CN105261727B - Electrochemical cell and preparation method thereof - Google Patents
Electrochemical cell and preparation method thereof Download PDFInfo
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- CN105261727B CN105261727B CN201510676990.5A CN201510676990A CN105261727B CN 105261727 B CN105261727 B CN 105261727B CN 201510676990 A CN201510676990 A CN 201510676990A CN 105261727 B CN105261727 B CN 105261727B
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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
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/531—Electrode connections inside a battery casing
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/04—Construction or manufacture in general
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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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
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- 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
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- 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
Abstract
The invention belongs to the field of electrochemical cells, and particularly relates to an electrochemical cell which comprises the following components: the electrode plate comprises a coating layer and a current collector, wherein the coating layer is attached to the current collector, the thickness of one side of the coating layer is H, and the thickness of a tab is H; coating layers are arranged on the left side and the right side of the tab, and the thickness of the coating layers is less than or equal to 10 micrometers and is less than or equal to 2H-H; and a thickening layer is further arranged in the thickness direction of the overlapping area of the lug and the current collector, the thickness of the thickening layer is H1, and the thickness of the thickening layer is less than or equal to 60 mu m and less than or equal to (2H-H-H1) and less than or equal to 40 mu m. When the thickness of the cleaned two-layer coating layer (2H) and the sum of the lug thickness and the thickening layer are close to each other, the lug of the shaped battery can be tightly fixed by the electrode plates and the isolating films positioned above and below the lug, and the bare cell and the outer package are tightly connected together through the exposed lug, so that the bare cell and the outer package are fixed, and the dropping performance of the battery is improved.
Description
Technical Field
The invention belongs to the field of electrochemical cells, and particularly relates to an electrochemical cell and a preparation method thereof.
Background
After the 21 st century, various electronic device products such as mobile phones, notebooks, wearable devices and the like are in endless, and the lives of a large number of users are greatly enriched; meanwhile, electric vehicles and various energy storage power stations also sprout, develop and grow rapidly like spring bamboo shoots after rain. The above high-tech products have one common feature: high performance batteries are required to serve as energy storage components.
The existing batteries mainly comprise a primary battery and a secondary battery; the so-called primary battery, which is a battery that cannot be repeatedly charged, mainly includes a carbon zinc battery, an alkaline battery, a paste zinc-manganese battery, a cardboard zinc-manganese battery, an alkaline zinc-manganese battery, a button cell (a button zinc-silver battery, a button lithium-manganese battery, a button zinc-manganese battery), a zinc-air battery, a primary lithium-manganese battery, and the like, and a mercury battery; the secondary battery, i.e., a rechargeable battery, mainly includes a secondary alkaline zinc-manganese battery, a nickel-cadmium rechargeable battery, a nickel-hydrogen rechargeable battery, a lithium rechargeable battery, a lead-acid battery, and a solar battery. Lead-acid batteries can be divided into: open type lead-acid storage battery and totally-enclosed lead-acid storage battery. From the perspective of external packaging, the conventional batteries are mainly classified into flexible-packaged batteries and hard-shell-packaged batteries, and the flexible-packaged battery packaging film has small thickness and large plasticity, so that the battery is widely applied to various high-grade primary batteries and secondary batteries.
However, with the continuous upgrade of various electric devices, the battery has more requirements on the performance of the battery, such as higher energy density, faster charge and discharge speed, longer cycle life, better safety performance and the like; the energy density is directly related to the user experience effect of the product, and the safety performance of the battery cell is closely related to the safe use of the electric product and the life property and life safety of the user, so the energy density and the safety performance are concerned by battery manufacturers and users. How to improve the energy density of the battery and improve the safety performance of the battery becomes a key research direction of researchers in the field of batteries. In order to improve the energy density of the battery, the utility model with patent application No. 201420283159.4 invented an effective pole piece cleaning device: the laser system at least comprises a beam shaping mechanism for homogenizing the energy of the laser beam emitted by the laser emitting head, and the laser emitting head is electrically connected with the beam shaping mechanism. Compared with the prior art, the utility model has the advantages that the energy of the laser beam can be homogenized by arranging the beam shaping mechanism, and the foil in the pole piece can not be damaged, so that the welding quality of the pole ear is improved; and the residual of the coating can not be caused, so that the cleaning quality is improved, and the high energy and the low energy in the light beam can be effectively utilized, so that the maximum utilization of the laser energy is realized, and the utilization rate of the energy, the cleaning efficiency and the cleaning quality are improved. However, in the battery core prepared by the method, because the thickness of the tab is often smaller than that of the cleaned electrode coating layer, the tab cannot be fixed by the upper and lower electrode isolation films after the battery core is compacted, so that the tab is in a loose state, and cannot play a role in fixing the bare battery core and the external package after being made into a finished battery, so that the safety performance of the battery core, particularly the performances of falling, rollers and the like are obviously reduced.
