TWI552365B - Interconnection materials for solar cells, interconnections for solar cells, and solar cells with interconnectors - Google Patents

Description

Solar cell interconnect material, solar cell interconnect, and solar cell with interconnector

The present invention relates to a solar cell interconnector material, a solar cell interconnector, and a solar cell unit with an interconnector.

The solar cell interconnector functions as a wiring material that is connected between solar cells composed of crystalline germanium (Si) and that collects electric energy converted by the solar cell. In recent years, a flat copper wire coated with a solder which is coated with a flat copper wire by solder fusion plating has been used as an interconnector material for such a solar cell.

However, when such a flat copper wire coated with solder is used as a material for an interconnector for a solar cell, there are the following problems. That is, the thermal experience generated by soldering the flat copper wire covering the solder and the solar cell causes the tin (Sn) contained in the solder to diffuse into the copper (Cu) constituting the flat copper wire to form copper- An intermetallic compound of tin (Cu-Sn). This copper-tin-tin intermetallic compound is brittle and therefore causes the formation or cracking of Kirkendall void (pores) and has poor quality. .

On the other hand, for example, Patent Document 1 proposes a solar cell interconnector material in which copper plating is applied to a flat aluminum substrate and is covered by solder fusion plating. Further, in Patent Document 1, a flat aluminum substrate is used in which the tensile strength at normal temperature is 80 N/mm ² or less and the 0.2% endurance is 40 N/mm ² or less.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: JP-A-2006-49666

The present invention has been made in view of the actual circumstances, and an object thereof is to provide a method for effectively preventing deformation and breakage of a ruthenium crystal wafer (crystallization enthalpy) during bonding, and winding a bobbin or a reel. Good interconnector materials for solar cells, and interconnectors for solar cells. Moreover, the object of the present invention is also to provide a solar cell unit with an interconnector obtained by using the interconnector for a solar cell.

The present inventors have found that an aluminum (Al) substrate having a tensile strength of 81 to 100 N/mm ² is used as a substrate constituting a solar cell interconnector material, and is sequentially formed on the surface thereof from the substrate side. The nickel plating layer and the tin plating layer can solve the above problems, and thus the present invention has been completed.

That is, according to the present invention, there is provided an interconnector material for a solar cell, characterized in that a surface of an aluminum substrate having a tensile strength of 81 to 100 N/mm ² has a nickel plating layer sequentially from the substrate side and Tin plating layer.

In the interconnector material for a solar cell of the present invention, the aluminum base material preferably contains copper in a proportion of 0.05 to 0.20% by weight.

In the interconnector material for a solar cell of the present invention, the aluminum base material preferably contains aluminum in a ratio of from 99.0 to 99.6 wt%.

Moreover, according to the present invention, there is provided an interconnector for a solar cell, characterized in that a surface of an aluminum substrate is obtained by forming a solder layer on a surface of a tin plating layer of the solar cell interconnect material. The substrate side has a tin-nickel alloy layer and a solder layer in this order.

Further, according to the present invention, there is provided a solar cell unit with an interconnector, characterized in that the solar cell interconnector of any of the above is connected to a solar cell unit.

In the solar cell unit with an interconnector of the present invention, the solar cell interconnector and the solar cell unit are connected by soldering.

According to the present invention, it is possible to provide an interconnector material for a solar cell which can effectively prevent deformation and breakage of a germanium crystal wafer during bonding, and which has good winding properties for a bobbin or a reel, and interconnection for solar cells. Device. Moreover, according to the present invention, a solar cell unit with an interconnector obtained by using the solar cell interconnector can be provided.

100‧‧‧Connector materials for solar cells

200‧‧‧Solar interconnectors for solar cells

10‧‧‧Aluminum substrate

20‧‧‧ Nickel plating

30‧‧‧ tin plating

40‧‧‧ tin-nickel plating

50‧‧‧ solder layer

Fig. 1 is a view showing the configuration of a solar cell interconnector material 100 of the present embodiment.

