1.364847 九、發明說明： 【發明所屬之技術領域】 处本發明與一種導電勝有關，特別是關於一種用於太陽 ^電池之導電膠’其係、用以形成太陽能電池基材之背部電 【先前技術】 、太陽能發電產業是一個充滿發展遠景之新興產業，已 逐漸從能源概念產業中脫顆而出。目前國際油價節節高 漲’全球的石油資源有限，加上京都議定書對於廢氣減量 之％保意識抬頭，使得傳統燃石油、燃煤等發電方式受到 限制。故此，世界主要國家近年來積極研發以潔淨之再生 能源來取代礦物燃料發電’以減輕傳統發電方式所產生之 f染問題。在替代性能源中，無論是太陽能、風能、地熱 能、生質能等，均為各先進國家共同推展之目標，其中， 尤以太陽能之應用需求最為強烈。據太陽能研究機構 sdW調查顯*，在過去二十年内，太陽能光電的需求 呈現向上發展的趨勢。從太陽能光電系統安裝量來看，全 球的安裝量自2001年至2006年，已從34〇Mw攀升至 1，744MW，5年之間的成長逾4倍，每年平均增幅約刑。 可預見太陽能發電在未來人類能源利用方面扮演的角色越 來越重要。 太陽能電池（S〇lar cell)是一種可將光能轉換成電能之 裝置，其-般是以半導體材料’如包含單晶矽、多晶矽及 非晶矽等矽基材，或是化合物半導體，如GaAs GaPhp、 5 1364847 ▲ GaAs等m、v族元素化合物基材所製成。以矽基材而 言，業者一般作法是在P型石夕基材（p-type)正面的受光區域 摻雜鱗原子（Ph〇sphGnis)來形成—負電極區，而其背面未受 光之區域則為對應之正電極端。上述半導體基材中所形成 之PN接面（PN juncti〇n)會將特定波長⑷之入射光能量轉 換成電子電洞對（e-· h+ pair)往兩電極相反方向移動而產 生出電机’該電流即為太陽能電池的電能來源。一般而言， #碎基材的受光面還會鍍上一層抗反射膜（ARC，如氮化石夕 SiNx薄膜），來避免光反射造成㈣量損失，以增加太陽能 電池的轉換效率η (effieieney)。除了上述太陽能電池之半 導體基材外，業者一般都會在pN介面完成後於石夕基材背 面形成一層！呂背面電場（BSF，back ㈣，即背紹 電極）。鋁背面電場可減少少數載子（及電子e_、電洞h+) ，背面復合（reCOmbinati〇n)的機率，亦可用來作為電池的 旁面電極，進而改善太陽能電池的轉換效 •，最簡單的方式係為㈣材背面塗佈一層 、’·。使銘原子擴散進人發晶片内，形成—高銘摻雜濃度 (Al_dopani)之 P+層。 ▲為了將太陽能電池所產生的電流導引出來成為可用之 電能，半導體基材的兩端還須形成金屬電極來將電流導至 外部的電流負載端（load)。然，基材受光面（即正面）之金屬 電極會擋住受光面而阻礙太陽光之吸收，故太陽能電池的 正面金屬電極面積越小越好，以增加太陽能電池的受光區 域。故此，現今-般的金屬電極主要是利用網印技術⑽咖 6 1364847 ::=?能電池的兩正反面印製出網狀電極結構。 所明的網印電極備製，即係利用網印的方 ： 漿料（如銀膠）依昭所1舛 導電金屬1.364847 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a conductive conductor, and more particularly to a conductive adhesive for a solar cell, which is used to form a back surface of a solar cell substrate. Technology] The solar power industry is an emerging industry full of development prospects and has gradually emerged from the energy concept industry. At present, the international oil price is rising steadily. The global petroleum resources are limited. Together with the Kyoto Protocol's awareness of the reduction in emissions, the traditional power generation methods such as burning oil and burning coal are limited. Therefore, in recent years, major countries in the world have actively developed research and development to replace fossil fuel power generation with clean renewable energy to reduce the problem of dyeing caused by traditional power generation methods. Among the alternative energy sources, whether it is solar energy, wind energy, geothermal energy, biomass energy, etc., are the goals of advanced countries. Among them, the demand for solar energy is the strongest. According to the solar research institute sdW survey, in the past two decades, the demand for solar photovoltaics has shown an upward trend. From the perspective of the installation of solar photovoltaic systems, the global installed capacity has climbed from 34〇Mw to 1,744MW from 2001 to 2006, and has grown more than four times in five years, with an average annual increase of about a sentence. It is foreseeable that the role of solar power in the future use of human energy is becoming more and more important. A solar cell (S〇lar cell) is a device that converts light energy into electrical energy, and is generally a semiconductor material such as a germanium substrate containing a single crystal germanium, a polycrystalline germanium or an amorphous germanium, or a compound semiconductor such as GaAs GaPhp, 5 1364847 ▲ GaAs and other m and v element compound substrates. In the case of a ruthenium substrate, it is common practice for the substrate to be doped with a squamous atom (Ph〇sphGnis) in the light-receiving region on the front side of the P-type substrate (p-type) to form a negative electrode region, and the back surface is not exposed to light. Then it is the corresponding positive electrode end. The PN junction formed in the semiconductor substrate converts incident light energy of a specific wavelength (4) into an electron hole pair (e-·h+ pair) to move in opposite directions of the two electrodes to generate a motor. 'This current is the source of electrical energy for solar cells. In general, the light-receiving surface of the #shred substrate is also plated with an anti-reflection film (ARC, such as Nitride XiNx film) to avoid (four) loss of light reflection to increase the conversion efficiency of solar cells η (effieieney) . In addition to the above-mentioned solar cell semiconductor substrate, the industry generally forms a layer on the back side of the Shixi substrate after the pN interface is completed! Lu back electric field (BSF, back (four), that is, the back electrode). The electric field on the back side of the aluminum can reduce the probability of a few carriers (and electron e_, hole h+) and back recombination (recombinati〇n), and can also be used as a side electrode of the battery to improve the conversion efficiency of the solar cell. The method is to apply a layer on the back of the (four) material, '·. The Ming atom is diffused into the human hair wafer to form the P+ layer of the high-density doping concentration (Al_dopani). ▲ In order to direct the current generated by the solar cell into usable electrical energy, a metal electrode must be formed at both ends of the semiconductor substrate to conduct current to an external current load. However, the metal electrode on the light-receiving surface (i.e., the front surface) of the substrate blocks the light-receiving surface and hinders the absorption of sunlight. Therefore, the smaller the surface of the metal electrode of the solar cell, the better, so as to increase the light-receiving area of the solar cell. Therefore, the current metal electrode is mainly printed with a mesh electrode structure by using the screen printing technology (10) coffee 6 1364847 ::=? The known screen printing electrode is prepared, that is, the screen using the screen printing: slurry (such as silver glue) according to Zhaozhao 1舛 conductive metal
