Kev tsim thiab tsim cov roj teeb lithium ion yog txheej txheem sib txuas los ntawm ib kauj ruam thev naus laus zis. Raws li tag nrho, kev tsim cov roj teeb lithium suav nrog cov txheej txheem tsim hluav taws xob, cov txheej txheem roj teeb sib dhos thiab cov kua dej zaum kawg, precharge, tsim thiab kev laus. Hauv peb theem ntawm cov txheej txheem no, txhua tus txheej txheem tuaj yeem muab faib ua ob peb txheej txheem tseem ceeb, txhua kauj ruam yuav muaj kev cuam tshuam zoo rau kev ua haujlwm kawg ntawm lub roj teeb.

In the process stage, it can be subdivided into five processes: paste preparation, paste coating, roller pressing, cutting and drying. In the battery assembly process, and according to the different battery specifications and models, roughly divided into winding, shell, welding and other processes. In the final stage of liquid injection, including liquid injection, exhaust, sealing, prefilling, formation, aging and other processes. The electrode manufacturing process is the core content of the whole lithium battery manufacturing, which is related to the electrochemical performance of the battery, and the quality of slurry is particularly important.

Ib, lub hauv paus kev xav ntawm 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.

Cov kua dej uas tsis yog-newtonian yog hais txog cov kua dej uas tsis txaus siab rau Newton txoj kev sim txoj cai ntawm viscosity, uas yog, kev sib raug zoo ntawm shear stress thiab shear strain rate tsis yog linear. Non-newtonian kua yog dav pom nyob rau hauv lub neej, ntau lawm thiab xwm. Polymers concentrated solutions thiab suspensions ntawm polymers feem ntau tsis yog-Newtonian kua. Cov kua roj ntsha feem ntau tam sim no txhais tau tias tsis yog-Newtonian kua. Cov kua dej uas tsis yog-newtonian suav nrog cov ntshav, cov qog ntshav, thiab cov kua dej cystic, nrog rau “cov kua nruab nrab” xws li cytoplasm.

Electrode slurry yog tsim los ntawm ntau yam khoom siv raw nrog qhov sib txawv ntawm lub ntiajteb txawj nqus thiab particle loj, thiab yog tov thiab dispersed nyob rau hauv cov khoom-kua theem. Cov slurry tsim yog cov kua uas tsis yog-Newtonian. Lithium roj teeb slurry tuaj yeem muab faib ua qhov zoo slurry thiab tsis zoo slurry ob yam, vim slurry system (roj, dej) sib txawv, nws qhov xwm txheej yuav txawv. Txawm li cas los xij, cov kev ntsuas hauv qab no tuaj yeem siv los txiav txim siab cov khoom ntawm slurry:

1. Viscosity ntawm slurry

Viscosity yog ib qho kev ntsuas ntawm cov kua viscosity thiab ib qho kev qhia ntawm cov kua zog ntawm nws qhov tshwm sim hauv kev sib txhuam. Thaum cov kua ntws tawm, nws tsim kev sib txhuam sab hauv ntawm nws cov molecules, uas yog hu ua viscosity ntawm cov kua. Viscosity yog qhia los ntawm viscosity, uas yog siv los ua tus yam ntxwv ntawm cov khoom tiv thaiv muaj feem xyuam rau cov khoom ua kua. Viscosity muab faib ua dynamic viscosity thiab conditional viscosity.

Viscosity txhais tau tias yog Ib khub ntawm daim phiaj sib luag, thaj tsam A, Dr Sib nrug, ntim nrog A kua. Tam sim no siv lub thrust F mus rau lub phaj sab sauv los tsim kev hloov ceev DU. Vim hais tias cov viscosity ntawm cov kua hloov no quab yuam txheej los ntawm txheej, txhua txheej ntawm cov kua kuj txav raws li, tsim ib tug tshaj tawm gradient du / Dr, hu ua shear rate, sawv cev los ntawm R ‘. F / A yog hu ua shear stress, qhia raws li τ. Kev sib raug zoo ntawm shear rate thiab shear stress yog raws li nram no:

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

Newtonian kua conforms rau Newton lub mis, viscosity tsuas yog hais txog qhov kub thiab txias, tsis shear tus nqi, τ yog proportional rau D.

