CN101859720A - Method for measuring surface contact resistivity of crystalline silicon solar battery - Google Patents

Abstract

The invention discloses a method for measuring the surface contact resistivity of a crystalline silicon solar battery. The method concretely comprises the following steps of: (1) manufacturing a crystalline silicon solar battery by using a common process, wherein screens with uniform models are used in the process; (2) taking out a strip structure from the obtained crystalline silicon solar battery along the main grid direction to be used as a battery testing sample, wherein the battery testing sample is provided with a plurality of grid lines; (3) sequentially arranging the grid lines at equal intervals in parallel to form a testing area, calculating the working current IO of a single grid line according to characteristic parameters obtained from a standard battery current and voltage test, setting a constant output current IO by adopting a current source table, and sequentially measuring the voltage Vn of the first grid line and other grid lines under the constant output current IO; and (4) calculating migration length LT and the resistance R's of a diffusion layer film under the grid lines according to the contact resistance rC and the tail contact resistance RO of the grid lines, and finally obtaining the surface contact resistivity Rho C of the crystalline silicon solar battery. In the invention, the battery manufactured by using the common process is used as the measuring sample without additionally manufacturing screens, therefore, the difficulty of the process for manufacturing the battery and the measuring cost are both reduced.

Description

A kind of method of measuring surface contact resistivity of crystalline silicon solar battery

Technical field

The present invention relates to the crystal silicon solar energy battery technical field of performance test, particularly a kind of method of measuring surface contact resistivity of crystalline silicon solar battery.

Background technology

The electrode optimization of solar cell is to improve battery performance, an important channel that reduces production costs, and the good and bad contact resistivity that important indicator is a solar cell of judge electrode performance, the size of contact resistivity is not only relevant with the figure of contact, also relevant with diffusion technology and contact formation technology, the ohmic contact quality of different grid line figures can reflect by the size of contact resistivity, therefore, by being calculated, the research of contact resistivity can reflect diffusion, the problem that exists in the technologies such as electrode making and sintering, and the optimal design of electrode pattern also needs the contact resistivity under earlier definite specific process conditions.

At present, the most frequently used surface contact resistivity of crystalline silicon solar battery method of measurement is Transmission line method (TLM) and Core Scan method, with respect to Core Scan method, Transmission line method is used more, the test process of this method is: the grid line of at first making different spacing at battery surface, measure the voltage of adjacent grid line under the constant current, measurements and calculations by other parameter, draw the battery surface contact resistivity according to the derivation of equation, but, the defective of this method of measurement is: crystal silicon solar energy battery generally adopts method for printing screen to make, owing to will make the grid line of unequal-interval at battery surface, just can not adopt the web plate of existing unified model, promptly have the web plate of equidistant grid line, therefore, need when adopting this method of measurement to make web plate separately, like this, not only increased the complexity of cell making process, and, make the overall measurement cost raise because the web plate manufacturing cost is higher.

And use Core Scan method need adopt special tester, when test, the probe of tester need penetrate the SiNx of solar cell surface, contact with the Si of inside battery and could realize measuring, therefore, the insertion that battery is subjected to probe in measuring process will inevitably form certain damage, in addition, the contact resistivity that this method of testing obtains is also not accurate enough, often can only compare than usefulness, and can not be as the actual value of battery surface contact resistivity; And tester is comparatively expensive, and its price generally is 200～3,000,000 RMB, and the probe of adding tester damages easily, and renewal cost is higher, makes that the battery testing cost is higher.

In addition, also have the method for measurement of some other less usefulness, as circular Transmission line method, this kind method exists the shortcoming that the battery testing sample has complex manufacturing technology too; In addition, also have two-point method, 3 contact methods and 4 contact methods etc., the resultant measurement result of these methods is all not accurate enough.

Summary of the invention

The object of the present invention is to provide a kind of simple, cost is low, measurement result is measured surface contact resistivity of crystalline silicon solar battery accurately method, with the battery that adopts common process to finish as specimen, reduce the technology difficulty that battery sample is made, also reduced the measurement cost simultaneously.