h “ 计之圖形印刷在已經過摻雜的矽A ，並在適當的燒結㈣下將: 劑揮發，使全眉類如φ主二 旬水付7的有機溶 間良好的歐姆形成”金，形綱之 1良姆接觸，進而成為太陽能電池的正反面金屬電 疋’過細的電極網線易造成斷線，或使其電阻升古 能電池的轉換效率，故如何達到細線化又： ::整體的發電效率便為此領域之技術重點。一般而 吕’金屬電極的膜厚約為10〜2 (加㈣⑽）寬度約為12〇2〇〇 而正面金屬的網線 能電、、也雷搞古二 ⑽。以此類技術來製作太陽 -電池電極有自動化、高產能及成本低之優點。 ，就—般太陽能電池碎基材而言（即非受光面）， 2㈣極結構包含了銀電極部分（網線電極部分）與銘電 極部分（及上述之背部雷揚邱八、 牙丨冤琢邛刀）。目别一般業界作法是先 在石夕基材的背面先用網印方式印上銀電極圖形，之後在於 其上形成鋁電極層，如圖—所示。由於鋁的可銲性 rderabiHty)很差，無法以直接焊接方式將各太陽能電池 連結’故—般業者會使用數條焊接帶1⑽dedng nbbon)銲在太陽能電池背部部分的銀電極區域上，使各發 電模塊間彼此電性連結整合。在圖—結構中，銀電極·石夕基 材介面2(即fire through層）以及紹電極石夕基材介面3(即 BSF層）會於燒結絲中會形成共晶層而使其緊密接合但 銀與銘之間不易形成共晶結構，其介面處易發生剝離現象 1^64847 (peeling)，使得銀電極與鋁電極間產生裂隙讓太陽能電池 .整體性能下降。故此，除了轉換效率測試外，太陽能電池 模組於製成後還須於背部進行焊接帶丨之拉力測試以及銀 電極與鋁電極介面的剝離測試，以確保模組背部結構的穩 固。 综上所言，可知除了形成PN接面的半導體基材外， 製作太陽能電池最主要的材料就是導電膠（paste)的部分。 目前習知技術中的導電膠都是由金屬粉末（特別是銀粉）、 玻璃熔塊（glass frit)、有機載體（vehicie)、以及添加劑 (additive)等原料所組成。其成分、含量、比例、製程參數 等都會影響到最後電極產物之性能。以背面金屬電極為 例，除了上述有關焊接帶拉力大小與銀鋁電極介面剝離程 度外，其用以形成之導電銀膠與鋁膠優劣亦會直接影響到 其太陽能電池性能之轉換.效率η、開路電壓Uopen circuit voltage)、短路電流 isc(sh〇rt circuh current)、填充因子 ρ ρ Φ (mi faCtor)、串聯電阻 Rs(series resistance)、以及分流電阻 Rsh (shunt resistance)等’亦會決定有效之燒結溫度範圍 與黏著力（adhesion strength)之大小。故如何調配出一種能 改善上述各項太陽能電池性能之導電膠為目前業界研發之 重點。 【發明内容】 鑑於上述習知技術之缺點，本發明提出了一種用於太 陽I電池之導電膠，其組成包含了一定比例範圍之銀粉、 鋁粉、玻璃熔塊、有機載體以及添加劑等，係用以形成太 8 1364847h “The graphic is printed on the already doped 矽A, and under proper sintering (4): The agent is volatilized, so that the whole eyebrows such as φ main levy water pay 7 The shape of the 1 good contact, and then become the front and back of the solar cell metal 疋 'too thin electrode network line is easy to cause disconnection, or its resistance to the conversion efficiency of the ancient energy battery, so how to achieve thinning and: :: The overall power generation efficiency is the technical focus of this area. Generally, the film thickness of the metal electrode is about 10~2 (plus (4) (10)) and the width is about 12〇2〇〇, while the wire of the front metal can be electrically, and also the second (10). Using such technology to make solar-battery electrodes has the advantages of automation, high productivity and low cost. As far as the solar cell is broken (ie, the non-light-receiving surface), the 2 (four)-pole structure includes the silver electrode portion (the wire electrode portion) and the electrode portion (and the back of the above-mentioned Lei Yang Qiu, the gums) Sickle). The general industry practice is to first print the silver electrode pattern on the back side of the Shixi substrate by screen printing, and then form the aluminum electrode layer on it, as shown in the figure. Since the solderability of aluminum is very poor, it is impossible to connect the solar cells by direct soldering. Therefore, the manufacturer will use several solder strips 1 (10) dedng nbbon to solder the silver electrode area on the back part of the solar cell to make each power generation. Modules are electrically connected to each other. In the structure of the structure, the silver electrode, the stone substrate interface 2 (ie, the fire through layer), and the electrode substrate 3 (ie, the BSF layer) form a eutectic layer in the sintered wire to make it tightly bonded. However, it is not easy to form a eutectic structure between silver and Ming, and the peeling phenomenon is likely to occur at the interface of 1^64847 (peeling), which causes cracks between the silver electrode and the aluminum electrode to cause the solar cell to deteriorate. Therefore, in addition to the conversion efficiency test, the solar cell module must be subjected to a tensile test of the solder ribbon and a peel test of the silver electrode and the aluminum electrode interface on the back to ensure the stability of the back structure of the module. In summary, it can be seen that in addition to the semiconductor substrate forming the PN junction, the most important material for fabricating a solar cell is the portion of the conductive paste. The conductive adhesives in the prior art are all composed of raw materials such as metal powder (especially silver powder), glass frit, organic carrier (vehicie), and additive. Its composition, content, ratio, process parameters, etc. all affect the performance of the final electrode product. Taking the back metal electrode as an example, in addition to the above-mentioned relationship between the tensile strength of the soldering strip and the peeling degree of the silver-aluminum electrode interface, the advantages and disadvantages of the conductive silver paste and the aluminum adhesive formed by the conductive strip directly affect the