯、聚砜、非晶态α-烯烃共聚物及其衍生物中的至少一种；所述金属材料包括Ni、Ti、Cu、Ag、Au、Pt、Fe、Co、Cr、W、Mo、Al、Mg、K、Na、Ca、Sr、Ba、Si、Ge、Sb、Pb、In、Zn、不锈钢(SUS)及其合金中的至少一种。上述高分子材料和金属材料制备的隔板不仅具有离子绝缘的特性，可以避免发生电解液高压分解以及电极组件内短路，还具有较好的延展性，能够根据电极组件的膨胀情况而拉伸变形，从而为电极组件灵活使用腔体空间提供了可能，并能够防止隔板与包装壳的密封连接被破坏，提高封装的可靠性。
在本申请的一些实施例中，封装层的材料包括聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯-醋酸乙烯共聚物、乙烯-丙烯酸乙酯共聚物、乙烯-丙烯酸共聚物、乙烯-乙烯醇共聚 物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚酰胺、聚酯、非晶态α-烯烃共聚物及其衍生物中的至少一种。上述材料容易与包装壳的内表面热封而粘结在一起从而有效地提高隔板与包装壳的密封性，从而提高电化学装置的封装可靠性。
在本申请的一些实施例中，隔板的拉伸率δ满足10％≤δ≤40％，隔板的拉伸率在上述范围内，可以在改善电化学装置的能量密度、安全性的同时，不影响电化学装置的结构稳定性。
在本申请的一些实施例中，隔板的厚度为10μm至100μm。隔板的厚度在上述范围内，能够改善电化学装置的能量密度及安全性能。
在本申请的一些实施例中，隔板的厚度为10μm至30μm，封装层厚度为20μm至40μm。
在本申请的一些实施例中，第一电极组件的膨胀率与第二电极组件的膨胀率的比值为k，1＜k≤5。将两个电极组件的膨胀率限制在特定的比例范围内，避免第一电极组件的膨胀率过大，从而导致第一电极组件向第二腔体过分挤压而超出隔板的延展能力，造成隔板的密封连接破坏。
本申请第二方面提供了一种电子装置，其包括本申请第一方面提供的电化学装置。因此，该电子装置具有良好的膨胀性能和能量密度。
附图说明
为了更清楚地说明本申请实施例和现有技术的技术方案，下面对实施例和现有技术中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例。
图1为本申请一些实施例的电化学装置分解结构示意图；
图2为本申请一些实施例的隔板结构的俯视图；
图3为本申请一些实施例的隔板结构的主视图；
图4为本申请一些实施例的隔板结构的俯视图；
图5为本申请一些实施例的隔板结构的主视图；
图6为本申请一些实施例的隔板结构的俯视图；
图7为本申请一些实施例的隔板结构的主视图；
图8为本申请一些实施例的隔板的结构示意图。
附图标记：001.电化学装置；11.第一电极组件；12.第二电极组件；20.隔板；21.封装部；22.主体部；30.封装层；40.包装壳；41.第一包装体；42.第二包装体。
具体实施方式
为使本申请的目的、技术方案及优点更加清楚明白，以下参照附图和实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员所获得的所有其他技术方案，都属于本申请保护的范围。
需要说明的是，本申请的内容中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。具体技术方案如下：
如图1和图2所示，本申请第一方面的实施例提供了一种电化学装置001，其包括包装壳40、隔板20、第一电极组件11和第二电极组件12；隔板20包括封装部21和主体部22，封装部21与包装壳40连接从而将包装壳40在隔板20的两侧分别限定出第一腔体(图中未示出)和第二腔体(图中未示出)，第一电极组件11设置在第一腔体中，第二电极组件12设置在第二腔体中。
