# US 11,908,958 B2 · Metallization structures for solar cells

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- Number: US 11,908,958 B2
- Document ID: US11908958B2
- Status: Granted
- Kind: B2
- Application number: 15/396,246
- Filed: 2016-12-30
- Published: 2018-07-05
- Granted: 2024-02-20
- Earliest claimed: 2016-12-30
- Applicants: Maxeon Solar Pte. Ltd.
- Inventors: Matthieu Minault Reich; Seung Bum Rim
- Web page: https://patentgrep.com/patent/US11908958B2

## CPC

- H10F 77/937: {Busbar structures for modules}
- H10F 10/146: {Back-junction photovoltaic cells, e.g. having interdigitated base-emitter regions on the back side}
- H10F 19/908: {for back-contact photovoltaic cells}
- H10F 77/215: {Geometries of grid contacts}
- H10F 77/219: {Arrangements for electrodes of back-contact photovoltaic cells}
- H10F 77/935: {for photovoltaic devices or modules}
- H10F 71/137: {Batch treatment of the devices}
- H10F 77/1642: {including only Group IV materials}
- H10F 77/311: {for photovoltaic cells}
- H10F 77/315: {the coatings being antireflective or having enhancing optical properties}
- H10F 77/703: {of the semiconductor bodies, e.g. textured active layers}
- Y02E 10/50: Photovoltaic [PV] energy
- Y02E 10/546: Polycrystalline silicon PV cells
- Y02E 10/547: Monocrystalline silicon PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Methods of fabricating a solar cell including metallization techniques and resulting solar cells, are described. In an example, forming a first semiconductor region and a second semiconductor region on the back side of a substrate. A first conductive busbar can be formed above the first semiconductor region. A first portion of a second conductive busbar can be formed above the second semiconductor region. A second portion of the second conductive busbar can be formed above the second semiconductor region, where a separation region separates the second portion and the first portion of the second conductive busbar. A third conductive busbar can be formed above the first semiconductor region. A first conductive bridge can be formed above the separation region, where the first conductive bridge electrically connects the first conductive busbar to the third conductive busbar.

## Claims

### Claim 1

A solar cell, the solar cell having a front side which faces the sun during normal operation and a back side opposite the front side, the solar cell comprising:
a substrate having a first semiconductor region and a second semiconductor region disposed in or above the back side of the solar cell;
a first conductive busbar disposed above the first semiconductor region and extending in a first direction and including a plurality of first conductive fingers extending in a second direction that is orthogonal to the first direction;
a second conductive busbar including a first portion and a second portion disposed above the second semiconductor region and extending in the first direction and including a plurality of second conductive fingers extending in the second direction, wherein a first separation region separates the first and second portions of the second conductive busbar;
a third conductive busbar disposed above the first semiconductor region and extending in the first direction and including a plurality of third conductive fingers extending in the second direction, wherein the plurality of first and the plurality of second conductive fingers form an alternating pattern in the first direction, and the plurality of second and the plurality of third conductive fingers form another alternating pattern in the first direction; and
a first conductive bridge electrically connecting the first conductive busbar to the third conductive busbar and extending in the second direction, wherein the first conductive bridge extends beyond sides of the first conductive busbar and the third conductive busbar, the first conductive bridge including one of the plurality of first conductive fingers and one of the plurality of third conductive fingers.

### Claim 2 (depends on 1)

The solar cell of claim 1, further comprising:
a first portion of a fourth conductive busbar disposed above the second semiconductor region;
a second portion of the fourth conductive busbar disposed above the second semiconductor region, wherein a second separation region separates the second portion and the first portion of the fourth conductive busbar;
a fifth conductive busbar disposed above the first semiconductor region; and
a second conductive bridge electrically connecting the third conductive busbar to the fifth conductive busbar, wherein the second conductive bridge is disposed above the second separation region.

### Claim 3 (depends on 1)

The solar cell of claim 1, wherein the first, second and third conductive busbars comprise a seed metal layer.

### Claim 4 (depends on 1)

The solar cell of claim 1, wherein the first, second and third conductive busbars comprise a plated metal or a conductive foil.

### Claim 5 (depends on 1)

The solar cell of claim 1, wherein the first, second and third conductive busbars comprise a metal selected from the group consisting of aluminum, nickel, silver, cobalt, copper, titanium and tungsten.

### Claim 6 (depends on 1)

The solar cell of claim 1, wherein the first and third conductive busbars have the same polarity.

### Claim 7 (depends on 1)

The solar cell of claim 1, wherein the first and third conductive busbars have a positive polarity and the first and second portions of the second conductive busbar has a negative polarity.

### Claim 8 (depends on 1)

The solar cell of claim 1, further comprising a local discontinuity in the substrate located between the first and third conductive busbars and below the first conductive bridge.

