CN105261781A - Electrochemical cell and preparation method thereof - Google Patents
Electrochemical cell and preparation method thereof Download PDFInfo
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- CN105261781A CN105261781A CN201510716088.1A CN201510716088A CN105261781A CN 105261781 A CN105261781 A CN 105261781A CN 201510716088 A CN201510716088 A CN 201510716088A CN 105261781 A CN105261781 A CN 105261781A
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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
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Abstract
The invention belongs to the field of energy storage devices, and particularly relates to an electrochemical battery which comprises a naked electric core, an electrolyte and an external packaging structure, wherein the naked electric core comprises a positive electrode, a separation film and a negative electrode; the positive electrode consists of a positive electrode tab and a positive electrode piece; the negative electrode consists of a negative electrode tab and a negative electrode piece; the positive electrode tab and the negative electrode tab are led out from different sides of the electrochemical cell; in the electrochemical cell, one side of the positive (negative) pole tab is led out, the extension amount of the negative (positive) pole tab is less than or equal to that of the isolating film, and the extension amount of the isolating film is less than or equal to that of the positive (negative) pole tab; the battery core with the structure is simple in manufacturing process, and the prepared battery core has excellent electrochemical performance, higher packaging reliability, smaller self-discharge rate and better drop resistance.
Description
Technical Field
The invention belongs to the technical 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 the users are greatly enriched; meanwhile, electric vehicles and various energy storage power stations can sprout, develop and grow rapidly like spring bamboo shoots in the rainy season. The above high-tech products have one common feature: high performance, low cost 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, as the quality of life of people improves, higher requirements, namely longer standby time, are put forward for electronic products; this requires a higher energy density of the power supply that powers the electronic product.
The existing ways to increase the energy density are: selecting electrochemical systems with higher energy density, such as a high-voltage lithium cobaltate anode, a silicon cathode and the like; a manufacturing process with higher precision is selected, and the consistency of the battery capacity is improved, so that the average capacity of the battery is improved; a substrate having a thinner thickness, such as 6 μm copper foil, 8 μm aluminum foil, 64 μm aluminum plastic film, or the like, is selected. But the high-voltage system has poorer safety performance and higher cost; the silicon cathode has low first efficiency, poor cycle performance and high cost; the high-precision manufacturing process has huge equipment investment and high manufacturing cost; thinner substrates, in turn, tend to mean higher process control requirements, higher material costs; none of these solutions therefore increases the manufacturing costs.
With the increase of personalized electronic products, such as the horizontal emergence of flexible devices, it puts higher requirements on batteries: i.e. a flexible battery. However, in the bending process of the flexible battery, the interface inside the battery core is often a weak link and is easily damaged, so that the performance of the flexible battery is poor; therefore, the number of internal interfaces of the flexible battery is reduced as much as possible, and the method is a reliable method for improving the performance of the flexible battery.
Meanwhile, in order to pursue higher energy density, the width of an effective packaging area is often reduced in the manufacturing process; and new materials and new battery structures are continuously generated, and higher requirements on the packaging reliability of the battery are also put forward.
In view of the above, there is a need for a novel electrochemical cell and a method for manufacturing the same, which not only can increase the energy density of the cell, improve the packaging reliability of the cell, reduce the cost (material cost or/and manufacturing cost), but also have excellent flexibility and electrochemical properties when it is a flexible cell.