Fig. 2 is a view showing the configuration of the solar cell interconnector material 200 of the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Connector material for solar cells>

Fig. 1 is a view showing the configuration of a solar cell interconnector material 100 of the present embodiment. As shown in FIG. 1, the solar cell interconnector material 100 of the present embodiment is formed by sequentially forming a nickel plating layer 20 and a tin plating layer 30 on both surfaces of an aluminum substrate 10.

In the present embodiment, the aluminum base material 10 has a tensile strength of 81 to 100 N/mm ² and a tensile strength of 87 to 95 N/mm ² . When the tensile strength is less than 81 N/mm ² as the aluminum base material 10, the solar cell interconnector material 100 becomes too soft, and the winding property of the bobbin or the reel is lowered. That is, when the solar cell interconnector material 100 is too soft, a large tension cannot be applied when wound on a bobbin or a reel, and the obtained solar cell interconnector is wound on a bobbin or a reel. When transported, there will be a twist or break in the winding. Further, when excessive tension is applied to prevent the winding from being staggered or loosened, the solar cell interconnector material 100 is easily plastically deformed, which tends to cause work hardening or breakage. Alternatively, when wound on a bobbin or a reel, there may be a winding abnormality, and it may be difficult to join the solar cell unit. Therefore, when the solar cell interconnector material 100 is too soft, the windability is lowered. On the other hand, when the tensile strength exceeds 100 N/mm ² as the aluminum base material 10, the solar cell interconnector material 100 becomes too hard, and when welded to the solar battery cell, excessive stress is applied, and a solar cell occurs. The unit produces the disadvantage of warping or the disadvantage of rupturing the solar cell unit.

Further, the tensile strength of the aluminum base material 10 can be measured under conditions of, for example, 25 ° C and a tensile speed of 5 mm/min.

In addition, the aluminum base material 10 used in the present embodiment is not particularly limited as long as the tensile strength is in the above range, but aluminum is preferably used as a main component, and is preferably 0.05 to 0.20% by weight, more preferably 0.10 to 0.18 by weight, in addition to aluminum. The proportion of % contains copper. When the nickel plating layer 20 to be described later is formed by containing the copper in the above-mentioned content ratio, zinc is easily adhered to the aluminum substrate in the pre-treated zinc (Zn) replacement treatment, and the nickel plating layer 20 can be favorably formed. Or tin plating applied to the nickel plating layer 20, and solder plating. Therefore, as a result, the solder wettability of the aluminum substrate 10 can be improved. In addition, when copper is contained in the above-mentioned content ratio, the strength is increased by solid solution strengthening, precipitation hardening, or heat resistance is improved, and the higher tensile strength is 81 N/mm ² or more. In the case of the aluminum base material, the stress applied when the solar cell interconnector material 100 is solder-bonded to the solar cell unit can be alleviated, and deformation and breakage of the solar cell during bonding can be effectively prevented. When the content ratio of copper is too small, it is difficult for zinc to adhere to the aluminum substrate 10, and the solder wettability of the aluminum substrate 10 is lowered, and the solar cell interconnector material 100 is bonded to the solar cell unit. The tendency to reduce the effect. On the other hand, when the content ratio of copper is too large, the effect of improving the adhesion of zinc to the aluminum substrate 10 and the stress relaxation effect when the solar cell interconnector material 100 is bonded to the solar cell unit are increased by increasing the content ratio. It has reached saturation, so there is a tendency to be disadvantageous in terms of cost.

In addition, the aluminum base material 10 used in the present embodiment preferably has an aluminum content of 99.0 to 99.6% by weight, and by setting the content ratio of aluminum to the above range, the adhesion to the solar cell can be improved. When the content ratio of aluminum is too small, the solar cell interconnector material 100 becomes too hard, and there is a tendency to apply excessive stress to the solar cell unit at the time of bonding. On the other hand, when the aluminum content ratio is excessive, the solar cell interconnector The material 100 becomes too soft and there is a drop in the winding property of the bobbin and the reel.