conversion of the performance of the solar cell. Efficiency η, Open circuit voltage (Uopen circuit voltage), short circuit current isc (sh〇rt circuh current), fill factor ρ ρ Φ (mi faCtor), series resistance Rs (series resistance), and shunt resistance Rsh (shunt resistance), etc. will also determine effective The sintering temperature range and the strength of the adhesion strength. Therefore, how to deploy a conductive adhesive that can improve the performance of the above solar cells is the focus of current research and development in the industry. SUMMARY OF THE INVENTION In view of the above disadvantages of the prior art, the present invention provides a conductive paste for a solar I battery, the composition of which comprises a certain proportion of silver powder, aluminum powder, glass frit, organic carrier and additives, etc. Used to form too 8 1364847
1 I 陽能電池基材之背部電極以將太陽能電池產生之電流出。 在本發明一實施例中，其導電膠的玻璃熔塊組成中含 有鉍（Bi)與/或鉍氧化物，可增加導電膠燒結後其電極在矽 基材上的黏著力。 在本發明另一實施例中，其比較了導電膠銀粉之粒徑 大小與形狀對於電極在石夕基材上黏著力之影響。 曰在本發明又一實施例中，其比較了導電膠中玻璃熔塊 含里對於電極在石夕基材上黏著力之影響。 在本發明又一實施例中，其比較了導電膠中鋁粉含量 對於電極在石夕基材上黏著力之影響。 本發明導電膠之製作方式亦於本發明書中揭示，其係 將本發明之導電膠以網印方式印在半導體基材上，並於高 溫爐中將其燒結成固態的電極。 本發明之目的，為提供一種含级成分之太陽能電池導1 I The back electrode of the solar cell substrate to discharge the current generated by the solar cell. In an embodiment of the invention, the glass frit of the conductive paste contains bismuth (Bi) and/or lanthanum oxide, which increases the adhesion of the electrode to the ruthenium substrate after sintering of the conductive paste. In another embodiment of the invention, the effect of the size and shape of the conductive colloidal silver powder on the adhesion of the electrode to the substrate is compared. In another embodiment of the present invention, the effect of the glass frit in the conductive paste on the adhesion of the electrode to the substrate is compared. In still another embodiment of the present invention, the effect of the aluminum powder content in the conductive paste on the adhesion of the electrode to the stone substrate is compared. The method of making the conductive paste of the present invention is also disclosed in the present invention, which is obtained by screen printing a conductive paste of the present invention on a semiconductor substrate and sintering it into a solid electrode in a high temperature furnace. The object of the present invention is to provide a solar cell guide with a graded component
本發明之另—目的，為提供—種太陽能電池用導電 膠、、具有優良的光電轉換效率”與電極黏著力。 hi發r之又—目的’為提供上述本發明太陽能電池用 導電膠之製作方法。 以述之t式、目#、觀點、特徵及優點將隨著 下=佳：施例"細的描述及其伴隨之圖式而愈見明 顯，其細卽描述與圖式僅用 ^ ^ ^ 僅用以述明本發明。而本發明之範 可將由隨附之專利請求項來定義。 【實施方式】 9 工,364847 此處本發明將針對發明具體實施例及其觀點加以詳细 描述，此類描述為解釋本發明之結構或步驟流程，其係供 以說明之用而非予以本發明中請專利範圍限制之實^因 此，除說明書中之具體實施例與較佳實施例外，本發 可廣泛施行於其他不同的實施例中。 太陽能電池背面亦需導電膠，目的在於製作電極及連 接焊接帶（dbbon)以利電池串接。本發明所提出之導電膠係 用以形成太陽能電池基材背面之銀電極（即非受光面），盆 技術特徵在於改善該銀電極與石夕基材之間的拉力（銀電極 於石夕基材上之黏著力）、剝離程度（peeling，銀電極與銘電 極介面間剝離現象)、以及整體太陽能電池轉換效率黏 著力越高，代表導電勝燒結後電極與石夕基材之間的接合越 好。為達上述目的，本發明之導電勝成分大體上包含了銀 粉（Ag)、鋁粉(A1)、玻璃熔塊（frit)、有機載體^ 及各類添加劑（additives)。列表中關於拉力、剝離程度、轉 φ換效率測試之細節亦會於系列的實施例中描述。 銀疋導電性非常好的介質，於發明實施例中，銀粉顆 粒可為片狀（flake)、球狀（spherical)或兩者之混合。於本發 明中，其銀粉粒徑約分佈在〇5〜1〇〇 μηι之間下面的^ 施例中將就不同的銀粒粒徑大小與形狀來作比較。於本發 明令，只要導電膠銀成分含量能達到本發明之目的，本^ 明並不會特别對其比例加以限定。不過就實施例而言，其 銀粉比例約佔整體導電膠重量5〇〜9〇wt %(重量百分比）為 佳。 ’ 1364847 1 在本發明實施例中，有機載體是分別以有機溶劑與樹 脂調配而成，其有機溶劑最好是由二種以上的溶劑混合而 成’如醇醚類的二甘醇一丁醚（Butyl Carbit01, DB)、 权油醇（alpha- Tei^pineoi)、Texan〇i成膜劑等；樹脂亦以二 種以上不同分子量的纖維素混合為佳，如乙基纖維素 (Ethyl cellulose ’ EC)、木松香、聚丙烯腈或其混合物。在 實施例中，只要有機載體的含量能達到本發明之目的，本 心明並不會特別對其比例加以限定。不過就實施例而言， 其比例含量佔約整體導電膠重量1〇〜25wt %為佳。 在玻璃熔塊方面，其組成中含有鉍Bismuth與/或鉍氧 化物Bi2〇3之成分，並還包含了其他如Si〇2、B2〇3、Ai2(^、Another object of the present invention is to provide a conductive paste for a solar cell, which has excellent photoelectric conversion efficiency and electrode adhesion. The purpose of the present invention is to provide the conductive paste for the solar cell of the present invention. The method of t-type, mesh #, viewpoint, features and advantages will be more and more obvious with the following description: the example & detailed description and its accompanying schema, the detailed description and the schema are only used. ^ ^ ^ is only used to describe the present invention, and the scope of the present invention will be defined by the accompanying patent claims. [Embodiment] 9 work, 364847 The present invention will be described in detail with respect to the specific embodiments of the invention DETAILED DESCRIPTION OF THE INVENTION The descriptions of the present invention are intended to be illustrative of the structure or the steps of the present invention, which are intended to be illustrative and not to limit the scope of the invention in the present invention. The present invention can be widely applied to other different embodiments. The back side of the solar cell also needs conductive adhesive, the purpose is to make the electrode and the connection soldering strip (dbbon) to facilitate the battery serial connection. The conductive adhesive proposed by the invention The silver electrode (ie, the non-light-receiving surface) for forming the back surface of the solar cell substrate is characterized in that the tensile force