Purpose of the present invention realizes by following technical measures: a kind of method of measuring surface contact resistivity of crystalline silicon solar battery is characterized in that specifically may further comprise the steps:

(1) adopts the common process crystal silicon solar energy battery that completes, in this manufacture craft, use unified model web plate to form uniformly-spaced grid line at battery surface;

(2) battery that step (1) is obtained therefrom takes out a strip structure as the battery testing sample along the main grid direction, and the position of taking out this specimen on the battery is a hollow, and described battery testing sample surfaces has several grid lines;

(3) each grid line formation test zone of uniformly-spaced arranging side by side successively, the characterisitic parameter that is obtained by the test of battery standard current/voltage calculates the operating current I of wall scroll grid line _o, adopt the current source table to set the constant output electric current I _o, measure first grid line and all the other grid lines more successively in the constant output electric current I _oUnder voltage V _n

(4) each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5), calculate the grid line contact resistance r of described test zone according to curve fit straight line intercept A _C

(6) measure terminal contact resistance R _E, list respectively about grid line contact resistance r _CWith terminal contact resistance R _EEquation, calculate migration length L _TWith diffusion layer sheet resistance R ' under the grid line _S

(7) result of calculation that obtains according to step (6) calculates surface contact resistivity of crystalline silicon solar battery ρ at last _C

The present invention therefrom takes out a strip structure as the battery testing sample with the battery sheet that common process completes along the main grid direction, measure first grid line and the voltage of all the other grid lines under the constant output electric current on the battery testing sample again, to realize the measurement of voltage between the unequal interval grid line, make the present invention in the process of making battery, can use the web plate of existing unified model, and need not to make in addition web plate, reduce the technology difficulty that battery sample is made, also reduced the measurement cost simultaneously; The present invention obtains the grid line contact resistance in tested zone with the linear extrapolation method, and simple, intuitive in addition, is also measured terminal contact resistance, and the derivation by existing formula obtains contact resistivity, makes that the measurement result of contact resistivity is very accurate; And, because method of measurement equipment needed thereby of the present invention is more cheap, reduced the measurement cost; Operation is simple for method of measurement of the present invention, also considered current delivery effective mobility length in measuring process, and the measurement accuracy that improves contact resistivity has been played positive effect.

As one embodiment of the present invention, in step (1), the making step of described common process is: 1. use the p type single crystal silicon sheet, behind cleaning and the removal affected layer, put into NaOH solution and make surperficial matte light trapping structure; 2. in diffusion furnace, feed POCL ₃P-n junction is made in diffusion, obtains the diffusion layer square resistance; 3. remove phosphorosilicate glass, the p-n junction at plasma etching edge; 4. plasma chemical vapor deposition is made antireflective SiNx film; 5. adopt method for printing screen to form Metal Contact; 6. the back side adopts the Ag/Al slurry to print back electrode, and seal Al slurry forms back of the body electric field; 7. electrode before adopting slurry to make; 8. in highest temperature district temperature, carry out sintering, obtain crystal silicon solar energy battery.

The present invention ignores metallic resistance in described step (6), suppose that grid line length much larger than the grid line width, draws r _C=(L _T/ w) R ' _SCoth (d/L _T), wherein, w is a grid line length, d is the grid line width; Measure terminal contact resistance R _E, promptly on two adjacent grid lines, add constant current I _E, measure the voltage between time adjacent and adjacent grid line, obtain R _E, according to calculating formula:

Obtain migration length L _TWith diffusion layer sheet resistance R ' under the grid line _S

In step (6), migration length L _TBeing defined as along grid line Width voltage attenuation is the corresponding length in 1/e place of grid line edge voltage, draws calculating formula

The migration length L that draws according to described step (6) _TWith diffusion layer sheet resistance R ' under the grid line _S, obtain surface contact resistivity of crystalline silicon solar battery ρ _C

As a kind of preferred implementation of the present invention, in described step (2), described battery testing sample width is for being less than or equal to 5mm, and described battery testing sample surfaces has 8～12 grid lines.

The present invention is measuring terminal contact resistance R _EThe time, adding constant current I on two adjacent grid lines more than 3 groups at least _E, measure the voltage between time adjacent and adjacent grid line in every group of grid line.

Compared with prior art, the present invention has following significant effect:

(1) crystal silicon solar energy battery of the present invention adopts common manufacture craft when making, and the web plate of use is the web plate of unified model, and need not independent making, therefore can reduce technology difficulty, reduces simultaneously and measures cost.

(2) method of measurement equipment needed thereby of the present invention is more cheap, and method of measurement is simple, is convenient to implement.

(3) the present invention has considered current delivery effective mobility length in measuring process, also terminal contact resistance is measured, and has improved the accuracy of surface contact resistivity measurement result.

(4) unified model web plate of the present invention can only form uniformly-spaced grid line at battery surface, when measuring the voltage of each grid line under operating current, the method of measurement that the present invention adopts is the voltage of measuring successively between first grid line and all the other grid lines, can realize the effect of voltage measurement between the unequal interval grid line equally.