Cov kua dej uas tsis yog-newtonian tsis ua raws li Newton tus qauv τ/D = f(D). Lub viscosity ntawm qhov muab τ / D yog ηa, uas yog hu ua pom meej viscosity. Lub viscosity ntawm cov kua uas tsis yog-Newtonian nyob ntawm qhov kub thiab txias, tab sis kuj nyob ntawm tus nqi shear, lub sij hawm, thiab shear thinning los yog shear thickening.

2. Slurry khoom

Slurry yog cov kua uas tsis yog-Newtonian, uas yog cov khoom sib xyaw ua kua. Yuav kom ua tau raws li qhov yuav tsum tau ua ntawm txheej txheej txheej tom ntej, slurry yuav tsum muaj peb yam nram qab no:

① Cov khoom lag luam zoo. Fluidity tuaj yeem pom los ntawm agitating lub slurry thiab cia nws ntws ib txwm. Zoo continuity, nruam tawm thiab tawm txhais tau hais tias zoo liquidity. Fluidity muaj feem xyuam rau cov ntsiab lus thiab viscosity ntawm slurry,

(2) leveling. Lub smoothness ntawm slurry cuam tshuam lub flatness thiab evenness ntawm txheej.

③ Rheology. Rheology hais txog cov yam ntxwv deformation ntawm slurry hauv ntws, thiab nws cov khoom cuam tshuam rau qhov zoo ntawm cov ntawv ncej.

3. Slurry dispersion foundation

Lithium ion roj teeb electrode manufacturing, cathode muab tshuaj txhuam los ntawm cov nplaum, tus neeg sawv cev, cov khoom siv cathode; Cov tshuaj tsis zoo yog tsim los ntawm cov nplaum, graphite hmoov thiab lwm yam. Kev npaj ntawm qhov zoo thiab qhov tsis zoo slurry suav nrog cov txheej txheem thev naus laus zis, xws li kev sib xyaw, kev sib cais thiab kev sib cais ntawm cov kua thiab kua, kua thiab cov khoom siv, thiab nrog rau kev hloov pauv ntawm qhov kub thiab txias, viscosity thiab ib puag ncig hauv cov txheej txheem no. Cov txheej txheem sib xyaw thiab dispersion ntawm lithium ion roj teeb slurry tuaj yeem muab faib ua cov txheej txheem sib xyaw macro thiab cov txheej txheem micro dispersion, uas yog ib txwm nrog rau tag nrho cov txheej txheem ntawm lithium ion roj teeb slurry npaj. Kev npaj ntawm slurry feem ntau mus dhau cov theem hauv qab no:

① Qhuav hmoov sib tov. Particles sib cuag ib leeg nyob rau hauv daim ntawv ntawm dots, dots, dav hlau, thiab kab,

② Semi-qhuav av nkos theem. Nyob rau theem no, tom qab cov hmoov qhuav sib tov sib xyaw, cov kua nplaum los yog cov kuab tshuaj ntxiv, thiab cov khoom siv raw yog ntub thiab av nkos. Tom qab lub zog stirring ntawm lub tov khoom, cov khoom yuav raug rau shear thiab kev sib txhuam ntawm txhua yam quab yuam, thiab yuav muaj kev sib txhuam sab hauv ntawm cov khoom. Nyob rau hauv txhua qhov quab yuam, cov khoom siv raw khoom feem ntau yuav tawg heev. Cov theem no muaj qhov cuam tshuam tseem ceeb ntawm qhov loj thiab viscosity ntawm cov slurry tiav.

③ Dilution thiab dispersion theem. Tom qab kneading, hnyav tau ntxiv maj mam los kho slurry viscosity thiab cov ntsiab lus khoom. Nyob rau theem no, dispersion thiab agglomeration coexist, thiab thaum kawg mus txog stability. Nyob rau theem no, cov khoom tawg yog feem ntau cuam tshuam los ntawm kev siv dag zog, kev sib txhuam ntawm cov hmoov thiab kua, kev kub ceev dispersion shear quab yuam, thiab cuam tshuam kev cuam tshuam ntawm slurry thiab ntim phab ntsa.