Disclosure of Invention
The invention aims to: aiming at the defects of the prior art, the provided electrochemical battery comprises a naked battery cell, electrolyte and an outer packaging structure, wherein the naked battery cell comprises a positive electrode, a separation film and a negative electrode; the positive electrode consists of a positive electrode tab and a positive electrode piece; the negative electrode consists of a negative electrode tab and a negative electrode piece; the positive electrode tab and the negative electrode tab are led out from different sides of the electrochemical cell; in the electrochemical battery, one side of the positive electrode tab is led out, the extension (overlap, which can be defined as that the distance from the electrode plate edge corresponding to the naked electric core edge and the separation film edge to the parallel line is the extension) of the negative electrode plate is less than or equal to the extension of the separation film by taking any line in the naked electric core main body and parallel to the naked electric core edge as a reference, the extension of the separation film is less than or equal to the extension of the positive electrode plate, the extension of the positive electrode plate-the extension of the negative electrode plate = c, and the positive electrode plate with the width of c is of a positive electrode extension structure; or/and in the electrochemical cell, one side of the cathode tab is led out, the extension amount of the anode electrode plate is less than or equal to that of the isolating film, the extension amount of the isolating film is less than or equal to that of the cathode electrode plate, the extension amount of the cathode electrode plate-the extension amount of the anode electrode plate = a, and the cathode electrode plate with the width of a is in a cathode electrode extension structure; an electronic conduction blocking layer is arranged between one side of the bare cell where the positive electrode lug is located and the outer packaging structure; or/and an electronic conduction blocking layer is arranged between one side of the negative pole lug of the naked battery cell and the outer packaging structure. The battery core with the structure is simple in manufacturing process, and the prepared battery has excellent electrochemical performance, higher packaging reliability, smaller self-discharge rate and better anti-drop performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
an electrochemical cell comprising a bare cell, an electrolyte, and an outer packaging structure, the bare cell comprising a positive electrode, a separator, and a negative electrode; the positive electrode consists of a positive electrode tab and a positive electrode piece; the negative electrode consists of a negative electrode tab and a negative electrode piece; the positive electrode tab and the negative electrode tab are led out from different sides of the electrochemical cell; in the electrochemical cell, one side of the positive electrode tab is led out, the extension (overlap) of the negative electrode plate is less than or equal to that of the isolating membrane, the extension of the isolating membrane is less than or equal to that of the positive electrode plate, the extension of the positive electrode plate-the extension of the negative electrode plate = c, and the positive electrode plate with the width of c is a positive electrode extension structure end; or/and in the electrochemical cell, one side of the cathode tab is led out, the extension amount of the anode electrode plate is less than or equal to that of the isolating film, the extension amount of the isolating film is less than or equal to that of the cathode electrode plate, the extension amount of the cathode electrode plate-the extension amount of the anode electrode plate = a, and the cathode electrode plate with the width of a is a cathode electrode extension structure end; an electronic conduction blocking layer is arranged between one side of the bare cell where the positive electrode lug is located and the outer packaging structure; or/and an electronic conduction blocking layer is arranged between one side of the negative pole lug of the naked battery cell and the outer packaging structure. The battery core with the structure is simple in manufacturing process, and the prepared battery has excellent electrochemical performance, higher packaging reliability, smaller self-discharge rate and better anti-drop performance.
As an improvement of the electrochemical cell, the edge of the negative electrode is subjected to anti-burr short-circuit treatment on one side of the electrochemical cell, on which the positive electrode tab is led out, and the treatment width d1 is less than or equal to 4mm; or/and the edge of the positive electrode is subjected to burr-proof short-circuit treatment on the side, led out of the negative electrode lug, of the electrochemical cell, and the treated width d2 is less than or equal to 4mm. Because burrs are easily generated on the split edges of the electrodes, the self-discharge rate of the battery is high, and even the safety problem occurs, so that the battery has better performance after the burr short circuit prevention treatment is carried out; meanwhile, the burr prevention treatment may reduce the gram capacity of the electrode active material, increase the thickness of the electrode and influence the energy density of the battery, so that the width is not suitable to be too wide (less than or equal to 4 mm).
As an improvement of the electrochemical cell of the present invention, the burr short-circuit prevention treatment includes at least one of ceramic layer coating, glue layer coating, roll pressing and high-pressure ablation treatment; the thickness h of the ceramic layer or the adhesive layer is less than or equal to 4 mu m.
The improved positive electrode of the electrochemical cell comprises a positive current collector and a positive coating, the negative electrode comprises a negative current collector and a negative coating, and the protrusion amount of the positive coating is less than or equal to that of the negative coating in the whole electrochemical cell; the naked electric core is in a winding structure or/and a lamination structure; the outer packaging structure is selected from one of an aluminum plastic film, a stainless steel film, an aluminum shell, a stainless steel shell and a plastic shell.
The anode tab comprises two parts, namely an anode current collector slitting tab and an anode conducting strip tab, the anode current collector slitting tab and the anode conducting strip tab are welded together or/and are bonded together through conducting glue, and the anode current collector slitting tab is electronically conducted to the outside of the outer package through the anode conducting strip tab; the negative pole utmost point ear includes that the negative pole mass flow body cuts utmost point ear and two parts of negative pole conducting strip utmost point ear, the negative pole mass flow body cut utmost point ear with the welding of negative pole conducting strip utmost point ear is in the same place or/and through the bonding of conductive adhesive together, and the negative pole mass flow body cuts utmost point ear and passes through negative pole conducting strip utmost point ear electron switches on extremely outside the extranal packing.