In view of the above, there is a need for a new battery which can improve the energy density of the battery and has high safety performance.
Disclosure of Invention
The invention aims to: aiming at the defects of the prior art, the provided electrochemical cell comprises an electrode plate, an isolating film, an outer package and electrolyte, wherein the electrode plate comprises a tab, a current collector and a coating layer, the tab is electrically conducted with the current collector, the coating layer is attached to the current collector, the thickness of one side of the coating layer is H, and the thickness of the tab is H; coating layers are arranged on the left side and the right side of the tab, and the thickness of the coating layers is less than or equal to 10 micrometers and is less than or equal to 2H-H; and a thickening layer is further arranged in the thickness direction of the overlapping area of the lug and the current collector, the thickness of the thickening layer is H1, and the thickness of the thickening layer is less than or equal to 60 mu m and less than or equal to (2H-H-H1) and less than or equal to 40 mu m. When the thickness of the cleaned two-layer coating layer (2H) and the sum of the lug thickness and the thickening layer are close to each other, the lug of the shaped battery can be tightly fixed by the electrode plates and the isolating films positioned above and below the lug, and the bare cell and the outer package are tightly connected together through the exposed lug, so that the bare cell and the outer package are fixed, and the dropping performance of the battery is improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
an electrochemical cell comprises an electrode plate, an isolating membrane, an outer package and electrolyte, wherein the electrode plate comprises a tab, a current collector and a coating layer, the tab is electrically conducted with the current collector, the coating layer is attached to the current collector, the thickness of one side of the coating layer is H, and the thickness of the tab is H; coating layers are arranged on the left side and the right side of the tab, and the thickness of the coating layers is less than or equal to 10 mu m and is less than or equal to 2H-H; and a thickening layer is further arranged in the thickness direction of the overlapping area of the lug and the current collector, the thickness of the thickening layer is H1, and the thickness of the thickening layer is less than or equal to 60 mu m and less than or equal to (2H-H-H1) and less than or equal to 40 mu m.
As an improvement of the electrochemical battery, the electronic conduction mode of the pole lug and the current collector is that the pole lug and the current collector are directly welded or a conductive bonding layer is arranged between the pole lug and the current collector for bonding.
As an improvement of the electrochemical cell of the present invention, at the position of electron conduction between the tab and the current collector, there is no coating on one side of the current collector close to the tab, and there is a coating or no coating on one side of the current collector away from the tab; the conductive bonding layer arranged between the electrode lug and the current collector is at least one part of the thickening layer.
As an improvement of the electrochemical cell of the invention, the size of 20 mu m is less than or equal to (2H-H); less than or equal to-10 μm and less than or equal to (2H-H-H1) and less than or equal to 30 μm.
As an improvement of the electrochemical cell of the present invention, the thickening layer is located on at least one of a surface of the tab, between the tab and the current collector, and a side of the current collector facing away from the tab.
As an improvement of the electrochemical cell of the present invention, the thickening layer between the tab and the current collector is a conductive adhesive layer; the thickening layer on the surface of the pole lug or on the side of the current collector departing from the pole lug is an adhesive tape.
The conductive adhesive layer is conductive adhesive or/and metal adhesive; the adhesive tape comprises a substrate or/and an adhesive layer; the base material is selected from at least one of hot melt adhesive, polypropylene, modified polypropylene, cloth base, kraft paper, crepe paper, fiber, PVC, PE foam and polyimide; the adhesive layer is at least one selected from acrylate adhesive, composite structural adhesive, thermosetting polymer adhesive, hot melt adhesive, pressure-sensitive adhesive, inorganic adhesive, rubber adhesive, natural adhesive and adhesive. Such as organosilicon pressure-sensitive adhesive, polyvinylidene fluoride, styrene butadiene rubber, polyurethane, conductive adhesive, polyacrylate and the like.