Daim duab

Analysis of parameters affecting slurry properties

Nws yog ib qho tseem ceeb Performance index los xyuas kom meej qhov sib xws ntawm lub roj teeb nyob rau hauv cov txheej txheem ntawm cov roj teeb ntau lawm uas lub slurry yuav tsum muaj zoo stability. Nrog rau qhov kawg ntawm kev sib xyaw slurry, sib tov nres, slurry yuav tshwm sim kev sib haum xeeb, flocculation thiab lwm yam tshwm sim, ua rau cov khoom loj, uas yuav muaj kev cuam tshuam ntau dua rau cov txheej txheem tom ntej thiab lwm yam txheej txheem. Lub ntsiab tsis zoo ntawm slurry stability yog fluidity, viscosity, khoom cov ntsiab lus thiab ceev.

1. Viscosity ntawm slurry

Qhov ruaj khov thiab tsim nyog viscosity ntawm electrode paste yog qhov tseem ceeb heev rau txheej txheej txheej ntawm cov ntawv electrode. Lub viscosity siab dhau los yog qis dhau yog tsis tsim nyog rau polar piece txheej, slurry nrog siab viscosity tsis yooj yim rau precipitate thiab dispersion yuav zoo dua, tab sis lub siab viscosity tsis conducive rau leveling nyhuv, yog tsis conducive rau txheej; Viscosity tsawg dhau tsis zoo, viscosity tsawg, txawm hais tias cov slurry ntws zoo, tab sis nws nyuaj rau qhuav, txo qhov ziab kom zoo ntawm txheej, txheej txheej tawg, slurry particle agglomeration, deg ntom ntom tsis zoo.

Qhov teeb meem uas feem ntau tshwm sim hauv peb cov txheej txheem tsim khoom yog qhov hloov pauv ntawm viscosity, thiab “hloov” ntawm no tuaj yeem muab faib ua kev hloov tam sim thiab hloov zoo li qub. Kev hloov pauv hloov pauv yog hais txog qhov hloov pauv loj hauv cov txheej txheem ntsuas viscosity, thiab qhov hloov pauv zoo li qub yog hais txog kev hloov pauv viscosity tom qab lub sijhawm. Lub viscosity txawv ntawm siab mus rau qis, los ntawm siab mus rau qis. Feem ntau hais lus, cov ntsiab lus tseem ceeb cuam tshuam rau slurry viscosity yog qhov ceev ntawm kev sib xyaw slurry, lub sijhawm tswj, cov khoom sib xyaw kom haum, ib puag ncig kub thiab av noo, thiab lwm yam. Muaj ntau yam, thaum peb ntsib viscosity hloov yuav tsum tau soj ntsuam thiab daws nws li cas? Lub viscosity ntawm slurry yog qhov tseem ceeb txiav txim siab los ntawm cov ntawv khi. Xav txog tias yam tsis muaj PVDF / CMC / SBR (Daim duab 2, 3), lossis yog tias lub binder tsis muab cov khoom muaj sia nyob zoo, puas yuav muaj cov khoom muaj sia nyob thiab cov khoom siv hluav taws xob tsim cov kua dej uas tsis yog-Newtonian nrog txheej txheej? Tsis txhob! Yog li ntawd, txhawm rau txheeb xyuas thiab daws qhov laj thawj ntawm kev hloov pauv ntawm slurry viscosity, peb yuav tsum pib los ntawm qhov xwm txheej ntawm kev sib khi thiab slurry dispersion degree.

Daim duab

FIG. 2. Molecular qauv ntawm PVDF

Daim duab

Daim duab 3. Molecular mis ntawm CMC

(1) viscosity nce

Cov tshuab slurry sib txawv muaj cov cai hloov viscosity sib txawv. Tam sim no, lub ntsiab slurry system yog zoo slurry PVDF / NMP oily system, thiab tsis zoo slurry yog graphite / CMC / SBR aqueous system.