As an improvement of the electrochemical cell of the present invention, the electron conduction barrier layer is located between the exterior packaging structure and the positive electrode protruding structure end or/and the negative electrode protruding structure end or located inside the exterior packaging structure; the thickness h1 of the electronic conduction barrier layer is less than or equal to 0.5mm; in the bare cell, on one side of the positive electrode lug, the thickness of the central area of the bare cell-the thickness of the area without the negative electrode = h2; on one side of the negative electrode lug, the thickness of the central area of the bare cell-the thickness of the area without the positive electrode = h3; and h1 is less than or equal to h2, and h1 is less than or equal to h3, sets up electron barrier layer promptly after, naked electric core is in the thickness that has set up electron barrier layer region still be less than or equal to naked electric core central area thickness, consequently sets up the thickness that electron barrier layer can not additionally increase the battery to can not reduce the energy density of battery, and electron conduction barrier layer comprises insulating polymer.
As an improvement of the electrochemical cell, the electron conduction barrier layer arranged on the side, extending out, of the positive electrode lug is tightly wrapped on the surface of the end, extending out of the positive electrode, of the extending structure to play a role in tightly shaping the extending out structure of the positive electrode, and the wrapping length L1 is less than or equal to c; the electronic conduction blocking layer arranged on the side, extending out, of the negative electrode lug is tightly wrapped on the surface of the end, extending out of the negative electrode, of the negative electrode to play a role in tightly shaping the extending out structure of the negative electrode, and the wrapping length L2 is less than or equal to a; the electron conduction barrier layer is of a porous structure, the aperture is smaller than or equal to 1cm, and the distance between the adjacent edges of two adjacent holes is smaller than or equal to 1cm; the aperture is too large, the contact area of the barrier layer and the electrode extending structure is reduced, the surface pressure applied to the contact part is increased, and the electrode structure is easy to damage; the distance between the edges of the two holes is too large, so that the electrolyte diffusion path is increased, and the electrolyte infiltration speed is slowed down.
The invention also comprises a preparation method of the electrochemical cell, which mainly comprises the following steps:
step 1, preparing an electrode slice: preparing electrode slurry, coating the electrode slurry on a current collector to form a coating area and a hollow foil area, and then primarily cutting to obtain an electrode slice with the width of the hollow foil area being 1-50 mm;
step 2, assembling a naked battery cell: assembling the electrode slice obtained in the step (1) with an isolation film and a counter electrode to obtain a bare cell, wherein the extension amount of the hollow foil is larger than that of the isolation film, and the extension amount of the isolation film is larger than that of the counter electrode;
step 3, forming the lug: cutting the empty foil material extending out of the bare cell obtained in the step (2) to obtain a current collector cut tab, wherein the extension amount of the current collector in a non-tab area after cutting is larger than or equal to that of an isolation film, and the extension amount of the isolation film is larger than that of a counter electrode; then cutting the current collector into tabs and bonding the tabs with the conductive sheets;
step 4, preparing a finished electrochemical cell: and (4) respectively arranging electronic insulation structures on two electrode lug sides of the bare cell which is manufactured in the step (3) and subjected to electrode lug forming, and then putting the bare cell into a shell/bag, drying, injecting liquid, forming and shaping to obtain the finished electrochemical cell.
As an improvement of the preparation method of the electrochemical cell of the invention, the coating in the step 1 is at least one of transverse separation longitudinal continuous coating, transverse continuous longitudinal separation and transverse separation longitudinal separation coating; the separation area forms the empty foil area; the width of the empty foil area obtained after the initial slitting is 2 mm-10 mm.
As an improvement of the preparation method of the electrochemical cell, the coating in the step 1 is continuous coating, the forming mode of the hollow foil area comprises at least one of solvent cleaning (after continuous coating, a solvent is used for removing a coating layer part to obtain a gap area meeting the specification requirement), laser cleaning (after continuous coating, a laser ablation technology is used for removing the coating layer part to obtain the gap area meeting the specification requirement), auxiliary layer stripping (namely, an auxiliary layer is preset in the coating gap area, and after continuous coating, the auxiliary layer and a current collector are separated by adopting a special means to achieve the purpose of removing the redundant coating to obtain the gap area); 3, the method for distinguishing and cutting the hollow foils stretched out from the bare cell is mechanical cutting or laser cutting (because the bare cell is formed, the hollow foils needing to be cut are overlapped together, the thickness is larger, the cutting difficulty is larger, and the effect of cutting by using laser is better, namely, the cutting is more orderly and the cutting burrs are less); and 4, the electronic insulation structure contains holes, and the tabs penetrate through the holes.