Further, the aluminum base material 10 used in the present embodiment may contain bismuth (Si), iron (Fe), manganese (Mn), chromium (Cr), zinc, titanium (Ti) or the like in addition to aluminum or copper. The content of these components is usually the remainder relative to the content of aluminum and copper. The content of these other components is preferably 0.10% by weight or less. When the content of the other components is too large, the solar cell interconnector material 100 becomes too hard, and the bonding property to the solar cell unit tends to decrease.

The thickness of the aluminum base material 10 is not particularly limited as long as it is sufficient to ensure sufficient conductivity of the solar cell interconnector, but is preferably 0.1 to 0.5 mm.

The nickel plating layer 20 is plated by nickel on the aluminum substrate 10. Formed by the application. The method of forming the nickel plating layer 20 on the aluminum substrate 10 is not particularly limited. However, since it is difficult to directly provide a nickel plating layer on the aluminum surface, it is preferred to form a zinc layer by displacement plating in advance. A nickel plating layer 20 is formed. Hereinafter, a method of forming a zinc layer as a base layer will be described.

First, the aluminum plate constituting the aluminum base material 10 is subjected to degreasing treatment, and then, after acid etching and soil removal, zinc replacement plating is performed. The zinc displacement plating is performed by a single zincate treatment subjected to a nitric acid immersion treatment and a zinc replacement treatment step. In this case, the water washing treatment is performed after the respective steps. Further, the zinc layer formed by the zinc replacement treatment was only slightly dissolved when the nickel plating layer was applied. In this case, by using the aluminum base material 10 as the aluminum base material 10, the zinc can be easily adhered to the aluminum base material 10, and a good zinc layer can be formed, and nickel plating can be favorably formed on the zinc layer. The coating layer 20. On the other hand, when the content ratio of copper is outside the above range as the aluminum base material 10, it is difficult for zinc to adhere to the aluminum base material, and the plating property of the nickel plating layer 20 on the zinc layer is deteriorated.

Further, the zinc layer is preferably formed so that the amount of the film in the state after nickel plating is preferably in the range of 5 to 500 mg/m ² , more preferably in the range of 30 to 300 mg/m ² . Further, the amount of the film of the zinc layer can be adjusted by appropriately selecting the zinc ion concentration and the immersion time in the treatment liquid. Further, the zinc displacement plating may be performed by a double zincate treatment which is subjected to a step of undergoing a nitric acid immersion treatment or a zinc substitution treatment and then subjected to a zinc substitution treatment.

Next, the nickel plating layer 20 is formed by applying nickel plating to the zinc layer as the underlayer. The nickel plating layer 20 can be formed by any plating method using electroplating or electroless plating. Nickel plating layer 20 has a good thickness It is 0.2 μm or more, more preferably 0.2 to 3.0 μm, and still more preferably 0.5 to 2.0 μm. When a solder layer is formed on the tin plating layer 30 constituting the solar cell interconnector material 100, the nickel plating layer 20 is diffused into the tin plating layer 30 by heat generated when the solder layer is formed, as will be described later. A layer of a nickel-tin alloy layer.

The tin plating layer 30 is formed by performing tin plating on the nickel plating layer 20. The tin plating layer 30 can be formed by any one of an electroplating method or an electroless plating method. The thickness of the tin plating layer 30 is preferably from 0.5 to 3.0 μm. When the thickness of the tin plating layer 30 is too thin, when a solder layer is formed on the tin plating layer 30, the solder wettability is lowered, and it is difficult to form a good solder layer. On the other hand, when the thickness of the tin plating layer 30 is too thick, the effect of improving the wettability of the solder by increasing the thickness is saturated, which is disadvantageous in terms of cost. When the aluminum base material 10 is used as the aluminum base material 10 in the above range, the nickel plating layer 20 and the tin plating layer 30 are favorably formed on the aluminum base material 10, whereby the solder wettability can be improved. The solder layer is formed more well.

