A method of evaluating a power storage device includes at least [a] to [f] below. [a] A power storage device is prepared. [b] A charge level of the power storage device is adjusted to produce a first potential difference between a positive electrode and a negative electrode. [c] The positive electrode or the negative electrode is selected as a reference electrode. [d] After the charge level is adjusted, an operation to insert a conductive rod-shaped member into a stack portion along a direction of stack of the positive electrode and the negative electrode is performed while a second potential difference between the reference electrode and the rod-shaped member is measured. [e] The rod-shaped member is stopped. [f] The power storage device is evaluated based on a state of the power storage device after the rod-shaped member is stopped.

A method of evaluating a power storage device includes at least [a] to [f] below. [a] A power storage device is prepared. [b] A charge level of the power storage device is adjusted to produce a first potential difference between a positive electrode and a negative electrode. [c] The positive electrode or the negative electrode is selected as a reference electrode. [d] After the charge level is adjusted, an operation to insert a conductive rod-shaped member into a stack portion along a direction of stack of the positive electrode and the negative electrode is performed while a second potential difference between the reference electrode and the rod-shaped member is measured. [e] The rod-shaped member is stopped. [f] The power storage device is evaluated based on a state of the power storage device after the rod-shaped member is stopped.

A method for detecting internal short circuit of a battery, includes: discharging a battery with a first current I.sub.1 at a moment t.sub.1; calculating a first discharge voltage drop ΔV.sub.1 of the battery at a moment t.sub.1+dt; discharging the battery with a second current I.sub.2 at a moment t.sub.2, where I.sub.1≠I.sub.2; calculating a second discharge voltage drop ΔV.sub.2 of the battery at a moment t.sub.2+dt; and determining, based on the first current I.sub.1, the first discharge voltage drop ΔV.sub.1, the second current I.sub.2, and the second discharge voltage drop ΔV.sub.2, whether the battery has an internal short circuit. In this application, whether the battery has an internal short circuit can be accurately determined, thereby ensuring safety of an electronic apparatus and a user.

A method for detecting internal short circuit of a battery, includes: discharging a battery with a first current I.sub.1 at a moment t.sub.1; calculating a first discharge voltage drop ΔV.sub.1 of the battery at a moment t.sub.1+dt; discharging the battery with a second current I.sub.2 at a moment t.sub.2, where I.sub.1≠I.sub.2; calculating a second discharge voltage drop ΔV.sub.2 of the battery at a moment t.sub.2+dt; and determining, based on the first current I.sub.1, the first discharge voltage drop ΔV.sub.1, the second current I.sub.2, and the second discharge voltage drop ΔV.sub.2, whether the battery has an internal short circuit. In this application, whether the battery has an internal short circuit can be accurately determined, thereby ensuring safety of an electronic apparatus and a user.

In an arithmetic system, a data acquisition unit acquires operation data at least including a voltage of a battery mounted on an identical product (for example, an electrically-driven vehicle of an identical vehicle type) and a state of charge (SOC) from a plurality of individuals of the product via a network. A detector statistically processes the plurality of pieces of acquired operation data to detect an individual on which a battery different from specifications of the product is mounted.

A method for generating an electrochemical impedance spectrum for a battery includes: collecting, in a discharge state of a battery, battery discharge information of the battery periodically according to a preset collection interval, where the battery discharge information includes collection time, and current information and voltage information associated with the collection time; performing Fourier transform according to the collection interval and battery discharge information, to obtain multiple frequency-based first battery signals; determining a second battery signal from the multiple first battery signals, where the second battery signal includes a voltage signal greater than or equal to a preset voltage threshold; and determining an electrochemical impedance at a corresponding frequency according to the second battery signal, and constructing an electrochemical impedance spectrum according to all the electrochemical impedance.

A deterioration estimation device (1) includes: a discharge control unit (11) configured to discharge a lead-acid battery (3) or a lead-acid battery module (4) that includes a plurality of lead-acid batteries until the lead-acid battery (3) or the lead-acid battery module (4) reaches a predetermined SOC; and a first estimation unit (11) configured to estimate a rate of deterioration of the lead-acid battery (3) or the lead-acid battery module (4) based on internal resistance or conductance derived when the lead-acid battery (3) or the lead-acid battery module (4) is discharged.

A deterioration estimation device (1) includes: a discharge control unit (11) configured to discharge a lead-acid battery (3) or a lead-acid battery module (4) that includes a plurality of lead-acid batteries until the lead-acid battery (3) or the lead-acid battery module (4) reaches a predetermined SOC; and a first estimation unit (11) configured to estimate a rate of deterioration of the lead-acid battery (3) or the lead-acid battery module (4) based on internal resistance or conductance derived when the lead-acid battery (3) or the lead-acid battery module (4) is discharged.

A method for estimating an impedance of a battery. The method includes the steps of: acquiring data of the battery during at least a predetermined time range, the data including at least a plurality of voltage measurements and a plurality of current measurements; determining a time window within the predetermined time range, the time window starting after a relaxed voltage interval and including a dynamic load interval, determining an initial voltage, the initial voltage being the voltage measurement at the start of the time window, determining a plurality of dynamic voltages based on the voltage measurements in the time window and the initial voltage, executing a subspace identification analysis based on the plurality of current measurements and on the plurality of dynamic voltages, and computing the impedance from an output of the subspace identification analysis.

A method for estimating an impedance of a battery. The method includes the steps of: acquiring data of the battery during at least a predetermined time range, the data including at least a plurality of voltage measurements and a plurality of current measurements; determining a time window within the predetermined time range, the time window starting after a relaxed voltage interval and including a dynamic load interval, determining an initial voltage, the initial voltage being the voltage measurement at the start of the time window, determining a plurality of dynamic voltages based on the voltage measurements in the time window and the initial voltage, executing a subspace identification analysis based on the plurality of current measurements and on the plurality of dynamic voltages, and computing the impedance from an output of the subspace identification analysis.