Patent Description:
Solar cells are devices that convert light energy into electrical energy, based on a characteristic of a semiconductor.

The solar cells have a PN junction structure where a positive (P)-type semiconductor and a negative (N)-type semiconductor are joined to each other. When sunlight is incident on a solar cell having the PN junction structure, a hole and an electron are generated in the semiconductors by energy of the incident sunlight. At this time, due to an electric field which is generated in a PN junction, the hole (+) moves to the P-type semiconductor, and the electron (-) moves to the N-type semiconductor, thereby generating an electric potential to produce power.

The solar cells may be categorized into thin film type solar cells and wafer type solar cells.

The wafer type solar cells are solar cells which are manufactured by using, as a substrate, a semiconductor material such as a silicon wafer, and the thin film type solar cells are solar cells which are manufactured by forming, as a thin film type, a semiconductor on a substrate such as glass.

The wafer type solar cells have an advantage which is better in efficiency than the thin film type solar cells, but the thin film type solar cells have an advantage where the manufacturing cost is reduced compared to the wafer type solar cells.

Therefore, a solar cell where the wafer type solar cell is combined with the thin film type solar cell has been proposed. Hereinafter, a related art solar cell will be described with reference to the drawing.

A method of manufacturing a solar cell according to the related art includes the following process.

First, a process of preparing a substrate with a plurality of division parts formed therein is performed. The division parts are for dividing the substrate into a plurality of pieces.

Subsequently, a process of forming a one-surface electrode on one surface of the substrate is performed, and the one-surface electrode is cured.

Subsequently, a process of forming an other-surface electrode on the other surface of the substrate is performed, and the other-surface electrode is cured. Therefore, a base substrate with the one-surface electrode and the other-surface electrode formed thereon is manufactured.

Subsequently, a process of distributing a bonding material onto the other-surface electrode is performed. The bonding material may be a material having a bonding force which enables separated pieces to be bonded to one another.

Subsequently, a process of dividing the substrate into a plurality of pieces by using the division parts is performed. Accordingly, the base substrate may be separated into a plurality of unit cells.

Subsequently, a process of bonding the plurality of unit cells by using the bonding material is performed, and bonded unit cells are cured. Accordingly, a solar cell is manufactured.

Here, the solar cell according to the related art is implemented so that the unit cells are bonded to one another by the bonding material. Due to this, because a generated power should pass through the bonding material in a process where the generated power flows through the unit cells, the solar cell according to the related art has a problem where the power generating efficiency of the solar cell is reduced by a resistance of the bonding material.

Document <CIT> discloses a bonding process of adjacent unit solar cells wherein the electrodes that are in contact with each other are soldered together. In further embodiments of said document, additional adhesive materials are used during the bonding process.

Document <CIT> discloses a bonding process of adjacent unit solar cells wherein the electrodes are in direct contact with each other. Further embodiments of said document also disclose the use of electrically conductive adhesive in order to couple the adjacent unit solar cells.

Document <CIT> discloses a process wherein the electrodes of adjacent unit solar cells are bonded through a conductive adhesive bonding material.

The present invention is devised to solve the above-described problems and relates to a method of manufacturing a solar cell, which may decrease the degree of reduction in power generating efficiency of the solar cell caused by a resistance of a bonding material.

The invention is defined by the appended independent claims, with embodiments being set forth in the appended dependent claims, in the following description and in the drawings.

The present invention may include the following elements, for solving the above-described technical problem.

A method of manufacturing a solar cell according to the present invention comprises: a substrate preparing process of preparing a substrate where a plurality of division parts for dividing the substrate into a plurality of pieces are formed; a first electrode forming process of forming a plurality of first base electrodes having conductivity on one surface of the substrate; a first curing process of curing the first base electrode; a second electrode forming process of forming a plurality of second base electrodes, having conductivity and an uncured state, on the other surface of the substrate; a division process of dividing the substrate into a plurality of pieces through the division parts to form a plurality of unit cells including a first unit cell and a second unit cell, each of the first unit cell and the second unit cell including a first cell electrode in a cured state and a second cell electrode in an uncured state; and a bonding process of bonding the first unit cell and the second unit cell through the first cell electrode of the first unit cell and the second cell electrode of the second unit cell without a bonding material, the first unit cell the second unit cell partially overlapping each other.

A solar cell may include: a first unit cell manufactured by using one of a plurality of pieces formed by dividing a base substrate; and a second unit cell coupled to the first unit cell. The first unit cell may include a first cell electrode formed on a first unit substrate to have conductivity. The second unit cell may include a second cell electrode formed on a second unit substrate to have conductivity. The second cell electrode and the first cell electrode may be bonded to each other without a bonding material, thereby coupling the second unit cell to the first unit cell.

A solar cell may include: a first unit cell manufactured by using one of a plurality of pieces formed by dividing a base substrate; and a second unit cell coupled to the first unit cell. The first unit cell may include a first cell electrode formed on a first unit substrate to have conductivity. The second unit cell may include a second cell electrode formed on a second unit substrate to have conductivity. The second cell electrode and the first cell electrode may be bonded to each other to couple the second unit cell to the first unit cell.