Compared with the prior art, the flexible device and the preparation method thereof have the following advantages:
1. the battery cell structure is prepared without cutting the lug before electrode assembly, so that the manufacturing cost corresponding to punching and winding alignment of the lug is greatly reduced, and the dual purposes of reducing the process and reducing the battery cell cost are achieved;
2. the burr-proof short-circuit treatment is added on the edge of the electrode, so that the influence of the cut burr edge of the electrode on the self-discharge and safety performance of the battery can be effectively solved, and the battery core with small self-discharge and high safety performance is obtained;
3. an electronic conduction blocking layer is arranged between the anode electrode extending structure or/and the cathode electrode extending structure and the outer packaging structure, so that the sharp part of the electrode extending structure can be effectively blocked from externally packaging materials, the extending structure is prevented from damaging the externally packaging materials, and the packaging reliability and the anti-falling performance of the battery are prevented from being influenced;
h2 is not less than 4.h1, h3 is not less than 1, promptly sets up the electron barrier layer back, and naked electric core is still being less than or equal to naked electric core central zone thickness at the thickness that has set up electron barrier layer region, consequently sets up the thickness that electron barrier layer can not additionally increase the battery to reduce the energy density of battery.
Drawings
Fig. 1 is a schematic top view of an electrochemical cell of the present invention.
Fig. 2 is a schematic cross-sectional view of the main body of an electrochemical cell according to the present invention.
FIG. 3 is a schematic cross-sectional view of an electrochemical cell body of the present invention (including a burr short-circuit prevention treatment layer and an electron transfer barrier layer).
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.
Comparative example
Preparing an electrode plate: uniformly stirring lithium cobaltate serving as a positive electrode active substance, PVDF (polyvinylidene fluoride) serving as a bonding agent and NMP (N-methyl pyrrolidone) serving as a conductive agent, coating to obtain a coil material forming a coating area and an empty foil area along the coating direction, cold-pressing and splitting, and cutting tabs to obtain a positive plate to be wound; and uniformly stirring graphite serving as a negative electrode active substance, SBR and CMC serving as adhesives, super-P serving as a conductive agent and water serving as a solvent, coating to obtain a coil material forming a coating area and a hollow foil area along the coating direction, cold-pressing and slitting, and cutting tabs to obtain the negative electrode sheet to be wound.
And winding the positive plate to be wound, the negative plate to be wound and the isolating film together to obtain a bare cell with positive and negative electrode lugs extending out from the same side, and then performing rotary welding, top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain a finished product cell.
Example 1
FIG. 1 is a schematic top view of one construction of an electrochemical cell of the present invention: the negative electrode tab 01 and the positive electrode tab 02 are distributed on two opposite sides of the cell main body 03, that is, the positive electrode tab 02 and the negative electrode tab 01 are not led out from the same side of the cell main body 03. Fig. 2 is a schematic cross-sectional view of an electrochemical cell body according to the present invention, which can be seen from the figure, in which a negative electrode sheet 11 is obtained by coating a negative electrode coating on a negative electrode current collector 10, a positive electrode sheet 14 is obtained by coating a positive electrode coating on a positive electrode current collector 13, and a separator 12 is located between the negative electrode sheet 10 and the positive electrode sheet 14; the left side of the schematic diagram is provided with a negative plate extending structure 11a and a separation film extending structure 12a, and the extending amounts of the negative electrode extending structure 11a and the separation film structure 12a on the side are equal and are both larger than the extending amount of the positive electrode; on the right side of the schematic diagram, the positive plate extending structure 14a (which is a hollow foil, the length of the positive plate hollow foil area on the side is longer, and a tab and positive plate extending structure 14a can be formed by cutting) and the isolating film extending structure 12b, and the extending amounts of the positive plate extending structure 14a and the isolating film extending structure 12b on the side are equal to each other and are both greater than the extending amount of the negative electrode. Fig. 3 is still a schematic cross-sectional view of the electrochemical cell main body of the present invention (including the burr-proof short-circuit treatment layer and the electron conduction barrier layer), the left side in fig. 3 is the negative electrode extending structure end, the electron conduction barrier layer 20a is tightly wrapped on the surface, the wrapping length L2< a, and the burr-proof short-circuit treatment layer 21a is disposed on the surface of the negative electrode sheet corresponding to the edge of the positive electrode; in fig. 3, the right side is the positive electrode extending structure end, the electronic conduction barrier layer 20b is tightly wrapped on the surface, and the wrapping length L1< c; and a burr short-circuit prevention treatment layer 21b is provided at the edge of the positive electrode coating layer.
The difference between the specific preparation process of the battery cell and the comparative example is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by taking lithium cobaltate as a positive electrode active substance, PVDF as a bonding agent and Super-P as a conductive agent NMP as a solvent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area is 10mm after splitting), and coating a ceramic layer with the thickness of hc of 4 mu m and the width of d1 of 4mm at the head of a positive electrode coating layer as a burr short circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 50 mm), and a ceramic layer with the thickness ha of 4 mu m and the width d2 of 4mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding and is used as a burr short circuit prevention treatment layer, so that a negative electrode sheet to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 30 mu m, the aperture D is 0.5cm, and the hole spacing L is 0.5cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery core.