在本申请的一些实施例中，隔板20的拉伸率δ≥10％；在电化学装置001循环过程中，由于隔板20的延展性，当第一电极组件11的膨胀率大于第二电极组件12的膨胀率时，膨胀率较大的第一电极组件11能够向膨胀率较小的第二电极组件12的一侧进行挤压，占用原本用于容纳膨胀率较小的第二电极组件12的腔体空间，因此，一方面，包装壳40的腔体空间可以被膨胀后的电极组件灵活使用，而不过分增加整个电化学装置001的体积，使得电化学装置001的能量密度得以改善。另一方面，第一电极组件11和/或第二电极组件12的膨胀不会对隔板20与包装壳40的密封连接产生不利影响，保证密封的可靠性，提高了电化学装置001的安全性能。此外，在面临电化学装置001跌落时，具有延展性的隔板20可以对电极组件产生缓冲作用，防止隔板20与包装壳40的密封连接会受力破坏，提高了电化学装置001的跌落通过率。
需要说明的是，考虑到电极组件的膨胀率上限以及跌落测试的模拟场景，本申请对隔板20的拉伸率的上限不做特别限制，只要能够满足隔板20的拉伸率δ≥10％，即可满 足本申请的目的。优选地，所述隔板的的拉伸率δ≤40％，避免因为拉伸率过大，导致在电化学装置使用过程中，电极组件在包装壳内来回晃动而影响结构稳定性。
在本申请的一些实施例中，为实现隔板20的延伸率δ≥10％，隔板20的材料包括高分子材料或金属材料中的至少一种。
在本申请的一些实施例中，隔板20的材料包括高分子材料，高分子材料的密度小，可以降低隔板20的重量，从而提高电化学装置001的能量密度。并且，在机械滥用情况(例如，穿钉、撞击、挤压等)下，高分子材料产生碎屑的概率更小，且对机械破损表面包裹效果更好，可以改善上述机械滥用情况下的安全性能，从而使安全测试通过率得以提高，进一步提高电化学装置001的安全性能。例如，高分子材料可以包括聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯、聚萘二甲酸乙二醇酯、聚醚醚酮、聚酰亚胺、聚酰胺、聚乙二醇、聚酰胺酰亚胺、聚碳酸酯、环状聚烯烃、聚苯硫醚、聚乙酸乙烯酯、聚四氟乙烯，聚亚甲基萘、聚偏二氟乙烯，聚萘二甲酸亚乙酯、聚碳酸亚丙酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)、有机硅、维尼纶、聚丙烯(PP)、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚苯醚、聚酯、聚砜、非晶态α-烯烃共聚物及其衍生物等中的至少一种。
在本申请的一些实施例中，隔板20的材料包括金属材料，金属材料的隔离可靠性强，且韧性及致密性好，加工厚度可以做到更薄，能够提高电化学装置001的能量密度。例如，金属材料可以包括Ni、Ti、Cu、Ag、Au、Pt、Fe、Co、Cr、W、Mo、Al、Mg、K、Na、Ca、Sr、Ba、Si、Ge、Sb、Pb、In、Zn、不锈钢(SUS)及其合金等中的至少一种。
在本申请的一些实施例中，隔板20的材料包括高分子材料和金属材料的复合材料。例如，复合材料可以包括Ni金属复合PP、Ag金属复合PET等。
在本申请的一些实施例中，如图2所示，隔板20的结构可以是平板状，上述的高分子材料和金属材料将能够实现隔板20的延展性能。
在本申请的一些实施例中，通过改变隔板20的形状实现隔板20的延展性能。本申请中，隔板20包括封装部21和主体部22，封装部21与包装壳40密封连接，为了保证封装部21与包装壳40的封装可靠性，封装部21需要保持其平整性从而与包装壳40实现紧密连接，主体部22通过设置预变形结构来实现隔板20的延展性能，预变形结构用来为电 极组件的膨胀提供额外的容纳空间，从而防止膨胀的电极组件对封装部21的拉扯而导致密封失效。
如图3至图7所示，在本申请的一些实施例中，预变形结构包括图3示出的弧形结构、图5示出的波浪形结构或图7示出的凹槽状结构等中的至少一种。本领域技术人员可以理解，上述预变形结构也可以包括其他形状，只要利于隔板拉伸率δ的提高，均在本申请保护范围内。上述预变形结构的设置，能够增加隔板20的拉伸率δ，为电极组件的膨胀提供额外的空间，从而有效缓解电化学装置001的膨胀，改善电化学装置001的膨胀性能。