A unit cell may include: a unit substrate manufactured by using one of a plurality of pieces formed by dividing a base substrate; and a cell electrode formed on the unit substrate to have conductivity. The cell electrode may include a lower cell electrode and an upper cell electrode respectively formed on one surface and the other surface of the unit substrate. One of the upper cell electrode and the lower cell electrode may be formed in an uncured state.

According to the present invention, the following effects are obtained.

The present invention may be implemented so that a series of process of distributing and injecting a bonding material is omitted, and thus, may decrease a time for manufacturing a solar cell.

The present invention may be implemented to fundamentally prevent the power generating efficiency of the solar cell from being reduced by the resistance of the bonding material, thereby enhancing the quality of a finished solar cell.

Advantages and features of the present invention, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings. Rather, these embodiments are provided so that present invention will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Furthermore, the present invention is only defined by scopes of claims.

A shape, a size, a ratio, an angle, and a number disclosed in the drawings for describing embodiments of the present invention are merely an example, and thus, the present invention is not limited to the illustrated details. In the following description, when the detailed description of the relevant known technology is determined to unnecessarily obscure the important point of the present invention, the detailed description will be omitted. In a case where 'comprise', 'have', and 'include' described in the present specification are used, another part may be added unless 'only-' is used. The terms of a singular form may include plural forms unless referred to the contrary.

In describing a position relationship, for example, when a position relation between two parts is described as 'on~', 'over-', `under~', and 'next-', one or more other parts may be disposed between the two parts unless 'just' or 'direct' is used.

In describing a time relationship, for example, when the temporal order is described as 'after-', `subsequent~', 'next-', and 'before-', a case which is not continuous may be included unless 'just' or 'direct' is used.

It will be understood that, although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms.

Features of various embodiments of the present invention may be partially or overall coupled to or combined with each other, and may be variously inter-operated with each other and driven technically as those skilled in the art can sufficiently understand. The embodiments of the present invention may be carried out independently from each other, or may be carried out together in co-dependent relationship.

Hereinafter, an embodiment of a solar cell <NUM> obtained according to the present invention will be described in detail with reference to the accompanying drawings. A unit cell <NUM> is included in the solar cell <NUM>, and thus, will be described along with describing an embodiment of the solar cell <NUM>. Hatchings and dots illustrated in <FIG> do not illustrate a cross-sectional surface and are illustrated for distinguishing elements.

Referring to <FIG>, the solar cell <NUM> converts light energy of sunlight into electrical energy. The solar cell <NUM> may be implemented as a wafer type solar cell and a thin film type solar cell. Hereinafter, an embodiment where the solar cell <NUM> is implemented as a wafer type solar cell will be described, but based thereon, it is obvious to those skilled in the art that the solar cell <NUM> is implemented as a thin film type solar cell.

Referring to <FIG>, the solar cell <NUM> may be manufactured as a module type where a plurality of unit cells <NUM> are bonded to one another. Each of the unit cells <NUM> is manufactured by using one of a plurality of pieces which are formed by dividing a base substrate <NUM> (illustrated in <FIG>). In the solar cell <NUM>, the base substrate <NUM> may be in a state before being divided into the unit cells <NUM>. The base substrate <NUM> includes a substrate <NUM> (illustrated in <FIG>), a first base electrode <NUM> (illustrated in <FIG>) formed on one surface 110a of the substrate <NUM>, and a second base electrode <NUM> (illustrated in <FIG>) formed on the other surface 110b of the substrate <NUM>. In <FIG>, the solar cell <NUM> is illustrated as including five unit cells <NUM>, <NUM>', <NUM>", <NUM>‴, and <NUM>"", but this is an example and the solar cell <NUM> according to the present invention may include two to four unit cells <NUM> or six or more unit cells <NUM>. Each of the unit cells <NUM> may be implemented to be approximately equal, except for a disposed position thereof.

Referring to <FIG>, each of the unit cells <NUM> includes a unit substrate <NUM> and a cell electrode <NUM>.

The unit substrate <NUM> is formed by dividing the base substrate <NUM> (illustrated in <FIG>). The unit substrate <NUM> may have a certain conductive polarity. The unit substrate <NUM> may be formed to be equal to the number of pieces which are formed by dividing one base substrate <NUM>. For example, when the base substrate <NUM> is divided into five pieces, the unit substrate <NUM> may be formed as five. The unit substrate <NUM> may be a portion of the substrate <NUM> (illustrated in <FIG>).

The cell electrode <NUM> is formed on the unit substrate <NUM>. The cell electrode <NUM> may have conductivity. The cell electrode <NUM> may be formed of a metal material, having good conductivity, such as Ag, Al, Ag+Al, Ag+Mg, Ag+Mn, Ag+Sb, Ag+Zn, Ag+Mo, Ag+Ni, Ag+Cu, or Ag+Al+Zn.

The cell electrode <NUM> includes a lower cell electrode <NUM> and an upper cell electrode <NUM>.

