Bayerische Motoren Werke Aktiengesellschaft

Moritz Schindler

Stefan Schaeck

Markus Mauerer

Stefan SCHÄCK

An energy storage apparatus for an onboard electrical system of a motor vehicle has a first electrical energy store characterized by a first voltage characteristic curve defining the quiescent voltage of the first store depending on the relative state of charge of the first store, and a second electrical energy store which can be connected in parallel with the first electrical energy store by a controllable switching element and which is characterized by a second voltage characteristic curve defining the quiescent voltage of the second electrical energy store depending on the relative state of charge of the second store. A first voltage value range covered by the first voltage characteristic curve and a second voltage value range which is covered by the second voltage characteristic curve partially overlap. The energy storage apparatus further has a device for determining the state of charge of the first energy store and/or of the second energy store. The device establishes the state of charge either by a quiescent voltage measurement device or by a state of charge determination device by balancing a respective battery current. The device opens the controllable switching element when the motor vehicle is in a state similar to the quiescent state and a quality value determined during a previous state of charge determination process in parallel with the state of charge and expressing the quality of the balancing exceeds a predefined threshold value. When the two criteria are fulfilled, the quiescent voltage measurement device for determining the state of charge of at least the first energy store is activated.

Energy storage apparatus for a motor vehicle and method for operating the energy storage apparatus

An electrical distribution system includes a first energy store and a second energy store. The two energy stores are connected in parallel. Characteristic values of the first and/or second energy store are detected and a regeneration phase of the first energy store is implemented depending on the detected characteristic values. In the regeneration phase, a first operating voltage is preset and provided by means of a generator in such a way that said first operating voltage contributes to the second energy store having, after a preset time span, a higher open-circuit voltage than the first energy store.

Method for operating an onboard network

A motor vehicle is provided having a control device, an electronic power unit and an energy storage system including first and second electric energy storage devices connectable in parallel so as to have a common base voltage at respectively different states of charge. The base voltage is substantially adjustable by the electronic power unit. A predictive energy management system executed by the control device determines a predefined setpoint value of a base voltage as a function of a predicted charge balance of the energy storage device.

Energy management for a motor vehicle having coupled energy storage devices

A motor vehicle includes a generator, electric consuming devices, a first electric energy storage device and a second energy storage device connected in parallel with the first energy storage device. The two electric energy storage devices, in a storage range, have at least partially overlapping characteristic open-circuit voltage curves. The first energy storage device has a first state-of-charge-dependent characteristic charging internal-resistance curve. The second energy storage device has a second state-of-charge-dependent characteristic charging internal-resistance curve. The first energy storage device has a first state-of-charge-dependent characteristic discharging internal-resistance curve and the second energy storage device has a second state-of-charge-dependent characteristic discharging internal-resistance curve. The first characteristic charging internal-resistance curve extends over an entire relative state-of-charge range in the direction of higher resistances above the second characteristic charging internal-resistance curve. The first characteristic discharging internal-resistance curve extends over an entire relative state-of-charge range in the direction of higher resistances below the second characteristic discharging internal-resistance curve. The two energy storage devices are interconnected with one another in a voltage-neutral manner.

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Munich, Germany

Moritz Schindler