Kugadzirwa uye kugadzirwa kwe lithium ion bhatiri inzira yakanyatsobatanidzwa nedanho rimwe retekinoroji. Pakazara, kugadzirwa kwe lithium bhatiri kunosanganisira iyo electrode kugadzira maitiro, bhatiri kusangana maitiro uye yekupedzisira jekiseni remvura, precharge, kuumbwa uye kuchembera maitiro. Mumatanho matatu aya ekuita, imwe neimwe nzira inogona kukamurwa kuita akati wandei maitiro akakosha, nhanho imwe neimwe ichava nemhedzisiro yakakura pakuita kwekupedzisira kwebhatiri.

Muchikamu chekugadzirisa, inogona kupatsanurwa kuita maitiro mashanu: kugadzirira paste, paste coating, roller pressing, kucheka nekuomesa. Mukugadzirisa kwebhatiri, uye zvinoenderana neyakasiyana bhatiri zvirevo uye modhi, zvakakamurwa kuita mhepo, shell, welding uye mamwe maitiro. Muchikamu chekupedzisira chejekiseni remvura, kusanganisira jekiseni remvura, kupera, kuisa chisimbiso, prefilling, kuumbwa, kuchembera uye mamwe maitiro. Iyo electrode yekugadzira maitiro ndiyo yepakati yemukati mese yelithium bhatiri yekugadzira, iyo ine hukama ne electrochemical performance yebhatiri, uye kunaka kwe slurry kunonyanya kukosha.

One, the basic theory of slurry

Lithium ion battery electrode slurry is a kind of fluid, usually can be divided into Newtonian fluid and non-Newtonian fluid. Among them, non-Newtonian fluid can be divided into dilatancy plastic fluid, time dependent non-Newtonian fluid, pseudoplastic fluid and bingham plastic fluid. Newtonian fluid is a low viscosity fluid which is easy to deform under stress and the shear stress is proportional to the deformation rate. Fluid in which the shear stress at any point is a linear function of the rate of shear deformation. Many fluids in nature are Newtonian fluids. Most pure liquids such as water and alcohol, light oil, low molecular compound solutions and low-velocity flowing gases are Newtonian fluids.

Non-newtonian fluid inoreva mvura isingagutse mutemo waNewton wekuedza we viscosity, kureva kuti, hukama huri pakati peshear stress uye shear strain rate haina mutsara. Non-newtonian fluids inowanikwa zvakanyanya muhupenyu, kugadzira uye zvisikwa. Mapolymer akadzika mhinduro uye kumiswa kwemapolymers kazhinji asiri eNewtonian zvinwiwa. Mvura zhinji yebhayoloji yava kutsanangurwa semvura isiri yeNewtonian. Non-newtonian fluids inosanganisira ropa, lymph, uye cystic fluids, pamwe ne “semi-fluids” yakadai se cytoplasm.

Electrode slurry is composed of a variety of raw materials with different specific gravity and particle size, and is mixed and dispersed in solid-liquid phase. The slurry formed is a non-Newtonian fluid. Lithium battery slurry can be divided into positive slurry and negative slurry two kinds, due to the slurry system (oily, water) different, its nature will vary. However, the following parameters can be used to determine the properties of slurry:

1. Viscosity ye slurry

Viscosity chiyero chemvura inonamira uye ratidziro yesimba remvura pane mukati mayo friction phenomenon. Kana mvura ichiyerera, inoburitsa kukweshana kwemukati pakati pemamorekuru ayo anonzi viscosity yemvura. Viscosity inoratidzwa ne viscosity, iyo inoshandiswa kuratidza iyo inopikisa chinhu chine chekuita nemidziyo yemvura. Viscosity yakakamurwa kuita dynamic viscosity uye conditional viscosity.

