Provided are a thermal battery system and an ignition method of the same, wherein the thermal battery system includes: a thermal battery assembly including a plurality of thermal batteries arranged in series and in parallel; an ignition circuit connected to the plurality of thermal batteries in the thermal battery assembly; and a control unit configured to control the ignition circuit such that each of the plurality of thermal batteries in the thermal battery assembly is selectively ignited, wherein the control unit is configured to selectively ignite one of the plurality of thermal batteries in an active matrix manner by controlling an ignition circuit.

Some embodiments are directed to a dual activation mode thermal battery for powering a load. The thermal battery can include a first power source activable upon receiving mechanical energy. The thermal battery can also include a second power source activable through one of the electrical power produced by the first power source and external electrical stimuli, the second power source is configured to, upon activation provide a voltage for powering the load, wherein the first power source and the second power source are thermally and electrically isolated and the initiator thermal energy output from one initiator is prevented from initiating the other power source directly.

A battery cell housing and control system enables the use of liquid battery power systems in various applications, including downhole environments. The cell housing includes a plurality of conductive terminals spaced there-around to provide conductivity between the electrochemical solution and the load. Sensors provide orientation data to the control system to thereby determine which terminals should be activated to provide power to a load.

A battery cell housing and control system enables the use of liquid battery power systems in various applications, including downhole environments. The cell housing includes a plurality of conductive terminals spaced there-around to provide conductivity between the electrochemical solution and the load. Sensors provide orientation data to the control system to thereby determine which terminals should be activated to provide power to a load.

A method for depassivation of a lithium-thionyl battery includes applying at least one current test load (LAST) (101) to an electrode of the battery (10), wherein at least one of a shape, a magnitude or points in time of the application of the at least one current test load (LAST) occurs dependent on a measurement of a response signal (u(t), du(t) on the battery (10), and energy of the at least one current test load (LAST) is drawn from the battery (10), comparing the response signal (u(t), du(t) of the battery (10) arising from application of the at least one current test load (LAST) to at least one predefined criterion (103), and establishing an operating state (12) or issuing an error message depending on satisfaction of the at least one predefined criterion (103).

In one embodiment, a depassivating circuit includes a battery, a resistive load coupled to the battery, and a magnetic field sensor. The magnetic field sensor detects a presence of a magnetic field. The magnetic field sensor depassivates the battery by causing current from the battery to flow through the resistive load, in response to the presence of the magnetic field. The magnetic field sensor detects removal of the magnetic field. The magnetic field sensor ends depassivation of the battery, in response to the removal of the magnetic field.

A battery management system includes thermal batteries, sensors, a clock, a processor, and memory storing a data structure, and is configured to receive energy parameters and time data, calculate a rate of energy usage of the thermal batteries based on the received data, and execute battery commands to activate or disable selected thermal batteries. Energy usage data can be stored as individual data points over time, and battery commands can be received from an external computer. The system determines when to activate a second battery based on a predetermined threshold of estimated electrical energy of a first thermal battery. A battery management method includes receiving signals for voltage, current, temperature, and time duration, estimating electrical energy based on these parameters, and activating a second battery when the estimated energy falls below a predetermined threshold.

Some embodiments are directed to a dual activation mode thermal battery for powering a load. The thermal battery can include a first power source activable upon receiving mechanical energy. The thermal battery can also include a second power source activable through one of the electrical power produced by the first power source and external electrical stimuli, the second power source is configured to, upon activation provide a voltage for powering the load, wherein the first power source and the second power source are thermally and electrically isolated and the initiator thermal energy output from one initiator is prevented from initiating the other power source directly.

A method for determining the self-discharge current of a lithium-ion battery provided with a positive electrode, a negative electrode, and an electrolyte arranged between the positive and negative electrodes includes charging the battery until a metal lithium layer is formed between the electrolyte and the negative electrode, measuring the open-circuit voltage of the battery at two moments, and determining the self-discharge current from the variation of the voltage measured between the two moments.

A method for depassivation of a lithium-thionyl battery includes applying at least one current test load (LAST) (101) to an electrode of the battery (10), wherein at least one of a shape, a magnitude or points in time of the application of the at least one current test load (LAST) occurs dependent on a measurement of a response signal (u(t), du(t) on the battery (10), and energy of the at least one current test load (LAST) is drawn from the battery (10), comparing the response signal (u(t), du(t) of the battery (10) arising from application of the at least one current test load (LAST) to at least one predefined criterion (103), and establishing an operating state (12) or issuing an error message depending on satisfaction of the at least one predefined criterion (103).