between the silver electrode and the stone substrate (the adhesion of the silver electrode to the stone substrate) and the peeling are improved. The degree (peeling, the peeling phenomenon between the silver electrode and the electrode surface), and the higher the conversion efficiency of the overall solar cell conversion efficiency, the better the bonding between the electrode and the stone substrate after the conduction wins. For the above purpose, The conductive component of the invention generally comprises silver powder (Ag), aluminum powder (A1), glass frit, organic carrier, and various additives. The list relates to tensile force, peeling degree, and conversion efficiency. The details of the test will also be described in the series of embodiments. The silver enamel is very conductive, and in the embodiment of the invention, the silver powder particles may be flake, spherical or a mixture of the two. In the present invention, the particle size distribution of the silver powder is approximately between 〇5~1〇〇μηι. The following examples will compare the particle size and shape of the different silver particles. to make The content can achieve the purpose of the present invention, and the present invention is not particularly limited in its proportion. However, in the embodiment, the proportion of silver powder is about 5 〇 9 9 wt% (% by weight). In the embodiment of the present invention, the organic vehicle is prepared by mixing an organic solvent and a resin, and the organic solvent is preferably a mixture of two or more solvents, such as diethylene glycol monool such as an alcohol ether. Ether (Butyl Carbit01, DB), oleyl alcohol (alpha-Tei^pineoi), Texan〇i film former, etc.; resin is also better mixed with two or more different molecular weight cellulose, such as ethyl cellulose (Ethyl cellulose 'EC), wood rosin, polyacrylonitrile or a mixture thereof. In the examples, as long as the content of the organic vehicle can attain the object of the present invention, the present invention is not particularly limited in its proportion. However, in the case of the embodiment, the proportion of the conductive paste is preferably from about 1 to 25 wt%. In terms of glass frit, the composition contains bismuthumth and/or bismuth oxide Bi2〇3, and also contains other such as Si〇2, B2〇3, Ai2(^,
ZnO Tl2〇3、Pb〇、Sr〇、Zr02、K20、P2〇5 成分不同比例 之組合。就實施例而言，其比例含量佔約整體導電膠重量 1〜10wt %為佳。 此外，本發明導電膠亦可視各項需求添加一定含量的 _ 添加劑，如分散劑（dispersant)、流平劑（leveUing agent)、 觸變劑（thixotropic agent)、穩定劑（stabiHzer)、黏度調節劑 (viscosity adjuster)、以及介面活性劑（surfactant)等助劑， 其含量約佔導電膠整體〇〜5wt%之間。此添加劑會在有機 載體做成後添加，其主要作用係為調整膠體之黏度且具有 潤濕與粒子均勻分散的功能’亦可增進燒結後金屬粒子的 緊密度、導t度，&添加二種以上#添加物能達到更佳的 效果。 首先參照表一，其為本發明一實施例中設計以不同玻 1364847 璃組成與銀粒形狀來測試電極的拉力、轉換效率以及剝離 程度之實驗。該實驗依所使用的銀粒形狀（片狀、球形）分 成兩大組，每大組再依所使用之玻璃種類（玻璃II、III、IV、 V、VII)分成五個比較組，上述分組之目的在於比較導電膠 令銀粒之形狀以及玻璃熔塊之成分對整體導電膠性質造成 的影響。於本實施例中，片狀銀粒組所使用之銀粉為銀粉 III，球形銀粒組所使用之銀粉為銀粉VII，兩組銀粉之組 成比例皆佔整體導電膠69.3 wt%的重量百分比。有關各銀 粉種類詳細之規格請參照表二，而各實驗組使用之玻璃炫 塊成分請參照表三。 组別 1 2 3 4 5 6 7 8 9 10 鈒粒形狀 片狀 片狀 片狀 片狀 片狀 球形 球形 球形 球形 球形 銀粉種類69.3 wt% 銀粉皿 銀粉m 銀粉皿 銀粉m 銀粉m 銀粉νπ 銀粉νπ 銀粉νπ 銀粉νπ 銀粉νπ 玻璃種類4.20 wt% 玻瑀Π 玻瑀IV 玻璃W 玻璃V 玻璃111 玻璃π 玻璃IV 玻璃νπ 玻璃V 玻瑀π 剝離程度 優 優 優 優 優 優 劣 優 優 劣 拉力(N) 1.34 2.68 2.36 0.82 2.27 3.14 3.29 4.12 3.21 4.08 效率(％) 14.95% 15,31% 15.20% 15.14% 15.44% 15.17% 15.20% 15.22% 15.23% 15.27%A combination of different ratios of ZnO Tl2〇3, Pb〇, Sr〇, Zr02, K20, and P2〇5 components. For the examples, the proportion of the conductive paste is preferably from 1 to 10% by weight based on the total weight of the conductive paste. In addition, the conductive paste of the present invention may also add a certain amount of additives such as a dispersant, a leve Uing agent, a thixotropic agent, a stabilizer (stabiHzer), a viscosity modifier, depending on various requirements. (viscosity adjuster), and an auxiliary agent such as surfactant, which accounts for about 5% by weight of the conductive adhesive. The additive is added after the organic carrier is formed, and its main function is to adjust the viscosity of the colloid and have the function of uniform dispersion of the particles and the particles. It can also improve the tightness and conductivity of the metal particles after sintering, and add More than the above # additives can achieve better results. Referring first to Table 1, an experiment for designing the tensile strength, conversion efficiency, and peeling degree of an electrode by using a glass composition of 1364847 and a silver particle shape in an embodiment of the present invention. The experiment is divided into two groups according to the shape of the silver particles (sheet, sphere) used, and each group is divided into five comparison groups according to the type of glass used (glasses II, III, IV, V, VII). The purpose is to compare the shape of the conductive paste with the shape of the silver particles and the composition of the glass frit to the properties of the overall conductive paste. In the present embodiment, the silver powder used in the flake silver group is silver powder III, and the silver powder used in the spherical silver group is silver powder VII, and the composition ratio of the two groups of silver