A 12 volt automotive battery system includes a first battery coupled to an electrical system, in which the first battery include a first battery chemistry, and a second battery coupled in parallel with the first battery and selectively coupled to the electrical system via a first switch, in which the second battery includes a second battery chemistry that has a higher coulombic efficiency than the first battery chemistry. The first switch couples the second battery to the electrical system during regenerative braking to enable the second battery to capture a majority of the power generated during regenerative braking. The 12 volt automotive battery system further includes a variable voltage alternator that outputs a first voltage during regenerative braking to charge the second battery and a second voltage otherwise, in which the first voltage is higher than the second voltage.

An apparatus for detecting swelling of a battery module, which includes a swelling detection panel having an edge in contact with an inner surface of a battery module housing; a slant portion configured to protrude from the inner surface of the battery module housing and having a slant surface extending from a first location adjacent to the edge of the swelling detection panel to a second location while forming a predetermined angle with the inner surface; a contact sensor unit installed to the inner surface of the battery module housing immediately adjacent to an end of the slant surface corresponding to the second location; and a control unit configured to receive a swelling detection signal from the contact sensor unit when the edge of the swelling detection panel contacts the contact sensor unit, and to control an alarm unit to output an alarm message.

An electricity storage device includes a plurality of cell batteries C.sub.1 to C.sub.M serially connected; and a management module including a balance circuit that can selectively cause electricity to be discharged from each of the plurality of cell batteries, and a controller. The controller includes a current-voltage acquiring unit that acquires a charging current and the respective voltages of the plurality of cell batteries and a balance control unit that, if a determination condition and an execution condition are satisfied, determines a lowest-voltage cell battery having a lowest voltage among the plurality of cell batteries and controls the balance circuit such that electricity is discharged from the plurality of cell batteries other than the lowest-voltage cell battery for time periods in accordance with differences between the lowest voltage and the respective voltages of the cell batteries when the determination condition and the execution condition are satisfied.

A power tool includes a first connecting port, a second connecting port, a motor module, a first switching member, a second switching member, and a control device. The first switching member is connected between the motor module and the first connecting port. The second switching member is connected between the motor module and the second connecting port. The control device is connected to the first switching member and the second switching member. A control method thereof includes: switch on the first switching member and the second switching member when the control device determines that both the first connecting port and the second connecting port are respectively connected to a battery and a difference between voltages inputted to the first connecting port and the second connecting port is smaller than a predetermined voltage difference, allowing two batteries to supply power to the motor module at the same time.

A power management device is a power management device that controls a temperature inside a housing in a power storage system that includes a power storage device including a storage battery and the housing for housing the power storage device. The power management device includes an acquisition unit that acquires status information indicating a status of the power storage system, a calculation unit that calculates a target temperature in the housing based on an allowable capacity deterioration rate of the storage battery, and an air volume control unit that controls an air volume of a fan provided in the housing based on the status information and the target temperature.

Provided is a battery pack comprising a plurality of batteries; and a plurality of memories that correspond respectively to the batteries and that each record deterioration information of the corresponding battery. Each set of a battery and a corresponding memory may be formed integrally as a battery cell. As a result, the deterioration information of each battery cell can be known even after the battery pack is disassembled.

A battery pack and charger platform including a voltage coupling circuit comprising an input that receives an input voltage and an output that sends an output voltage, a voltage monitoring circuit having an input coupled to the voltage coupling circuit output and an output, and a power source having an input coupled to the voltage monitoring circuit output, the power source input receives an input voltage representative of a charge instruction.

A lithium secondary battery pack of the present invention includes: a lithium secondary battery including an electrode body formed of a positive electrode and a negative electrode facing each other and a separator interposed therebetween, and a non-aqueous electrolyte; a PTC element; and a protection circuit including a field effect transistor. The lithium secondary battery has an energy density per volume of 450 Wh/L or more, the lithium secondary battery has a current density of 3.0 mA/cm.sup.2 or less, and a relational expression (1) and a relational expression (2) below are established where A (mΩ) is an impedance of the lithium secondary battery and B (mΩ) is an impedance of the entire circuit unit of the lithium secondary battery pack excepting the impedance A (mΩ) of the lithium secondary battery:
A≤50 mΩ  (1)
B/A≤1  (2).

A battery system includes a battery module, a housing, a gas conveyor, and a gas sensor. The battery module is interconnected between a first system terminal and a second system terminal by a plurality of high current connectors, and the housing includes: a plurality of exterior walls enclosing the battery module and the plurality of high current connectors; and a partition wall within the housing. The gas conveyor is configured to circulate a gas flow through a flow channel loop formed within the housing by the partition wall and the exterior walls, and the gas sensor is arranged in the flow channel loop and is configured to detect an excess concentration of a gas species in the gas flow.

A system is provided with a set of removable battery packs and a set of power tools each including a motor, a controller, and a battery receiving portion. For each power tool, the controller is configured to identify a type of battery pack coupled to the battery receiving portion and limit a maximum amount of electric current drawn from the battery pack by the motor based on the identified type of the battery pack. The greater a ratio of an impedance of the motor to an impedance of the battery pack, the less the controller limits the maximum amount of electric current drawn from the battery pack such that for a given battery pack of the set of removable battery packs, the lower the impedance of the motor, the more current the motor draws from the given battery pack.