A battery-powered system includes a battery pack (10; 71; 81) connected to an electrical equipment (30; 50; 76; 86). The battery pack includes a first positive electrode terminal (11), a first negative electrode terminal (12), a first communication terminal (13), a first data input circuit (23), and a first limiting circuit (D11; D72; D82) that limits a flow of electric current in a direction from the first negative electrode terminal to the first communication terminal via the first data input circuit. The connected equipment includes a second positive electrode terminal (31; 51), a second negative electrode terminal (32; 52), a second communication terminal (33; 53), a second data input circuit (43; 63; 77; 87), and a second limiting circuit (D31; D51; D77; D87) that limits a flow of electric current in a direction from the second negative electrode terminal to the second communication terminal via the second data input circuit.

A battery-powered tool (200) may include a first tool-side electrical contact (251), a battery detection switch (220), a tool load (300), and a load connection switching device (210). The load connection switching device (210) may be configured to make an electrical connection between the first tool-side electrical contact (251) and the tool load (300) in response to a state change of the battery detection switch (220). The tool (200) may define engagement positions with the battery (110). In the first engagement position, a first battery-side electrical contact (111) is electrically coupled to a first tool-side electrical contact (251), and the battery detection switch (220) is not physically engaged. In the second engagement position, the first battery-side electrical contact (111) is electrically coupled to the tool-side electrical contact (251), and the battery detection switch (220) is physically engaged to cause a state change of the battery detection switch (220).

A battery module includes a battery cell stack in which a plurality of battery cells are stacked; and a first plate and a second plate disposed on one side and the other side of the battery cell stack, respectively, to discharge heat generated by the plurality of battery cells externally. The plurality of battery cells include a receiving portion having a quadrangular shape, and a sealing portion, partially disposed on an outer periphery of the receiving portion. The battery cell stack is provided, by alternately stacking, at least one first battery cell of which a surface on which the sealing portion is not disposed faces the first plate, and at least one second battery cell of which a surface on which the sealing portion is not disposed faces the second plate.

A secondary battery connecting to an external circuit through a first output terminal and a second output terminal. The secondary battery comprises an accumulator, a plurality of protective circuits and a switch element. Each of the protective circuits comprises two fuses connected in series to form a series circuit, a heater for blowing the fuses and a rectifier element in parallel connection to the heater. The series circuits of the two fuses are connected to each other in parallel. One end of the rectifier and the heater is connected to a junction between the two fuses, and another end of u) the rectifier and the heater connect to the switch element. One of the two fuses of each of the protective circuits connects to the first output terminal, and the switch element connects to the second output terminal.

A power storage device includes an electrode assembly, a case, first and second electrode terminals, and a current interrupting mechanism. The current interrupting mechanism interrupts a current through an electrical current-carrying path when the internal pressure of the case reaches a preset pressure. The current interrupting mechanism includes a mechanism insulating portion, which insulates the first electrode terminal including the current interrupting mechanism from an end face of the electrode assembly, and a terminal insulating portion, which insulates the second electrode terminal from the end face of the electrode assembly. The projecting dimension from a wall portion to the mechanism insulating portion including the first electrode terminal is equal to the projecting dimension from the wall portion to the terminal insulating portion including the second electrode terminal.

A secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; an electrode tab electrically connected to the electrode assembly; a current collector plate electrically connected to the electrode tab; a case accommodating the electrode assembly, the electrode tab, the current collector plate, and an electrolyte therein; a cap plate sealing the case and including a safety vent at one region; and a current interruption device connected to the safety vent and the electrode tab.

A battery pack and charger system includes a first battery pack having a first set of battery cells and configured to provide only a first operating voltage and a second battery pack having a second set of battery cells and configured to provide the first operating voltage and a second operating voltage that is different from the first operating voltage and a battery pack charger configured to be able to charge the first battery pack and the second battery pack.

A battery pack including a protective circuit module including a circuit board extending in a first direction, an electrode tab coupling part on the circuit board, and a protection layer between the electrode tab coupling part and the circuit board; and a battery cell including an electrode tab protruding at one end and having a polarity, the electrode tab being coupled to a top surface of the electrode tab coupling part, wherein the electrode tab of the battery cell, the electrode tab coupling part, and the protection layer of the protective circuit module are stacked and coupled in a second direction perpendicular to the first direction.

A spacer (first spacer 114) has an insulating property, is used in a battery pack 100, obtained by electrically interconnecting unit cells 110 that are stacked one atop another, by means of a bus bar 132 along the stacking direction (Z direction) of the unit cells, each having a cell body 110H, which includes a power-generating element 111 and is formed in a flat shape, and an electrode tab 112, which is drawn out from the cell body 110H and whose distal end portion 112d is folded along the thickness direction of the cell body 110H; and is provided between each of the unit cells. The first spacer has an abutting portion 114h, a recessed portion 114i, and a communicating portion 114j. The abutting portion abuts the distal end portion of the electrode tab along the stacking direction of the unit cells. The recessed portion is recessed in a direction intersecting the stacking direction of the unit cells so as to be separated from the distal end portion of the electrode tab. The communicating portion allows an inner side of the recessed portion to communicate with the outside of the recessed portion.

A battery protective circuit may include: a first switch connected between a negative pack terminal of a battery pack and an output node to control an electrical connection between the negative pack terminal and the output node; a first resistor connected between the output node and a ground; and a controller configured to control on or off of the first switch and to determine a short circuit state between pack terminals of the battery pack based on an output voltage of the output node.