<Connectors for solar cells>

FIG. 2 is a view showing the configuration of the solar cell interconnector 200 of the present embodiment. The solar cell interconnector 200 of the present embodiment is manufactured by forming a solder layer 50 on the tin plating layer 30 of the solar cell interconnector material 100 using the solar cell interconnector material 100 shown in FIG. As shown in FIG. 2, a tin-nickel alloy layer 40 and a solder layer 50 are sequentially formed on both surfaces of the aluminum substrate 10.

The solder layer 50 can be formed by the solar power shown in FIG. The tin plating layer 30 of the cell interconnector material 100 is formed by applying molten solder plating. Further, in the present embodiment, the solder plating layer 50 is formed by molten solder plating, whereby the nickel plating of the solar cell interconnector material 100 shown in Fig. 1 is formed by the heat generated when the solder layer 50 is formed. Diffusion occurs between the cladding layer 20 and the tin plating layer 30. Therefore, as shown in FIG. 2, a tin-nickel alloy layer 40 is formed under the solder layer 50.

Further, the temperature of the molten solder plating bath when the solder layer 50 is formed is preferably from 140 to 350 ° C, more preferably from 180 to 300 ° C. Further, the immersion time in the case of performing molten solder plating is preferably from 3 to 15 seconds. When the bath temperature of the molten solder plating is too low, or when the immersion time for the molten solder plating is too short, the formation of the solder layer 50 is insufficient, and on the other hand, when the bath temperature of the molten solder plating is too high, or the molten solder plating is performed When the immersion time at the time of application is too long, the tin component contained in the solder layer 50 is diffused to the aluminum substrate 10, causing solid solution hardening between aluminum and tin, and cracking or peeling of the tin-nickel alloy layer 40 occurs. The situation.

The thickness of the solder layer 50 is not particularly limited, and is preferably 10 to 50 μm, more preferably 15 to 40 μm per side.

As described above, the tin-nickel alloy layer 40 causes diffusion between the nickel plating layer 20 and the tin plating layer 30 constituting the solar cell interconnector material 100 shown in FIG. 1 when the solder layer 50 is formed. An alloy layer formed. In the present embodiment, the thickness of the nickel plating layer 20 before the thermal diffusion of the tin-nickel alloy layer 40 is preferably 0.2 μm or more, more preferably 0.2 to 3.0 μm, still more preferably 0.5 to 2.0 μm. The tin-nickel alloy layer after thermal diffusion can be made by the thickness of the nickel plating layer 20 before the thermal diffusion falls within the range 40 is continuously formed so as to cover the surface of the aluminum substrate 10. That is, the tin-nickel alloy layer 40 after thermal diffusion can be formed in an uninterrupted portion. Therefore, it is possible to effectively prevent the disadvantage that the aluminum substrate 10 and the tin-nickel alloy layer 40 are adhered to each other with the discontinuous portion as a starting point, and the crack or peeling of the tin-nickel alloy layer 40 is liable to occur. Or through the crack generated during processing, when the corrosive material enters, a potential difference is generated in the interrupted portion due to the corrosive substance, so that the corrosion is disadvantageous.

Further, in the present embodiment, the nickel strength of the tin-nickel alloy layer 40 in the case of analysis by the high-frequency glow discharge luminescence spectrometry is higher than the nickel strength of the nickel plating layer 20 before the thermal diffusion, and the "tin-nickel alloy layer" is used. When the ratio of the nickel strength of 40 to the strength of nickel of the nickel plating layer 20 before thermal diffusion is expressed, it is preferably 0.15 or more, more preferably 0.18 or more, still more preferably 0.34 or more. Further, the upper limit of the ratio is not particularly limited, but is usually 1 or less.