The lower cell electrode <NUM> is formed on one surface 11a of the unit substrate <NUM>. The one surface 11a of the unit substrate <NUM> may be a surface of the unit substrate <NUM> facing a downward direction in which a height of the solar cell <NUM> according to the present invention is approximately lowered. The one surface 11a of the unit substrate <NUM> may be a surface of the unit substrate <NUM> facing an upward direction which is a direction opposite to the downward direction. The lower cell electrode <NUM> may be one electrode of the first base electrode <NUM> (illustrated in <FIG>).

The upper cell electrode <NUM> is formed on the other surface 11b of the unit substrate <NUM>. When the one surface 11a of the unit substrate <NUM> is the surface of the unit substrate <NUM> facing the downward direction, the other surface 11b of the unit substrate <NUM> may be a surface of the unit substrate <NUM> facing the upward direction. Hereinafter, an example where "one surface" and "the other surface" are surfaces of specific elements facing the downward direction and the upward direction will be described. Also, the terms "upper" and "lower" described in the present specification are for distinguishing elements, and it is obvious to those skilled in the art that the terms "upper" and "lower" do not denote a specific direction. The upper cell electrode <NUM> may be one electrode of the second base electrode <NUM> (illustrated in <FIG>).

One of the upper cell electrode <NUM> and the lower cell electrode <NUM> is formed in an uncured state PC. Therefore, the solar cell <NUM> according to the present invention may implement a bonding force for bonding the unit cells <NUM> through an electrode having the uncured state PC. The uncured state PC is a state where an electrode has a bonding force. The electrodes <NUM> and <NUM> may have mobility in the uncured state PC. When one of the upper cell electrode <NUM> and the lower cell electrode <NUM> is in a cured state HC, the other electrode is formed in the uncured state PC. Even in this case, the solar cell <NUM> according to the present invention may implement a bonding force for bonding the unit cells <NUM> through an electrode having the uncured state PC. The cured state HC is a state where an electrode does not have a bonding force. The electrodes <NUM> and <NUM> may have a certain external appearance without having mobility in the cured state HC.

Referring to <FIG>, a solar cell <NUM> obtained according to the present invention includes a first unit cell <NUM> and a second unit cell <NUM>.

The first unit cell <NUM> is one of the unit cells <NUM>. The first unit cell <NUM> is manufactured by using one of a plurality of pieces which are formed by dividing the base substrate <NUM>. Power generated by the solar cell <NUM> according to the present invention may move to the second unit cell <NUM> through the first unit cell <NUM>.

Referring to <FIG>, the first unit cell <NUM> includes a first unit substrate <NUM> and a first cell electrode <NUM>.

The first unit substrate <NUM> is a portion of the substrate <NUM> (illustrated in <FIG>). The first unit substrate <NUM> is formed by dividing the base substrate <NUM>. The first unit substrate <NUM> may have a certain conductive polarity.

The first cell electrode <NUM> is formed on the first unit substrate <NUM>. The first cell electrode <NUM> is formed on each of one surface 21a and the other surface 21b of the first unit substrate <NUM>. The first cell electrode <NUM> may have conductivity. The first cell electrode <NUM> may be formed of a material such as Ag, Al, Ag+Al, Ag+Mg, Ag+Mn, Ag+Sb, Ag+Zn, Ag+Mo, Ag+Ni, Ag+Cu, or Ag+Al+Zn.

The first cell electrode <NUM> includes a first lower cell electrode <NUM> and a first upper cell electrode <NUM>.

The first lower cell electrode <NUM> is formed on one surface 21a of the first unit substrate <NUM>. The first lower cell electrode <NUM> may be formed on the one surface 21a of the first unit substrate <NUM> disposed in the downward direction. The first lower cell electrode <NUM> may be one electrode of the first base electrode <NUM> (illustrated in <FIG>). The first lower cell electrode <NUM> may be formed in one state of the cured state HC and the uncured state PC.

The first upper cell electrode <NUM> is formed on the other surface 21b of the first unit substrate <NUM>. The first upper cell electrode <NUM> may be formed on the other surface 21b of the first unit substrate <NUM> disposed in the upward direction. The first upper cell electrode <NUM> may be one electrode of the second base electrode <NUM> (illustrated in <FIG>). The first upper cell electrode <NUM> is formed in a state which differs from the first lower cell electrode. For example, when the first lower cell electrode <NUM> is in the cured state HC, the first upper cell electrode <NUM> is formed in the uncured state PC. When the first lower cell electrode <NUM> is in the uncured state PC, the first upper cell electrode <NUM> is formed in the cured state HC.

The second unit cell <NUM> is one unit cell coupled to the first unit cell <NUM> among the unit cells <NUM>. The second unit cell <NUM> may be coupled to the first unit cell <NUM> in the upward direction of the first unit cell <NUM>. The second unit cell <NUM> is manufactured by using one of a plurality of pieces which are formed by dividing the base substrate <NUM>.

The second unit cell <NUM> includes a second unit substrate <NUM> and a second cell electrode <NUM>.

The second unit substrate <NUM> is a portion of the substrate <NUM> (illustrated in <FIG>). The second unit substrate <NUM> is formed by dividing the base substrate <NUM> (illustrated in FIG. The second unit substrate <NUM> may have a certain conductive polarity.