powder accounts for 69.3 wt% of the total conductive rubber. Please refer to Table 2 for the detailed specifications of each silver powder type, and refer to Table 3 for the glass block components used in each experimental group. Group 1 2 3 4 5 6 7 8 9 10 鈒 grain shape sheet-like sheet-like sheet-like spherical spherical spherical spherical spherical silver powder type 69.3 wt% silver powder silver powder m silver powder silver powder m silver powder m silver powder νπ silver powder νπ silver powder Νπ Silver powder νπ Silver powder νπ Glass type 4.20 wt% Glass 瑀 Glass 瑀 IV Glass W Glass V Glass 111 Glass π Glass IV Glass νπ Glass V 瑀 π Peeling degree excellent and excellent excellent and bad good and bad strength (N) 1.34 2.68 2.36 0.82 2.27 3.14 3.29 4.12 3.21 4.08 Efficiency (%) 14.95% 15,31% 15.20% 15.14% 15.44% 15.17% 15.20% 15.22% 15.23% 15.27%
(表一） 銀粒種類 平均粒徑 純度 形狀 銀粒I 3.45 >99% 片狀 銀粒Π 5.06 >99% 片狀 銀粒皿 3.88 >99% 片狀 銀粒IV 1.79 >99% 球形 銀粒V 2.8 >99% 球形 銀粒VI 2.12 >99% 球形 銀粒νπ 5.51 >99% 球形 (表二） 12 Ιβ64847 » 玻璃種類 Si02 B2〇3 Al2〇3 ZnO Bi2〇3 τι2〇3 PbO SrO Zr02 k2o p2o5 玻璃Π 9.77% 5.33% 2.93% <1% <1% <1% 80.47% <1% 0.99% <1% <1% 玻璃HI 4.84% 8.31〇/〇 <1% 7.07% 76.99% <1% <1% 2.26% <1% <1% 玻璃IV 9.82% 8.77% 5.21% <1% 60.81% <1% <1% 14.81% <1% <1% <Ί〇Λ 玻瑀V 13.66% 4.67% 1.43% 39.02% <1% <1% 40.01% <1% 0.18% <1% <1% 玻璃VD 23.73% 8.39% 6.31% <1% 38.18% 20.40% <1% <1% <1% 1.77% <1% (表三） 如表三所示’本發明實施例使用了約佔整體導電勝 4.20 wi %比例的玻璃熔塊，其成分包含了別2〇3、Si〇2、 B2O3、Al2〇3、ZnO、T1203、PbO、SrO、Zr〇2、κ20、p2〇5 等各種金屬氧化物組成。表三中所示之重量百分比為該成 分玻璃溶塊整體之比例。 復參照表一，從各組測試結果顯示，本實施例中導電 膠依使用的銀粒形狀與玻璃種類會對拉力（即電極的黏著 力）衫響，但對於太陽能電池整體的轉換效率以及電極的剝 離程度也沒有顯著的關係。導電膠所使用的銀粉粒徑越 小，其所能達到的拉力值就越大，如圖二所示，平均粒徑 2.2μιη大小之球形銀粉可以達到近6牛頓（N)大小的拉力水 準，相較之下，5.5μπι大小之球形銀粉粒徑僅能達到約35 牛頓（Ν)的拉力水平。此外須注意的是，片狀銀粉所能達到 =拉力並不如球狀銀粉佳，如圖中的三角形標記所示，儘 官其片狀銀粉平均粒徑有3 8μπι之大小，但所能達到的拉 力Κ準僅有3·〇牛頓（ν)左右，較之5 5μπι粒徑大小之球形 銀粉還=如。同樣的實驗結果可以在圖三中觀察到，其為 本發月貫施例巾》別使用球形銀粉與片狀銀粉搭配不同玻 璃炼塊成分之拉力關係圖。從圖中可知，在使用相同玻璃 溶塊的情況下’球形銀粉所能達到的拉力值都較片狀銀粉 13 ^364847 來的大，顯示呈球狀的銀粉 内部結構較為密實盥石u 其產生之背銀電極 構季乂為在實，與矽基材的表面接合性佳。反 狀銀粒為主體之導電膠經 結構1Λ?、、η > ώ ^ 、。 八產生之为銀電極内部 構二洞多，與矽基材之間的接合性差。(Table 1) Silver Species Average Particle Size Purity Shape Silver Particles I 3.45 > 99% Flaky Silver Particles 5.06 > 99% Flaky Silver Discs 3.88 > 99% Flaky Silver Particles IV 1.79 > 99% Spherical silver particles V 2.8 > 99% spherical silver particles VI 2.12 > 99% spherical silver particles νπ 5.51 > 99% spherical (Table 2) 12 Ιβ64847 » Glass type Si02 B2〇3 Al2〇3 ZnO Bi2〇3 τι2〇 3 PbO SrO Zr02 k2o p2o5 glass crucible 9.77% 5.33% 2.93% <1% <1% <1% 80.47% <1% 0.99% <1% <1% glass HI 4.84% 8.31〇/〇 <1% 7.07% 76.99% <1% <1% 2.26% <1% <1% Glass IV 9.82% 8.77% 5.21% <1% 60.81% <1% <1% 14.81% <1% <1% <Ί〇Λ Glass V 13.66% 4.67% 1.43% 39.02% <1% <1% 40.01% <1% 0.18% <1% <1% Glass VD 23.73% 8.39% 6.31% <1% 38.18% 20.40% <1% <1% <1% 1.77% <1% (Table 3) As shown in Table 3, the embodiment of the present invention uses approximately The overall conductivity wins 4.20 wi% of the glass frit, and its composition contains other 2〇3, Si〇2, B2O3, Al2〇3, ZnO, T1203, PbO, SrO, Zr〇2, κ20, p2 5 and other metal oxides. The weight percentages shown in Table 3 are the ratio of the integral glass solubilized block as a whole. Referring to Table 1, the test results of each group show that in the present embodiment, the shape and shape of the silver particles used in the conductive adhesive are squeaking to the tensile force (ie, the adhesion of the electrode), but the conversion efficiency and the electrode of the solar cell as a whole are There is also no significant relationship between the degree of stripping. The smaller the particle size of the silver powder used for the conductive paste, the greater the tensile force it can achieve. As shown in Figure 2, the spherical silver powder with an average particle size of 2.2 μm can reach a pull level of approximately 6 Newtons (N). In contrast, a particle size of 5.5 μm spherical silver powder can only reach a tensile level of about 35 Newtons (Ν). In addition, it should be noted that the flaky silver powder can reach = the tensile force is not as good as the spherical silver powder, as shown by the triangular mark in the figure, the average particle size of the flaky silver powder is 3 8μπι, but it can be achieved. The tensile force is only about 3·〇 Newton (ν), compared with the spherical silver powder of 5 5μπι size. The same experimental results can be observed in Fig. 3, which is a tensile force diagram of the composition of different glass refining blocks using spherical silver powder and flake silver powder. It can be seen from the figure that in the case of using the same glass dissolution block, the tensile force value of the spherical silver powder is larger than that of the flake silver powder 13 ^ 364847, and the spherical silver powder has a dense internal structure and is produced by vermiculite u. The back silver electrode has a good seasonality and good adhesion to the surface of the tantalum substrate. The reverse-shaped silver particles are the main conductive paste structure 1Λ?, η > ώ ^,. Eight is produced as a silver electrode with a large internal cavity and poor adhesion to the tantalum substrate.