Assembling the battery: the same as in comparative example 1;
example 2
The difference from the embodiment 1 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring lithium cobaltate serving as a positive electrode active substance, PVDF (polyvinylidene fluoride) serving as a binder and a Super-P (N-methyl pyrrolidone) serving as a conductive agent NMP (N-methyl pyrrolidone) serving as a solvent, coating to obtain a coil material forming a coating area and an empty foil area along the coating direction, and then cold-pressing and slitting (the width of the empty foil area after slitting is 10 mm) to obtain a positive plate to be wound; and (2) uniformly stirring graphite serving as a negative electrode active substance, SBR and CMC serving as adhesives, super-P serving as a conductive agent and water serving as a solvent, coating to obtain a coil material forming a coating area and an empty foil area along the coating direction, and then cold-pressing and slitting (the width of the empty foil area after slitting is 50 mm) to obtain the negative electrode sheet to be wound.
Assembling a naked battery cell: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: and performing rotary welding, top sealing, drying, liquid injection, standing, formation, shaping and degassing on two tabs of the bare cell subjected to tab forming to obtain a finished product cell.
The rest is the same as the embodiment 1, and the description is omitted.
Example 3
The method is different from the embodiment 1 in that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by using lithium cobaltate as a positive electrode active substance, PVDF as a binder and NMP (N-methyl pyrrolidone) as a conductive agent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area after splitting is 2 mm), and coating a ceramic layer with the thickness of hc of 1 mu m and the width of d1 of 2mm at the head of a positive electrode coating layer as a burr short-circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 1 mu m and the width d2 of 2mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding to serve as a burr short circuit prevention treatment layer, so that a negative electrode piece to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 30 mu m, the aperture D is 0.5cm, and the hole spacing L is 0.5cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery core.
The rest is the same as embodiment 1, and the description is omitted.
Example 4
The difference from the embodiment 1 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by taking lithium cobaltate as a positive electrode active substance, PVDF as a bonding agent and Super-P as a conductive agent NMP as a solvent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area is 2mm after splitting), and coating a ceramic layer with the thickness of hc of 1 mu m and the width of d 1mm at the head of a positive electrode coating layer as a burr short circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 1 mu m and the width d2 of 1mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding and is used as a burr short circuit prevention treatment layer, so that a negative electrode sheet to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the bare cell to obtain a current collector cutting lug, and cutting the current collector cutting lug at the extending end of the negative electrode, wherein the extending amount of the isolating film is more than 0.5mm larger than that of the positive electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the following steps of performing rotary welding on two tabs of a bare cell after tab forming, then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 30 mu m, the aperture D is 0.5cm, and the hole distance L is 0.5cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery core.
The rest is the same as the embodiment 1, and the description is omitted.
Example 5
The difference from the embodiment 1 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by taking lithium cobaltate as a positive electrode active substance, PVDF as a bonding agent and Super-P as a conductive agent NMP as a solvent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area is 2mm after splitting), and coating a ceramic layer with the thickness hc of 0.2 mu m and the width d1 of 2mm at the head of a positive electrode coating layer as a burr short circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 0.2 mu m and the width d2 of 2mm is coated on the surface of a negative electrode corresponding to the slitting edge of a wound positive electrode to serve as a burr-proof short circuit treatment layer, so that a negative electrode piece to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 30 mu m, the aperture D is 0.5cm, and the hole spacing L is 0.5cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery cell.
The rest is the same as the embodiment 1, and the description is omitted.
Example 6
The difference from the embodiment 3 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by using lithium cobaltate as a positive electrode active substance, PVDF as a binder and NMP (N-methyl pyrrolidone) as a conductive agent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area after splitting is 2 mm), and coating a ceramic layer with the thickness of hc of 1 mu m and the width of d1 of 2mm at the head of a positive electrode coating layer as a burr short-circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 1 mu m and the width d2 of 2mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding to serve as a burr short circuit prevention treatment layer, so that a negative electrode piece to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 500 mu m, the aperture D is 1cm, and the hole spacing L is 1cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery cell.
The rest is the same as embodiment 3 and is not described again.
Example 7
The difference from the embodiment 3 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by using lithium cobaltate as a positive electrode active substance, PVDF as a binder and NMP (N-methyl pyrrolidone) as a conductive agent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area after splitting is 2 mm), and coating a ceramic layer with the thickness of hc of 1 mu m and the width of d1 of 2mm at the head of a positive electrode coating layer as a burr short-circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 1 mu m and the width d2 of 2mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding to serve as a burr short circuit prevention treatment layer, so that a negative electrode piece to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 100 mu m, the aperture D is 0.1cm, and the hole spacing L is 0.1cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery core.