The invention also comprises a preparation method of the electrochemical cell, which mainly comprises the following steps:
step 1, preparing an electrode plate: preparing an electrode plate, removing part of the coating in a film coating area, and then arranging an electrode tab; obtaining an electrode plate for later use;
step 2, assembling the battery core: assembling the electrode pole piece and the isolation film to obtain a bare cell, arranging a thickening layer at the position where a tab is arranged, then putting the bare cell into a shell/bag, packaging, injecting liquid and standing;
step 3, preparing a finished battery: and (4) forming and shaping the battery core prepared in the step (2) to obtain a finished battery.
As an improvement of the preparation method of the electrochemical cell, the method for removing the partial coating in the coating area in the step 1 comprises at least one of solvent cleaning, laser cleaning and partial coating removal after presetting structures on the current collector before coating.
As an improvement of the preparation method of the electrochemical cell, the diaphragm of which the coating area is partially coated in the step 1 is a positive diaphragm or/and a negative diaphragm; and the coating area is completely or partially removed from the coating layer.
Compared with the prior art, the invention has the advantages that: when the thickness of the cleaned two-layer coating layer (2H) and the sum of the lug thickness and the thickening layer are close to each other, the lug of the shaped battery can be tightly fixed by the electrode plates and the isolating films positioned above and below the lug, and the bare cell and the outer package are tightly connected together through the exposed lug, so that the bare cell and the outer package are fixed, and the dropping performance of the battery is improved.
Detailed Description
The present invention and its advantageous effects will be described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.
In the comparative example 1, the following examples were conducted,
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m on the empty foil area at the head of the membrane to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then welding nickel electrode lugs with the width of 1cm and the thickness of 60 mu m on the empty foil area at the head of the diaphragm to obtain a negative plate for later use;
preparing a naked battery cell: selecting an isolating membrane with the thickness of 12 mu m, and winding the isolating membrane with the positive plate and the negative plate together to obtain a bare cell with a lug led out from the middle area of a cell electrode for standby application, wherein in the bare cell, the thickness of the lug is lower than the thickness of the cleaned coating layer, so that the lug area of the cell is not the thickest area of the cell, the thickness of the lug does not influence the overall thickness of the battery, and the battery with higher energy density is obtained;
preparing a finished battery: and (3) placing the bare cell in an aluminum-plastic film for top-side sealing, then drying, injecting liquid, after the electrolyte is fully soaked, performing clamp formation at 75 ℃ and 0.6MPa, and then shaping, degassing and sealing to obtain a finished product cell.
In the comparative example 2, the following examples were conducted,
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm in the middle area of the membrane by using laser, and then welding an aluminum tab with the width of 1cm and the thickness of 60 mu m to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector, coating negative electrode slurry on the surface of the current collector, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm in the middle area of the membrane by using laser, and then welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m to obtain a negative electrode plate for later use;
preparing a naked battery cell: selecting an isolating membrane with the thickness of 12 mu m, and winding the isolating membrane with the positive plate and the negative plate together to obtain a bare cell with a lug led out from the middle area of a cell electrode for standby application, wherein in the bare cell, the thickness of the lug is lower than the thickness of the cleaned coating layer, so that the lug area of the cell is not the thickest area of the cell, the thickness of the lug does not influence the overall thickness of the battery, and the battery with higher energy density is obtained;
preparing a finished battery: and (3) placing the bare cell in an aluminum-plastic film for top-side sealing, then drying, injecting liquid, after the electrolyte is fully soaked, carrying out clamp formation at 75 ℃ and 0.6MPa, and then shaping, degassing and sealing to obtain a finished product cell.
Example 1, unlike comparative example 2, this example includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm in the middle area of the diaphragm by using laser, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is organic silicon pressure-sensitive adhesive) with the thickness of 20 mu m on the surface of the aluminum lug to serve as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 20 mu m on the surface of the nickel electrode lug to serve as a thickening layer to obtain a negative electrode plate for later use;
the rest is the same as comparative example 2, and the description thereof is omitted.