本申请对制备预变形结构的方法没有特别限制，只要能够实现本申请目的即可。例如，在主体部22上通过模具热压制得弧形结构、波浪形结构或凹槽状结构等。
在本申请的一些实施例中，如图8所示，电化学装置001还包括封装层30，封装层30设置在隔板20表面的四周边缘处或隔板20的整个表面上。由此，隔板20能够与第一包装体41的封印边和第二包装体42的封印边实现密封连接，以使电化学装置001整体密封性更好，从而进一步提高电化学装置001的封装可靠性。
在本申请的一些实施例中，封装层30设置在隔板20的封装部21。这样，封装部21通过封装层30分别与上包装体41的封印边和下包装体42的封印边实现密封连接，使电化学装置001整体密封性更好。进一步地，主体部22上无需设置封装层30，因此隔板20的厚度可以设置得更薄，为电极组件提供更多的容纳空间，以使电化学装置001的体积减小，从而提升电化学装置001的能量密度。
在本申请的一些实施例中，封装层30的材料包括聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯-醋酸乙烯共聚物、乙烯-丙烯酸乙酯共聚物、乙烯-丙烯酸共聚物、乙烯-乙烯醇共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚酰胺、聚酯、非晶态α-烯烃共聚物及其衍生物中的至少一种。上述材料容易与包装壳40如铝塑膜的内表面热封而粘结在一起从而有效地提高隔板20与包装壳40的密封性，从而提高电化学装置001的封装可靠性。需要说明的是，本申请对封装温度、封装时间和封装压力没有特别限制，只要能够实现本申请目的即可。例如，封装材料为聚丙烯，封装温度为180℃至195℃，封装时间为2s至4s，封装压力为0.2MPa至0.5MPa。
在本申请的一些实施例中，隔板20的厚度至少为10μm，优选为10μm至30μm，在 一些实施例中，隔板20的厚度优选为30μm至60μm。在一些实施例中，隔板20的厚度可以包括以下数值中的任一个：10μm、20μm、30μm、40μm50μm、60μm、70μm、80μm、90μm或100μm等；当隔板20的厚度太薄(例如小于10μm)时，会影响隔板20对电解液的阻隔性，隔板20两侧的第一腔体和第二腔体中的电解液容易渗透隔板20，从而影响电化学装置001的电化学性能；当隔板20的厚度太厚(例如大于100μm)时，使得电化学装置001体积增大，从而降低电化学装置001的能量密度。
在本申请的一些实施例中，封装层30的厚度为20μm至40μm。例如，封装层30的厚度的下限值可以包括以下数值中的任一个：20μm、25μm或30μm等；封装层30的厚度的上限值可以包括以下数值中的任一个：32μm、36μm或40μm等。当封装层30的厚度太薄(例如小于20μm)时，会影响隔板20与包装壳40之间的密封效果，从而影响电化学装置001的封装可靠性；当封装层30的厚度太厚(例如大于40μm)时，电化学装置001的封印边过厚，不利于封印边的折边处理，从而影响电化学装置001的封装可靠性，并且，封印边过厚，使电化学装置001的体积增大，会造成电化学装置001的能量密度的下降。
应当理解的是，本申请中封装层的厚度指的是位于隔板一侧表面的封装层的厚度。隔板的厚度是指隔板呈平板状时的厚度。对于设置预变形结构的隔板，隔板的厚度是指在设置预变形结构前，隔板呈平板状时的厚度。
在本申请的一些实施例中，第一电极组件11的膨胀率与第二电极组件12的膨胀率的比值为k，1＜k≤5。在电化学装置001充放电过程中，由于电极极片反弹或释放气体等原因造成第一电极组件11和第二电极组件12发生不同程度的膨胀，且第二电极组件12的膨胀率小于第一电极组件11的膨胀率，膨胀率较大的第一电极组件11能够向膨胀率较小的第二电极组件12的一侧进行挤压，占用原本用于容纳膨胀率较小的第二电极组件12的腔体空间，从而能够防止电化学装置001整体膨胀率的增大，有效改善电化学装置001的膨胀性能。这样，也能够避免电化学装置001的体积增大，继而改善电化学装置001的能量密度。