Viscosity inotsanangurwa seA pair of parallel plates, area A, Dr Apart, izere neA liquid. Ikozvino shandisa yekusundira F kune yekumusoro ndiro kuburitsa vheji shanduko DU. Nekuti viscosity yemvura inotamisa iyi simba layer ne layer, imwe neimwe yemvura inofambawo zvinoenderana, ichigadzira velocity gradient du/ Dr, inonzi shear rate, inomiririrwa neR ‘. F/A inonzi shear stress, inotaridzwa se τ. Hukama huri pakati peshear rate uye shear stress ndohunotevera:

(F/A) = eta (du/Dr)

Newtonian fluid inopindirana neformula yaNewton, viscosity inongoenderana netembiricha, kwete shear rate, τ inoenzana neD.

Zvinwiwa zvisiri-newtonian hazvienderane neformula yaNewton τ/D=f(D). Iyo viscosity pane yakapihwa τ/D i ηa, inodaidzwa kuti apparent viscosity. Iko viscosity yezvisiri zveNewtonian zvinwiwa zvinoenderana kwete chete netembiricha, asiwo pachiyero chekugera, nguva, uye kutetepa kwekucheka kana kukora kwekucheka.

2. Slurry properties

Slurry isiri yeNewtonian fluid, inova musanganiswa wakasimba-mumvura. Kuti isangane nezvinodiwa zveinotevera coating process, slurry inofanirwa kuve neanotevera maitiro matatu:

① Kuva nemari yakanaka. Fluidity inogona kucherechedzwa nekuzunguza slurry uye kuibvumira kuyerera nemasikirwo. Kuenderera mberi kwakanaka, kuenderera mberi nekudzima zvinoreva kushaya mari. Fluidity ine hukama kune yakasimba yemukati uye viscosity ye slurry,

(2) kuenzana. Kutsetseka kwe slurry kunokanganisa flatness uye kuenzana kwejasi.

③ Rheology. Rheology inoreva deformation hunhu hwe slurry mukuyerera, uye zvimiro zvayo zvinokanganisa kunaka kwepole sheet.

3. Slurry dispersion hwaro

Lithium ion bhatiri electrode kugadzira, cathode paste nekunamira, conductive agent, cathode zvinhu kuumbwa; Iyo isina kunaka paste inoumbwa neadhesive, graphite poda uye zvichingodaro. Kugadzirira kwakanaka uye kwakashata slurry kunosanganisira akatevedzana tekinoroji maitiro, sekusanganisa, kunyungudika uye kuparadzira pakati pemvura uye mvura, mvura uye yakasimba zvinhu, uye inoperekedzwa nekuchinja kwekushisa, viscosity uye zvakatipoteredza mune iyi nzira. Iko kusanganisa uye kuparadzira maitiro e lithium ion bhatiri slurry inogona kukamurwa kuita macro kusanganisa maitiro uye micro dispersion process, iyo inogara ichiperekedzwa neyese maitiro e lithium ion bhatiri slurry kugadzirira. Kugadzirira kweslurry kunowanzopfuura nematanho anotevera:

① Dry poda kusanganisa. Zvimedu zvinosangana muchimiro chemavara, madotsi, ndege, uye mitsetse,

② Semi-yakaoma dope rekukanya. Panguva ino, mushure mekunge hupfu hwakaoma hwasanganiswa zvakaenzana, iyo binder liquid kana solvent inowedzerwa, uye iyo mbishi inonyorova uye ine madhaka. Mushure mekusimudzira kwakasimba kwemusanganisi, zvinhu zvinoiswa pasi pekuveura uye kupesana kwesimba remagetsi, uye pachava nekukakavadzana kwemukati pakati pezvimedu. Pasi pesimba rimwe nerimwe, zvimedu zvezvinhu zvakasvibiswa zvinowanzopararira zvakanyanya. Iyi nhanho ine mhedzisiro yakakosha pahukuru uye viscosity yekupedzwa slurry.

③ Dilution and dispersion stage. After kneading, solvent was added slowly to adjust slurry viscosity and solid content. At this stage, dispersion and agglomeration coexist, and finally reach stability. At this stage, the dispersion of materials is mainly affected by mechanical force, frictional resistance between powder and liquid, high-speed dispersion shear force, and the impact interaction between slurry and container wall.

