In one aspect the invention provides an assessment apparatus which includes two terminal connectors configured to electrically connect the assessment apparatus to the positive and negative terminals of a battery being assessed. The apparatus also includes a response measurement system configured to measure the terminal voltage and current of the battery when supplied with at least one alternating test current having a frequency less than 1 Hz and/or less than an impedance transition frequency associated with the battery being assessed. Also provided is a processor in communication with the response measurement system and being configured to output a performance assessment indicator for the battery being assessed by calculating at least one impedance for the battery using terminal voltage and current measurements communicated by the response measurement system.

A method of testing a battery includes the following steps. Step A1 is a step of preparing a test target battery. Step A2 is a step of measuring magnetism when applying an electric current to the test target battery. Step A3 is a step of obtaining a current distribution of the test target battery based on the magnetism measured in step A2. Step A4 is a step of comparing the current distribution of the test target battery obtained in step A3 with a normal current distribution that is obtained in advance, with predetermined reference positions being aligned with each other.

A system and method for providing an application-independent estimation of the state of health (SOH) of a battery. A battery terminal voltage, under a non-zero load, when a specific amount of charge has been drawn from the battery is compared to stored terminal voltage test data obtained under the same conditions. An estimate of SOH is provided in response to the comparison.

A modified battery cell for simulating failure conditions includes an electrical cell and a controllable voltage source. A transistor gate is joined to a positive output of the source and to a negative tab of the cell at the transistor source. One side of a resistor implanted in the cell is joined to the transistor drain and the other side is joined to the cell positive tab. Controlling voltage source voltage allows current to flow from the transistor source to the transistor drain and through the resistor. Current flow through the resistor causes heating within the electrical cell that can be monitored to simulate an electrical cell failure. A method for testing an electrical cell is also provided.

A self-discharge inspection method for a power storage device having a property that while the power storage device is pressed under a first load and charged with a first device voltage, in which a device voltage decreases when a load is reduced from the first load, includes detecting the first device voltage of the power storage device pressed under the first load and charged, continuously applying a power-supply voltage equal to the first device voltage from an external power supply, detecting a power-supply current flowing to the power storage device, determining a self-discharge state of the power storage device based on the detected power-supply current, and reducing the load applied to the power storage device from the first load by a load reduction amount before the power-supply current stabilizes after start of the voltage continuously applying.

A method of management of a battery that powers a component of a device may include monitoring a terminal voltage and a terminal current of the battery under a load that is drawing a current on the battery to provide power to a component of the device and modeling the battery as a battery model that approximates a relationship between the monitored terminal voltage and terminal current over at least one of: a certain frequency range; a certain duration, a certain amplitude range, an applied load, a set of conditions of the battery, and a set of conditions of the load. The relationship between the terminal voltage and the terminal current may have a frequency-dependent characteristic including at least two time constants. The two time constants may represent a time-varying relationship between an input and output of the battery model.

The invention presents a method for monitoring a battery state without interruption of functioning a battery system using a battery twin is presented. Wherein the battery system comprises a plurality of battery cells connected to each other, and wherein the battery twin comprises at least one battery twin cell that is identical to at least one of the battery cells of the battery system. The method comprises a step of measuring at least one parameter of the at least one battery cell of the battery system, wherein such measured at least one parameter describes working conditions of the at least one battery cell and/or the whole battery system. Further, the method comprises an offline measurement part, which comprises reproduction of the working conditions described with the measured at least one parameter on the battery twin. It should be done in such way that the at least one parameter of the battery twin under the reproduced working conditions is equal to the measured at least one parameter of the at least one battery cell of the battery system. After that, while the battery twin is working under the reproduced working conditions, at least one further parameter of the battery twin is measured. Such further parameters of the battery twin are measured without interruption of functioning the battery system. After the offline measurement part, the method further comprises a step of making judgment about the battery state based on the measured at least one further parameter of the battery twin. Such judgement about the battery state can be made of the at least one battery cell and/or of the battery system in whole.

A control unit in a battery management apparatus discharges constant direct current from a battery for a predetermined time period or charges the battery with the constant direct current for the predetermined time period to diagnose a state of the battery. A change point is identified where a rise in voltage given by subtracting open circuit voltage of the battery from measured voltage of the battery is varied from a curved line shape to a straight line shape with respect to transition of an increase of a value in which an elapsed time since start of charge-discharge is defined as a square root of time. A rise in voltage from the voltage when the charge-discharge is started to the change point is identified as a rise in voltage caused by resistance components of electrolyte, a negative electrode, and a positive electrode of the battery and a rise in voltage after the change point is identified as a rise in voltage caused by a diffusion resistance component of the battery.

The present invention provides a battery safety test device includes: a mechanical switch element having one end connected to either a battery positive or negative electrode and the other end connected to an electronic switching element; the electronic switching element having one end connected to the mechanical switch element and the other end connected to the other of the battery positive or negative electrode; a voltage sensor for measuring a voltage of the battery after the mechanical switch element and the electronic switching element are turned on; and a current sensor for measuring a current of the battery after the mechanical switch element and the electronic switching element are turned on.

A durability evaluation method of a secondary battery includes a durability step of continuing to apply an alternating current voltage of a durability frequency to a first secondary battery for evaluation over a durability test period, and an evaluation step of evaluating durability of an associated battery reaction associated with the durability frequency from among battery reactions of the first secondary battery. A temperature and a state of charge of the first secondary battery are adjusted to a first temperature and a first state of charge, respectively.