A metamaterial-based substrate (meta-substrate) for piezoelectric energy harvesters. The design of the meta-substrate combines kirigami and auxetic topologies to create a high-performance platform including preferable mechanical properties of both metamaterial morphable structures. The creative design of the meta-substrate can improve strain-induced vibration applications in structural health monitoring, internet-of-things systems, micro-electromechanical systems, wireless sensor networks, vibration energy harvesters, and other applications whose efficiency is dependent on their deformation performance. The meta-substrate energy harvesting device includes a meta-material substrate comprising an auxetic frame having two kirigami cuts and a piezoelectric element adhered to the auxetic frame by means of a thin layer of elastic glue.

Provided is a switched capacitor-based electrical stimulation device which supplies a direct current (DC) power, detects a charging voltage charged in any one of a plurality of capacitors, controls the DC power supplied to a capacitor module to repeat a charging level and a resting level according to a charging pattern when the charging voltage is lower than a target voltage, and outputs an electric current to electrodes which contact a human body based on an output pattern.

Disclosed herein are systems and methods for overvoltage protection. A system, such as a vehicle, for overvoltage protection of a supercapacitor system for an electric vehicle, the system includes a plurality of supercapacitor groups, each supercapacitor group comprising two or more of the plurality of supercapacitors. The system includes a plurality of overvoltage protector units, each the plurality of overvoltage protector units operable to detect the voltage of each of the two or more supercapacitors within the respective one of the supercapacitor groups. The system includes a controller comprising a processor with access to a memory, wherein the control system is operable to determine which of the plurality of supercapacitor groups to connect to the electric vehicle based on data sent from the respective overvoltage protector units.

A system for powering an electric vehicle includes at least one electrochemical battery, a supercapacitor adder module including at least one supercapacitor battery, and a controller configured, in response to detecting that an external charging source is connected to the supercapacitor adder module, to disconnect the at least one electrochemical battery from the electric vehicle, charge the at least one supercapacitor battery from the external charging source via the supercapacitor adder module, charge the at least one electrochemical battery from the external charging source via the supercapacitor adder module, and reconnect the at least one electrochemical battery to the electric vehicle.

Methods, systems, and devices for temperature-dependent charging of supercapacitor energy storage units of asset tracking devices are provided. An example method for temperature-dependent charging involves obtaining a temperature reading measured at an asset tracking device, the asset tracking device located at an asset to monitor travel of the asset, determining a target voltage for a supercapacitor energy storage unit of the asset tracking device based on the temperature reading to balance utilization of a capacity of the supercapacitor energy storage unit against temperature-dependent deterioration of the supercapacitor energy storage unit, and controlling a charging interface of the asset tracking device to charge the supercapacitor energy storage unit to the target voltage.

Disclosed herein are systems and methods for energy management. A system, such as a vehicle, includes a plurality of energy storage units that include a supercapacitor and an electrochemical battery. The system includes plurality of energy storage units including a supercapacitor and an electrochemical battery, the supercapacitor comprising a plurality of selectable power sources. The system includes a processor configured to detect a connection of an external charging system to recharge at least one of a supercapacitor and the electrochemical battery, wherein the supercapacitor comprises selectable power sources; in response to detecting the connection of the external charging system, determine whether a fault exists and is associated with at least one of charging or discharging; and control the charging the supercapacitor based on whether the fault exists.

Disclosed herein are systems and methods for energy management. A system, such as a vehicle, includes a plurality of energy storage units that include a supercapacitor and an electrochemical battery. The system includes an energy controller that identifies a safety threshold associated with at least a subset of the energy storage units. The energy controller tracks historical power draw from the plurality of energy storage units over time in power tracking data, and identifies a power draw based on the power tracking data. The energy controller switches between a first configuration and a second configuration based on the identified power draw crossing the safety threshold. The first configuration is configured for drawing power from the electrochemical battery and disconnecting from the supercapacitor, while wherein the second configuration is configured for drawing power from the supercapacitor and disconnecting from the electrochemical battery.

A method for powering an electric vehicle including an electrochemical battery and one or more supercapacitor batteries includes determining self-discharge rate data for the one or more supercapacitor batteries and, in response to the self-discharge rate data satisfying at least one threshold condition, notifying a user to charge the one or more supercapacitor batteries, otherwise performing operations including: measuring current within a first path connecting the electrochemical battery to the electric vehicle; storing data representing the measured current in a database; determining a current use pattern from stored current data in the database; and in response to the current use pattern satisfying a first switching condition, switching in the one or more supercapacitor batteries in place of the electrochemical battery.

Systems and methods are provided for electrochemical battery testing in supercapacitor-toelectrochemical hybrid systems, which may be provided in an electric vehicle. Such systems may include at least one electrochemical battery and an supercapacitor adder module and connections, and electrochemical battery testing module. In conjunction with a supercapacitor adder module, the electrochemical battery testing module applies a variety of tests and measures various parameters of one or more electrochemical batteries connected to an electric vehicle.

To provide a constant voltage DC supply device capable of supplying a direct current at a predetermined voltage for a long time irrespective of characteristics of a storage battery and the like. The constant voltage DC supply device for supplying a direct current at a predetermined voltage from a specific power generation unit, including: a plurality of power storage units 10a, 10b; a drive units 30 that is connected to the power storage units and rotating/driving by power supplied from any one of the power storage units; a plurality of the power generation units 40a, 40b connected to the drive units, respectively, and generating power by driving of the drive units; and a control unit 30 for controlling connection between the plurality of power storage units and the driving unit and between the power generation units other than the specific power generation unit 40b and the power storage units 40a, in which wherein the control unit executes control such that, when a voltage of the power storage unit supplying the power to the drive unit falls to a first voltage or less, the power is supplied from the power storage unit other than power storage part and to charge at least one power storage part other than that power storage unit is charged.