Embodiment 2, unlike embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm in the middle area of the diaphragm by using laser, welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is organic silicon pressure-sensitive adhesive) with the thickness of 40 mu m on the surface of the aluminum lug to serve as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm in the middle area of the diaphragm by using laser, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is organic silicon pressure-sensitive adhesive) with the thickness of 40 mu m on the surface of the nickel electrode lug to be used as a thickening layer to obtain a negative electrode sheet for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Embodiment 3, different from embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating the positive electrode slurry on the surface of the current collector, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm in the middle area of the diaphragm by using laser, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is organic silicon pressure-sensitive adhesive) with the thickness of 50 mu m on the surface of the aluminum lug to serve as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector, coating negative electrode slurry on the surface of the current collector, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 50 mu m on the surface of the nickel electrode lug to serve as a thickening layer to obtain a negative electrode plate for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Embodiment 4, unlike embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and then sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 60 mu m on the surface of the aluminum lug to be used as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector, coating negative electrode slurry on the surface of the current collector, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 60 mu m on the surface of the nickel electrode lug to serve as a thickening layer to obtain a negative electrode plate for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Example 5, unlike example 1, this example includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm in the middle area of the diaphragm by using laser, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and then sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is organic silicon pressure-sensitive adhesive) with the thickness of 80 mu m on the surface of the aluminum lug to serve as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm in the middle area of the diaphragm by using laser, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is organic silicon pressure-sensitive adhesive) with the thickness of 80 mu m on the surface of the nickel electrode lug to serve as a thickening layer to obtain a negative electrode sheet for later use;
the rest is the same as embodiment 1, and the description is omitted.
Embodiment 6, unlike embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating the positive electrode slurry on the surface of the current collector, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and then sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 90 mu m on the surface of the aluminum lug to be used as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector, coating negative electrode slurry on the surface of the current collector, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 90 mu m on the surface of the nickel electrode lug to serve as a thickening layer to obtain a negative electrode plate for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Embodiment 7, different from embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and then sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 100 mu m on the surface of the aluminum lug to be used as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then, cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 100 mu m on the surface of the nickel electrode lug to serve as a thickening layer to obtain a negative electrode plate for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Embodiment 8, different from embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating positive electrode slurry on the surface of the aluminum foil, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then cleaning a double-sided blank area with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, then welding an aluminum lug with the width of 1cm and the thickness of 60 mu m, and then sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 120 mu m on the surface of the aluminum lug to be used as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using laser in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m, and sticking a layer of adhesive paper (the base material is polypropylene, and the adhesive layer is an organic silicon pressure-sensitive adhesive) with the thickness of 120 mu m on the surface of the nickel electrode lug to be used as a thickening layer to obtain a negative electrode plate for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Example 9, unlike example 1, this example includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, arranging a layer of foaming adhesive with the length of 4cm and the width of 1.5cm in a surface fixing area (the arrangement position of the foaming adhesive is positioned in the middle area of a finished battery pole piece), then coating anode slurry, wherein the foaming adhesive falls off in the drying process, so that a coating coated on the surface of the foaming adhesive falls off to obtain a hollow foil area (with the length of 4cm and the width of 1.5 cm), and then carrying out cold pressing to obtain an anode membrane with the single-side coating thickness of 60 mu m; welding an aluminum lug with the width of 1cm and the thickness of 60 mu m on the empty foil area, and sticking a layer of adhesive paper (the base material is a cloth base, and the adhesive layer is silica gel) with the thickness of 60 mu m on the empty foil area opposite to the aluminum lug to be used as a thickening layer to obtain a positive plate for later use;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector, arranging a layer of foaming adhesive with the length of 4cm and the width of 1.5cm on a fixed area on the surface of the current collector (the arrangement position of the foaming adhesive is positioned in the middle area of a finished battery pole piece), then coating negative pole slurry on the surface of the current collector, and in the drying process, enabling the foaming adhesive to fall off to ensure that a coating coated on the surface of the current collector falls off to obtain a hollow foil area (with the length of 4cm and the width of 1.5 cm), and then cold-pressing and waiting until a single-side coated negative pole piece with the thickness of 70 mu m; then cleaning a double-sided blank area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm by using a solvent in the middle area of the diaphragm, welding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m on the blank foil area, and sticking a layer of adhesive paper (the base material is kraft paper, and the adhesive layer is styrene butadiene rubber) with the thickness of 60 mu m on the blank foil area opposite to the nickel electrode lug as a thickening layer to obtain a negative electrode sheet for later use;
the rest is the same as the embodiment 1, and the description is omitted.