Description of drawings

The present invention is described in further detail below in conjunction with the drawings and specific embodiments.

Fig. 1 is the schematic diagram that each grid line is uniformly-spaced arranged side by side;

Fig. 2 is a principle schematic of measuring the voltage of each grid line under operating current;

Fig. 3 is that parameter indicates schematic diagram;

Fig. 4 is that electric current is assembled schematic diagram under the grid line;

Fig. 5 is terminal measuring contact resistance schematic diagram;

Fig. 6 is embodiment 1V _n-n curve chart;

Fig. 7 is embodiment 2V _n-n curve chart;

Fig. 8 is embodiment 3V _n-n curve chart;

Fig. 9 is embodiment 4V _n-n curve chart;

Figure 10 is embodiment 5V _n-n curve chart.

Embodiment

Embodiment 1

Shown in Fig. 1～5, a kind of method of measuring surface contact resistivity of crystalline silicon solar battery of the present invention, wherein, and Fig. 1～5th, the principle key diagram of the embodiment of the invention, this method specifically may further comprise the steps:

(1) adopt the common process crystal silicon solar energy battery 1 that completes, use unified model web plate to form uniformly-spaced grid line 2 at battery surface in this manufacture craft, Fig. 1 is a schematic diagram, schematically shows grid line 2 and is positioned on the silicon base 3;

Make the 1# test battery: use P type 12.5cm * 12.5cm monocrystalline silicon piece, resistivity 1.1～1.2 Ω cm ², behind cleaning and the removal affected layer, put into NaOH solution and make surperficial matte light trapping structure; In diffusion furnace, feed POCL ₃P-n junction is made in diffusion, obtains about diffusion layer square resistance 45 Ω/, removes phosphorosilicate glass, the p-n junction at plasma etching edge; Plasma chemical vapor deposition (being called for short PECVD) is made antireflective SiNx film, and the about 70nm of thickness forms Metal Contact with method for printing screen; Back electrode is printed with the Ag/Al slurry in the back side, and seal Al slurry forms back of the body electric field; Electrode before adopting slurry Du Pont PV159 to make, web plate used in manufacturing process is existing unified model web plate, be 325 orders, line footpath 23 μ m, thickness 30 μ m design thin grid width 90 μ m, grating spacing L=2.32mm, carry out sintering for 875 ℃ in highest temperature district temperature, obtain the 1# test battery.

(2) as shown in Figure 1, the 1# battery that step (1) is obtained therefrom takes out the strip structure 21 of a long 21mm, wide w=2mm as 1# battery testing sample along the main grid direction, the position of taking out this specimen on the 1# battery is a hollow, and the battery testing sample surfaces has 9 grid lines 2;

(3) each grid line 2 formation test zone of uniformly-spaced arranging side by side successively carries out standard I V (current/voltage) test to 1# battery testing sample, reads characterisitic parameter from IV (current/voltage) data of 1# battery testing sample, i.e. the maximum power point electric current I of battery _MP=5.2A obtains battery operated current density, J thus _MP=I _MP/ A _C=5.2A/148.6cm ²=35mA/cm ²(wherein, A _CBe 125 * 125 monocrystalline silicon piece areas), calculate the operating current I that flows through the wall scroll grid line _o=J _MP* L * w=35mA/cm ²* 2.32mm * 2mm=1.625mA.

Measure the grid line width with metallomicroscope, test result is as follows: the μ m of unit

??81.79

??93.23

??88.21

??87.48

??89.27

??94.39

??92.39

??99.7

??104.96

??93.29

(table 1)

Try to achieve grid line mean breadth d=92.47 μ m=0.09247mm.The concrete measuring process of above grid line width is not to measure each grid line width successively, because in battery manufacturing process, web plate grid line width is a certain value, when grid line is printed on the battery, the grid line width can great changes will take place, therefore when measuring the grid line width, selection wherein several grid lines measurements gets final product, and can guarantee that all the mean value of grid line width is in error range; In the present embodiment, the measured value of grid line width has 9, when measuring, employing to a certain grid line width measure repeatedly, the mode do not measured of some grid line width grid line width of only measuring once, having carries out, also the mean value that can guarantee the grid line width is in error range, so the method for measurement of grid line width can be used flexibly.

Adopt KEITHLEY 2400 current source tables to set the constant output electric current I _o=1.625mA.As shown in Figure 2, measure first grid line and all the other grid lines successively in the constant output electric current I _oUnder voltage V _n, then have:

(1) $V_n=I({2r}_C+\frac{{\mathrm{nLR}}_S}{w})$

Shown in Fig. 2,3, n is the grid line sequence number, and L is the distance between the two adjacent grid lines, and w is a grid line length, r _CBe the grid line contact resistance of test zone, R _SBe diffusion layer square resistance, LR _S/ w is the resistance between the two adjacent grid lines.