By setting the ratio of "the nickel strength of the tin-nickel alloy layer 40/the nickel strength of the nickel plating layer 20 before the thermal diffusion" to the above range, the tin component in the tin-nickel alloy layer 40 can be prevented from being diffused to the aluminum base. The solid solution hardening between aluminum and tin generated in the material 10 prevents cracking or peeling of the tin-nickel alloy layer 40.

Further, the method of setting the ratio of the "nickel strength of the tin-nickel alloy layer 40 to the nickel strength of the nickel plating layer 20 before thermal diffusion" to the above range is not particularly limited, but is, for example, nickel plating before thermal diffusion. The thickness of the cladding layer 20 is 0.2 μm or more, the temperature of the molten solder plating bath when the solder layer 50 is formed, and the method of controlling the immersion time during the molten solder plating to the above range.

Further, as shown in FIG. 2, the solar cell interconnector 200 of the present embodiment may be formed by forming a tin-nickel alloy layer 40 on the aluminum substrate 10 via the nickel plating layer 20 instead of the aluminum substrate. The composition of the tin-nickel alloy layer 40 is directly formed on 10. In particular, depending on the thickness of the nickel plating layer 20 before thermal diffusion, the bath temperature of the molten solder plating when the solder layer 50 is formed, and the immersion time for the molten solder plating, there is also a tin component to the nickel plating layer. The spread of 20 is not fully carried out. Therefore, in this case, the nickel plating layer 20 remains between the aluminum base material 10 and the tin-nickel alloy layer 40.

Further, the solar cell interconnector 200 of the present embodiment preferably has a 0.2% proof stress of 40 to 80 N/mm ² , more preferably 40 to 70 N/mm ² . When the 0.2% proof stress is in the above range, the stress applied to the solar cell at the time of bonding can be alleviated, the solder wettability can be improved, and the bondability to the solar cell can be improved. Further, 0.2% of the endurance can be measured, for example, at 25 ° C and a tensile speed of 5 mm/min.

In the solar cell interconnector 200 of the present embodiment, since the aluminum base material 10 is used in a tensile strength of 81 to 100 N/mm ² , the following effects are exhibited. In other words, in the solar cell interconnector 200 of the present embodiment, since the tensile strength is 81 N/mm ² or more, the winding property of the bobbin or the reel can be effectively prevented from being lowered. Further, according to the solar cell interconnector 200 of the present embodiment, since the tensile strength is 100 N/mm ² or less, the stress applied to the solar cell can be alleviated during bonding, so that the solar cell at the time of bonding can be effectively prevented. Deformation and damage of the unit.

Further, the solar cell interconnector 200 of the present embodiment Since the tin-nickel alloy layer 40 formed by diffusion between the nickel plating layer 20 and the tin plating layer 30 by the heat when the solder layer 50 is formed is provided, the heat history due to soldering can be effectively prevented. The occurrence of defects such as cracking or peeling of the tin-nickel alloy layer 40.

Therefore, with the solar cell interconnector 200 of the present embodiment, the solar cell unit with the interconnector obtained by soldering the solar cell interconnector 200 and the solar cell unit is excellent in quality and excellent in cost. .

Further, in the solar cell interconnector 200 of the present embodiment, the tin-nickel alloy layer 40 and the solder layer 50 are sequentially formed in accordance with the above method by, for example, forming both sides of an elongated aluminum plate (coil). The creator is cut to the necessary width to obtain. The solar cell interconnector 200 thus obtained has the tin-nickel alloy layer 40 and the solder layer 50 formed on the upper and lower surfaces, and the tin-nickel alloy layer is not formed on the surface (cut surface) in the thickness direction. 40 and solder layer 50.