另:方面就玻㈣塊成分來看，可以觀察到使用玻璃 1玻璃W及玻璃VII之實驗組所能達到之拉力值較佳， 順所搭配者為片狀或球形之銀粒。參照表三之成分，其 共通點在於玻璃熔塊中含有高比例的色氧化物一兰也，顯 二鉍或鉍氧化物成分有助於提升導電膠之拉力值一。此外， 广尤片狀銀粒之實驗組而έ，可發現使用玻璃η與玻璃v組 別的拉力表現特別差，其原因在於使用高含量的氧化鉛 PbO與氧化鋅Ζη〇，此兩金屬氧化物雖於太陽能電池其他 性能有所助益，但明顯會使電極所具備之拉力下降。 現在請參閱下表。表四所示者為本發明另一實施例中 針對銀粒形狀、玻璃熔塊含量以及助劑（即添加劑）添加與 否所作的實驗比較。 組別 1 2 3 4 5 6 7 8 9 銀粒形妝 片狀 片狀 片狀 球形 球形 球形 球形 球形 球形 銀粉種類 / wt% 銀粒I 73.50% 65.10% 65.10% 銀粒VI 73.50% 72.30% 71.30% 70.30% 69.30% 65.10% 玻璃融塊 wt% 玻璃IV 0% 1.20% 2.20% 3.20% 4.20% 8.40% 玻璃V 8.4% 8.4% _ 助劑 無 無 有 有 有 有 有 有 有 剝離裎唐 ~劣 優 優 優 優 優 優 優 拉力ΓΝ) 0.1 0.7 1.2 0.3 1.7 3.1 4.1 5.86 6.81 效率f%) 14.50% 14.96% 15.17% 15.18% 15.21% 15.35% 15.25% 15.24% 14.88% (表四） Ιβ64847 本實把例令分別使用銀粒j片狀銀粉與銀粒νι片狀銀 粉，其比例介於整體導電膠65丨〜73 5 wt%之間視其所使 用的玻璃熔塊含量而定。銀粒j與銀粒¥1詳細規格請參照 上面表二。使用球形銀粉之實驗組針對不同的玻璃熔塊含 量來作比較，從實驗數據可以發現當玻璃熔塊的含量越 多，所能達到的電極拉力值就越大，其關係如圖四所示。 在不使用任何玻璃熔塊的實驗條件下，所能達到之拉力值 籲幾乎接近零，而8 wt%含量之玻璃熔塊卻能達到6牛頓（N) 優異的拉力表現，顯示玻璃熔塊含量越高，背銀電極中熔 融玻璃更易與熔融的銀粒相互擴散，形成一導電的共晶結 構，分佈在熔融銀粒空隙及銀_矽介面及銀_鋁介面上，故 強化背銀電極結構，使得整體拉力值增加。須注意者，使 用的玻璃熔塊含量過多，會使焊接變得困難，且電阻值 增大。以本實施例而言，其玻璃含量最佳值應佔整體導電 膠1〜10 wt %的比例。 • 另一方面，在表四片狀銀粒的實驗組方面，可觀察到 助劑（additive)的添加與否對整體拉力值與電極之剝離現 象程度（peeling)有很大的影響。導電膠中若不添加任何的 助劑，其内部組成粒子如銀粒、鋁粒、玻璃熔塊等便無法 在有機載體中均勻分散，燒結後所形成之銀電極結構較為 鬆散，銀-鋁介面或銀-矽介面亦無法獲得良好的接合，故 其剝離程度與拉力表現都不佳，電池的轉換效率亦有明顯 的下降。就本發明實施例而言，其添加助劑含量應佔整體 導電膠0〜5 wt %的比例為佳。 15 1364847 接下來請參照下表，表五所示者 =粒含量多寡與電極拉力、轉換效率之關係實= 在同樣銀粒形狀、含量以及玻璃炼塊種類表 ::率亦的比例越高’所能達到的電池轉 、革才越π，故可知於背部銀膠中添加铭粒有 整體太陽能電池之轉換效率。作相心η 神兴双手但相對者，鋁粒的含量越高， “所具備的拉力就越小，下降幅度非常嚴重。故實際應 用中可就電性、電極剝離及拉力之考量選擇㈣的最佳調 -己比來it到吾人所需之太陽能電池特性。京尤本發明實施 例而言，其！呂粒含量以佔整體導電膠〇〜5 wt %的比例為 佳。 組別 I Π m 銀粒形肤 球形 球形 球形 銀粒粒徑 銀粒VI 69.30% 65.93% 64.93% 玻璃融塊 玻璃IV 4.20% 4.95% 4.95% 铭粒wt % 0% 3.37% 4.37% 拉力(N) 5.86 3.23 1.5 效率 15.24% 15.35% 15.41% 儘管本發明上面列表與說明中有對其實施方式中各成 分之組成與含量作明確之定義，本領域之熟習技藝者須認 知者’上述本發明實施例中導電膠之各成分組成與含量並 非褐限於一特定的數值，其組成與含量範圍將視該成分能 否達到發明之目的來作定義。 16 1364847 下面之實施例中將描述導電膠之配製方法。須注意該 配置方法之步驟、成分比例、各實驗參數僅供以說明本發 明之實施方式，非欲就本發明之請求項加以限定。 Λ 百先，先將一定成分比例之鋁粒、玻璃熔塊加到有機 載體中’用混合器（mixer)先行預混。該有機載體可為乙基 纖維素樹脂（EC，ethyl cellulose)與二乙二醇丁鍵（DB，butyi 參carbltol)之混合物，但並不限於僅能使用此類的有機溶 劑。在其他的實施例中，亦可使用其他醇醚類溶劑或可溶 $維素樹脂類之有機溶劑，如木松香、聚丙稀腈、松油醇 荨。該#機载體内亦可添加一定比例的添加劑或助劑 (:ddltlves)，這些添加劑可以是黏度調整劑、分散助劑、觸 灸助劑、潤濕助劑等功能性添加劑。於本實施例中，該玻 2炫塊可含有許多氧化物玻璃成分，其組成與比例由實驗 者自行決定。在第-次預混後，接著將銀粒添加到已預混 修的處合物中，再用混合器加以預混。預混完成後，包含銀 粒:銘粒、玻璃炫塊、有機載體以及添加劑之混合物會使 二三滾筒捏合機（3_rollmill)幫助分散研磨均勻混合後所 付到之糊狀或膏狀物即為導電膠。On the other hand, in terms of the composition of the glass (four) block, it can be observed that the experimental group using the glass 1 glass W and the glass VII can achieve a better tensile value, and the matched ones are flakes or spherical silver particles. Referring to the composition of Table 3, the common point is that the glass frit contains a high proportion of color oxides, and the bismuth or bismuth oxide component contributes to the increase of the tensile strength of the conductive paste. In addition, the experimental group of Guangyu flaky silver particles found that the tensile strength of the glass η and the glass v group was particularly poor, because the high content of lead oxide PbO and zinc oxide Ζ 〇 〇, the two metal oxidation Although the material is helpful in other properties of the solar cell, it obviously causes the tensile force of the electrode to decrease. Please refer to the table below now. Table 4 shows an experimental comparison of silver particle shape, glass frit content, and additive (i.e., additive) addition in another embodiment of the present invention. Group 1 2 3 4 5 6 7 8 9 Silver-grained-shaped sheet-like flaky spherical spherical spherical spherical spherical silver powder type / wt% Silver granule I 73.50% 65.10% 65.10% Silver granule VI 73.50% 72.30% 71.30% 70.30% 69.30% 65.10% Glass melt wt% Glass IV 0% 1.20% 2.20% 3.20% 4.20% 8.40% Glass V 8.4% 8.4% _ Auxiliary Nothing There are some peeling 裎 唐~ Inferior excellent优优优优拉力ΓΝ) 0.1 0.7 1.2 0.3 1.7 3.1 4.1 5.86 6.81 Efficiency f%) 14.50% 14.96% 15.17% 15.18% 15.21% 15.35% 15.25% 15.24% 14.88% (Table 4) Ιβ64847 This example uses silver grains separately. j flake silver powder and silver νι flake silver powder, the ratio of which is between 65 丨 and 73 5 wt% of the total conductive adhesive depending on the glass frit content used. Silver grain j and silver grain ¥1 For detailed specifications, please refer to Table 2 above. The experimental group using spherical silver powder was compared for different glass frit contents. From the experimental data, it can be found that the more the glass frit content, the larger the electrode pull value can be achieved, and the relationship is shown in Fig. 4. Under the experimental conditions without using any glass frit, the tensile force can reach almost zero, while the 8 wt% glass frit can reach 6 Newtons (N). The tensile strength shows the glass frit content. The higher the molten glass in the back silver electrode is, the easier it is to diffuse