The second cell electrode <NUM> is formed on the second unit substrate <NUM>. The second cell electrode <NUM> is formed on each of one surface 31a and the other surface 31b of the second unit substrate <NUM>. The second cell electrode <NUM> may have conductivity. The second cell electrode <NUM> may be formed of a material such as Ag, Al, Ag+Al, Ag+Mg, Ag+Mn, Ag+Sb, Ag+Zn, Ag+Mo, Ag+Ni, Ag+Cu, or Ag+Al+Zn.

The second cell electrode <NUM> and the first cell electrode <NUM> are bonded to each other without a bonding material, and thus, couple the second unit cell <NUM> to the first unit cell <NUM>. That is, as the second cell electrode <NUM> and the first cell electrode <NUM> are bonded to each other, the second unit cell <NUM> is coupled to the first unit cell <NUM>. Accordingly, the solar cell <NUM> obtained according to the present invention may realize the following effects.

First, the solar cell <NUM> obtained according to the present invention is implemented so that the unit cells <NUM> and <NUM> are bonded to each other through the cell electrodes <NUM> and <NUM>. Therefore, comparing with the related art where the unit cells <NUM> are bonded to each other by using a bonding material, in the solar cell <NUM>, a series of process of distributing a bonding material is omitted in a process of manufacturing a solar cell. Accordingly, in the solar cell <NUM>, a time taken in manufacturing a solar cell may be reduced, and thus, the productivity of solar cells may increase.

Second, the solar cell <NUM> obtained according to the present invention is implemented so that the unit cells <NUM> and <NUM> are bonded to each other without a bonding material, and thus, a generated power needs not move to the bonding material. Accordingly, the solar cell <NUM> may fundamentally prevent the power generating efficiency of the solar cell from being reduced by the resistance of the bonding material, thereby enhancing the quality of a finished solar cell.

The second cell electrode <NUM> and the first cell electrode <NUM> may be formed of the same material, and thus, may be bonded to each other. For example, the second cell electrode <NUM> and the first cell electrode <NUM> may all be formed of an Ag material. Therefore, the solar cell <NUM> obtained according to the present invention is implemented to decrease an internal resistance thereof. This is because a resistance is more reduced in a case, where power moves to the same material, than a case where power moves to different materials, in a process where power moves to the first cell electrode <NUM> and the second cell electrode <NUM>. Accordingly, the solar cell <NUM> obtained according to the present invention may more increase the power generating efficiency of a solar cell.

The second cell electrode <NUM> includes a second lower cell electrode <NUM> and a second upper cell electrode <NUM>.

The second lower cell electrode <NUM> is formed on one surface 31a of the second unit substrate <NUM>. The second lower cell electrode <NUM> may be formed on the one surface 31a of the second unit substrate <NUM> disposed in the downward direction. The second lower cell electrode <NUM> may be one electrode of the first base electrode <NUM>. The second lower cell electrode <NUM> is formed in one state of the cured state HC and the uncured state PC.

The second upper cell electrode <NUM> is formed on the other surface 31b of the second unit substrate <NUM>. The second upper cell electrode <NUM> may be formed on the other surface 31b of the second unit substrate <NUM> in the upward direction. The second upper cell electrode <NUM> may be one electrode of the second base electrode <NUM>. When the second lower cell electrode <NUM> is in the cured state HC, the second upper cell electrode <NUM> is formed in the uncured state PC. When the second lower cell electrode <NUM> is in the uncured state PC, the second upper cell electrode <NUM> is formed in the cured state HC.

The solar cell <NUM>, as illustrated in <FIG>, is implemented so that the second lower cell electrode <NUM> and the first upper cell electrode <NUM> are bonded to each other, and thus, the second unit cell <NUM> is coupled to the first unit cell <NUM>. Hereinafter, an example where the second lower cell electrode <NUM> and the first upper cell electrode <NUM> are bonded to each other and thus the second unit cell <NUM> is coupled to the first unit cell <NUM> will be described, but this is an example and the second unit cell <NUM> may be coupled to the first unit cell <NUM> as the second upper cell electrode <NUM> and the first lower cell electrode <NUM> are bonded to each other.

At least one of the second lower cell electrode <NUM> and the first upper cell electrode <NUM> is formed in the uncured state PC. Therefore, the solar cell <NUM> may implement a bonding force for coupling the unit cells <NUM> and <NUM>. When at least one of the second lower cell electrode <NUM> and the first upper cell electrode <NUM> is formed in the uncured state PC, the other electrode is formed in the cured state HC, and thus, the second unit cell <NUM> is coupled to the first unit cell <NUM>.

Referring to <FIG> and <FIG>, the first upper cell electrode <NUM> is formed in the uncured state PC, and thus, the second lower cell electrode <NUM> is bonded thereto, whereby a thickness thereof may be reduced. Therefore, in the solar cell <NUM>, a total thickness thereof may be reduced, and thus, a distance by which a generated power moves may be reduced. Accordingly, the solar cell <NUM> may be implemented to decrease a total resistance thereof. The thickness may be a length with respect to a first axial direction (an X-axis direction) which corresponds to a direction parallel to each of the upward direction and the downward direction and corresponds to the same direction as a direction in which the second unit cell <NUM> is apart from the first unit cell <NUM>.