① Lub viscosity ntawm qhov zoo slurry nce tom qab lub sijhawm. Ib qho laj thawj (ntev lub sijhawm tso kawm) yog tias cov slurry sib tov nrawm nrawm dhau, cov ntawv nplaum tsis tau yaj tag, thiab PVDF hmoov yog tag nrho yaj tom qab lub sijhawm, thiab cov viscosity nce. Feem ntau hais lus, PVDF xav tau tsawg kawg 3 teev kom yaj tag nrho, txawm tias qhov nrawm nrawm npaum li cas tsis tuaj yeem hloov pauv qhov cuam tshuam no, qhov hu ua “kev nrawm ua rau pov tseg”. Qhov thib ob yog vim li cas (ntev ntev) yog tias nyob rau hauv cov txheej txheem ntawm slurry sawv, lub colloid hloov los ntawm lub xeev sol mus rau lub xeev gel. Lub sijhawm no, yog tias nws yog homogenized ntawm qeeb qeeb, nws cov viscosity tuaj yeem rov qab los. Qhov thib peb yog vim li cas yog cov qauv tshwj xeeb yog tsim ntawm colloid thiab cov khoom muaj sia thiab cov khoom siv hluav taws xob. Lub xeev no yog irreversible, thiab lub slurry viscosity yuav rov qab tsis tau tom qab nce.

Lub viscosity ntawm qhov tsis zoo slurry nce. Lub viscosity ntawm qhov tsis zoo slurry feem ntau yog tshwm sim los ntawm kev puas tsuaj ntawm cov qauv molecular ntawm cov ntaub ntawv, thiab cov viscosity ntawm slurry yog nce tom qab oxidation ntawm molecular saw tawg. Yog hais tias cov khoom yog dispersed ntau heev, lub particle loj yuav txo tau heev, thiab lub viscosity ntawm slurry kuj yuav nce.

(2) viscosity txo

① Lub viscosity ntawm zoo slurry txo. Ib qho ntawm cov laj thawj, cov nplaum colloid hloov pauv hauv tus cwj pwm. Muaj ntau qhov laj thawj rau qhov kev hloov pauv, xws li lub zog shear quab yuam thaum lub sij hawm hloov slurry, kev hloov zoo ntawm cov dej nqus los ntawm cov ntaub ntawv, cov qauv kev hloov pauv thiab degradation ntawm nws tus kheej hauv cov txheej txheem ntawm kev sib tov. Qhov thib ob yog vim li cas yog qhov tsis sib xws stirring thiab dispersion ua rau thaj tsam loj ntawm cov khoom siv hauv slurry. Qhov thib peb yog vim li cas nyob rau hauv cov txheej txheem ntawm nplawm, cov nplaum yog raug rau lub zog shear quab yuam thiab kev sib txhuam ntawm cov khoom siv thiab cov khoom siv nyob, thiab kev hloov ntawm cov khoom ntawm qhov kub thiab txias, ua rau txo qis viscosity.

Lub viscosity ntawm qhov tsis zoo slurry txo. Ib qho laj thawj yog tias muaj cov impurities sib xyaw hauv CMC. Feem ntau ntawm impurities hauv CMC yog insoluble polymer resin. Thaum CMC miscible nrog calcium thiab magnesium, nws viscosity yuav raug txo. Qhov laj thawj thib ob yog sodium hydroxymethyl cellulose, uas feem ntau yog kev sib xyaw ntawm C / O. Lub zog daim ntawv cog lus tsis muaj zog heev thiab yooj yim puas los ntawm shear quab yuam. Thaum lub stirring ceev ceev dhau los yog lub sij hawm stirring ntev dhau lawm, tus qauv ntawm CMC tej zaum yuav puas. CMC plays lub luag hauj lwm thickening thiab stabilizing nyob rau hauv qhov tsis zoo slurry, thiab plays lub luag hauj lwm tseem ceeb nyob rau hauv dispersion ntawm raw cov ntaub ntawv. Thaum nws cov qauv raug rhuav tshem, nws yuav ua rau muaj kev cuam tshuam slurry thiab txo viscosity. Qhov thib peb yog vim li cas yog kev puas tsuaj ntawm SBR binder. Hauv kev tsim khoom tiag tiag, CMC thiab SBR feem ntau raug xaiv los ua haujlwm ua ke, thiab lawv lub luag haujlwm txawv. SBR feem ntau plays lub luag hauj lwm ntawm binder, tab sis nws yog nquag mus demulsification nyob rau hauv lub sij hawm ntev stirring, ua rau cov nyiaj tsis ua hauj lwm thiab viscosity txo ntawm slurry.

