Disclosure is a multi-voltage battery pack which includes: a housing, battery strings disposed inside the housing and including a plurality of battery cells, a battery interface disposed on the housing for use with the power tool, and a converting assembly disposed within the housing and electrically connected to the battery strings. The converting assembly has a first state, a second state, and a third state. The multi-voltage battery pack can separately output a first operating voltage, a second operating voltage, and a third operating voltage. The third operating voltage is greater than the second operating voltage, and the second operating voltage is greater than the first operating voltage.

Lithium-metal batteries with improved dimensional stability are presented along with methods of manufacture. The lithium-metal batteries incorporate an anode cell that reduces dimensional changes during charging and discharging. The anode cell includes a container having a first portion and a second portion to form an enclosed cavity. The first portion is electrically-conductive and chemically-stable to lithium metal. The second portion is permeable to lithium ions and chemically-stable to lithium metal. The anode cell also includes an anode comprising lithium metal and disposed within the cavity. The anode is in contact with the first portion and the second portion. The cavity is configured such that volumetric expansion and contraction of the anode during charging and discharging is accommodated entirely therein.

A battery system comprises multiple electrochemical units for receiving, storing, and providing electricity; an integrated network of specially arranged conductors for carrying and transmitting electricity from, to, among, and/or between the electrochemical units; and various strategically interspersed current-regulating devices for predeterminatively routing electricity through the conductors. The electrochemical units may be in the form of cells, modules, packs, or other types of containers or enclosures. The conductors are arranged to enable two or more connection modes, said connection modes being selected from the group consisting of series, parallel, and series-parallel connections. The current-regulating devices are positioned in proximity to desired rerouting points and are capable of controlling the path of electricity through the network of conductors and thereby selectively and temporarily altering the connection mode of the electrochemical units.

An electrical apparatus includes a battery pack, an electrical apparatus main body and a control unit. The battery pack has a plurality of cell units of which connection states are able to be switched and a plurality of battery side connection terminals. The electrical apparatus main body has a battery pack mounting portion to which the battery pack is mounted, a plurality of device side connection terminals to which the plurality of battery side connection terminals are connectable, and a load device to which power is supplied from the battery pack. The control unit is configured to stop or limit power supply from the battery pack to the load device when a voltage imbalance is generated between the plurality of cell units or a contact failure is generated between the plurality of battery side connection terminals and the plurality of device side terminals.

3-D magnesium voltaic cells have a magnesium anode coated on multiple opposing surfaces with a continuous protective/electrolyte layer that is ionically conductive and electronically insulating. The resulting protected 3-D magnesium anode is coated on multiple opposing surfaces with a continuous cathode layer that is electronically and ionically conductive, and includes a magnesium storage medium. Suitable magnesium anodes, in particular, magnesium foam anodes, can be made by pulsed galvanostatic deposition of magnesium on a copper substrate. The protective layer can be formed by electropolymerization of a suitable methylacrylate ester. The continuous cathode layer can be a slurry cathode having powders of an electronic conductor and a reversible magnesium storage component suspended in a magnesium electrolyte solution.

The present application relates to a series-parallel switching device and a battery pack including the series-parallel switching device. The series-parallel switching device used for the battery pack is disclosed. The battery pack includes a first battery and a second battery. The switching device includes: a switching circuit, which is configured to be electrically coupled with the first battery and the second battery, where the switching circuit is configured to receive a control signal, and the switching circuit is controlled by the control signal to switch the first battery and the second battery between a parallel state and a series state, or switch the first battery or the second battery to a disconnection state.

The application relates to a distributed large-scale system of an all-vanadium redox flow battery, comprising a main electrical energy storage center, power distribution subsystems and a control subsystem. If the power of the power distribution subsystem does not meet a preset power requirement and/or the distance between the power distribution subsystem and the main electrical energy storage center exceeds a preset distance, a sub electric energy storage center connected with the main electrical energy storage center is arranged in the power distribution subsystem. The power distribution subsystem comprises an electric energy load point and/or an electric energy access point. The main electrical energy storage center and the plurality of power distribution subsystems are electrically connected with the control subsystem respectively. The power supply system has the effect of meeting the power increase and decrease requirements of a plurality of distributed external loads or power supply systems.

An energy storage system according to an embodiment of the present disclosure includes: a plurality of cell arrays, each including a respective plurality of battery cells connected in parallel; and a plurality of switches coupled to the plurality of cell arrays, and configured to connect the plurality of cell arrays in series, wherein the plurality of switches are operable to connect the plurality of cell arrays in parallel.

A power tool is provided including a power supply interface receiving a medium-voltage-rated removable battery pack having a maximum rated voltage in the range of 40 to 80 volts, and a brushless direct current (BLDC) motor. The motor includes a rotor and a stator having at least three stator windings corresponding to at least three phases of the motor, the rotor being moveable by the stator when the stator windings are appropriately energized within the corresponding phases. A multi-phase inverter bridge circuit is disposed between the power supply interface and the motor, and a controller is configured to output drive signals to the inverter bridge circuit to control flow of current from the battery pack to the motor such that the motor produces a maximum power output of at least approximately 1750 watts at a torque of approximately 1.5 to 2 Newton-meters.

A series formation system is provided. The series formation system includes at least two formation modules and a power module. The power module is connected in series with the at least two formation modules. The at least two formation modules are connected in series. The power module is configured to supply power to the at least two formation modules. Each of the formation modules includes a battery cell and a formation control circuit. The formation control circuit is electrically connected to the battery cell. The formation control circuit is configured to control a voltage or a current provided by the power module to the battery cell, so that the battery cell is switched between a constant current charging mode and a constant voltage charging mode.