Embodiment 10, different from embodiment 1, this embodiment includes the following steps:
preparing a positive plate: selecting an aluminum foil with the thickness of 12 mu m as a current collector, coating the positive electrode slurry on the surface of the current collector, and performing cold pressing to obtain a positive electrode membrane with the single-side coating thickness of 70 mu m; then, cleaning a single-side hollow foil area with the length of 4cm and the width of 1.5cm in the middle area of the membrane by using a solvent, and then bonding an aluminum lug with the width of 1cm and the thickness of 60 mu m in the single-side hollow foil area by using conductive adhesive to obtain a positive plate for later use, wherein the thickness of a bonding layer is 10 mu m;
preparing a negative plate: selecting a copper foil with the thickness of 8 mu m as a current collector body, coating negative electrode slurry on the surface of the current collector body, and coating a negative electrode sheet with the thickness of 70 mu m on one side after cold pressing; then cleaning a single-side empty foil area (staggered with the position of the positive electrode lug) with the length of 4cm and the width of 1.5cm in the middle area of the membrane by using a solvent, and then bonding a nickel electrode lug with the width of 1cm and the thickness of 60 mu m by using conductive adhesive to obtain a negative electrode plate for later use, wherein the thickness of the bonding layer is 10 mu m;
the rest is the same as embodiment 1, and the description is omitted.
The testing process comprises the following steps:
and (3) capacity testing: the capacity test of the cells of the examples and comparative examples was carried out in an environment of 35 ℃ according to the following procedure: standing for 3min; charging to 4.2V at constant current of 0.5C and charging to 0.05C at constant voltage; standing for 3min; discharging at constant current of 0.5C to 3.0V to obtain first discharge capacity D0; the capacity test was completed after standing for 3min, and the obtained results are shown in table 1.
And (3) thickness testing: the thickness of the battery (thickness between the front and back of the cell) was measured using a micrometer, and the results are shown in table 1.
Volumetric energy density: and calculating according to the tested battery capacity, voltage, length, width and the like.
Safety test (drop test): from comparative example 1 and examples 1 to 10, 10 cells were each taken out for a drop test: fixing the battery in a drop test fixture by using a double faced adhesive tape, testing the initial voltage V0 of the drop test fixture, placing the fixture on a test bench with the height of 1.5m in an environment of room temperature and 25 ℃, enabling the head of the battery core to move downwards in a free-falling manner, and circulating for 10 times to finish the drop test. Testing the final voltage V1 of the electric core after standing for 1H, calculating the voltage drop to be delta V, considering that the drop test is invalid when the delta V is more than 2mV, and counting the number of the invalid voltage; and at the same time, whether the appearance is damaged or not is observed.
TABLE 1 summary of test results of each comparative example and example
As can be seen from table 1, when the present invention is used, not only the volume energy density of the battery can be increased, but also the prepared battery cell has high safety performance (drop performance).
From examples 1 to 8, when the thickness of the thickened layer is small (less than 50 μm), the thickness of the electrode layer cannot be filled and cleaned, and the tab cannot be completely fixed by the upper and lower electrodes and the isolating films, so that the tab cannot connect the bare cell with the external package firmly enough, and the drop performance of the cell can be improved, but cannot be completely solved. When the thickness of the thickened layer is larger (more than 90 mu m), the thickness of the lug and the thickness of the thickened layer exceed the thickness of the cleaned double-sided coating, and the final area of the battery cell is still at the position of the lug, so that the overall thickness of the battery is increased, and the energy density of the battery is reduced.
From the examples 1 to 10, the present invention can effectively improve the energy density of the battery and solve the problem of the safety performance (drop performance) of the battery, which indicates that the present invention has universality.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (10)
1. An electrochemical battery comprises an electrode pole piece, an isolating film, an outer package and electrolyte, wherein the electrode pole piece comprises a lug, a current collector and a coating layer, the lug is in electronic conduction with the current collector, the coating layer is attached to the current collector, the thickness of one side of the coating layer is H, and the thickness of the lug is H; the method is characterized in that:
the coating layers are arranged on the left side and the right side of the tab, and the thickness of the coating layers is less than or equal to 10 micrometers (2H-H);
in the thickness direction, the overlapping area of the electrode lug and the current collector is also provided with a thickening layer, the thickness of the thickening layer is H1, and the thickness of the thickening layer is more than or equal to-60 mu m and less than or equal to (2H-H-H1) and less than or equal to 40 mu m.
2. The electrochemical cell of claim 1, wherein the tab is in electronic communication with the current collector by direct welding or by providing a conductive adhesive layer between the tab and the current collector.
3. The electrochemical cell of claim 2, wherein, in the position of electron conduction between the tab and the current collector, the side of the current collector close to the tab has no coating layer, and the side of the current collector away from the tab has a coating layer or no coating layer; the conductive bonding layer arranged between the electrode lug and the current collector is at least one part of the thickening layer.