The rest is the same as embodiment 3, and the description is omitted.
Example 8
The difference from the embodiment 3 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by taking lithium cobaltate as a positive electrode active substance, PVDF as a bonding agent and Super-P as a conductive agent NMP as a solvent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area is 2mm after splitting), and coating a ceramic layer with the thickness of hc of 1 mu m and the width of d1 of 2mm at the head of a positive electrode coating layer as a burr short circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 1 mu m and the width d2 of 2mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding to serve as a burr short circuit prevention treatment layer, so that a negative electrode piece to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the bare cell to obtain a current collector cutting lug, and cutting the current collector cutting lug at the extending end of the negative electrode, wherein the extending amount of the isolating film is more than 0.5mm larger than that of the positive electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 10 mu m, the aperture D is 0.1cm, and the hole spacing L is 0.1cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery core.
The rest is the same as embodiment 3 and is not described again.
Example 9
The difference from the embodiment 3 is that the method comprises the following steps:
preparing an electrode plate: uniformly stirring and coating by using lithium cobaltate as a positive electrode active substance, PVDF as a binder and NMP (N-methyl pyrrolidone) as a conductive agent to obtain a coil material forming a coating area and a hollow foil area along the coating direction, then cold-pressing and splitting (the width of the hollow foil area after splitting is 2 mm), and coating a ceramic layer with the thickness of hc of 1 mu m and the width of d1 of 2mm at the head of a positive electrode coating layer as a burr short-circuit prevention treatment layer to obtain a positive plate to be wound; graphite is used as a negative electrode active substance, SBR and CMC are used as adhesives, super-P is used as a conductive agent, water is used as a solvent, the materials are uniformly stirred and coated to obtain a coil material which forms a coating area and a hollow foil area along the coating direction, then cold pressing is carried out to strip the coil material (the width of the hollow foil area after the strip is divided is 5 mm), and a ceramic layer with the thickness ha of 1 mu m and the width d2 of 2mm is coated on the surface of a negative electrode corresponding to the cut edge of a positive electrode after winding to serve as a burr short circuit prevention treatment layer, so that a negative electrode piece to be wound is obtained.
Assembling naked battery cells: winding the positive plate to be wound, the negative plate and the isolating membrane to obtain a bare cell, leading out electrode tabs from two opposite ends of the bare cell at the moment, wherein the extension amounts of the positive and negative electrode hollow foils are both greater than the extension amount of the isolating membrane, and the extension amount of the isolating membrane is greater than the extension amount of the positive electrode by more than 0.5mm at the extension end of the negative electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode;
and (3) forming the tab: cutting the hollow foil material extending out of the naked electric core to obtain a current collector cut tab, and cutting the current collector cut tab, wherein the extension amount of the isolating film is more than 0.5mm larger than that of the anode electrode at the extension end of the cathode electrode; at the extending end of the positive electrode tab, the extending amount of the isolating film is more than 0.5mm larger than that of the negative electrode.
Preparing a finished electrochemical cell: the method comprises the steps of performing rotary welding on two tabs of a bare cell after tab forming, and then respectively arranging PET green glue with porous structures at an extending end of a positive electrode and an extending section of a negative electrode, wherein L1 is not less than c, L2 is not less than a, the thickness h1 of the green glue used is 30 mu m, the aperture D is 0.1cm, and the hole spacing L is 4cm; and then carrying out top sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain the finished product battery core.
The rest is the same as embodiment 3 and is not described again.
And (3) battery cell multiplying power performance test: carrying out multiplying power test on the battery cell in an environment of 35 ℃, wherein the process is as follows: standing for 3min; charging to 4.2V at constant current of 0.5C and charging to 0.05C at constant voltage; standing for 3min; constant current discharge is carried out at 0.2C until the voltage reaches 3.0V, and the first discharge capacity D0 is obtained. Standing for 3min; charging to 4.2V at constant current of 0.5C and charging to 0.05C at constant voltage; standing for 3min; and discharging the mixture to 3.0V at constant current of 2C to obtain the first discharge capacity D1. Rate performance Rate = D1/D0, and the obtained results are shown in table 1.
Safety test (drop test): from each of comparative examples and examples 1 to 9, 10 cells were taken out and subjected to a drop test: fixing the battery in a drop test fixture by using a double faced adhesive tape, 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 mode, and circulating for 10 times to finish the drop test. And observing whether the appearance is damaged or not, and recording data.