(3) Cov xwm txheej tshwj xeeb (zoo li jelly-zoo li lub sijhawm siab thiab qis)

Nyob rau hauv tus txheej txheem ntawm kev npaj zoo muab tshuaj txhuam, cov muab tshuaj txhuam tej zaum hloov mus rau hauv jelly. Muaj ob lub laj thawj tseem ceeb rau qhov no: thawj, dej. Xav txog tias kev nqus dej noo ntawm cov khoom muaj sia thiab kev tswj cov dej noo hauv cov txheej txheem sib tov tsis zoo, cov dej noo nqus ntawm cov khoom siv raw lossis cov av noo ntawm qhov sib tov yog siab, ua rau cov dej nqus dej los ntawm PVDF rau hauv jelly. Qhov thib ob, tus nqi pH ntawm slurry lossis khoom siv. Qhov siab dua tus nqi pH, kev tswj cov dej noo yog nruj dua, tshwj xeeb tshaj yog kev sib xyaw ntawm cov khoom siv nickel siab xws li NCA thiab NCM811.

Lub viscosity ntawm slurry fluctuates, ib qho ntawm cov laj thawj yuav yog tias cov slurry tsis ruaj khov nyob rau hauv cov txheej txheem kuaj, thiab cov viscosity ntawm slurry yog heev cuam tshuam los ntawm kub. Tshwj xeeb tshaj yog tom qab dispersed ntawm kev kub ceev, muaj ib tug tej yam kub gradient nyob rau hauv lub internal kub ntawm slurry, thiab lub viscosity ntawm txawv qauv tsis zoo ib yam. Qhov thib ob yog vim li cas dispersion tsis zoo ntawm slurry, cov khoom nyob, cov ntaub ntawv, cov neeg sawv cev tsis zoo dispersion, slurry tsis zoo fluidity, ntuj slurry viscosity siab los yog tsawg.

2. Qhov loj ntawm slurry

Tom qab cov slurry tau ua ke, nws yog ib qho tsim nyog los ntsuas nws qhov loj me, thiab txoj kev ntsuas particle loj feem ntau yog txoj kev scraper. Particle loj yog ib qho tseem ceeb parameter rau characterize lub slurry zoo. Particle loj muaj ib qho tseem ceeb ntawm cov txheej txheem txheej, dov txheej txheem thiab roj teeb ua haujlwm. Raws li txoj cai, qhov me me ntawm slurry loj yog, qhov zoo dua. Thaum cov particle loj dhau lawm, kev ruaj ntseg ntawm slurry yuav raug cuam tshuam, sedimentation, slurry sib xws tsis zoo. Nyob rau hauv cov txheej txheem ntawm extrusion txheej, yuav muaj cov khoom thaiv, ncej qhuav tom qab pitting, ua rau cov teeb meem zoo. Nyob rau hauv cov txheej txheem dov hauv qab no, vim qhov tsis sib xws ntawm kev ntxhov siab nyob rau hauv qhov chaw tsis zoo, nws yog ib qho yooj yim uas yuav ua rau cov ncej tawg thiab cov micro-cracks hauv zos, uas yuav ua rau muaj kev puas tsuaj loj rau kev caij tsheb kauj vab, piv txwv kev ua haujlwm thiab kev nyab xeeb ntawm lub roj teeb.

Cov khoom muaj txiaj ntsig zoo thiab tsis zoo, cov nplaum nplaum, cov khoom siv hluav taws xob thiab lwm cov ntaub ntawv tseem ceeb muaj qhov sib txawv ntawm qhov ntau thiab tsawg. Nyob rau hauv tus txheej txheem ntawm stirring, yuav muaj kev sib tov, extrusion, kev sib txhuam, agglomeration thiab lwm yam kev sib cuag hom. Nyob rau hauv cov theem ntawm raw cov ntaub ntawv yog maj sib tov, wetted los ntawm hnyav, loj cov khoom tawg thiab maj tending mus rau stability, yuav muaj ib tug uneven khoom sib tov, tsis zoo adhesion dissolution, loj agglomeration ntawm nplua particles, hloov nyob rau hauv cov khoom nplaum thiab lwm yam kev mob. coj mus rau tiam ntawm cov khoom loj.