本申请对第一电极组件11和第二电极组件12各自的膨胀率没有特别限制，只要小于10％，能够实现本申请目的即可。例如，第一电极组件11的膨胀率可以为5％至10％，第二电极组件12的膨胀率可以为1％至5％。膨胀率大于10％时，膨胀后的电极组件将超出隔板与包装壳的封装强度，导致隔板与包装壳的密封性被破坏，对电化学装置的安全性 带来不良影响。
在本申请中，对电极组件的结构没有特别限制，只要能够实现本申请目的即可。例如，电极组件的结构可以包括卷绕结构或叠片结构中的至少一种。
本申请的电化学装置001还可以包括发生电化学反应的其他装置，例如锂金属二次电池、锂聚合物二次电池或锂离子聚合物二次电池等。
本申请对电化学装置001的制备过程没有特别限制，只要能够实现本申请目的即可。例如，电化学装置001可以通过以下过程制备：将正极极片和负极极片经由隔膜重叠，并根据需要将其卷绕或折叠等操作后放入包装壳40内，将电解液注入包装壳40内并封口。此外，也可以根据需要将防过电流元件、导板等置于壳体中，从而防止电化学装置001内部的压力上升、过充放电。
本申请的第二方面提供了一种电子装置，包含本申请第一方面所提供的电化学装置001。该电子装置具有良好的能量密度和安全性能。
本申请的电子装置没有特别限制，其可以包括但不限于：笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
本申请中所用的术语一般为本领域技术人员常用的术语，如果与常用术语不一致，以本申请中的术语为准。
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
拉伸率δ的测试：
打开高铁拉力机电源，确认拉力机上下夹具在水平位置、拉力杆能够正常上下、拉力机的速度控制为50mm/min；采用切刀机裁切宽度15mm、长度100mm的样品，每一隔板种类的样品准备至少2个平行样，调整上下两固定夹在同一垂直面对齐；打开上固定 夹，将样品一端夹在上固定夹，样品另一端夹在下固定夹，确定样品装上固定夹后不能打滑，且样品放正后固定；点击清零和运行按钮开始测试，最终拉力判定结果如下：拉力测试完毕，机台会自动停止，拉力机输出力、位移和时间；
拉伸率计算：拉伸率δ＝ΔL/L×100％，ΔL为拉力机上输出的位移与原标距长度之差，L为原标距长度。
隔板厚度的测试：
采用扫描电子显微镜(SEM)截面测试各层厚度，取隔板材料样品中央部位裁切出长方体形状，将样品放置离子抛光机进行抛光处理，抛光完成后放置SEM下方观察，可观察得到隔板的厚度。
膨胀率的测试：
将SOC＝50％的锂离子电池在电池测厚机(型号PPG650gf，深圳奥拓美)下测量厚度，记为T1；然后，将电池以0.5C充电至4.35V，并以0.5C电流放电至3.0V，以此为一个充放电循环(Cycle)，每50Cycle测一次电池厚度，直至电池/测试到500cycle，记录最终的电池厚度为T500。
膨胀率＝(T500-T1)/T1×100％。
能量密度计算：
将锂离子电池在25℃下充电至4.45V后，用激光测厚仪测试锂离子电池的长、宽、高，得到锂离子电池的体积(V)，再采用0.2C放电至3V，得到锂离子电池放电容量(C)和平均电压平台(U)，其体积能量密度(ED)可通过如下公式计算得到：ED＝C×U/V。
实施例1
<电极组件的制备>
分别制备一批第一电极组件和一批第二电极组件，选择其中一第一电极组件制备第一电池，选择其中一第二电极组件制备第二电池，然后将第一电池和第二电池分别进行循环测试计算膨胀率，将第一电池的膨胀率认为是第一电极组件的膨胀率，大小为10％，将第二电池的膨胀率认为是第二电极组件的膨胀率，大小为2％。
<隔板的制备>