Self-discharge test: from each of comparative examples and examples 1 to 9, 30 cells were taken out and subjected to a self-discharge test: charging to 3.8V with 0.5C in 35 ℃ environment, and CV to 0.05C; then taking out the battery core, standing for 48h in an environment at 45 ℃, wherein the test voltage is V1, standing for 72h at room temperature, and then the test voltage is V2, and then the self-discharge rate of the battery is = (V1-V2)/72 (mV/h)
The process difficulty is as follows: the difficulty when only setting up the electronic insulation layer, when the adhesive tape thickness is great, the hardness is higher, is not convenient for operate.
TABLE 1 electric property table of the batteries of comparative example and example
From table 1, it can be seen from comparison between comparative examples and examples 1 to 9 that the battery cell prepared by using the present invention has higher rate capability, higher volumetric energy density, lower self-discharge rate and better drop resistance.
From examples 1 to 5, it can be seen that when the thickness of the burr-proof short-circuit layer is too large, the thickness of the battery increases, which affects the energy density of the battery, but when the thickness is too small, the short-circuit-proof effect cannot be obtained.
From the embodiments 6 to 9, when the thickness of the electronic insulation layer is too small, the insulation layer is very easy to pierce in the dropping process of the battery so as to pierce the external package, thereby affecting the dropping performance test of the battery, and when the thickness of the electronic insulation layer is too large, the hardness is large, so that the process operation is inconvenient; when the hole spacing is too large, the electrolyte infiltration effect is influenced, the gram capacity of the battery electrode material is reduced, and the energy density of the battery is influenced.
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 modifications, substitutions or alterations based on the present invention will fall 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 cell comprising a bare cell, an electrolyte, and an outer packaging structure, the bare cell comprising a positive electrode, a separator, and a negative electrode; the positive electrode consists of a positive electrode tab and a positive electrode piece; the negative electrode consists of a negative electrode tab and a negative electrode piece; the method is characterized in that:
the positive electrode tab and the negative electrode tab are led out from different sides of the electrochemical cell;
in the electrochemical cell, one side of the anode tab is led out, the extension (overlap) of the cathode electrode plate is less than or equal to that of the isolating film, the extension (overlap) of the isolating film is less than or equal to that of the anode electrode plate, the extension (overlap) of the anode electrode plate-the extension (overlap) of the cathode electrode plate is = c, and the anode electrode plate with the width of c is an extension structure end of the anode electrode;
or/and in the electrochemical cell, one side of the cathode tab is led out, the extension amount of the anode electrode plate is less than or equal to that of the isolating film, the extension amount of the isolating film is less than or equal to that of the cathode electrode plate, the extension amount of the cathode electrode plate-the extension amount of the anode electrode plate = a, and the cathode electrode plate with the width of a is an extension structure end of the cathode electrode; .
An electronic conduction blocking layer is arranged between one side of the bare cell where the positive electrode lug is located and the outer packaging structure; or/and an electronic conduction blocking layer is arranged between one side of the negative pole lug of the naked battery cell and the outer packaging structure.
2. The electrochemical cell as claimed in claim 1, wherein, on the side of the electrochemical cell from which the positive electrode tab is led out, the edge of the negative electrode or/and the edge of the coating area of the positive electrode are subjected to a burr-preventing short-circuiting treatment, and the treated width d1 is less than or equal to 4mm; or/and the edge of the positive electrode or/and the edge of the surface of the negative electrode corresponding to the edge of the positive electrode on the side of the electrochemical cell, from which the negative electrode tab is led out, is subjected to anti-burr short circuit treatment, and the treated width d2 is less than or equal to 4mm.
3. An electrochemical cell according to claim 2, wherein the anti-bur shorting treatment comprises at least one of ceramic layer coating, bondline coating, roll pressing, and high pressure ablation treatment; the thickness h of the ceramic layer or the adhesive layer is less than or equal to 4 mu m.
4. The electrochemical cell of claim 1, wherein the positive electrode comprises a positive current collector and a positive coating, the negative electrode comprises a negative current collector and a negative coating, and the protrusion of the positive coating is less than or equal to the protrusion of the negative coating in the whole electrochemical cell; the naked electric core is in a winding structure or/and a lamination structure; the outer packaging structure is selected from one of an aluminum plastic film, a stainless steel film, an aluminum shell, a stainless steel shell and a plastic shell.
5. The electrochemical cell of claim 1, wherein the positive electrode tab comprises two parts, namely a positive electrode current collector slitting tab and a positive electrode conductive tab, the positive electrode current collector slitting tab is welded with the positive electrode conductive tab or/and is bonded together through a conductive adhesive, and the positive electrode current collector slitting tab is electronically conducted to the outside of the outer package through the positive electrode conductive tab; the negative pole utmost point ear includes that the negative pole mass flow body cuts utmost point ear and two parts of negative pole conducting strip utmost point ear, the negative pole mass flow body cut utmost point ear with the welding of negative pole conducting strip utmost point ear is in the same place or/and through the bonding of conductive adhesive together, and the negative pole mass flow body cuts utmost point ear and passes through negative pole conducting strip utmost point ear electron switches on extremely outside the extranal packing.