V _nMeasurement result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7	??8
									??V n	??94.23??mV	??183.67??mV	??0.27223??V	??0.35874??V	??0.44390??V	??0.52950??V	??0.61356??V	??0.70017??V

(table 2)

(4) as shown in Figure 6, each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5) obtain fitting a straight line intercept A=11.214mV, fitting a straight line slope B=86.286mV;

Contact resistance multiply by contact area and just can obtain contact resistivity in theory, but in fact the interface that contacts with substrate of grid line material is very complicated, and contact area is difficult to determine; In addition, the not all interface that joins is all to current flowing generation effect.The existence of emitter resistance and contact resistance makes contact portion voltage be exponential damping (V (x)=V ₀Exp (x/L _T)).As shown in Figure 4, electric current may only conduct by the part contact interface.For screen printing electrode, contact interface is very complicated, contact-making surface irregular, migration length L _TBeing defined as along grid line Width voltage attenuation is the corresponding length in 1/e place of grid line edge voltage, draws calculating formula:

(2) $L_T=\sqrt{{\mathrm{\ρ}}_C/{R^{\′}}_S}$

Wherein, R ' _SBe diffusion layer sheet resistance under the grid line, ρ _CIt is contact resistivity.

Ignore metallic resistance, suppose that grid line length much larger than the grid line width, draws:

(3)r _C＝(L _T/w)R′ _S?coth(d/L _T)

Wherein, w is a grid line length, and d is the grid line width; In order to obtain contact resistivity ρ _C, need to measure terminal contact resistance R _E, promptly on two adjacent grid lines, add constant current I _E, electric current I _EWith operating current I in the step (3) _oNumerical value identical, measure the voltage between time adjacent and adjacent grid line, draw:

(4)R _E＝V _E/I _E

As shown in Figure 5, measure terminal contact resistance R _E, on adjacent grid line, add constant current I _E=I=1.625mA measures the voltage between middle 5 grid lines time adjacent and adjacent grid line.

??n	??1	??2	??3	??4	??5
						??V En/mV	??5.251	??5.266	??5.356	??5.274	??5.346

(table 3)

Try to achieve V _EMean value is 5.299mV.

According to Semiconductive Theory, draw calculating formula:

(5) $R_E=\frac{{R^{\′}}_S{L}_T}{w}\·\frac{1}{\sinh (d/L_T)}$

Obtain by (1) formula: ${2\mathrm{Ir}}_C=A=11.214\mathrm{mV}\→r_C=\frac{A}{2I}=\frac{11.214}{2\×1.625}=3.450\mathrm{\Ω}$

Obtain by (4) formula: R _E=V _E/ I _E=5.299/1.625=3.261 Ω

By (3) formula (L _T/ w) R ' _SCoth (d/L _T)=r _C=3.450

→(L _T/2)R′ _S?coth(0.09247/L _T)＝3.450??①

By (5) formula $\frac{{R^{\′}}_S{L}_T}{w}\·\frac{1}{\sinh (d/L_T)}=R_E=3.261$

$\&RightArrow;\frac{{R^{\&prime;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; L\; T"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">S</figure-callout>}}{L}_T{}_{}}{2}\&CenterDot;\frac{1}{\sinh (0.09247/L_T)}=3.261$ ②

Solve an equation and 1. 2. draw migration length L _T=0.272mm, diffusion layer sheet resistance R ' under the grid line _S=8.288 Ω.

By (2) formula: calculate surface contact resistivity of crystalline silicon solar battery ${\mathrm{\&rho;}}_C=L_T^2{R}_S^{\&prime;}=0.615\mathrm{\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">mm</figure-callout>}}^2=6.15\mathrm{m\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">cm</figure-callout>}}^2.$

Embodiment 2

The difference of present embodiment and embodiment 1 is:

(1) make in the 2# test battery process: make and adopt slurry Du Pont PV149 to make preceding electrode, used web plate is 325 orders, line footpath 23 μ m, thickness 20 μ m, design thin grid width 100 μ m, grating spacing L=2.4mm carries out sintering for 890 ℃ in highest temperature district temperature;

(2) the 2# battery that step (1) is obtained therefrom take out a long 21mm, wide w=2mm along the main grid direction strip structure as 2# battery testing sample, the battery testing sample surfaces has 8 grid lines;

(3) 2# battery testing sample is carried out standard I V (current/voltage) test, from IV (current/voltage) data of 2# battery testing sample, read characterisitic parameter, the maximum power point electric current I of battery _MP=5.2A obtains battery operated current density, J thus _MP=I _MP/ A _C=5.2A/148.6cm ²=35mA/cm ²(A _CBe 125 * 125 monocrystalline silicon piece areas), calculate the operating current I that flows through the wall scroll grid line _o=J _MP* L * w=35mA/cm ²* 2.4mm * 2mm=1.68mA.