Thaum peb nkag siab tias dab tsi ua rau cov khoom tshwm sim, peb yuav tsum daws cov teeb meem no nrog cov tshuaj tsim nyog. Raws li rau cov hmoov qhuav sib xyaw ntawm cov ntaub ntawv, kuv tus kheej xav tias qhov sib tov ceev muaj me ntsis cuam tshuam rau qib ntawm cov hmoov qhuav sib xyaw, tab sis lawv xav tau sijhawm txaus los xyuas kom meej qhov sib xws ntawm cov hmoov qhuav sib xyaw. Tam sim no qee cov tuam ntxhab xaiv cov nplaum nplaum thiab qee qhov xaiv cov kua nplaum zoo, ob lub nplaum sib txawv txiav txim siab cov txheej txheem sib txawv, kev siv cov nplaum nplaum yuav tsum tau siv sij hawm ntev dua kom yaj, txwv tsis pub nyob rau hauv lig yuav tshwm o, rebound, viscosity hloov, thiab lwm yam. agglomeration ntawm nplua particles yog inevitable, tab sis peb yuav tsum xyuas kom meej tias muaj txaus kev sib txhuam ntawm cov ntaub ntawv los pab kom cov agglomeration hais kom tshwm extrusion, crushing, conducive rau nws. Qhov no xav kom peb tswj cov ntsiab lus ntawm cov txheej txheem sib txawv ntawm slurry, cov ntsiab lus tsis tshua muaj zog yuav cuam tshuam rau kev sib txhuam dispersion ntawm cov khoom.

3. Cov ntsiab lus ntawm slurry

The solid content of slurry is closely related to the stability of slurry, the same process and formula, the higher the solid content of slurry, the greater the viscosity, and vice versa. In a certain range, the higher the viscosity, the higher the stability of slurry. When we design the battery, we generally deduce the thickness of the core-core from the capacity of the battery to the design of the electrode sheet, so the design of the electrode sheet is only related to the surface density, live matter density, thickness and other parameters. The parameters of electrode sheet are adjusted by coater and roller press, and the solid content of slurry has no direct influence on it. So, does the level of solid content of slurry matter little?

(1) Cov ntsiab lus ntawm cov khoom muaj qee yam cuam tshuam rau kev txhim kho qhov sib xyaw ua haujlwm thiab txheej txheej ua haujlwm. Qhov siab dua cov ntsiab lus ntawm cov khoom, lub sijhawm luv dua lub sijhawm nplawm, kev siv cov kuab tshuaj tsawg dua, cov txheej txheem ziab kom qhuav ntau dua, txuag lub sijhawm.

(2) Cov ntsiab lus khoom muaj qee yam yuav tsum tau ua rau cov khoom siv. Slurry nrog cov ntsiab lus siab muaj qhov poob siab dua rau cov khoom siv, vim tias qhov siab dua cov ntsiab lus, cov khoom siv hnyav dua.

(3) Lub slurry nrog cov ntsiab lus siab ruaj khov dua. Cov txiaj ntsig kev ntsuas kev ruaj ntseg ntawm qee qhov slurry (raws li qhia hauv daim duab hauv qab no) qhia tias TSI (instability Performance index) ntawm 1.05 hauv cov lus sib xyaw yog siab dua li ntawm 0.75 hauv high-viscosity stirring txheej txheem, yog li cov slurry stability tau los ntawm high-viscosity. stirring txheej txheem yog zoo dua li uas tau los ntawm pa stirring txheej txheem. Tab sis cov slurry nrog cov ntsiab lus siab tseem yuav cuam tshuam rau nws cov fluidity, uas yog qhov nyuaj heev rau cov khoom siv thiab cov kws tshaj lij ntawm txheej txheej txheej.

Daim duab

(4) Lub slurry nrog cov ntsiab lus siab tuaj yeem txo qhov tuab ntawm cov txheej txheej thiab txo cov roj teeb sab hauv.

4. Pulp ntom

Qhov ntom ntawm qhov loj me yog qhov tseem ceeb parameter kom pom qhov sib xws ntawm qhov loj me. Cov nyhuv dispersion ntawm qhov loj tuaj yeem txheeb xyuas los ntawm kev ntsuas qhov ntom ntawm qhov loj ntawm ntau txoj haujlwm. Hauv qhov no yuav tsis rov ua dua, dhau los ntawm cov ntsiab lus saum toj no, kuv ntseeg tias peb npaj cov tshuaj electrode zoo.