# US 10,770,902 B2 · Solar cell system and method for controlling solar cell system

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- Number: US 10,770,902 B2
- Document ID: US10770902B2
- Status: Granted
- Kind: B2
- Application number: 15/911,316
- Filed: 2018-03-05
- Published: 2019-03-21
- Granted: 2020-09-08
- Earliest claimed: 2017-09-19
- Assignees: Kabushiki Kaisha Toshiba
- Applicants: Kabushiki Kaisha Toshiba
- Inventors: Soichiro Shibasaki; Mutsuki Yamazaki; Sara Yoshio; Naoyuki Nakagawa; Kazushige Yamamoto; Yuya Honishi
- Web page: https://patentgrep.com/patent/US10770902B2

## CPC

- H10F 10/142: comprising multiple PN homojunctions, e.g. tandem cells
- H02J 3/38: Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
- H02J 3/381: {Dispersed generators}
- H02J 3/46: Controlling the sharing of generated power between the generators, sources or networks
- H02S 40/30: Electrical components
- H10F 19/902: {for series or parallel connection of photovoltaic cells}
- H10F 77/122: comprising only Group IV materials
- H10F 77/126: {comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS]}
- H10F 77/935: {for photovoltaic devices or modules}
- H02J 2101/24: Photovoltaics
- Y02E 10/541: CuInSe2 material PV cells
- Y02E 10/544: Solar cells from Group III-V materials
- Y02E 10/547: Monocrystalline silicon PV cells
- Y02E 10/56: Power conversion systems, e.g. maximum power point trackers
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

According to one embodiment, a solar cell system includes a first solar cell including a first terminal and a second terminal, a second solar cell including a third terminal and a fourth terminal, and a voltage converter including a fifth terminal and a sixth terminal. The third terminal is electrically connected to the first terminal. The fifth terminal is electrically connected to the fourth terminal. The voltage converter causes a second absolute value to be smaller than a first absolute value. The first absolute value is of a difference between a first potential difference and a second potential difference. The first potential difference is between the first and second terminals. The second potential difference is between the first and fourth terminals. The second absolute value is of a difference between the first and third potential differences. The third potential difference is between the first and sixth terminals.

## Claims

### Claim 1

A solar cell system, comprising:
a first solar cell including a first terminal and a second terminal;
a second solar cell including a third terminal and a fourth terminal, the third terminal being electrically connected to the first terminal; and
a voltage converter including a fifth terminal and a sixth terminal, the fifth terminal being electrically connected to the fourth terminal,
the voltage converter being configured to cause a second absolute value to be smaller than a first absolute value, the first absolute value being determined based on a difference between a first potential difference and a second potential difference, the first potential difference being between the first terminal and the second terminal, the second potential difference being between the first terminal and the fourth terminal, the second absolute value being determined based on a difference between the first potential difference and a third potential difference, the third potential difference being between the first terminal and the sixth terminal,
wherein the first absolute value changes temporally.

### Claim 2 (depends on 1)

The system according to claim 1, further comprising an interconnect electrically connecting the sixth terminal and the second terminal.

### Claim 3 (depends on 1)

The system according to claim 1, wherein
the first solar cell includes a first photoelectric conversion layer,
the first terminal is electrically connected to a portion of the first photoelectric conversion layer,
the second terminal is electrically connected to another portion of the first photoelectric conversion layer,
the second solar cell includes a second photoelectric conversion layer,
the third terminal is electrically connected to a portion of the second photoelectric conversion layer, and
the fourth terminal is electrically connected to another portion of the second photoelectric conversion layer.

### Claim 4 (depends on 3)

The system according to claim 3, wherein
the portion of the first photoelectric conversion layer is of a first conductivity type,
the other portion of the first photoelectric conversion layer is of a second conductivity type,
the portion of the second photoelectric conversion layer is of the first conductivity type, and
the other portion of the second photoelectric conversion layer is of the second conductivity type.

### Claim 5 (depends on 3)

The system according to claim 3, wherein a first bandgap of the first photoelectric conversion layer is different from a second bandgap of the second photoelectric conversion layer.

### Claim 6 (depends on 5)

The system according to claim 5, wherein the first bandgap is larger than the second bandgap.

### Claim 7 (depends on 1)

The system according to claim 1, wherein
the first potential difference increases in a first interval, and
the second potential difference decreases in the first interval.

### Claim 8 (depends on 1)

The system according to claim 1, wherein
a change in a first interval of the first absolute value is larger than a change in the first interval of the second absolute value, or
the second absolute value substantially does not change in the first interval.

### Claim 9 (depends on 1)

The system according to claim 1, wherein the voltage converter modifies an absolute value of the third potential difference according to a temporal change of the first absolute value.

### Claim 10 (depends on 1)

The system according to claim 1, wherein the voltage converter modifies a fourth potential difference between the fifth terminal and the sixth terminal according to a temporal change of the first absolute value.

### Claim 11 (depends on 1)

The system according to claim 1, wherein
the voltage converter further includes a seventh terminal,
a signal corresponding to the first potential difference is input to the seventh terminal, and
a potential of the sixth terminal changes according to the signal.

### Claim 12 (depends on 1)

The system according to claim 1, wherein
the voltage converter further includes a power supply terminal, and
electrical power is supplied from the first solar cell to the power supply terminal.

### Claim 13 (depends on 1)

The system according to claim 1, wherein
the first solar cell has a first surface,
the first solar cell spreads along the first surface, and
at least a portion of the second solar cell overlaps at least a portion of the first solar cell in a first direction crossing the first surface.

### Claim 14 (depends on 1)

The system according to claim 1, wherein
the first solar cell includes a chalcopyrite material, and
the second solar cell includes silicon.

### Claim 15 (depends on 1)

The system according to claim 1, wherein
the first solar cell includes a plurality of first solar cell elements connected in series,
the first terminal is connected to one of the plurality of first solar cell elements, and
the second terminal is connected to another one of the plurality of first solar cell elements.

### Claim 16 (depends on 1)

The system according to claim 1, wherein the second solar cell includes a plurality of second solar cell elements connected in series,
the third terminal is connected to one of the plurality of second solar cell elements, and
the fourth terminal is connected to another one of the plurality of second solar cell elements.

### Claim 17 (depends on 1)

The system according to claim 1, wherein the voltage converter includes a DC-DC converter.

### Claim 18

A method for controlling a solar cell system, the solar cell system including a first generator and a second generator, the first generator including a first solar cell, the second generator including a second solar cell connected in parallel with the first generator, the method comprising:
converting a second solar cell voltage of the second solar cell to reduce a difference between a first output voltage of the first generator and a second output voltage of the second generator, wherein
a first solar cell voltage of the first solar cell increases in a first interval, and
the second solar cell voltage decreases in the first interval.

### Claim 19

A solar cell system, comprising:
a first solar cell including a first terminal and a second terminal;
a second solar cell including a third terminal and a fourth terminal, the third terminal being electrically connected to the first terminal;
a voltage converter including a fifth terminal and a sixth terminal, the fifth terminal being electrically connected to the fourth terminal, and
an interconnect electrically connecting the sixth terminal and the second terminal,
the voltage converter being configured to cause a second absolute value to be smaller than a first absolute value, the first absolute value being determined based on a difference between a first potential difference and a second potential difference, the first potential difference being between the first terminal and the second terminal, the second potential difference being between the first terminal and the fourth terminal, the second absolute value being determined based on a difference between the first potential difference and a third potential difference, the third potential difference being between the first terminal and the sixth terminal.