Measure the grid line width with metallomicroscope, test result is as follows: the μ m of unit

??93.46

??103.21

??99.19

??90.16

??94.79

(table 4)

Try to achieve grid line mean breadth d=96.162 μ m=0.096162mm.

Adopt KEITHLEY 2400 current source tables to set the constant output electric current I _o=1.68mA measures the voltage V of each grid line under this electric current successively _n, measurement result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7
								??V n	??101.298mV	??197.254mV	??0.29198V	??0.3866V	??0.47906V	??0.56963V	??0.66685V

(table 5)

(4) as shown in Figure 7, each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5) obtain fitting a straight line intercept A=9.1691mV, fitting a straight line slope B=93.875mV;

Measure terminal contact resistance R _E, on adjacent grid line, add constant current I _E=I=1.68mA measures the voltage between middle 5 grid lines time adjacent and adjacent grid line, and the result is as follows:

??n	??1	??2	??3	??4	??5
						??V En/mV	??2.272	??2.795	??1.607	??3.631	??2.583

(table 6)

Try to achieve V _EMean value is 2.5776mV.

Obtain by (1) formula: ${2\mathrm{Ir}}_C=A=9.1691\mathrm{mV}\&RightArrow;r_C=\frac{A}{2I}=\frac{9.1691}{2\&times;1.68}=2.729\mathrm{\&Omega;}$

Obtain by (4) formula: R _E=V _E/ I _E=2.5776/1.68=1.533 Ω

By (3) formula (L _T/ w) R ' _SCoth (d/L _T)=r _C=2.729

→(L _T/2)R′ _S?coth(0.096162/L _T)＝2.729③

By (5) formula $\frac{{R^{\&prime;}}_S{L}_T}{w}\&CenterDot;\frac{1}{\sinh (d/L_T)}=R_E=1.533$

$\&RightArrow;\frac{{R^{\&prime;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; L\; T"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">S</figure-callout>}}{L}_T{}_{}}{2}\&CenterDot;\frac{1}{\sinh (0.09247/L_T)}=1.533$ ④

Solve an equation and 3. 4. draw migration length L _T=0.082mm, diffusion layer sheet resistance R ' under the grid line _S=55.357 Ω.

By (2) formula: calculate surface contact resistivity of crystalline silicon solar battery ${\mathrm{\&rho;}}_C=L_T^2{R}_S^{\&prime;}=0.295\mathrm{\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">mm</figure-callout>}}^2=2.95\mathrm{m\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">cm</figure-callout>}}^2.$

Embodiment 3

The difference of present embodiment and embodiment 1 is:

(1) makes in the 3# test battery process: logical POCL in diffusion furnace ₃P-n junction is made in diffusion, obtains about diffusion layer square resistance 70 Ω/;

(2) the 3# battery that step (1) is obtained therefrom take out a long 24mm, wide w=5mm along the main grid direction strip structure as 3# battery testing sample, the battery testing sample surfaces has 11 grid lines;

(3) 3# battery testing sample is carried out standard I V (current/voltage) test, the maximum power point electric current I of reading battery from IV (current/voltage) data of 3# battery testing sample _MP=4.93A obtains battery operated current density, J thus _MP=I _MP/ A _C=4.93A/148.6cm ²=33.2mA/cm ²(A _CBe 125 * 125 monocrystalline silicon piece areas), calculate the operating current I that flows through the wall scroll grid line _o=J _MP* L * w=33.2mA/cm ²* 2.32mm * 5mm=3.685mA.

Measure the grid line width with metallomicroscope, test result is as follows: the μ m of unit

??109.56

??96.47

??103.96

??97.68

??99.34

??95.25

??93.42

??105.4

??98.73

(table 7)

Try to achieve grid line mean breadth d=99.979 μ m=0.099979mm.

