Photovoltaic device, manufacturing method thereof, and photovoltaic module

Patent metadata

Field	Value
Publication number	US-9252305-B2
Application number	US-201213979272-A
Country	US
Kind code	B2
Filing date	Mar 2, 2012
Priority date	Mar 3, 2011
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A photovoltaic device includes a silicon substrate of a first conduction type that includes an impurity diffusion layer on one surface side; a light-receiving-surface side electrode that includes a plurality of grid electrodes electrically connected to the impurity diffusion layer; and a back-surface side electrode formed on the other surface side of the silicon substrate wherein the impurity diffusion layer includes a first impurity diffusion layer and a second impurity diffusion layer, and wherein the first impurity diffusion layer is formed so that a direction perpendicular to a longitudinal direction of the grid electrodes is a longitudinal direction thereof, and so that an area ratio of the first impurity diffusion layer to a band region is equal to or lower than 50%.

First claim

The invention claimed is:

1. A photovoltaic device comprising:
a silicon substrate of a first conduction type that includes an impurity diffusion layer on one surface side, the impurity diffusion layer having an impurity element of a second conduction type diffused therein;
a light-receiving-surface side electrode that includes a plurality of grid electrodes electrically connected to the impurity diffusion layer and arranged parallel at a certain interval on the one surface side of the silicon substrate; and
a back-surface side electrode formed on the other surface side of the silicon substrate,
wherein the impurity diffusion layer includes a first impurity diffusion layer containing the impurity element at a first concentration and a second impurity diffusion layer containing the impurity element at a second concentration lower than the first concentration wherein the grid electrodes are formed on the second impurity diffusion layer, and
wherein the first impurity diffusion layer is formed so that a direction perpendicular to a longitudinal direction of the grid electrodes in the light-receiving-surface side electrode on the one surface side of the silicon substrate is a longitudinal direction thereof, and so that an area ratio of the first impurity diffusion layer to a band region arranged in the intervals between the grid electrodes is equal to or lower than 50%, a width of the band region being uniform and identical to a maximum width of the first impurity diffusion layer in a direction parallel to the longitudinal direction of the grid electrodes, a length of the band region in a longitudinal direction being identical to a length of the first impurity diffusion layer in the longitudinal direction of the first impurity diffusion layer.

2. The photovoltaic device according to claim 1 , wherein the first impurity diffusion layer has an intermittent pattern in the longitudinal direction.

3. The photovoltaic device according to claim 2 , wherein a ratio of a long-side length to a short-side length of each first impurity diffusion layer in the intermittent pattern is in a range equal to or larger than 1 and equal to or smaller than 5.

4. The photovoltaic device according to claim 3 , wherein
the longitudinal direction of each first impurity diffusion layer in the intermittent pattern intersects the longitudinal direction of the grid electrodes at an angle close to a right angle in a plane direction of the silicon substrate, and
an absolute value of a tangent (tan θ) of an error angle θ between a direction truly perpendicular to the longitudinal direction of the grid electrodes and the longitudinal direction of the each first impurity diffusion layer is equal to or smaller than a ratio of the short-side length to the long-side length of the each first impurity diffusion layer.

5. The photovoltaic device according to claim 1 , wherein
the first impurity diffusion layer is formed continuously in the longitudinal direction of the first impurity diffusion layer in a plane direction of the silicon substrate, and the longitudinal direction of the first impurity diffusion layer intersects the longitudinal direction of the grid electrodes at an angle close to a right angle, and
an absolute value of a tangent (tan θ) of an error angle θ between a direction truly perpendicular to the longitudinal direction of the grid electrodes and the longitudinal direction of the first impurity diffusion layer is equal to or smaller than a ratio of a maximum width of the first impurity diffusion layer in the longitudinal direction of the grid electrode to a half of an interval between the grid electrodes.

6. The photovoltaic device according to claim 1 , wherein when it is defined that a sheet resistance value of the first impurity diffusion layer is R 1 , a sheet resistance value of the second impurity diffusion layer is R 2 , and an area ratio of the first impurity diffusion layer to an entire surface of the impurity diffusion layer is r, the first impurity diffusion layer and the second impurity diffusion layer satisfy the following equation (1)

R
1

⁡

(

R
2

-
70

)

70
⁢

(

R
2

-

R
1

)

≤
r
≤

R
1

⁡

(

R
2

-
50

)

50
⁢

(

R
2

-

R
1

)

.

(
1
)

7. The photovoltaic device according to claim 6 , wherein when it is defined that a sheet resistance value of the first impurity diffusion layer is R 1 , a sheet resistance value of the second impurity diffusion layer is R 2 , and an area ratio of the first impurity diffusion layer to an entire surface of the impurity diffusion layer is r, the first impurity diffusion layer and the second impurity diffusion layer satisfy the following equation (2)

R
1

⁡

(

Assignees

• Hamamoto Satoshi
• Mitsubishi Electric Corp

Inventors

• Hamamoto Satoshi

Classifications

• H10F77/703

  of the semiconductor bodies, e.g. textured active layers · CPC title

• H10F77/211

  for photovoltaic cells · CPC title

• H10F71/121

  The active layers comprising only Group IV materials · CPC title

• H10F10/14

  Photovoltaic cells having only PN homojunction potential barriers · CPC title

• H10F10/00

  Individual photovoltaic cells, e.g. solar cells (electrolytic light-sensitive devices, e.g. dye-sensitised solar cells, H01G9/20) · CPC title