Alternatively, the solar cell interconnector 200 of the present embodiment can be obtained by, for example, forming a tin-nickel alloy layer 40 and a solder layer 50 over the entire surface of a flat aluminum wire according to the above method. Therefore, in this case, the obtained solar cell interconnector 200 is different from the above-described method in that it is not subjected to the dicing step, and thus becomes the same as the interconnector described in the above-mentioned Patent Document 1 (JP-A-2006-49666). The tin-nickel alloy layer 40 and the solder layer 50 are formed on either of the upper and lower surfaces and the surface in the thickness direction.

Moreover, the solar cell interconnector 200 of the present embodiment The size is not particularly limited, but the thickness is usually 0.1 to 0.7 mm, preferably 0.1 to 0.5 mm, and the width is usually 0.5 to 10 mm, preferably 1 to 6 mm, and the length is appropriately set according to the arrangement of the solar cells. Just fine.

Example

Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited to the examples.

<Example 1>

An aluminum plate (thickness: 0.3 mm, width: 40 mm, length: 120 mm) having a copper content of 0.05% by weight and an aluminum content of 99.6% by weight and the balance being manganese, zinc, bismuth, iron or the like was prepared as the aluminum substrate 10 for forming. material. Next, the aluminum substrate 10 was degreased with an alkali solution, followed by etching treatment in sulfuric acid, and then subjected to desmutting treatment in nitric acid, followed by immersion in sodium hydroxide containing: 150 g/L, sodium potassium tartrate (Rochelle Salt) : 50 g / L, zinc oxide: 25 g / L, ferrous chloride 1.5 g / L of the treatment liquid was subjected to zinc replacement treatment, and a zinc layer was formed on the aluminum substrate at a film amount of 100 mg / m ² .

Next, nickel plating was performed on the aluminum substrate 10 on which the zinc layer was formed under the following conditions, and a nickel plating layer 20 having a thickness of 0.5 μm was formed on the zinc layer.

Bath composition: nickel sulfate 250g / L, nickel chloride 45g / L, boric acid 30g / L

pH: 3~5

Bath temperature: 60 ° C

Current density: 1~5A/dm ²

In the present embodiment, the aluminum substrate 10 on which the nickel plating layer 20 is formed is used, and the plating peelability of the nickel plating layer 20 is evaluated. The evaluation of the plating peelability was specifically carried out on the nickel plating layer 20, using a dicing blade to cut into the aluminum substrate 10 at a pitch of 1.0 mm intervals, and then, in an ERICHSEN test machine, in a checkerboard pattern. The center was bulged by 7 mm, and CELLOTAPE (registered trademark) was used to observe the film peeling state of the bulging portion of the checkerboard, and was evaluated by the following criteria. The evaluation results are shown in Table 1. Further, the reason why the nickel plating layer 20 is formed and the plating peelability is evaluated is that if the nickel plating layer 20 is not fixed, the tin plating layer 30 and the solder layer 50 which are superposed on the nickel plating layer 20 are not fixed. .

○: peeling of the nickel plating layer 20 was not confirmed

×: peeling of the nickel plating layer 20 occurred

Next, the aluminum substrate 10 on which the nickel plating layer 20 was formed was subjected to tin plating under the following conditions. A tin plating layer 30 having a thickness of 0.5 μm was formed on the nickel plating layer 20, and the solar cell interconnector material 100 shown in Fig. 1 was obtained.

Bath composition: stannous sulfate 30g / L, sulfuric acid 70ml / L, the right amount of brightener and antioxidant

pH: 1~2

Bath temperature: 40 ° C

Current density: 2.5~10A/dm ²

Next, the obtained solar cell interconnector material 100 was immersed in tin--40% lead (Pb) solder which was adjusted to a bath temperature of 200 ° C. The solder layer 50 having a thickness of 20 μm was formed in the molten solder bath for 3 seconds to fabricate the solar cell interconnector 200 shown in Fig. 2 . In addition, the solar cell interconnector 200 manufactured in the present embodiment is a former for cutting, and can be suitably used as a solar cell interconnector by cutting simultaneously with the arrangement of solar cells or the like. Next, the obtained solar cell interconnector 200 was used to measure the tensile strength. The results are shown in Table 1.