For example, as illustrated in <FIG> and <FIG>, when the first upper cell electrode <NUM> is formed to have a first thickness D1 and the second lower cell electrode <NUM> is formed to have a second thickness D2, a third thickness D3 which is formed as the second lower cell electrode <NUM> and the first upper cell electrode <NUM> are bonded to each other may have a value which is less than a sum of the first thickness D1 and the second thickness D2. This is because one of the first upper cell electrode <NUM> and the second lower cell electrode <NUM> is formed in the uncured state PC. Accordingly, the solar cell <NUM> obtained according to the present invention may be implemented to decrease a total thickness thereof. The third thickness D3 may be a separation distance between the second unit cell <NUM> and the first unit cell <NUM> with respect to the first axial direction (the X-axis direction). In <FIG>, it is illustrated that the first upper cell electrode <NUM> is formed in the uncured state PC, but this is an example and the third thickness D3 may decrease as the second lower cell electrode <NUM> is formed in the uncured state PC.

When one of the second lower cell electrode <NUM> and the first upper cell electrode <NUM> is formed in the uncured state PC, as illustrated in <FIG>, the second lower cell electrode <NUM> and the first upper cell electrode <NUM> may be disposed to partially overlap each other with respect to the first axial direction (the X-axis direction). Accordingly, a total thickness of the solar cell <NUM> obtained according to the present invention may be reduced.

Hereinafter, an embodiment of a pattern of each of the first upper cell electrode <NUM> and the second lower cell electrode <NUM> will be described with reference to the accompanying drawings. When the second unit cell <NUM> is coupled to the first unit cell <NUM> as the second upper cell electrode <NUM> and the first lower cell electrode <NUM> are bonded to each other, the first lower cell electrode <NUM> may be implemented to be approximately equal to the below-described second lower cell electrode <NUM>, and the second upper cell electrode <NUM> may be implemented to be approximately equal to the first upper cell electrode <NUM>.

Referring to <FIG>, the first upper cell electrode <NUM> may include a first junction electrode <NUM>.

The second lower cell electrode <NUM> is bonded to the first junction electrode <NUM>. The first junction electrode <NUM> may be one electrode of the first upper cell electrode <NUM> bonded to the second lower cell electrode <NUM>. The first junction electrode <NUM> may be coupled to the first unit substrate <NUM>. The first junction electrode <NUM> may be formed in the cured state HC.

The first junction electrode <NUM> may include a first junction surface 1A and an inserting groove G.

The first junction surface 1A (illustrated in <FIG>) may be one surface of the first junction electrode <NUM> facing the second lower cell electrode <NUM>. In this case, the other surface of the first junction electrode <NUM> may face the first unit substrate <NUM>. The second lower cell electrode <NUM> may be bonded to the first junction surface 1A.

The inserting groove G is formed in the first junction surface 1A. The inserting groove G may be formed by a process of processing a certain deep groove from the first junction surface 1A. The inserting groove G may be formed to have the same size as that of the first upper cell electrode <NUM> with respect to the first axial direction (the X-axis direction). In <FIG>, it is illustrated that fourteen inserting grooves G are formed in the first junction surface 1A, but this is an example and one to thirteen inserting grooves G or fifteen or more inserting grooves G may be formed in the first junction surface 1A.

Referring to <FIG>, the first junction electrode <NUM> may include a first junction finger bar 1F.

The first junction finger bar 1F may perform a function of moving power, generated from the first unit substrate <NUM>, to the second lower cell electrode <NUM>. The first junction finger bar 1F is formed with the inserting groove G being disposed inward therefrom. The first junction finger bar 1F may include a first junction finger member formed in a second axial direction (a Y-axis direction) and a second junction finger member formed in a third axial direction (a Z-axis direction) vertical to the second axial direction (the Y-axis direction). The second junction finger member and the first junction finger member may be coupled to each other. The second junction finger member and the first junction finger member may be disposed to surround the inserting groove G. For example, two second junction finger members and two first junction finger members may be disposed outside the inserting groove G. One second junction finger member and two first junction finger members may also be disposed outside the inserting groove G. <FIG> illustrates three first junction finger members and twelve second junction finger members. The second axial direction (the Y-axis direction) may be a direction vertical to the first axial direction (the X-axis direction). The third axial direction (the Z-axis direction) may be a direction vertical to each of the second axial direction (the Y-axis direction) and the first axial direction (the X-axis direction).

Referring to <FIG>, the first upper cell electrode <NUM> may include a first non-junction electrode <NUM>.

The first non-junction electrode <NUM> is coupled to the first junction electrode <NUM>. The first non-junction electrode <NUM> may be coupled to the first junction electrode <NUM> and may perform a function of moving the power, generated from the first unit substrate <NUM>, to the first junction electrode <NUM>. The first non-junction electrode <NUM> may be one electrode of the first upper cell electrode <NUM> which is not bonded to the second lower cell electrode <NUM>. The first non-junction electrode <NUM> may be coupled to the first unit substrate <NUM>. The first non-junction electrode <NUM> may be formed in the cured state HC which is the same state as that of the first junction electrode <NUM>.