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Kuongororwa kwezvimiro zvinokanganisa slurry properties

Iyo yakakosha index kuti ive nechokwadi chekuenderana kwebhatiri munzira yekugadzirwa kwebhatiri iyo slurry inofanirwa kuve nekugadzikana kwakanaka. Nekupera kweiyo yakasanganiswa slurry, kusanganisa kunomira, slurry ichaonekwa kugadzirisa, flocculation uye zvimwe zviitiko, zvichikonzera zvidimbu zvakakura, izvo zvichave nemhedzisiro yakakura pakuputira kunotevera uye mamwe maitiro. Iwo makuru ma paramita eku slurry kugadzikana ndeye fluidity, viscosity, yakasimba yemukati uye density.

1. Viscosity ye slurry

Iyo yakagadzikana uye yakakodzera viscosity ye electrode paste inonyanya kukosha kune iyo yekupfekedza maitiro e electrode sheet. Iyo viscosity yakanyanya kukwirira kana yakaderera haina kukonzeresa polar piece coating, iyo slurry ine yakakwira viscosity haisi nyore kudonha uye kupararira kuchava nani, asi iyo yakakwira viscosity haina kukonzeresa kuenzana mhedzisiro, haina kukonzeresa kupfeka; Viscosity yakaderera zvakanyanya haina kunaka, viscosity yakaderera, kunyangwe iyo slurry kuyerera yakanaka, asi yakaoma kuomeswa, kuderedza kuomeswa kweiyo coating, kuputika kwekuvhara, slurry particle agglomeration, surface density consistency haina kunaka.

Dambudziko rinowanzoitika mukugadzirwa kwedu ndiko kushanduka kwe viscosity, uye “shanduko” pano inogona kukamurwa kuita shanduko yekukurumidza uye static shanduko. Shanduko yenguva pfupi inoreva shanduko yakanyanyisa muyedzo ye viscosity, uye shanduko yakamira inoreva shanduko ye viscosity mushure menguva yenguva. Viscosity inosiyana kubva kumusoro kusvika pasi, kubva kumusoro kusvika pasi. Kazhinji kutaura, zvinhu zvikuru zvinokanganisa slurry viscosity ndiko kukurumidza kwekuvhenganisa slurry, nguva yekudzora, zvisungo kurongeka, tembiricha yezvakatipoteredza uye unyoro, etc. Pane zvinhu zvakawanda, patinosangana nekuchinja kwe viscosity kunofanira kuva sei kuongorora uye kugadzirisa? Iyo viscosity ye slurry inonyanya kutsanangurwa nebhainda. Fungidzira kuti pasina binder PVDF/CMC/SBR (FIG. 2, 3), kana kuti binder ikasabatanidza chinhu mhenyu zvakanaka, iyo yakasimba mhenyu chinhu uye conductive agent inogadzira mvura isiri yeNewtonian ine yunifomu yekupfeka? Usadaro! Naizvozvo, kuongorora nekugadzirisa chikonzero chekushanduka kwe slurry viscosity, isu tinofanirwa kutanga kubva pahunhu hwebhainda uye slurry dispersion degree.

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FIG. 2. Molecular chimiro chePVDF

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Mufananidzo 3. Molecular formula yeCMC

(1) viscosity inowedzera

Different slurry systems vane zvakasiyana viscosity shanduko mitemo. Parizvino, iyo mainstream slurry system yakanaka slurry PVDF/NMP mafuta system, uye yakaipa slurry igraphite /CMC/SBR aqueous system.