将封装层材料PP均匀分散到分散剂N-甲基吡咯烷酮(NMP)中，制备得到封装层材料的悬浊液；利用涂胶机，在厚度为10μm的隔板Al箔两个表面的封装部涂覆厚度为20μm的封装层材料；130℃烘干封装层材料悬浊液中的分散剂NMP，即完成了隔板的制备。经测试，隔板的拉伸率δ＝14％。
<锂离子电池的制备>
将冲坑成型的第二包装体(厚度为88μm的铝塑膜)置于组装夹具内，坑面朝上，将第二电极组件(膨胀率为2％)置于坑内，从第二电极组件引出一个正极极耳和一个负极极耳。其中，第二电极组件与测试的第二电池中的电极组件为同一批次。
然后，将隔板放置于第二电极组件上，在隔板上放置第一电极组件(膨胀率为10％)，从第一电极组件引出一个正极极耳和一个负极极耳。其中，第一电极组件与测试的第一电池中的电极组件为同一批次。然后，将第一包装体(厚度为88μm的铝塑膜)坑面朝下覆盖于第一电极组件之上，留出注液口和极耳伸出的区域，热封包装壳的其他位置，从而在隔板的两侧形成各自独立的第一腔体和第二腔体，得到组装后的电极组件。其中，热封温度为180℃，热封压力为0.5MPa。
在组装电极组件的两个腔体单独注入电解液，注液后进行封口。
然后，将第二电极组件的负极极耳与第一电极组件的正极极耳通过激光焊焊接在一起，使二者串联。充放电过程只需连接第二电极组件的正极极耳与第一电极组件的负极极耳即可。
实施例2
除了在<隔板的制备>中隔板的厚度为20μm、拉伸率δ＝25％以外，其余与实施例1相同。
实施例3
<隔板的制备>
将实施例1制备得到的隔板置于弧形模具中热压，即得到主体部为弧形结构的隔板，隔板的拉伸率δ＝14％。
其余与实施例1相同。
实施例4
除了在<隔板的制备>中隔板的材料选用PET、隔板厚度为30μm、隔板的拉伸率δ＝37％以外，其余与实施例3相同。
实施例5
除了在<隔板的制备>中模具为波浪形、隔板厚度为20μm、隔板的拉伸率δ＝15％以外，其余与实施例3相同。
实施例6
除了在<隔板的制备>中模具为波浪形、隔板的拉伸率δ＝25％以外，其余与实施例4相同。
实施例7
除了在<隔板的制备>中隔板材料选择为Ti、隔板的拉伸率δ＝20％以外，其余与实施例5相同。
实施例8
除了在<隔板的制备>中模具为凹槽形、隔板厚度为30μm、隔板的拉伸率δ＝15％以外，其余与实施例5相同。
实施例9
除了在<隔板的制备>中隔板的材料选用PET、隔板的拉伸率δ＝35％以外，其余与实施例8相同。
实施例10
除了在<隔板的制备>中隔板的材料选用Ti、隔板的拉伸率δ＝16％以外，其余与实施例8相同。
实施例11
除了在<隔板的制备>中模具为弧形、隔板的厚度为20μm、隔板的拉伸率δ＝20％以外，其余与实施例10相同。
实施例12
除了在<隔板的制备>中隔板的厚度为15μm、隔板的拉伸率δ＝22％以外，其余与实施例11相同。
对比例1
除了在<隔板的制备>中隔板的材料选用不锈钢、隔板的厚度为20μm、隔板的拉伸率δ＝6％以外，其余与实施例1相同。
对比例2
除了在<隔板的制备>中模具为弧形、隔板的拉伸率δ＝6％以外，其余与对比例1相同。
对比例3
除了在<隔板的制备>中模具为凹槽形、隔板的拉伸率δ＝5％以外，其余与实施例7相同。
实施例1至实施例12、对比例1至对比例3的制备参数和性能参数如表1所示：
Figure PCTCN2021115967-appb-000001
从实施例1、实施例2和对比例1可以看出，通过选用拉伸率δ在本申请范围内的隔板，能够有效改善电化学装置的膨胀性能，从而提高了电化学装置的能量密度。
从实施例3至实施例12和对比例2、对比例3可以看出，本申请通过隔板材料和隔板主体部上预变形结构的设置，使隔板的拉伸率δ在本申请范围内，能够显著改善电化学装置的膨胀性能，从而提高了电化学装置的能量密度。