The first non-junction electrode <NUM> may include a plurality of first non-junction finger bars 10F which are disposed apart from one another. The first non-junction finger bars 10F may be disposed apart from one another with respect to the second axial direction (the Y-axis direction). The first non-junction finger bars 10F may be formed to extend in the third axial direction (the Z-axis direction). The first non-junction finger bars 10F may be formed to have a linear shape in the third axial direction (the Z-axis direction). The first non-junction finger bars 10F may be coupled to the first junction electrode <NUM>. The first non-junction finger bars 10F may perform a function of moving the generated power to the first junction electrode <NUM>. <FIG> illustrates three first non-junction finger bars 10F.

Referring to <FIG>, the second lower cell electrode <NUM> may include a second junction electrode <NUM>.

The second junction electrode <NUM> is bonded to the first junction electrode <NUM>. The second junction electrode <NUM> may be one electrode of the second lower cell electrode <NUM> bonded to the first junction electrode <NUM>. The second junction electrode <NUM> may be coupled to the second unit substrate <NUM>. The second junction electrode <NUM> may be formed in the cured state HC.

Referring to <FIG> and <FIG>, the second junction electrode <NUM> may include a second junction surface 2A.

The second junction surface 2A may be one surface of the second junction electrode <NUM> facing the first upper cell electrode <NUM>. The other surface of the second junction electrode <NUM> may face the second unit substrate <NUM>. The second junction surface 2A may be bonded to the first junction electrode <NUM>. The second junction surface 2A may be formed to have a flat shape before the second junction electrode <NUM> and the first junction electrode <NUM> are bonded to each other. That is, the second junction surface 2A may be formed in a flat shape having no curve before the second junction electrode <NUM> and the first junction electrode <NUM> are bonded to each other.

Referring to <FIG>, the second junction electrode <NUM> may include an inserting member I.

The inserting member I is inserted into the inserting groove G as the second junction electrode <NUM> is bonded to the first junction electrode <NUM>. Therefore, the solar cell <NUM> according to the present invention may be implemented so that the second junction electrode <NUM> is supported by the first junction electrode <NUM>. Accordingly, the solar cell <NUM> according to the present invention may enhance a bonding force between the second junction electrode <NUM> and the first junction electrode <NUM>, thereby increasing a coupling force between the first unit cell <NUM> and the second unit cell <NUM>. The inserting member I may be formed in the uncured state PC and may be inserted into the inserting groove G.

The inserting member I may be formed in a shape corresponding to the inserting groove G. The second junction electrode <NUM> may include a plurality of inserting members I equal to the number of inserting grooves G.

Hereinabove, it has been described that the first junction electrode <NUM> includes the inserting groove G and the second junction electrode <NUM> includes the inserting member I, but it should be understood that this is an example and it is obvious to those skilled in the art that the first junction electrode <NUM> includes the inserting member I and the second junction electrode <NUM> includes the inserting groove G.

Referring to <FIG>, the second lower cell electrode <NUM> may include a second non-junction electrode <NUM>.

The second non-junction electrode <NUM> is coupled to the second junction electrode <NUM>. The second non-junction electrode <NUM> may be coupled to the second junction electrode <NUM> and may perform a function of moving power generated from the second unit substrate <NUM>. The second non-junction electrode <NUM> may be one electrode of the second lower cell electrode <NUM> which is not bonded to the first upper cell electrode <NUM>. The second non-junction electrode <NUM> may be coupled to the second unit substrate <NUM>. The second non-junction electrode <NUM> may be formed in the uncured state PC which is the same state as that of the second junction electrode <NUM>.

The second non-junction electrode <NUM> may include a plurality of second non-junction finger bars 20F which are disposed apart from one another. The second non-junction finger bars 20F may be disposed apart from one another with respect to the second axial direction (the Y-axis direction). The second non-junction finger bars 20F may be formed to extend in the third axial direction (the Z-axis direction). The second non-junction finger bars 20F may be coupled to the second junction electrode <NUM>. The second non-junction finger bars 20F may perform a function of moving the power generated from the second unit substrate <NUM>. <FIG> illustrates three second non-junction finger bars 20F.

Hereinafter, an embodiment of a method of manufacturing a solar cell according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to <FIG>, a method of manufacturing a solar cell according to the present invention may include a substrate preparing process.

The substrate preparing process is a process of preparing the substrate <NUM> where a plurality of division parts <NUM> for dividing the substrate <NUM> into a plurality of pieces are formed. The substrate preparing process may be performed by a substrate loading apparatus (not shown) which loads the substrate <NUM> into a processing space (not shown) for manufacturing a solar cell. The processing space may accommodate a plurality of manufacturing apparatuses needed for manufacturing a solar cell and may be wholly implemented as a chamber.