① Iyo viscosity yezvakanaka slurry inowedzera mushure menguva yenguva. Chimwe chikonzero (kuiswa kwenguva pfupi) ndechokuti slurry kusanganisa kukurumidza kukurumidza, binder haina kunyungudutswa zvakakwana, uye PVDF powder inonyungudutswa zvakakwana mushure mechinguva, uye viscosity inowedzera. Kazhinji kutaura, PVDF inoda kanenge maawa matatu kuti inyunguduke zvizere, zvisinei nekuti kukurumidza sei kumhanyisa hakugone kushandura chinhu ichi chinofurira, iyo inonzi “kukurumidza kunoparadza”. Chikonzero chechipiri (nguva refu) ndechekuti mukuita kwe slurry kumira, iyo colloid inoshanduka kubva kune sol state kuenda kune gel state. Panguva ino, kana iri homogenized painononoka kumhanya, viscosity yayo inogona kudzorerwa. Chikonzero chechitatu ndechekuti chimiro chakakosha chinoumbwa pakati pecolloid uye zvinhu zvinorarama uye conductive agent particles. Iyi mamiriro haachinjiki, uye slurry viscosity haigone kudzoreredzwa mushure mekuwedzera.

Iyo viscosity yeiyo yakaipa slurry inowedzera. Iyo viscosity yeasina kunaka slurry inonyanya kukonzerwa nekuparadzwa kweiyo molecular chimiro chebinder, uye viscosity ye slurry inowedzerwa mushure meiyo oxidation yeiyo molecular chain fracture. Kana izvo zvinyorwa zvakapararira zvakanyanya, saizi yechikamu ichaderedzwa zvakanyanya, uye viscosity ye slurry ichawedzerwawo.

(2) viscosity yakaderedzwa

① Iyo viscosity yezvakanaka slurry inodzikira. Chimwe chezvikonzero, adhesive colloid inochinja hunhu. Pane zvikonzero zvakawanda zvekuchinja, senge simba rakasimba rekugera panguva yekufambisa slurry, shanduko yemhando yekunyudzwa kwemvura nebinder, shanduko yemaitiro uye kudzikisira kwayo pachayo mukusanganiswa. Chikonzero chechipiri ndechekuti kusaenzana kubvongodza uye kupararira kunotungamirira kunzvimbo huru yekugara kwezvinhu zvakasimba mune slurry. Chikonzero chechitatu ndechekuti mukuita kubvongodza, chinonamira chinoiswa pasi pesimba rakasimba rekugera uye kukweshana kwemidziyo nezvinhu zvinorarama, uye shanduko yezvivakwa pakupisa kwakanyanya, zvichikonzera kuderera kwe viscosity.

Iyo viscosity yeiyo yakaipa slurry inoderera. Chimwe chezvikonzero ndechekuti kune tsvina yakasanganiswa muCMC. Mazhinji ehutsvina muCMC haana kunyungudika polymer resin. Kana CMC ichisanganiswa necalcium uye magnesium, viscosity yayo ichadzikiswa. Chikonzero chechipiri ndeye sodium hydroxymethyl cellulose, iyo inonyanya kusanganiswa kweC / O. Simba rezvisungo harina simba uye rinoparadzwa nyore nyore neshear force. Kana iyo yekumhanyisa ichimhanya zvakanyanya kana nguva yekukurudzira yakarebesa, chimiro cheCMC chinogona kuparadzwa. CMC inotora gobvu uye kudzikamisa basa mune yakashata slurry, uye inoita basa rakakosha mukuparadzirwa kwezvinhu mbishi. Kana chimiro chayo chaparadzwa, zvinozokonzeresa slurry kugadzirisa uye kuderedzwa kwe viscosity. Chikonzero chechitatu kuparadzwa kweSBR binder. Mukugadzirwa chaiko, CMC neSBR vanowanzo sarudzwa kuti vashande pamwe chete, uye mabasa avo akasiyana. SBR inonyanya kuita basa rebhainda, asi rinowanzoita demulsification pasi pekukurudzira kwenguva refu, zvichikonzera kukanganisa kwebhondi uye kuderedzwa kweviscosity ye slurry.

