Heating adiabatic calorimeter and methods of use
An apparatus and method for initiating thermochemical events in an adiabatic reaction calorimeter are provided. The apparatus and method may be used in safety research of lithium battery and reactive chemical thermal runaways. The apparatus comprises a motor-driven conductive heating element in thermal contact with the outer surface of the reaction in the sample container for heat transfer during heating ramp. The heating element is heated and coupled to the sample container to initiate thermal runaway and decoupled once thermal runaway is initiated, which is much faster than many existing slow heating methods used to initiate thermal runaway. Alternatively, when the heating element is kept attached until the completion of the thermal event, a power-compensation DSC curve is resulted.
1 . An apparatus for initiating thermal event in a sample container, the apparatus comprising:
a heating element operable to transition between a heating configuration and a non-heating configuration, wherein when the heating element is in the heating configuration, the heating element is operable to be in thermal contact with the sample container to transfer heat to a region of the sample container;
a sample temperature sensor operable to sense a sample temperature of the sample; and
a controller communicatively coupled with the sample temperature sensor and the heating element,
wherein the controller is operable to maintain a linear temperature scanning rate up to a detection threshold and/or throughout the thermal event;
wherein the controller is operable to determine, when a heating power regulated by the controller surpasses the detection threshold, that the thermal event is a thermal runaway or a thermal reaction,
wherein, when the thermal event is a thermal runaway, the heating element is transitioned to a non-heating configuration such that the heating element is not providing heat to the sample container,
wherein, when the thermal event is a thermal reaction, the heating element remains in the heating configuration to be thermally attached with the sample container throughout the entire course of the thermal event,
wherein the heating element is coupled with a thermally non-conductive component, wherein the thermally non-conductive component has an upper end and a lower end, and wherein the thermally non-conductive component comprises of ceramics, composites, glass, or any non-metallic materials.
2 . The apparatus of claim 1 , wherein the heating element includes a motion-controlled conductive heating element in thermal contact with an outer surface of the sample container to transfer the heat during a heating ramp;
wherein upon detection of an onset temperature of the thermal runaway, the motion-controlled conductive heating element is detached from the sample container allowing the runaway reaction to depart from a programmed temperature ramp and self-propel to reaction completion adiabatically.
3 . The apparatus of claim 1 , wherein the thermal reaction includes an endothermic event and/or an exothermic event,
wherein upon detection of an onset temperature of the endothermic event or the exothermic event, the heating element is operable to reduce the heating power and the heat transferred to the sample container to substantially sustain a linearity of a temperature ramp until the thermal event is complete.
4 . The apparatus of claim 1 , wherein upon detection of an onset temperature of the thermal runaway, the heating element is kept in thermal contact with the sample container and no longer providing heat to the sample container, allowing the heating power to depart from a programmed temperature ramp and self-propel to reaction completion.
5 . The apparatus of claim 1 , wherein upon detection of an onset temperature of the thermal runaway, the heating element is detached or separated from the sample container allowing the heating power to depart from a programmed temperature ramp and self-propel to reaction completion.
6 . The apparatus of claim 1 , wherein when the heating element transitions from the heating configuration to the non-heating configuration, the heating element is turned off.
7 . The apparatus of claim 1 , wherein when the heating element transitions from the heating configuration to the non-heating configuration, the heating element is moved a travel distance to be detached from the sample container.
8 . The apparatus of claim 7 , wherein the heating element is driven and controlled by a step-motor and/or a linear actuator, wherein the step-motor and/or the linear actuator controls the travel distance of the heating element.
9 . The apparatus of claim 1 , wherein the thermally non-conductive component is coupled with a driving screw.
10 . The apparatus of claim 1 , wherein the lower end of the thermally non-conductive component is supported via a springe coil so to keep the heating element, when in the heating configuration, in thermal contact with the sample container.
11 . The apparatus of claim 1 , wherein the heating element includes a resistive heating element.
12 . The apparatus of claim 1 , wherein when the heating element is in the heating configuration, the heating element is coupled in thermal contact with the sample container.
13 . The apparatus of claim 1 , further comprising a conductive heat transfer material that is configured to, when the heating element is in the heating configuration, be in contact with both the heating element and the sample container, the conductive heat transfer material operable to assist with thermal energy transfer between the heating element and the sample container.
14 . A method for initiating a thermal event in a sample container, the method comprising:
positioning a heating element to be in thermal contact with the sample container for transferring heat to the sample container;
providing an energy source electrically coupled to the heating element; and
sending one or more current pulses through the heating element to generate power pulses at the heating element to heat the sample to initiate the thermal event;
determining, when a heating power surpasses the detection threshold, that the thermal event is a thermal runaway or a thermal reaction,
when the thermal event is a thermal runaway, transitioning the heating element to a non-heating configuration such that the heating element is not providing heat to the sample container,
when the thermal event is a thermal reaction, maintaining the heating element in a heating configuration to be thermally attached with the sample container throughout the entire course of the thermal event,
wherein the heating element is coupled with a thermally non-conductive component, wherein the thermally non-conductive component has an upper end and a lower end, and wherein the thermally non-conductive component comprises of ceramics, composites, glass, or any non-metallic materials.
15 . The method of claim 14 , further comprising:
positioning a conductive heat transfer material between and in contact with both the heating element and the sample container to assist with thermal energy transfer between the heating element and the sample container.
16 . The method of claim 14 , further comprising:
sensing a sample temperature of the sample;
controlling the heating element such that the heating element is heated according to a predetermined temperature rate or held at the predetermined temperature in response to a temperature difference of the heating element and the sample.
17 . The method of claim 16 , wherein pulse-width-modulation is used to control the heating element power of the heating element.
18 . The method of claim 15 , wherein the thermal event includes a thermal runaway and/or a thermal reaction.
19 . The method of claim 18 , wherein the thermal reaction includes an endothermic event and/or an exothermic event.