The substrate <NUM> may have a certain conductive polarity. For example, the substrate <NUM> may be formed of an N-type silicon wafer or a P-type silicon wafer. Although not shown, the one surface 110a of the substrate <NUM> may be formed in a concave-convex structure. The substrate <NUM> may include a bottom surface disposed in the downward direction, a top surface disposed in the upward direction, and a side surface 110c connected to each of the bottom surface and the top surface of the substrate <NUM>. In this case, the one surface 110a of the substrate <NUM> may correspond to one of the bottom surface of the substrate <NUM>, the top surface of the substrate <NUM>, and the side surface 110c of the substrate <NUM>. For example, when the one surface 110a of the substrate <NUM> corresponds to the bottom surface of the substrate <NUM>, the other surface 110b of the substrate <NUM> corresponds to the top surface of the substrate <NUM>. In this case, each of a plurality of thin film layers formed on the one surface 110a of the substrate <NUM> and the other surface 110b of the substrate <NUM> may be formed in a concave-convex structure.

The division parts <NUM> are for dividing the substrate <NUM> into the plurality of pieces. The division parts <NUM> may be formed on the one surface 110a of the substrate <NUM>. The division parts <NUM> may be formed through a scribing process of processing a certain deep groove from the one surface 110a of the substrate <NUM>. The scribing process may be performed by a scribing apparatus (not shown) which irradiates a laser onto the substrate <NUM> to remove a certain region of the substrate <NUM>. In <FIG>, it is illustrated that the scribing process is performed on the one surface 110a of the substrate <NUM>, but this is an example and the scribing process may be performed on the other surface 110b of the substrate <NUM>. Also, in the present specification, an example where the division parts <NUM> are formed through the scribing process has been described, but this is an example and the division parts <NUM> may be formed by a process of digesting the substrate <NUM> into an etching bath (not shown), a dry etching process, or a process using a mask. In a case for dividing the substrate <NUM> into five pieces, as illustrated in <FIG>, four division parts <NUM> may be formed on the one surface 110a of the substrate <NUM>.

Although not shown, one or more thin film layers may be formed on the substrate <NUM>. Hereinafter, an example of a thin film layer formed on the substrate <NUM> will be described.

First, a first thin film layer may be formed on the substrate <NUM>. A process of forming the first thin film layer may be performed after the scribing process. The first thin film layer may be a semiconductor layer which is formed as a thin film type on the substrate <NUM>. The first thin film layer may form a PN junction along with the substrate <NUM>. Therefore, in a case where the substrate <NUM> is formed of an N-type silicon wafer, the first thin film layer may be a P-type semiconductor layer. The first thin film layer may be formed by using a chemical vapor deposition (CVD) process and/or the like. The first thin film layer may be formed in a PIN structure where a P-type semiconductor material, an I-type semiconductor material, and an N-type semiconductor material are sequentially stacked. As described above, when the first thin film layer is formed in the PIN structure, the I-type semiconductor material is depleted by the P-type semiconductor material and the N-type semiconductor material, and thus, an electric field is generated therein and a hole and an electron generated from sunlight are drifted by the electric field and are collected into the P-type semiconductor material and the N-type semiconductor material. In a case where the first thin film layer is formed in the PIN structure, it is preferable that the P-type semiconductor material is formed on the first thin film layer, and then, the I-type semiconductor material and the N-type semiconductor material are formed. The reason is for that the P-type semiconductor material is formed close to a light receiving surface so as to collection efficiency based on incident light because the drift mobility of a hole is lower than the drift mobility of an electron generally. The method of manufacturing a solar cell according to the present invention may form the first thin film layer to have a stacked structure. For example, the method of manufacturing a solar cell according to the present invention may form the first thin film layer to have a stacked structure having a tandem(PIN/PIN) type or a triple(PIN/PIN/PIN) type. The first thin film layer may be formed on at least one of the one surface 110a, the other surface 110b, and the side surface of the substrate <NUM>, or may be formed on each of the one surface 110a, the other surface 110b, and the side surface of the substrate <NUM>.

Subsequently, a second thin film layer is formed on the first thin film layer. A process of forming the second thin film layer may be performed after a process of forming the first thin film layer. The second thin film layer may be a transparent conductive layer. For example, the second thin film layer may be a transparent conductive oxide (TCO) layer. The first thin film layer may protect the first thin film layer, collect a carrier (for example, a hole (+)) generated in the substrate <NUM>, and move the collected carrier in the upward direction. The second thin film layer may be formed of a transparent conductive material such as indium tin oxide (ITO), ZnOH, ZnO:B, ZnO:Al, SnO<NUM>, or SnO<NUM>:F. The second thin film layer may be formed of a transparent conductive material such as ZnO, ZnO:B, ZnO:Al, or Ag by using a sputtering process or a metal organic CVD (MOCVD) process. The second thin film layer has a function which scatters sunlight to allow the sunlight to travel at various angles, and thus, increases a ratio of light re-incident on the first thin film layer.

Subsequently, a third thin film layer is formed on the second thin film layer. A process of forming the third thin film layer may be performed after a process of forming the second thin film layer. In a case which forms the third thin film layer on the second thin film layer, the first thin film layer may be implemented as an intrinsic semiconductor layer, the second thin film layer may be implemented as a semiconductor layer, and the third thin film layer may be implemented as a transparent conductive layer. In this case, the plurality of thin film layers may be formed by using a plasma enhanced CVD (PECVD) process and a sputtering process.