4. An electrochemical cell according to claim 1, wherein 20 μm ≦ (2H-H); less than or equal to-10 μm and less than or equal to (2H-H-H1) and less than or equal to 30 μm.
5. The electrochemical cell of claim 1, wherein said thickening is located on at least one of an outside surface of said tab, between said tab and said current collector, and a side of said current collector facing away from said tab.
6. The electrochemical cell of claim 5 wherein the thickening between the tab and the current collector is an electrically conductive adhesive layer; and the thickening layer on one side of the pole lug is an adhesive tape.
7. The electrochemical cell of claim 6, wherein the conductive adhesive layer is a conductive adhesive or/and a metal adhesive; the adhesive tape comprises a substrate or/and an adhesive layer; the substrate is selected from at least one of hot melt adhesive, polypropylene, modified polypropylene, cloth base, kraft paper, crepe paper, fiber, PVC, PE foam and polyimide; the adhesive layer is at least one selected from acrylate adhesive, composite structural adhesive, thermosetting high-molecular adhesive, hot melt adhesive, pressure-sensitive adhesive, inorganic adhesive, rubber adhesive and natural adhesive.
8. A method of making an electrochemical cell according to claim 1, comprising the steps of:
step 1, preparing an electrode plate: preparing an electrode plate, removing part of a coating layer in a coating area, and then arranging an electrode lug to obtain the electrode plate for later use;
step 2, assembling the battery core: assembling an electrode pole piece and an isolation film to obtain a bare cell, arranging a thickening layer at the position where a tab is arranged, then putting the bare cell into a shell/bag, packaging, injecting liquid and standing;
step 3, preparing a finished battery: and (4) forming and shaping the battery core prepared in the step (2) to obtain a finished battery.
9. A method for manufacturing an electrochemical cell according to claim 8, wherein the step 1 of removing a portion of the coating layer from the coating area comprises at least one of solvent cleaning, laser cleaning, and removing a portion of the coating layer after patterning the current collector before coating.
10. The method for preparing an electrochemical cell according to claim 8, wherein the membrane with the coating layer partially removed in the coating region in step 1 is a positive membrane or/and a negative membrane.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105576191A (en) * | 2016-02-26 | 2016-05-11 | 宁德新能源科技有限公司 | Battery pole piece and secondary battery adopting battery pole piece |
| CN106129327A (en) * | 2016-08-10 | 2016-11-16 | 欣旺达电子股份有限公司 | Anode slice of lithium ion battery and lithium ion battery |
| CN106299237B (en) * | 2016-09-27 | 2019-06-28 | 武汉艾特米克超能新材料科技有限公司 | Self-supporting pole piece and preparation method thereof, battery and its battery core |
| CN106654139B (en) * | 2017-01-03 | 2019-12-10 | 曙鹏科技（深圳）有限公司 | Lug and pole piece switching structure, battery cell and manufacturing method thereof |
| CN107768676A (en) * | 2017-09-05 | 2018-03-06 | 东莞市迈科新能源有限公司 | A kind of lithium ion battery and its pole piece |
| CN112970144B (en) * | 2018-12-19 | 2023-11-17 | 三洋电机株式会社 | Electrode plate for secondary battery and secondary battery using the same |
| CN112216842B (en) * | 2019-07-12 | 2022-01-11 | 宁德新能源科技有限公司 | Composite current collector, electrode pole piece and battery cell comprising same |
| CN110828775A (en) * | 2019-10-15 | 2020-02-21 | 江苏卓高新材料科技有限公司 | Current collector electrode structure, secondary battery and preparation method of secondary battery |
| CN112687993B (en) * | 2020-12-24 | 2023-02-24 | 宁德新能源科技有限公司 | Battery cell, battery and power utilization device |
| CN112750978B (en) * | 2020-12-30 | 2022-03-15 | 珠海冠宇电池股份有限公司 | Pole piece and battery |
| CN113036075B (en) * | 2021-02-26 | 2022-08-26 | 珠海冠宇电池股份有限公司 | Pole piece and battery cell |
| CN216120371U (en) * | 2021-11-04 | 2022-03-22 | 珠海冠宇电池股份有限公司 | Pole piece and battery |
| CN116848686A (en) * | 2022-09-22 | 2023-10-03 | 宁德新能源科技有限公司 | Electrochemical device, method for manufacturing the same, and electronic device |
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