综合上述分析可知，本申请提供的电化学装置，通过选择拉伸率δ≥10％的隔板，使得该电化学装置在循环过程中，在面对第一电极组件和第二电极组件出现差异膨胀的情况下，膨胀率较大的第一电极组件能够向膨胀率较小的第二电极组件的一侧进行挤压，占用原本用于容纳膨胀率较小的第二电极组件的腔体空间，有效改善了电化学装置的膨胀性能，使电化学装置的体积不过分增加，使得电化学装置的能量密度得以改善。还能够改善隔板与包装壳的密封可靠性，进而提高电化学装置的安全性能。
需要说明的是，在本文中，诸如“第一”和“第二”等之类的关系术语仅仅用来将一个实体与另一个实体区分开来，而不一定要求或者暗示这些实体之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其它变体意在涵盖非排他性的包含，从而使得包括一系列要素的物品或者设备不仅包括那些要素，而且还包括没有明确列出的其它要素，或者是还包括为这种物品或者设备所固有的要素。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (10)

  1. 一种电化学装置，其特征在于，包括：
    包装壳；
    隔板，所述隔板包括封装部和主体部，所述封装部与所述包装壳连接并将所述包装壳在所述隔板的两侧分别限定出第一腔体和第二腔体；所述隔板的拉伸率δ≥10％；
    第一电极组件，设置在所述第一腔体中；及
    第二电极组件，设置在所述第二腔体中。
  2. 根据权利要求1所述的电化学装置，其特征在于，所述主体部设置有预变形结构，预变形结构包括弧形结构、波浪形结构或凹槽状结构中的至少一种。
  3. 根据权利要求1所述的电化学装置，其特征在于，所述电化学装置还包括封装层，所述封装层设置在所述隔板表面的边缘处或所述隔板的整个表面上。
  4. 根据权利要求3所述的电化学装置，其特征在于，所述封装层设置在所述隔板的封装部。
  5. 根据权利要求1所述的电化学装置，其特征在于，所述隔板的材料包括高分子材料或金属材料中的至少一种，所述高分子材料包括聚对苯二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯、聚萘二甲酸乙二醇酯、聚醚醚酮、聚酰亚胺、聚酰胺、聚乙二醇、聚酰胺酰亚胺、聚碳酸酯、环状聚烯烃、聚苯硫醚、聚乙酸乙烯酯、聚四氟乙烯，聚亚甲基萘、聚偏二氟乙烯，聚萘二甲酸亚乙酯、聚碳酸亚丙酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)、有机硅、维尼纶、聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚苯醚、聚酯、聚砜、非晶态α-烯烃共聚物及其衍生物中的至少一种；所述金属材料包括Ni、Ti、Cu、Ag、Au、Pt、Fe、Co、Cr、W、Mo、Al、Mg、K、Na、Ca、Sr、Ba、Si、Ge、Sb、Pb、In、Zn、不锈钢(SUS)及其合金中的至少一种。
  6. 根据权利要求3所述的电化学装置，其特征在于，所述封装层的材料包括聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯-醋酸乙烯共聚物、乙烯-丙烯酸乙酯共聚物、乙烯-丙烯酸共聚物、乙烯-乙烯醇共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚酰胺、聚 酯、非晶态α-烯烃共聚物及其衍生物中的至少一种。
  7. 根据权利要求1所述的电化学装置，其特征在于，所述隔板的拉伸率δ≤40％，和/或，所述隔板的厚度为10μm至100μm。
  8. 根据权利要求7所述的电化学装置，其特征在于，所述隔板的厚度为10μm至30μm，所述封装层厚度为20μm至40μm。
  9. 根据权利要求1所述的电化学装置，其特征在于，所述第一电极组件的膨胀率与所述第二电极组件的膨胀率的比值为k，1＜k≤5。
  10. 一种电子装置，其特征在于，包括权利要求1至9中任一项所述的电化学装置。
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