with the molten silver particles to form a conductive eutectic structure, which is distributed in the voids of the molten silver particles and the silver-germanium interface and the silver-aluminum interface, so that the back silver electrode structure is strengthened. , so that the overall tensile value increases. It should be noted that the excessive amount of glass frit used will make welding difficult and the resistance value will increase. In the present embodiment, the optimum glass content should be in the proportion of 1 to 10 wt% of the entire conductive paste. • On the other hand, in the experimental group of the four-piece silver particles, it can be observed that the addition of additives has a great influence on the overall tensile force value and the peeling degree of the electrode. If no additives are added to the conductive paste, the internal constituent particles such as silver particles, aluminum particles, glass frits, etc., cannot be uniformly dispersed in the organic carrier, and the silver electrode formed after sintering is loosely structured, and the silver-aluminum interface is loose. Or the silver-tank interface can not get a good joint, so the degree of peeling and tensile performance are not good, and the conversion efficiency of the battery is also significantly reduced. For the embodiment of the present invention, the additive additive content should preferably be 0 to 5 wt% of the total conductive adhesive. 15 1364847 Next, please refer to the following table, the table shown in Table 5 = the relationship between the amount of grain content and the electrode pull force, conversion efficiency = in the same silver grain shape, content and glass refining type table:: the ratio of the rate is also higher ' The more the battery can be transferred to the leather, the more π, so it can be seen that the addition of the inscription in the back silver gel has the conversion efficiency of the overall solar cell. For the heart η, the hands of the gods are opposite, but the higher the content of aluminum particles, the smaller the tension is, and the drop is very serious. Therefore, in practical applications, the choice of electrical properties, electrode peeling and tensile force can be selected (4). The best tuning - has been compared to the solar cell characteristics required by ours. In the case of the invention of the invention, it is preferred that the content of the granules is ～5 wt % of the total conductive yam. Group I Π m silver grain shape spherical spherical silver particle size silver particle VI 69.30% 65.93% 64.93% glass melting glass IV 4.20% 4.95% 4.95% Ming grain wt % 0% 3.37% 4.37% tensile force (N) 5.86 3.23 1.5 efficiency 15.24% 15.35% 15.41% Although the above list and description of the present invention clearly defines the composition and content of the components in the embodiments thereof, those skilled in the art will recognize that the conductive paste of the above-described embodiments of the present invention The composition and content of each component are not limited to a specific value, and the composition and content range will be defined depending on whether the component can achieve the purpose of the invention. 16 1364847 The following examples will describe the preparation method of the conductive paste. The steps of the configuration method, the composition ratio, and the experimental parameters are only for explaining the embodiments of the present invention, and the requirements of the present invention are not limited. Λ 百先, firstly add a certain proportion of aluminum particles and glass frit In the organic vehicle, the mixture is premixed with a mixer. The organic carrier may be a mixture of ethyl cellulose resin (EC, ethyl cellulose) and diethylene glycol butyl bond (DB, butyi carbol), but not It is limited to the use of only such organic solvents. In other embodiments, other alcohol ether solvents or soluble organic solvents such as wood rosin, polyacrylonitrile, terpineol may also be used. The #machine carrier may also add a certain proportion of additives or auxiliaries (: ddltlves), which may be functional additives such as viscosity modifiers, dispersing aids, moxibustion aids, wetting aids, etc. In the example, the glass 2 block may contain a plurality of oxide glass components, the composition and ratio of which are determined by the experimenter. After the first premixing, the silver particles are then added to the premixed composition. Mix with the mixer Premixed. After the premixing is completed, it contains silver particles: the mixture of Ming granules, glass lumps, organic carriers and additives will make the two or three roller kneaders (3_rollmill) help to disperse and grind the paste or paste after the uniform mixing. The object is a conductive paste.
