BACKGROUND OF THE INVENTION

Field of the Invention

Embodiments of the invention relate to a solar cell module and a method for manufacturing the same.

Discussion of the Related Art

A solar cell generally includes a substrate and an emitter region, which are formed of semiconductors of different conductive types, for example, a p-type and an n-type, and electrodes respectively connected to the substrate and the emitter region. A p-n junction is formed at an interface between the substrate and the emitter region.

In particular, a solar cell, in which electrodes are not formed on a light receiving surface of a silicon substrate and n-type electrodes and p-type electrodes are formed only on another surface of the silicon substrate, has been continuously studied and developed, so as to increase efficiency of the solar cell. Further, a module technology for electrically connecting the plurality of solar cells each having the above-described configuration has been continuously studied and developed.

Examples of the module technology typically include a method for electrically connecting the plurality of solar cells using metal interconnectors and a method for electrically connecting the plurality of solar cells using a wiring substrate, on which wires are previously formed.

SUMMARY OF THE INVENTION

In one aspect, there is a method for manufacturing a solar cell module including a cell forming operation of forming a plurality of first electrodes and a plurality of second electrodes, positioned in parallel with each other on a back surface of a semiconductor substrate, at which a p-n junction is formed for each of a plurality of solar cells; and a tabbing operation including at least one of a connection operation of performing a thermal process to connect a first conductive line to the plurality of first electrodes included in each of the plurality of solar cells using a conductive adhesive and to connect a second conductive line to the plurality of second electrodes included in each of the plurality of solar cells using the conductive adhesive and an optional string forming operation of performing a thermal process and connecting the first conductive line included in one solar cell and the second conductive line included in other solar cell adjacent to the one solar cell to an interconnect to form a string, in which the plurality of solar cells are connected in series in a first direction, wherein the tabbing operation including at least one of the connection operation and the string forming operation includes at least two thermal processes each having a different maximum temperature.

A plurality of first connection points may be positioned in a portion where the plurality of first electrodes and the first conductive line cross or overlap each other, and a plurality of second connection points may be positioned in a portion where the plurality of second electrodes and the second conductive line cross or overlap each other. The connection operation may include a thermal process of the plurality of first connection points and the plurality of second connection points at a first maximum temperature and a thermal process of the plurality of first connection points and the plurality of second connection points at a second maximum temperature different from the first maximum temperature.

The connection operation may include a temporary attachment process for thermally processing at least a portion of the plurality of first connection points and at least a portion of the plurality of second connection points at the first maximum temperature, and a main attachment process for thermally processing all of the first and second connection points including the at least a portion of the plurality of first and second connection points at the second maximum temperature higher than the first maximum temperature.

The first maximum temperature of the temporary attachment process may be 70° C. to 150° C., and the second maximum temperature of the main attachment process may be 140° C. to 400° C. within a temperature range higher than the first maximum temperature.

The connection operation may include a high melting point thermal process for thermally processing a portion of the plurality of first connection points and a portion of the plurality of second connection points at the first maximum temperature, and a low melting point thermal process for thermally processing remaining first and second connection points among the plurality of first and second connection points at the second maximum temperature lower than the first maximum temperature.

The first maximum temperature of the high melting point thermal process may be 150° C. to 400° C., and the second maximum temperature of the low melting point thermal process may be 140° C. to 180° C. within a temperature range lower than the first maximum temperature.

The first and second conductive lines may be previously patterned on an insulating member. In the connection operation, each insulating member having the first and second conductive lines and each semiconductor substrate, on which the plurality of first and second electrodes are formed, may be connected to each other to form an individual integrated type element.

In the connection operation, an insulating layer may be formed between the first and second electrodes and between the first and second conductive lines.

Each of the first and second conductive lines may be formed as a plurality of conductive wires extending in the first direction or a plurality of conductive ribbons extending in the first direction. In the connection operation, the first and second conductive lines formed as the conductive wires or the conductive ribbons may be respectively connected to the plurality of first and second electrodes of each solar cell.

Each of the first and second conductive lines may overlap two semiconductor substrates of two adjacent solar cells. The two adjacent solar cells may be connected in series to each other to form the string in the connection operation, and the string forming operation may be omitted.

The tabbing operation may include the connection operation and the string forming operation. A maximum temperature of the thermal process of the connection operation may be different from a maximum temperature of the thermal process of the string forming operation.

The maximum temperature of the thermal process of the connection operation may be 140° C. to 400° C. The maximum temperature of the thermal process of the string forming operation may be different from the maximum temperature of the thermal process of the connection operation within a temperature range of 140° C. to 400° C.

For example, the maximum temperature of the thermal process of the string forming operation may be higher than the maximum temperature of the thermal process of the connection operation.

More specifically, the maximum temperature of the thermal process of the connection operation may be 140° C. to 180° C., and the maximum temperature of the thermal process of the string forming operation may be 150° C. to 300° C. within a temperature range higher than the maximum temperature of the thermal process of the connection operation.

For example, the maximum temperature of the thermal process of the string forming operation may be 240° C. to 280° C.

The thermal process of the string forming operation may include a temporary attachment process and a main attachment process performed at a maximum temperature higher than a maximum temperature of the temporary attachment process. The maximum temperature of the temporary attachment process of the string forming operation may be 80° C. to 100° C., and the maximum temperature of the main attachment process of the string forming operation may be 170° C. to 190° C.

The tabbing operation may further include a string connection operation of performing a thermal process and connecting the first conductive line connected to the last solar cell positioned at an end of one string extending in the first direction and the second conductive line connected to the last solar cell positioned at an end of other string, that is adjacent to the one string and extends in the first direction, to a bussing ribbon extending in a second direction crossing the first direction to connect the two adjacent strings. A maximum temperature of the thermal process of the string connection operation may be different from a maximum temperature of the thermal process of the string forming operation.

The maximum temperature of the thermal process of the string connection operation and the maximum temperature of the thermal process of the string forming operation may be different from each other within a temperature range of 140° C. to 400° C.

In another aspect, there is a solar cell module including a plurality of solar cells each including a semiconductor substrate and a plurality of first electrodes and a plurality of second electrodes, which are formed on a back surface of the semiconductor substrate and are separated from each other, and a plurality of conductive lines connected to the plurality of first electrodes included in one of the plurality of solar cells and the plurality of second electrodes included in other solar cell adjacent to the one solar cell, wherein a longitudinal direction of the plurality of conductive lines crosses a longitudinal direction of the plurality of first and second electrodes.

A conductive adhesive may connect the plurality of conductive lines to the plurality of first electrodes of the one solar cell and may connect the plurality of conductive lines to the plurality of second electrodes of the other solar cell.

An insulating layer may be positioned between each of the plurality of conductive lines and each of the plurality of second electrodes of the one solar cell and between each of the plurality of conductive lines and each of the plurality of first electrodes of the other solar cell.

A formation area of the insulating layer may be different from a formation area of the conductive adhesive at the back surface of the semiconductor substrate. More specifically, the formation area of the insulating layer may be greater than the formation area of the conductive adhesive at the back surface of the semiconductor substrate.

A metal pad extending in a direction, that is the same as the longitudinal direction of the plurality of first and second electrodes, may be connected to a portion of each of the plurality of conductive lines exposed between the one solar cell and the other solar cell.

Each of the plurality of conductive lines may use a conductive wire or a conductive ribbon having a stripe shape extending in one direction.