(3) Special circumstances (jelly-shaped timely high and low)

Mukugadzira paste yakanaka, paste dzimwe nguva inoshanduka kuita jelly. Pane zvikonzero zviviri zvikuru zveizvi: chekutanga, mvura. Tichifunga kuti kutorwa kwemwando kwezvinhu zvipenyu uye kutonga kwemwando mukusanganiswa hakuna kunaka, kutorwa kwemwando kwezvinhu zvakabikwa kana hunyoro hwenzvimbo yekusanganiswa kwakakwira, zvichikonzera kutorwa kwemvura nePVDF kuita jelly. Chechipiri, iyo pH kukosha kweslurry kana zvinhu. Iyo yakakwirira iyo pH kukosha ndeye, kutonga kwehunyoro kwakanyanyisa, kunyanya kusanganiswa kwepamusoro nickel zvinhu zvakaita seNCA neNCM811.

The viscosity of slurry fluctuates, one of the reasons may be that the slurry is not completely stabilized in the testing process, and the viscosity of slurry is greatly affected by temperature. Especially after being dispersed at high speed, there is a certain temperature gradient in the internal temperature of the slurry, and the viscosity of different samples is not the same. The second reason is poor dispersion of slurry, live material, binder, conductive agent is not good dispersion, slurry is not good fluidity, natural slurry viscosity is high or low.

2. Kukura kweslurry

Mushure mokunge slurry yasanganiswa, zvakakosha kuyera hukuru hwayo, uye nzira yekuenzanisa chiyero chechidimbu inowanzoita scraper nzira. Particle saizi yakakosha parameter kuratidza slurry mhando. Particle saizi ine yakakosha pesvedzero pakuita coating, rolling process uye bhatiri kuita. Nechepfungwa, iyo diki iyo saizi slurry, zviri nani. Kana iyo particle size yakakura kwazvo, kugadzikana kwe slurry kuchakanganiswa, sedimentation, slurry consistency haina kunaka. Mukuita extrusion coating, pachave nekuvharira zvinhu, danda rakaoma mushure megomba, zvichikonzera matambudziko emhando. Muchinotevera rolling process, nekuda kwekusaenzana kushushikana munzvimbo yakashata yekuputira, zviri nyore kukonzeresa kuputsika kwepole uye yemuno madiki-cracks, izvo zvinokonzeresa kukuvadza kukuru kukuita kwebhasikoro, chiyero chekuita uye kuchengetedza kuita kwebhatiri.

Zvakanaka uye zvisina kunaka zvinhu zvinoshanda, zvinonamira, conductive agents uye zvimwe zvinhu zvikuru zvine hukuru hwakasiyana hukuru uye densities. Mukuita kubvongodza, kuchave nekusanganisa, extrusion, friction, agglomeration uye mamwe maitiro akasiyana ekusangana. Mumatanho ezvigadzirwa zviri kusanganiswa zvishoma nezvishoma, zvakanyoroveswa nezvinonyungudutsa, zvinhu zvakakura zvichitsemuka uye zvishoma nezvishoma zvichidzikama, pachave nekusanganiswa kwezvinhu zvisina kuenzana, kuparara kwakashata kwekunamira, kusanganiswa kwakakomba kwezvidimbu zvakanaka, shanduko yeadhesive properties uye mamwe mamiriro. kutungamirira kuchizvarwa chezvikamu zvikuru.

