Energy storage device for a photovoltaic system, and method for operating an energy storage device of a photovoltaic system

• US 10,381,863 B2
• Filed: 07/09/2013
• Issued: 08/13/2019
• Est. Priority Date: 07/13/2012
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: May, Johanna
• Primary Examiner(s): Whitmore, Stacy
• Application Number:
  US13/937,719
• Publication Number:
  US 20140015471A1
• Time in Patent Office: 2,226 Days
• Field of Search: 320127, 320130, 320131, 320135, 307 66
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 50/30 using light, e.g. lasers
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/60 Thermal-PV hybrids
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 80/14 District level solutions, i.e. local energy networks

Abstract

An energy storage device for a photovoltaic system includes: at least one first energy store which has a first cycle stability; at least one second energy store which has a second cycle stability, the first cycle stability being higher than the second cycle stability; and a control device which is designed to discharge the first energy store in a first operating mode and to discharge the second energy store in a second operating mode.

Claims

1. An energy storage device for a photovoltaic system, comprising:

at least one first energy store which has a first cycle stability;

at least one second energy store which has a second cycle stability, wherein the first cycle stability is higher than the second cycle stability; and

a control device configured to discharge the first energy store in a first operating mode and to discharge the second energy store in a second operating mode, wherein the control device has a first connection for the first energy store and a second connection for the second energy store, the first connection and the second connection being separate from one another, wherein the control device is coupled to the first and second energy stores in order to enable electrical power from the first energy store and the second energy store to flow through the control device, wherein;

the control device is directly coupled to electric consumers that consume electrical power,

the control device is coupled to the photovoltaic system, the photovoltaic system generating electrical current from solar energy,

the first energy store is configured as a lithium-iron phosphate accumulator,

the second energy store is configured as a lead accumulator, and

the second operating mode is an operating mode in which;

the first energy store and the second energy store are not chargeable by the photovoltaic system on account of the photovoltaic system having ceased to generate the electrical current,

a delay occurs between a time at which the photovoltaic system ceases to generate the electrical current and a time at which the second energy store begins to be discharged from a fully charged state,

during the delay the first energy store is discharged until a time at which a state of charge of the first energy store is discharged to a predefined lower limiting value, and

the time at which the state of charge of the first energy store is discharged to the predefined lower limiting value coincides with the time at which the second energy store begins to be discharged from a fully charged state.

2. The energy storage device as recited in claim 1, wherein the first operating mode is an operating mode in which the first energy store and the second energy store are chargeable by the photovoltaic system.

3. The energy storage device as recited in claim 1, wherein the second operating mode is an operating mode in which the first energy store has a low state of charge.

4. The energy storage device as recited in claim 1, wherein the second operating mode is an operating mode in which there is an increased energy demand by consumers coupled to the first energy store and to the second energy store.

5. The energy storage device as recited in claim 1, wherein the first energy store and the second energy store are configured as electrical accumulators of the same type.

6. The energy storage device as recited in claim 1, wherein the control device is designed in such a way that for a correct connection, only a plug which corresponds to the connection fits into the connection.

7. The energy storage device as recited in claim 6, wherein the plug fits into the connection due to a shape of the plug fitting into the connection.

8. A control device for an energy storage device, wherein the energy storage device includes at least one first energy store which has a first cycle stability and at least one second energy store which has a second cycle stability, the first cycle stability being higher than the second cycle stability, the control device comprising:

a first connection for connecting to the at least one first energy store which has the first cycle stability;

a second connection for connecting to the at least one second energy store which has the second cycle stability; and

a control element configured to discharge the first energy store in a first operating mode and to discharge the second energy store in a second operating mode, wherein the control element connects to the first energy store via the first connection and connects to the second energy store via the second connection, the first connection and the second connection being separate from one another, wherein the control device is coupled to the first and second energy stores in order to enable electrical power from the first energy store and the second energy store to flow through the control device, wherein;

the control device is directly coupled to electric consumers that consume electrical power,

the control device is coupled to a photovoltaic system that generates electrical current from solar energy,

the first energy store is configured as a lithium-iron phosphate accumulator,

the second energy store is configured as a lead accumulator, and

the second operating mode is an operating mode in which;

the first energy store and the second energy store are not chargeable by the photovoltaic system on account of the photovoltaic system having ceased to generate the electrical current,

a delay occurs between a time at which the photovoltaic system ceases to generate the electrical current and a time at which the second energy store begins to be discharged from a fully charged state,

during the delay the first energy store is discharged until a time at which a state of charge of the first energy store is discharged to a predefined lower limiting value, and

the time at which the state of charge of the first energy store is discharged to the predefined lower limiting value coincides with the time at which the second energy store begins to be discharged from a fully charged state.

9. The control device as recited in claim 8, further comprising:

a human-machine interface configured to enable a user to input user data for establishing at least one of the first and second operating modes.

10. A method for operating an energy storage device of a photovoltaic system, the energy storage device having a first energy store which has a first cycle stability and a second energy store which has a second cycle stability, the first cycle stability being higher than the second cycle stability, the method comprising:

selectively establishing one of a first operating mode or a second operating mode;

discharging the first energy store in the first operating mode; and

discharging the second energy store in the second operating mode, wherein a control device has a first connection for the first energy store and a second connection for the second energy store, the first connection and the second connection being separate from one another, wherein the control device is coupled to the first and second energy stores in order to enable electrical power from the first energy store and the second energy store to flow through the control device, wherein;

the control device is directly coupled to electric consumers that consume electrical power,

the control device is coupled to the photovoltaic system, the photovoltaic system generating electrical current from solar energy,

the first energy store is configured as a lithium-iron phosphate accumulator,

the second energy store is configured as a lead accumulator, and

the second operating mode is an operating mode in which;

the first energy store and the second energy store are not chargeable by the photovoltaic system on account of the photovoltaic system having ceased to generate the electrical current,

a delay occurs between a time at which the photovoltaic system ceases to generate the electrical current and a time at which the second energy store begins to be discharged from a fully charged state,

during the delay the first energy store is discharged until a time at which a state of charge of the first energy store is discharged to a predefined lower limiting value, and

the time at which the state of charge of the first energy store is discharged to the predefined lower limiting value coincides with the time at which the second energy store begins to be discharged from a fully charged state.

11. The method as recited in claim 10, wherein the second energy store in the first operating mode is charged to a state of charge greater than 80% of nominal capacity of the second energy store.

12. The method as recited in claim 10, wherein the second energy store in the first operating mode is charged to a state of charge in the range of 50%-70% of nominal capacity of the second energy store.