### Claim 9 (depends on 8)

The solar cell of claim 8, wherein the first conductive bridge electrically connects portions of the first and third conductive busbar on opposing sides of the local discontinuity.

### Claim 10

A solar cell, the solar cell having a front side which faces the sun during normal operation and a back side opposite the front side, the solar cell comprising:
a substrate having a first semiconductor region and a second semiconductor region disposed in or above the back side of the solar cell;
a first conductive busbar disposed above the first semiconductor region and extending in a first direction and including a plurality of first conductive fingers extending in a second direction that is orthogonal to the first direction;
a second conductive busbar including a first portion and a second portion disposed above the second semiconductor region and extending in the first direction and including a plurality of second conductive fingers extending in the second direction, wherein a first separation region separates the first and second portions of the second conductive busbar;
a third conductive busbar disposed above the first semiconductor region and extending in the first direction and including a plurality of third conductive fingers extending in the second direction, wherein the plurality of first and the plurality of second conductive fingers form an alternating pattern in the first direction, and the plurality of second and the plurality of third conductive fingers form another alternating pattern in the first direction;
a first conductive bridge electrically connecting the first conductive busbar to the third conductive busbar and extending in the second direction, wherein the first conductive bridge extends beyond sides of the first conductive busbar and the third conductive busbar, the first conductive bridge including one of the plurality of first conductive fingers and one of the plurality of third conductive fingers; and
a second conductive bridge aligned to the first conductive bridge in the first direction and offset from the first conductive bridge in the second direction.

### Claim 11 (depends on 10)

The solar cell of claim 10, further
comprising: a first portion of a fourth conductive busbar disposed
above the second
semiconductor region;
a second portion of the fourth conductive busbar disposed above the second semiconductor region, wherein a second separation region separates the second portion and the first portion of the fourth conductive busbar; and
a fifth conductive busbar disposed above the first semiconductor region.

### Claim 12 (depends on 10)

The solar cell of claim 10, wherein the first, second and third conductive busbars comprise a seed metal layer.

### Claim 13 (depends on 10)

The solar cell of claim 10, wherein the first, second and third conductive busbars comprise a plated metal or a conductive foil.

### Claim 14 (depends on 10)

The solar cell of claim 10, wherein the first, second and third conductive busbars comprise a metal selected from the group consisting of aluminum, nickel, silver, cobalt, copper, titanium and tungsten.

### Claim 15

A solar cell, the solar cell having a front side which faces the sun during normal operation and a back side opposite the front side, the solar cell comprising:
a substrate having a first semiconductor region and a second semiconductor region disposed in or above the back side of the solar cell;
a first conductive busbar disposed above the first semiconductor region and extending in a first direction and including a plurality of first conductive fingers extending in a second direction that is orthogonal to the first direction;
a second conductive busbar including a first portion and a second portion disposed above the second semiconductor region and extending in the first direction and including a plurality of second conductive fingers extending in the second direction, wherein a groove is along a direction parallel to the first direction;
a third conductive busbar disposed above the first semiconductor region and extending in the first direction and including a plurality of third conductive fingers extending in the second direction, wherein the plurality of first and the plurality of second conductive fingers form an alternating pattern in the first direction, and the plurality of second and the plurality of third conductive fingers form another alternating pattern in the first direction; and
a first conductive bridge electrically connecting the first conductive busbar to the third conductive busbar and extending in the second direction, wherein the first conductive bridge extends beyond sides of the first conductive busbar and the third conductive busbar, the first conductive bridge including one of the plurality of first conductive fingers and one of the plurality of third conductive fingers.

### Claim 16 (depends on 15)

The solar cell of claim 15, further
comprising: a first portion of a fourth conductive busbar disposed
above the second
semiconductor region;
a second portion of the fourth conductive busbar disposed above the second semiconductor region, wherein a second groove separates the second portion and the first portion of the fourth conductive busbar;
a fifth conductive busbar disposed above the first semiconductor region; and
a second conductive bridge electrically connecting the third conductive busbar to the fifth conductive busbar, wherein the second conductive bridge is disposed above the second groove.

### Claim 17 (depends on 15)

The solar cell of claim 15, wherein the first, second and third conductive busbars comprise a seed metal layer.

### Claim 18 (depends on 15)

The solar cell of claim 15, wherein the first, second and third conductive busbars comprise a plated metal or a conductive foil.

### Claim 19 (depends on 15)

The solar cell of claim 15, wherein the first, second and third conductive busbars comprise a metal selected from the group consisting of aluminum, nickel, silver, cobalt, copper, titanium and tungsten.

### Claim 20 (depends on 11)

The solar cell of claim 11, wherein the second conductive bridge couples the fifth conductive busbar and the third conductive busbar.