Kana tangonzwisisa kuti chii chinoita kuti zvidimbu zvioneke, tinofanira kugadzirisa matambudziko aya nemishonga yakakodzera. Kana kuri kusanganiswa kwehupfu hwakaoma hwezvinhu, ini pachangu ndinofunga kuti musanganisi kumhanya ane simba shoma pachiyero chehupfu hwakaoma, asi vanoda nguva yakakwana kuti vave nechokwadi chekufanana kwekusanganiswa kwehupfu hwakaoma. Iye zvino vamwe vanogadzira vanosarudza powdery adhesive uye vamwe vanosarudza mvura mhinduro yakanaka yekunamira, maviri akasiyana anonamira anoona maitiro akasiyana, kushandiswa kweupfu hwekunamira kunoda nguva yakareba kuti inyunguduke, zvikasadaro mukunonoka kuchaonekwa kuzvimba, kudzokororwa, shanduko yeviscosity, nezvimwe. agglomeration pakati pezvimedu zvakanaka hazvidzivisiki, asi isu tinofanira kuona kuti pane kukweshana kwakakwana pakati pezvinhu kuti zvimedu zveagglomeration zvioneke extrusion, kupwanya, zvinogoneka kusanganisa. Izvi zvinoda kuti isu tidzore iyo yakasimba yemukati mumatanho akasiyana e slurry, yakanyanya kuderera yakasimba yemukati inozokanganisa friction dispersion pakati pezvimedu.

3. Solid content of slurry

Izvo zvakasimba zvemukati zve slurry zvine hukama zvakanyanya nekugadzikana kwe slurry, maitiro akafanana uye fomula, iyo yakakwirira yakasimba yemukati ye slurry, iyo yakakura viscosity, uye zvinopesana. Mune imwe nzvimbo, iyo yakakwirira viscosity, iyo yakakwirira kugadzikana kwe slurry. Kana isu tichigadzira bhatiri, isu tinowanzo tora ukobvu hwepakati-musimboti kubva pakusimba kwebhatiri kusvika kudhizaini yepepa re electrode, saka dhizaini yepepa re electrode inongoenderana nehusope hwepasi, mhenyu kusimba, ukobvu. uye mamwe ma parameters. Iyo parameter ye electrode sheet inogadziriswa necoater uye roller press, uye iyo yakasimba yemukati ye slurry haina simba rakananga pairi. Saka, iyo nhanho yezvakasimba zvemukati zve slurry zvine basa diki here?

(1) Solid yemukati ine imwe pesvedzero pakuvandudza kunyandura kunyatsoita uye kugona kwekupfeka. Iyo yakakwirira iyo yakasimba yemukati, iyo ipfupi nguva yekukurudzira, kushoma kushandiswa kwezvinonyungudutsa, kukwirisa kuomeswa kwekupotera, kuchengetedza nguva.

(2) Iyo yakasimba yemukati ine zvimwe zvinodiwa zvemidziyo. Slurry ine yakakwira yakasimba yemukati ine kurasikirwa kwepamusoro kumidziyo, nekuti iyo yakakwira iyo yakasimba yemukati, ndiyo yakanyanya kushata iyo michina inopfeka.

(3) Iyo slurry ine yakakwirira yakasimba yemukati yakagadzikana zvakanyanya. Mhedzisiro yekuedza mhedzisiro yeimwe slurry (sezvinoratidzwa mumufananidzo uri pazasi) inoratidza kuti TSI (instability index) ye1.05 mukukurudzira kwakajairika yakakwirira kupfuura iyo ye0.75 mune yakakwirira-viscosity inokurudzira maitiro, saka slurry kugadzikana kunowanikwa nepamusoro-viscosity. kubvongodza nzira iri nani pane iyo inowanikwa nenzira yakajairika. Asi iyo slurry ine yakakwira yakasimba yemukati inozokanganisa kuyerera kwayo, izvo zvinonetsa kune michina uye matekinoroji eiyo coating process.

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(4) Iyo slurry ine yakakwirira yakasimba yemukati inogona kuderedza ukobvu pakati pemachira uye kuderedza kupikisa kwemukati kwebhatiri.

4. Pulp density

Kuwanda kwehukuru ndiyo parameter yakakosha kuratidza kuenderana kwehukuru. Iyo yekuparadzira maitiro ehukuru inogona kusimbiswa nekuyedza density yehukuru munzvimbo dzakasiyana. Mune izvi hazvizodzokororwi, kuburikidza nepfupiso iri pamusoro, ndinotenda kuti tinogadzirira yakanaka electrode paste.