The method of manufacturing a solar cell according to the present invention may selectively form the first thin film layer, the second thin film layer, and the third thin film layer. That is, the method of manufacturing a solar cell according to the present invention may form one or more of the first thin film layer, the second thin film layer, and the third thin film layer, or may not form all of the first thin film layer, the second thin film layer, and the third thin film layer.

Referring to <FIG>, the method of manufacturing a solar cell according to the present invention includes a first electrode forming process.

The first electrode forming process is a process of forming a plurality of first base electrodes <NUM> having conductivity on the one surface 110a of the substrate <NUM>. The first electrode forming process may be performed after the substrate preparing process. The first base electrode <NUM> formed by performing the first electrode forming process may be formed of a material such as Ag, Al, Ag+Al, Ag+Mg, Ag+Mn, Ag+Sb, Ag+Zn, Ag+Mo, Ag+Ni, Ag+Cu, or Ag+Al+Zn. In <FIG>, it is illustrated that the first electrode forming process is performed on the one surface 110a of the substrate <NUM>, but this is an example and the first electrode forming process may be performed on the other surface 110b of the substrate <NUM>.

Referring to <FIG>, the method of manufacturing a solar cell according to the present invention includes a first curing process.

The first curing process is a process of curing the first base electrode <NUM>. The first curing process may be performed after the first electrode forming process. The first curing process may be performed by a heating apparatus (not shown) which heats the first base electrode <NUM>. As the first curing process is performed, the first base electrode <NUM> may be formed in the cured state HC.

Referring to <FIG>, the method of manufacturing a solar cell according to the present invention includes a second electrode forming process.

The second electrode forming process is a process of forming a plurality of second base electrodes <NUM>, having conductivity and the uncured state PC, on the other surface 110b of the substrate <NUM>. The second electrode forming process may be performed after the first electrode forming process. The second base electrode <NUM> formed by performing the second electrode forming process may be formed of a material such as Ag, Al, Ag+Al, Ag+Mg, Ag+Mn, Ag+Sb, Ag+Zn, Ag+Mo, Ag+Ni, Ag+Cu, or Ag+Al+Zn. In <FIG>, it is illustrated that the second electrode forming process is performed on the other surface 110b of the substrate <NUM>, but this is an example and the second electrode forming process may be performed on the one surface 110a of the substrate <NUM>.

The method of manufacturing a solar cell according to the present invention is implemented not to include a process of curing the second base electrode <NUM> after the second electrode forming process is performed. Accordingly, the method of manufacturing a solar cell according to the present invention may implement a bonding force which bonds the unit cells <NUM> through the second base electrode <NUM> having the uncured state PC.

Referring to <FIG>, the method of manufacturing a solar cell according to the present invention includes a division process.

The division process is a process of dividing the substrate <NUM> into a plurality of pieces through the division parts <NUM> to form the unit cells <NUM>. That is, the division process is a process of dividing the base substrate <NUM> through the division parts <NUM> to form a plurality of unit cells <NUM>. The division process may be performed by a division apparatus (not shown) which applies an external force, such as a bending force, to the base substrate <NUM>. The division process may be performed after the second electrode forming process. In a case for dividing the base substrate <NUM> into N (where N is an integer of <NUM> or more) number of unit cells <NUM>, the division process may be performed N-<NUM> times. For example, as illustrated in <FIG>, in a case for dividing the base substrate <NUM> into five unit cells <NUM>, the division process may be performed four times.

Referring again to <FIG>, the method of manufacturing a solar cell according to the present invention includes a bonding process.

The bonding process is a process of bonding the unit cells <NUM> through the second base electrode <NUM> having the uncured state PC. The bonding process may be performed by a bonding apparatus (not shown) which moves and bonds the divided unit cells <NUM>. The bonding process is performed after the division process. In a case where the base substrate <NUM> has been divided into N number of unit cells <NUM>, the bonding process may be performed N-<NUM> times. For example, as illustrated in <FIG>, in a case where the base substrate <NUM> has been divided into five unit cells <NUM>, the bonding process may be performed four times.

Although not shown, the method of manufacturing a solar cell according to the present invention may include a second curing process.

Claim 1:
A method of manufacturing a solar cell, the method comprising:
a substrate preparing process of preparing a substrate (<NUM>) where a plurality of division parts (<NUM>) for dividing the substrate into a plurality of pieces are formed;
a first electrode forming process of forming a plurality of first base electrodes (<NUM>) having conductivity on one surface (110a) of the substrate;
a first curing process of curing the first base electrode;
a second electrode forming process of forming a plurality of second base electrodes (<NUM>), having conductivity and an uncured state, on the other surface (110b) of the substrate;
a division process of dividing the substrate into a plurality of pieces through the division parts to form a plurality of unit cells (<NUM>) including a first unit cell (<NUM>) and a second unit cell (<NUM>), each of the first unit cell and the second unit cell including a first cell electrode in a cured state and a second cell electrode in an uncured state; and
a bonding process of bonding the first unit cell and the second unit cell through the first cell electrode (<NUM>) of the first unit cell and the second cell electrode (<NUM>) of the second unit cell without a bonding material, the first unit cell the second unit cell partially overlapping each other, .