Adopt KEITHLEY 2400 current source tables to set the constant output electric current I _o=3.685mA measures the voltage V of each grid line under this electric current successively _n, measurement result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7	??8	??9	??10
											??V n	??134.06??mV	??0.26122??V	??0.38826??V	??0.51272??V	??0.63570??V	??0.75693??V	??0.87622??V	??0.99475??V	??1.11103??V	??1.22733??V

(table 8)

(4) as shown in Figure 8, each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5) obtain fitting a straight line intercept A=22.08mV, fitting a straight line slope B=121.41mV;

Measure terminal contact resistance R _E, on adjacent grid line, add constant current I _E=I=3.69mA measures the voltage between middle 8 grid lines time adjacent and adjacent grid line, and the result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7	??8
									??V En/mV	??2.668	??3.105	??3.617	??3.146	??3.325	??1.866	??2.150	??1.636

(table 9)

Try to achieve V _EMean value is 2.69mV.

Obtain by (1) formula: ${2\mathrm{Ir}}_C=A=22.08\mathrm{mV}\&RightArrow;r_C=\frac{A}{2I}=\frac{22.08}{2\&times;3.685}=2.996\mathrm{\&Omega;}$

Obtain by (4) formula: R _E=V _E/ I _E=2.69/3.69=0.729 Ω

By (3) formula (L _T/ w) R ' _SCoth (d/L _T)=r _C=2.996

→(L _T/2)R′ _S?coth(0.099979/L _T)＝2.996????????⑤

By (5) formula $\frac{{R^{\&prime;}}_S{L}_T}{w}\&CenterDot;\frac{1}{\sinh (d/L_T)}=R_E=0.729$

$\&RightArrow;\frac{{R^{\&prime;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; L\; T"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">S</figure-callout>}}{L}_T{}_{}}{2}\&CenterDot;\frac{1}{\sinh (0.09247/L_T)}=0.729$ ⑥

Solve an equation and 5. 6. draw migration length L _T=0.05mm, diffusion layer sheet resistance R ' under the grid line _S=303.98 Ω.

By (2) formula: calculate surface contact resistivity of crystalline silicon solar battery ${\mathrm{\&rho;}}_C=L_T^2{R}_S^{\&prime;}=0.694\mathrm{\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">mm</figure-callout>}}^2=6.94\mathrm{m\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">cm</figure-callout>}}^2.$

Embodiment 4

The difference of present embodiment and embodiment 3 is:

(2) the 4# battery that step (1) is obtained therefrom take out a long 24mm, wide w=5mm along the main grid direction strip structure as 4# battery testing sample, the battery testing sample surfaces has 11 grid lines;

(3) 4# battery testing sample is carried out standard I V (current/voltage) test, the maximum power point electric current I of reading battery from IV (current/voltage) data of 4# battery testing sample _MP=4.93A obtains battery operated current density, J thus _MP=I _MP/ A _C=4.93A/148.6cm ²=33.2mA/cm ²(A _CBe 125 * 125 monocrystalline silicon piece areas), calculate the operating current I that flows through every grid line _o=J _MP* L * w=33.2mA/cm ²* 2.32mm * 5mm=3.685mA.

Measure the grid line width with metallomicroscope.Test result is as follows: the μ m of unit

??97.63

??102.46

??109.73

??96.34

??102.89

??99.54

??106.3

??103.85

??93.77

(table 10)

Try to achieve grid line mean breadth d=101.39 μ m=0.10139mm.

Different with above embodiment is, in the present embodiment, battery also carries out electroplating processes to battery electrode after highest temperature district carries out sintering, because the existence of SiNx, the contact width of metal and silicon base still is d.

Adopt KEITHLEY 2400 current source tables to set the constant output electric current I _o=3.685mA measures the voltage V of each grid line under this electric current successively _n, measurement result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7	??8	??9	??10
											??V n	??128.275??mV	??0.25335??V	??0.37981??V	??0.50398??V	??0.62653??V	??0.74802??V	??0.86975??V	??0.98952??V	??1.10757??V	??1.22445??V

(table 11)

(4) as shown in Figure 9, each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5) obtain fitting a straight line intercept A=12.71mV, fitting a straight line slope B=121.89mV;

Measure terminal contact resistance R _E, on adjacent grid line, add constant current I _E=I=3.69mA measures the voltage between middle 8 grid lines time adjacent and adjacent grid line, and the result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7	??8
									??V En/mV	??0.778	??0.954	??0.717	??0.820	??0.752	??0.531	??0.845	??0.784

(table 12)

Try to achieve V _EMean value is 0.773mV.