If刷彳 導電膠混合完成後，接著網印方式（s⑽n⑽此⑻將 二電膠印刷在石夕基材背面’此即石夕基材之背部銀電極部 /刀。背部銀勝完成網印後，再分別於石夕基材正面與背面印 上正面銀電極與背面銘電極。在本發明實施例中，其正面 17 1364847 銀電極採用DuP〇nt PV-145銀膠’背面鋁電極採用Gsc A168叙膠。電極印製完成後’整個矽基材會被置於—烘箱 中乾燥。對於不同性能的導電膠，其網印後所須之乾燥溫 度與時間會隨著有機載體使用之有機溶劑以及印刷重量而 有所不同。在本實施例中’其乾燥溫度設定在15〇〜2〇〇 °C ’乾燥時間為5〜15分鐘。 燒結锃年 鲁 乾燥步驟完成後，將整個矽基材置於一紅外線傳送帶 式燒結爐來對導電膠進行燒結製程。與本實施例中，其燒 結之峰值溫度（peak temperature)可在6〇〇〜8〇〇。〇之間做調 整，燒結過後的導電膠會在基材的正反面形成固態的電極 並與矽基板間產生接合。 量測程序 拉力測試（黏著力測試）： 電極製作完成後，將-錫條（在本發明中，其成份為锡 #船合金披覆在鋼片外表，截面寬約1 8〜2咖，其錫鉛比例 為60:40)用烙鐵焊接在石夕基材背部銀電極上，絡鐵頭使用 斜刀口形狀’其焊接溫度為32〇〜35〇ΐ，移動速度為 1〜5cm/s。完成焊接後，利用拉力機設定18〇。角、速度為 !20〜36〇mm/s之測試條件來測量背銀電極之拉力值 (adhesion strength) ° 剝離測試（peeling test): 使用3M 600 Scotch透明膠帶為測試帶，將膠帶以順 向方式緊密黏著於包含背銀電極與背銘電極之表面區域， 18 I?64847 其後將膠帶以9 〇。角撕故 如 會 角撕起。撕起後’觀察其剝落情形， 圖广所不。若背銀電極與背銀電 剝落並殘留在膠帶±，即未通過㈣賴，^層 反之，則通過測試，如圖五3所示。 所不 轉換效率7?測試： 上、使用太陽能測試機對製作出之太陽能模版進行電性測 试’其測試條件為在光源照射強度AM 1.5G的環境下。所 使用之太1¼此測試機台型號為QuickSun公司的12〇CA。 【圖式簡單說明】 本毛明可藉由說明書中若干較佳實施例與其詳細敘述 及Ik附圖式得以瞭解。然而，此領域之技藝者應得以領會 所有本發明之較佳實施例係用以說明而非就本發明之申請 專利範圍予以限定，其中： 圖一為本發明實施例中背部電極之示意圖； 圖二為本發明實施例中銀粉粒徑與拉力之關係圖； 圖三為本發明實施例中各組不同玻璃熔塊與拉力之關 係圖； 圖四為本發明實施例中各玻璃熔塊含量與拉力之關係 圖；以及 圖五為本發明實施例中剝離測試結果之圖像。 【主要元件符號說明】 1 焊接帶 2 介面 3 介面 19If the brush and conductive paste are mixed, then the screen printing method (s(10)n(10) (8) will print the second glue on the back of the stone substrate. This is the silver electrode part/knife of the back of the stone substrate. After the back of the silver wins the screen printing Then, the front side silver plate and the back side electrode are printed on the front and back sides of the Shixi substrate, respectively. In the embodiment of the invention, the front side of the silver plate is made of DuP〇nt PV-145 silver paste, and the back aluminum electrode is made of Gsc A168. After the electrode is printed, the whole substrate will be placed in an oven for drying. For different properties of the conductive paste, the drying temperature and time required for screen printing will be the same as the organic solvent used in the organic carrier. The printing weight varies. In the present embodiment, the drying temperature is set at 15 〇 2 〇〇 ° C. The drying time is 5 to 15 minutes. After the sintering 锃 Lulu drying step is completed, the entire ruthenium substrate is placed. The sintering process is performed on the conductive paste in an infrared belt type sintering furnace. In this embodiment, the peak temperature of the sintering can be adjusted between 6 〇〇 8 〇〇 〇, and the conductive after sintering. gum A solid electrode is formed on the front and back sides of the substrate and a joint is formed with the ruthenium substrate. Measurement procedure tensile test (adhesion test): After the electrode is fabricated, the tin strip (in the present invention, the composition is tin #船The alloy is coated on the outer surface of the steel sheet, and the cross-section is about 1 8~2 coffee. The tin-lead ratio is 60:40. It is soldered on the silver electrode on the back of the stone substrate with a soldering iron. The shape of the angle is determined by the shape of the oblique blade. It is 32〇~35〇ΐ, and the moving speed is 1~5cm/s. After the welding is completed, the tension of the back silver electrode is measured by setting the test condition of 18〇 with angle and speed of 20~36〇mm/s. Adhesion strength ° Peeling test: Using 3M 600 Scotch scotch tape as the test strip, the tape is adhered in a forward direction to the surface area containing the back silver electrode and the back electrode, 18 I?64847 The tape is torn at 9 〇. The corner is torn like a corner. After tearing up, 'observing the peeling off, the picture is wide. If the back silver electrode and the back silver are peeled off and left on the tape ±, that is not passed (four) Lai, ^ Layer, on the contrary, passes the test, as shown in Figure 5-3. No conversion efficiency 7? Test: On the solar tester, the solar test stencil was electrically tested. The test conditions were in the environment of the light source illumination intensity of 1.5 1.5 G. The test machine model used was too 11⁄4. It is a 12-inch CA of QuickSun. [Simplified description of the drawings] The present description can be understood by several preferred embodiments of the specification, detailed descriptions thereof and Ik drawings. However, those skilled in the art should be able to understand all of them. The preferred embodiments of the invention are intended to be illustrative and not to limit the scope of the invention, wherein: FIG. 1 is a schematic diagram of a back electrode according to an embodiment of the invention; FIG. 2 is a particle size and tension of a silver powder according to an embodiment of the invention. Figure 3 is a diagram showing the relationship between the different glass frits and the tensile force of each group in the embodiment of the present invention; Figure 4 is a diagram showing the relationship between the content of each glass frit and the tensile force in the embodiment of the present invention; and Figure 5 is an implementation of the present invention. An image of the peel test results in the example. [Main component symbol description] 1 Soldering strip 2 Interface 3 Interface 19