The tensile strength was measured by the following method. In other words, the maximum tensile load of the solar cell interconnector 200 was divided by the cross-sectional area of the parallel portion at 25 ° C and a tensile speed of 5 mm/min using a universal testing machine (RTC-1350A, manufactured by ORIENTEC Co., Ltd.). The value was measured as the tensile strength (the test piece was a test piece No. 5 described in JIS Z2241 which was punched by a press machine). Further, in the configuration of the solar cell interconnector 200 of the present embodiment, since the aluminum base material 10 accounts for a large portion, the tensile strength of the solar cell interconnector 200 becomes a tensile strength with the aluminum base material 10 alone. The values are approximately equal, and therefore, the tensile strength obtained by the evaluation can be judged as the tensile strength of the aluminum substrate 10.

<Examples 2 to 7>

The content ratio of copper and the content of aluminum were respectively: copper: 0.12% by weight, aluminum: 99.2% by weight (Example 2), copper: 0.07% by weight, aluminum: 99.2% by weight (Example 3), copper: 0.11 % by weight, aluminum: 99.1% by weight (Example 4), copper: 0.14% by weight, aluminum: 99.0% by weight (Example 5), copper: 0.18% by weight, aluminum: 99.3% by weight (Example 6), and copper : 0.20% by weight, aluminum: 99.2% by weight (Example 7) The aluminum plate was obtained as the material for forming the aluminum base material 10, and the solar cell interconnector 200 was obtained in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. Further, the aluminum plates used in the above Examples 2 to 7 were all composed of Si, Mn, zinc, Fe, or the like with respect to the aluminum and copper contents.

<Comparative Examples 1 to 4>

The content ratio of copper and the content of aluminum were respectively: copper: 0.21% by weight, aluminum: 96.7% by weight (Comparative Example 1), copper: 0.24% by weight, aluminum: 96.0% by weight (Comparative Example 2), copper: 0.05 The solar cell interconnector 200 was obtained in the same manner as in the first embodiment except for the aluminum plate having a weight %, aluminum: 96.5 wt% (Comparative Example 3), copper: 0.03 wt%, and aluminum: 99.6% by weight (Comparative Example 4). And the same evaluation was made. The results are shown in Table 1. Further, the aluminum plates used in Comparative Examples 1 to 4 were composed of ruthenium, manganese, zinc, iron, and the like with respect to the aluminum and copper contents.

[Table 1]

The results of tensile strength and plating peelability are shown in Table 1. Nickel was not used in Examples 1 to 7 using an aluminum substrate having a tensile strength of 81 to 100 N/mm ² and a copper content of 0.05 to 0.20% by weight and an aluminum content of 99.0 to 99.6 % by weight. The peeling of the plating layer 20 can be judged to be excellent in the formability of the nickel plating layer 20. Further, in Examples 1 to 7, since the nickel plating layer 20 is excellent in formability, it is possible to determine the formability of the tin plating layer 30 formed thereon, and further to wet the solder plating formed thereon. Excellent sex. On the other hand, a tensile strength less than 81N / mm ^2, or more than 100N / mm ^2, and the proportion of copper containing less than 0.05 wt% of the aluminum substrate of Comparative Example 4, the occurrence of the nickel plating layer becomes peeled 20 As a result, the formation of the nickel plating layer 20 is poor. Therefore, from this result, it can be judged that the formation of the tin plating layer 30 formed thereon in the comparative example 4 due to the poor formability of the nickel plating layer 20, and the soldering of the solder plating formed thereon Poor results.