Obtain by (1) formula: ${2\mathrm{Ir}}_C=A=12.71\mathrm{mV}\&RightArrow;r_C=\frac{A}{2I}=\frac{12.71}{2\&times;3.685}=1.725\mathrm{\&Omega;}$

Obtain by (4) formula: R _E=V _E/ I _E=0.773/3.69=0.209 Ω

By (3) formula (L _T/ w) R ' _SCoth (d/L _T)=r _C=1.725

→(L _T/2)R′ _S?coth(0.10080/L _T)＝1.725??????⑦

By (5) formula $\frac{{R^{\&prime;}}_S{L}_T}{w}\&CenterDot;\frac{1}{\sinh (d/L_T)}=R_E=0.209$ ⑦

$\&RightArrow;\frac{{R^{\&prime;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; L\; T"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">S</figure-callout>}}{L}_T{}_{}}{2}\&CenterDot;\frac{1}{\sinh (0.10080/L_T)}=0.209$ ⑧

Solve an equation and 7. 8. draw migration length L _T=0.04mm, diffusion layer sheet resistance R ' under the grid line _S=239.20 Ω.

By (2) formula: calculate surface contact resistivity of crystalline silicon solar battery ${\mathrm{\&rho;}}_C=L_T^2{R}_S^{\&prime;}=0.310\mathrm{\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">mm</figure-callout>}}^2=3.10\mathrm{m\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">cm</figure-callout>}}^2.$

Embodiment 5

The difference of present embodiment and embodiment 4 is:

(3) measure the grid line width with metallomicroscope, test result is as follows: the μ m of unit

??107.66

??98.74

??110.01

??101.4

??97.44

??104.33

??90.42

??98.57

??100.29

(table 13)

Trying to achieve the grid line mean breadth is d=100.98 μ m=0.10098mm.

Battery also carries out electroplating processes to battery electrode after highest temperature district carries out sintering, because the existence of SiNx, the contact width of metal and silicon base still is d.

Adopt KEITHLEY 2400 current source tables to set the constant output electric current I _o=3.685mA measures the voltage V of each grid line under this electric current successively _n, measurement result is as follows:

??n	??1	??2	??3	??4	??5	??6	??7	??8	??9	??10
											??V n	??132.04??mV	??0.2618??V	??0.3892??V	??0.4792??V	??0.6071??V	??0.7292??V	??0.8506??V	??0.9721??V	??1.0921??V	??1.2117??V

(table 14)

(4) as shown in figure 10, each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5) obtain fitting a straight line intercept A=16.513mV, fitting a straight line slope B=119.27mV;

Measure terminal contact resistance R _E, on adjacent grid line, add constant current I _E=I=3.69mA measures the voltage between middle 5 grid lines time adjacent and adjacent grid line, and the result is as follows:

??n	??1	??2	??3	??4	??5
						??V En/mV	??1.26	??1.28	??1.55	??1.27	??1.21

(table 15)

Try to achieve V _EMean value is 1.31mV.

Obtain by (1) formula: ${2\mathrm{Ir}}_C=A=16.513\mathrm{mV}\&RightArrow;r_C=\frac{A}{2I}=\frac{16.513}{2\&times;3.685}=2.241\mathrm{\&Omega;}$

Obtain by (4) formula: R _E=V _E/ I _E=1.31/3.69=0.356 Ω

By (3) formula (L _T/ w) R ' _SCoth (d/L _T)=r _C=2.241

→(L _T/2)R′ _Scoth(0.10080/L _T)＝2.241⑨

By (5) formula $\frac{{R^{\&prime;}}_S{L}_T}{w}\&CenterDot;\frac{1}{\sinh (d/L_T)}=R_E=0.356$

$\&RightArrow;\frac{{R^{\&prime;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; L\; T"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">S</figure-callout>}}{L}_T{}_{}}{2}\&CenterDot;\frac{1}{\sinh (0.10098/L_T)}=0.356$ ⑩

Solve an equation and 9. 10. draw migration length L _T=0.04mm, diffusion layer sheet resistance R ' under the grid line _S=239.20 Ω.

By (2) formula: calculate surface contact resistivity of crystalline silicon solar battery ${\mathrm{\&rho;}}_C=L_T^2{R}_S^{\&prime;}=0.442\mathrm{\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">mm</figure-callout>}}^2=4.42\mathrm{m\&Omega;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cm"\; filenames="HSA00000092962100011.png,HSA00000092962100013.png"\; state="\{\{state\}\}">cm</figure-callout>}}^2.$

