• The introduction of sensors into pouch cells is currently not done on an industrial scale. Beyond the state of the art, SENSIBAT is currently under demostration process of the following issues that can occur due to the introduction of sensors:
i) incompatibility of the sensors with the pouch cell assembly process:
SENSIBAT project demostrated that the Level 1 sensors are be compatible during the pouch cell assembly as they are chosen and designed to be as thin as possible. The level 2 sensors will be printed on the cell separator and therefore it is expected that they will not influence the assembling process.
ii) intervention of sensors during the transport or transfer of lithium ions between anode and cathode electrodes:
The SENSIBAT Level 1 sensors are attached to one side of the stacked battery electrode inside the cell where there is minimum flow of lithium ions, the level 2 sensors will be printed on the separator and the work done up to know demostrated that will be possible to minimaze the impact of the L2 sensor on the lithium ions transfer.
iii) sensors may react to produce by-products or dissolve in the electrolyte used
During the development of Level 1 sensor some difficulties on the the sensor encapsulation were found due to the exposure of the sensor to the electrolyte. This issue was overcomed adopting material choice and integrating a tempering step in the sensor encapsulation process.
• SENSIBAT project demostrated that it is possible to introduce the developed Level 1 sensors inside pouch-type lithium-ion cells, in the next project period it will be studied how these sensors are useful to maximise the performance, functionality and safety of a complete battery system over its entire lifetime (increase QRL), including forecasting the remaining lifetime under different use cases, especially the suitability for possible "second life" usage.
• SENSIBAT will analize the impact on the electrochemical behaviour and lifetime of cells of the SENSIBAT L1 integrated sensors. Once cell results are demonstrated, the developed sensing technology can be used without significant modifications in a pouch type NMC/graphite battery.
• The battery cells with integrated L1 sensors will be used to develop a 24V battery module with integrated sensors.
i) A complete battery module based on six prototype cells connected in series, with integrated sensors connected to the multicell monitoring IC (aic) and slave BMS will be developed.
ii) A master BMS connected to the slave BMS and programmed with advanced state estimation algorithms will be also developed.
• Finally, by making use of the data from the internal sensing technologies, robust and advanced state estimation functions are under developemet. Commonly used state estimation algorithms are been improved and novel safety concepts are under study.
i) This will allow to develop faster charge protocols based on temperature and pressure measurements inside the cell.
ii) In addition, safety limits are more accurately measured and understood leading to safer battery operation and use of full battery capacity.
iii) in the same way, better battery maintenance with the improved ability to detect, repair or replace defective cell components will be possible.
v) Finally, using detailed data, more sophisticated lifetime prediction models will be developed and this will allow improved preventive maintenance measurements to prolong its lifetime.