<Test for damage confirmation of 矽 crystal wafer and measurement of 0.2% endurance of aluminum substrate 100>

A cut sample of the solar cell interconnector 200 was obtained by cutting the solar cell interconnector 200 of Example 5 having a tensile strength of 100 N/mm ² to a width of 2.0 mm. Next, using the obtained cut sample, it was soldered to the germanium crystal wafer constituting the solar cell, and the deformation and breakage of the germanium crystal wafer were visually confirmed. As a result, no deformation or breakage occurred at all, which was a good result.

In addition, the obtained cut sample was subjected to a universal testing machine (RTC-1350A, manufactured by ORIENTEC Co., Ltd.) at a rate of 5 mm/min at 25 ° C and a tensile strength of 5 mm/min, and was 77.2 N/mm ² .

Here, the higher the tensile strength of the aluminum substrate 10 used, the harder the obtained solar cell interconnector 200 is. Therefore, the stress applied to the germanium crystal wafer tends to increase during bonding, and conversely, The lower the tensile strength of the aluminum substrate 10, the smaller the stress on the germanium crystal wafer during bonding. Therefore, Examples 1 to 4, 6, and 7 in which the tensile strength was less than 100 N/mm ² were also the same as in Example 5 having a tensile strength of 100 N/mm ² , and it was predicted that deformation of the germanium crystal wafer did not occur at the time of bonding. And damaged.

On the other hand, in Comparative Examples 1 to 3 in which the tensile strength exceeded 100 N/mm ² as the aluminum base material 10, the obtained solar cell interconnector 200 was too hard, and therefore, the stress applied to the ruthenium crystal wafer at the time of bonding was estimated. If it is too high, the crystal wafer will be deformed and damage will occur.

<Winding property>

Further, in Examples 1 to 7, the tensile strength of the aluminum base material 10 was 81 N/mm ² or more (and 100 N/mm ² or less), and when wound on a bobbin or a reel, winding was not caused to be staggered. Unwinding, winding abnormality, or no cracking is considered to be high in winding property. On the other hand, in Comparative Example 4 in which the tensile strength of the aluminum base material 10 was less than 81 N/mm ² , winding was staggered, untwisted, unwound, or broken when wound on a bobbin or a reel.虞, it is estimated that the winding property is low.

100‧‧‧Connector materials for solar cells

30‧‧‧ tin plating

20‧‧‧ Nickel plating

10‧‧‧Aluminum substrate

Claims (8)

A solar cell interconnector material characterized by having a nickel (Ni) plating layer and tin on the surface of an aluminum (Al) substrate having a tensile strength of 81 to 100 N/mm ² from the substrate side. (Sn) a plating layer in which the aluminum base material contains copper (Cu) in a ratio of 0.05 to 0.20% by weight, and the content ratio of other components other than Al and Cu is 0.35 to 0.86% by weight. The solar cell interconnector material of claim 1, wherein the aluminum substrate comprises aluminum in a ratio of 99.0 to 99.6 wt%. An interconnector for a solar cell, which is obtained by forming a solder layer on a surface of a tin plating layer of a solar cell interconnect material as claimed in claim 1 or 2, and on a surface of the aluminum substrate The substrate side has a tin-nickel (Sn-Ni) alloy layer and a solder layer in this order. An interconnector for a solar cell, which is obtained by forming a solder layer on a surface of a tin plating layer of a solar cell interconnect material as claimed in claim 1 or 2, and on a surface of the aluminum substrate The substrate side has a nickel plating layer, a tin-nickel alloy layer, and a solder layer in this order. A solar cell unit with an interconnector, characterized in that the solar cell interconnector of claim 3 is connected to a solar cell unit. A solar cell unit with an interconnector characterized in that the solar cell interconnector of claim 4 is connected to a solar cell unit. The solar cell unit of the interconnector of claim 5, wherein the aforementioned solar cell interconnector is connected to the aforementioned solar cell unit by soldering. The solar cell unit of the interconnector of claim 6, wherein the solar cell interconnector is connected to the solar cell unit by soldering.