Embodiments of the present invention are not limited thereto, according to foregoing of the present invention, ordinary skill knowledge and customary means according to this area, do not breaking away under the above-mentioned basic fundamental thought of the present invention prerequisite, the present invention is when carrying out the measurement of terminal contact resistance, can select 3 groups of above adjacent grid lines to measure arbitrarily gets final product, as in embodiment 1, can only select 3 groups of adjacent grid lines to measure, at first, selecting sequence number is 0 and 1 adjacent grid line, it is the 1st group, add constant current during measurement on these two grid lines, the measurement sequence number is the voltage between 1 and 2 grid lines, draws a magnitude of voltage; Selecting sequence number again is 3 and 4 adjacent grid lines, add constant current after, measure sequence number and be the voltage between 4 and 5 grid lines; Selecting sequence number at last is 6 and 7 adjacent grid lines, add constant current after, measure sequence number and be the voltage between 7 and 8 grid lines.Therefore the present invention can also make modification, replacement or the change of other various ways, all drops within the rights protection scope of the present invention.

Claims (6)

1. method of measuring surface contact resistivity of crystalline silicon solar battery is characterized in that specifically may further comprise the steps:

(1) adopts the common process crystal silicon solar energy battery that completes, in this manufacture craft, use unified model web plate to form uniformly-spaced grid line at battery surface;

(2) battery that step (1) is obtained therefrom takes out a strip structure as the battery testing sample along the main grid direction, and the position of taking out this specimen on the battery is a hollow, and described battery testing sample surfaces has several grid lines;

(3) each grid line formation test zone of uniformly-spaced arranging side by side successively, the characterisitic parameter that is obtained by the test of battery standard current/voltage calculates the operating current I of wall scroll grid line., adopt the current source table to set the constant output electric current I., measure first grid line and all the other grid lines more successively in the constant output electric current I.Under voltage V _n

(4) each the grid line voltage V that step (3) is obtained _nChange according to each grid line ordinal number n successively and be depicted as curve V _n=A+Bn;

(5), calculate the grid line contact resistance r of described test zone according to curve fit straight line intercept A _C

(6) measure terminal contact resistance R _E, list respectively about grid line contact resistance r _CWith terminal contact resistance R _EEquation, calculate migration length L _TWith diffusion layer sheet resistance R ' under the grid line _S

(7) result of calculation that obtains according to step (6) calculates surface contact resistivity of crystalline silicon solar battery ρ at last _C

2. the method for measurement surface contact resistivity of crystalline silicon solar battery according to claim 1, it is characterized in that: in step (1), the making step of described common process is: 1. use the p type single crystal silicon sheet, behind cleaning and the removal affected layer, put into NaOH solution and make surperficial matte light trapping structure; 2. in diffusion furnace, feed POCL ₃P-n junction is made in diffusion, obtains the diffusion layer square resistance; 3. remove phosphorosilicate glass, the p-n junction at plasma etching edge; 4. plasma chemical vapor deposition is made antireflective SiNx film; 5. adopt method for printing screen to form Metal Contact; 6. the back side adopts the Ag/Al slurry to print back electrode, and seal Al slurry forms back of the body electric field; 7. electrode before adopting slurry to make; 8. in highest temperature district temperature, carry out sintering, obtain crystal silicon solar energy battery.

3. the method for measurement surface contact resistivity of crystalline silicon solar battery according to claim 1 is characterized in that: in described step (6), ignore metallic resistance, suppose that grid line length much larger than the grid line width, draws calculating formula: r _C=(L _T/ w) R ' _SCoth (d/L _T), wherein, w is a grid line length, d is the grid line width; Measure terminal contact resistance R _E, promptly on two adjacent grid lines, add constant current I _E, measure the voltage between time adjacent and adjacent grid line, obtain R _E, according to calculating formula:

Obtain migration length L _TWith diffusion layer sheet resistance R ' under the grid line _S

4. the method for measurement surface contact resistivity of crystalline silicon solar battery according to claim 3 is characterized in that: in step (6), and migration length L _TBeing defined as along grid line Width voltage attenuation is the corresponding length in l/e place of grid line edge voltage, draws calculating formula

The migration length L that draws according to described step (6) _TWith diffusion layer sheet resistance R ' under the grid line _S, obtain surface contact resistivity of crystalline silicon solar battery ρ _C

5. the method for measurement surface contact resistivity of crystalline silicon solar battery according to claim 1, it is characterized in that: in described step (2), described battery testing sample width is for being less than or equal to 5mm, and described battery testing sample surfaces has 8～12 grid lines.

6. the method for measurement surface contact resistivity of crystalline silicon solar battery according to claim 3 is characterized in that: measure terminal contact resistance R _EThe time, adding constant current I on two adjacent grid lines more than 3 groups at least _E, measure the voltage between time adjacent and adjacent grid line in every group of grid line.

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