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

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.

What is claimed is: 
     
         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.   
     
     
         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 2 , wherein 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. 
     
     
         4 . The energy storage device as recited in  claim 3 , wherein the second operating mode is an operating mode in which the first energy store has a low state of charge. 
     
     
         5 . The energy storage device as recited in  claim 3 , 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. 
     
     
         6 . The energy storage device as recited in  claim 3 , wherein the first energy store and the second energy store are configured as electrical accumulators of the same type. 
     
     
         7 . The energy storage device as recited in  claim 6 , wherein the first energy store and the second energy store are configured as one of lead accumulators or lithium-ion accumulators. 
     
     
         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.   
     
     
         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.   
     
     
         11 . The method as recited in  claim 10 , wherein the first energy store and the second energy store are configured as lead accumulators, the second energy store in the first operating mode being 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 first energy store and the second energy store are configured as lithium-ion accumulators, the second energy store in the first operating mode being charged to a state of charge in the range of 50%-70% of nominal capacity of the second energy store.