Preventing harmful polarization of solar cells
View Patent ↗In one embodiment, harmful solar cell polarization is prevented or minimized by providing a conductive path that bleeds charge from a front side of a solar cell to the bulk of a wafer. The conductive path may include patterned holes in a dielectric passivation layer, a conductive anti-reflective coating, or layers of conductive material formed on the top or bottom surface of an anti-reflective coating, for example. Harmful solar cell polarization may also be prevented by biasing a region of a solar cell module on the front side of the solar cell.
1. A solar energy system comprising:
a solar cell module array comprising a plurality of backside contact solar cells, the solar cells being coupled in series such that a first node of the series is at a positive potential and a second opposing node of the series is at a negative potential relative to the first node, each solar cell in the plurality of backside contact solar cells having a doped front side diffusion region and a dielectric over the doped front side diffusion region;
a frame of a solar cell module in the solar cell module array;
an inverter configured to convert direct current generated by the solar cell module array to alternating current to be provided to a power grid;
wherein the first node of the series and the frame are grounded to reduce positive potential between the solar cells and the frame;
wherein the inverter is configured to receive a balanced voltage from the solar cell module array and further comprising: a resistor coupling the first node of the series to ground, the resistor having a value configured to unbalanace the balanced voltage from the solar cell module array.
2. A solar energy system comprising:
a series of backside contact solar cells in a solar cell module array, the series of backside contact solar cells having a first node and a second node opposite the first node, the first node being at a positive potential and the second node being at a negative potential relative to the first node, each solar cell in the series of backside contact solar cells having a front side facing the sun during normal operation and a backside opposite the front side;
a frame of a solar cell module in the solar cell module array, the frame being tied to ground;
an inverter configured to convert direct current generated by the solar cell module array to alternating current to be provided to a power grid;
wherein either the first node or the second node is tied to ground, the first node being tied to ground when solar cells in the series of solar cells have an N-type front side diffusion regions and the second node being tied to ground when solar cells in the series of solar cells have a P-type front side diffusion regions;
wherein the inverter is configured to receive a balanced voltage from the solar cell module array and further comprising: a resistor coupling the first node to ground, the resistor having a value configured to unbalanace the balanced voltage from the solar cell module array.
3. The solar energy system of claim 2 wherein the first node is tied to ground by way of a resistor.
4. A solar energy system comprising:
a series of backside contact solar cells in a solar cell module array, the series of backside contact solar cells having a first node and a second node opposite the first node, the first node being positive potential and the second node being at a negative potential relative to the first node, each solar cell in the series of backside contact solar cells having a front side facing the sun during normal operation and a backside opposite the front side;
a frame of a solar cell module in the solar cell module array, the frame being tied to ground;
an inverter configured to convert direct current generated by the solar cell module array to alternating current to be provided to power a grid;
wherein either the first node or the second node is tired to ground, the first node being tied to ground when solar cells in the series of solar cells have an N-type front side diffusion regions and the second node being tied to ground then solar cells in the series of solar cells have a P-type front side diffusion regions;
wherein the inverter is configured to receive a balanced voltage from the solar cell module array and further comprising:
a resistor coupling the second node to ground, the resistor having a value configured to unbalance the balanced voltage from the solar cell module array.
5. A solar energy system comprising:
(a) a plurality of solar cells, each of the solar cells comprising a backside contact solar cell comprising:
(i) a front side and a backside, the front side facing the sun during normal operation;
(ii) a plurality of metal contacts, each of the metal contacts being coupled to a corresponding collection region of the solar cell;
(iii) a dielectric passivation layer formed over a surface of a wafer that faces the sun during normal operation, the dielectric passivation layer being over a front side diffusion region; and
(iv) an anti-reflective coating formed over the dielectric passivation layer;
(b) a solar cell module array comprising the plurality of solar cells, the solar cell module array having a positive terminal at a positive voltage and a negative terminal at a negative voltage;
(c) a ground connection to a frame of a solar cell module in the solar cell module array;
(d) an inverter configured to convert direct current generated by the solar cell module array to alternating current to be provided to a power grid;
wherein either the positive terminal or the negative terminal of the solar cell module array is tied to ground, the positive terminal of the solar cell module array being tied to ground when the front side diffusion is N-type and the negative terminal of the solar cell module array being tied to ground when the front side diffusion is P-type;
wherein the inverter is configured to receive a balanced voltage from the solar cell module array and further comprising: a resistance coupling a terminal of the solar cell module array to the ground to unbalance the balanced voltage from the solar cell such that charge is prevented from leaking from the front side of solar cells; wherein the resistance couples the positive terminal of the solar cell module array to ground.
6. A solar energy system comprising:
(a) a plurality of solar cells, each of the solar cells comprising a backside contact solar cell comprising:
(i) a front side and backside, the front side facing the sun during normal operation;
(ii) a plurality of metal contacts, each of the metal contacts being coupled to a corresponding collection region of the solar cell;
(iii) a dielectric passivation layer formed over a surface of a wafer that faces the sun during normal operation, the dielectric passivation layer being over the front side diffusion region; and
(iv) an anti-reflective coating formed over the dielectric passivation layer;
(b) a solar cell module array comprising the plurality of solar cells, the solar cell module array having a positive terminal at a positive voltage and a negative terminal at a negative voltage;
(c) a ground connection to a frame of a solar cell module in the solar cell module array;
(d) an inverter configured to convert direct current generated by the solar cell module array to alternating current to be provided to a power grid;
wherein either the positive terminal or the negative terminal of the solar cell module array is tied to ground, the positive terminal of the solar cell module array being tied to ground when the front side diffusion is N-type and the negative terminal of the solar cell being tied to the ground when the front side diffusion is P-type;
wherein the inverter is configured to receive a balanced voltage from the solar cell module array and further comprising: a resistance coupling a terminal of the solar cell module array to the ground to unbalance the balanced voltage from the solar cell such that charge is prevented from leaking from the front side of solar cells;
wherein the resistance couples the negative terminal of the solar cell module array to ground.