6. An electrochemical cell according to claim 1, wherein the electron conducting barrier layer is located between the overwrap structure and the positive electrode protruding structure end or/and the negative electrode protruding structure end or on the inner side of the overwrap structure; the thickness h1 of the electron-conducting barrier layer is less than or equal to 0.5mm, and the electron-conducting barrier layer is composed of an insulating polymer.
7. The electrochemical cell as claimed in claim 1, wherein the electron conduction barrier layer disposed on the side of the positive electrode tab extending out is tightly wrapped on the surface of the end of the extending structure of the positive electrode, and the wrapping length L1 is not less than c; the electronic conduction blocking layer arranged on the side, extending out, of the negative electrode lug is tightly wrapped on the surface of the end, extending out, of the negative electrode, and the wrapping length L2 is not more than a; the electron conduction barrier layer is of a porous structure, the aperture is smaller than or equal to 1cm, and the distance between the adjacent edges of two adjacent holes is smaller than or equal to 1cm.
8. A method of making an electrochemical cell according to claim 1, comprising the steps of:
step 1, preparing an electrode slice: preparing electrode slurry, coating the electrode slurry on a current collector to form a coating area and a hollow foil area, and then primarily cutting to obtain an electrode slice with the width of the hollow foil area being 1-50 mm;
step 2, assembling a naked battery cell: assembling the electrode slice obtained in the step (1) with an isolating membrane and a counter electrode to obtain a bare cell, wherein the extension amount of a hollow foil area is larger than that of the isolating membrane, and the extension amount of the isolating membrane is larger than that of the counter electrode;
step 3, forming the lug: cutting the empty foil material extending out of the bare cell obtained in the step (2) to obtain a current collector cut tab, wherein the extension amount of the current collector in a non-tab area after cutting is larger than or equal to that of an isolation film, and the extension amount of the isolation film is larger than that of a counter electrode; then cutting the current collector into tabs and bonding the tabs with the conductive sheets;
step 4, preparing a finished electrochemical cell: and (4) respectively arranging electronic insulation structures on two electrode lug sides of the bare cell which is manufactured in the step (3) and subjected to electrode lug forming, and then putting the bare cell into a shell/bag, drying, injecting liquid, forming and shaping to obtain the finished electrochemical cell.
9. A method for preparing an electrochemical cell according to claim 8, wherein the coating of step 1 is at least one of a laterally separated longitudinally continuous coating, a laterally continuous longitudinally separated coating, and a laterally separated longitudinally separated coating; the separation area forms the empty foil area; the width of the empty foil area obtained after the initial slitting is 2 mm-10 mm.
10. A method for preparing an electrochemical cell according to claim 8, wherein the coating in step 1 is a continuous coating, and the formation of the empty foil region comprises at least one of solvent cleaning, laser cleaning, and auxiliary layer peeling; 3, the method for distinguishing and cutting the hollow foil extending out of the naked electric core is mechanical cutting or laser cutting; and 4, the electronic insulation structure contains holes, and the tabs penetrate through the holes.
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| CN109065818A (en) * | 2018-06-28 | 2018-12-21 | 合肥国轩高科动力能源有限公司 | Low-short-circuit-rate lithium ion power battery pole piece and preparation method thereof |
| CN113661398A (en) * | 2018-11-29 | 2021-11-16 | 株式会社Lg新能源 | Cell performance measuring method |
| CN113661398B (en) * | 2018-11-29 | 2024-06-07 | 株式会社Lg新能源 | Method for measuring performance of cell and method for measuring performance of secondary battery |
| CN110635162A (en) * | 2019-09-23 | 2019-12-31 | 深圳市泽塔电源系统有限公司 | Electrochemical energy storage device and method of manufacture |
| WO2021195851A1 (en) * | 2020-03-30 | 2021-10-07 | 宁德新能源科技有限公司 | Pole piece, electrode assembly using same, battery, and power utilization device |
| CN113644389A (en) * | 2020-04-27 | 2021-11-12 | 北京小米移动软件有限公司 | Battery module and manufacturing method thereof |
| CN113644389B (en) * | 2020-04-27 | 2023-05-16 | 北京小米移动软件有限公司 | Battery module and manufacturing method thereof |
| CN112670436A (en) * | 2020-12-17 | 2021-04-16 | 惠州市豪鹏科技有限公司 | Preparation method of battery pole piece |
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| CN105261781B (en) | 2018-11-16 |
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