Query: solid lithium ion internal resistance

title: Internal resistance matching for parallel connected lithium ion cells and impacts on battery pack cycle life
abstract: When assembling lithium ion cells into functional battery packs, it is common to connect multiple cells in parallel. Here we present experimental and modeling results demonstrating that, when lithium ion cells are connected in parallel and cycled at high rate, matching of internal resistance is important in ensuring long cycle life of the battery pack. Specifically, a 20% difference in cell internal resistance between two cells cycled in parallel can lead to approximately 40% reduction in cycle life when compared to two cells parallel connected with very similar internal resistance. We show that an internal resistance mismatch leads to high current into each cell during part of the charging cycle. Since capacity fading is strongly dependent on temperature, and hence on charging rate when this rate is sufficiently high, the high current leads to substantially accelerated capacity fade in both cells. A model, based on the formation of a solid electrolyte interphase, is able to explain the dependence of lifetime on resistance mismatch, and also identifies the importance of random sudden capacity losses.

title: Lithium ion Battery Thermal Safety by Early Internal Detection, Prediction and Prevention
abstract: Temperature rise in Lithium ion batteries (LIBs) due to solid electrolyte interfaces breakdown, uncontrollable exothermic reactions in electrodes and Joule heating can result in the catastrophic failures such as thermal runaway, which is calling for reliable real time electrode temperature monitoring. Here, we present a customized LIB setup developed for early detection of electrode temperature rise during simulated thermal runaway tests incorporating a modern additive manufacturing supported resistance temperature detector (RTD) An advanced RTD is embedded in a 3D printed polymeric substrate and placed behind the electrode current collector of CR2032 coin cells that can sustain harsh electrochemical operational environments (acidic electrolyte without Redox, short circuiting, leakage etc. without participating in electrochemical reactions. The internal RTD measured an average 5.8 degC higher temperature inside the cells than the external RTD with almost 10 times faster detection ability, prohibiting thermal runaway events without interfering in the LIBs' operation. A temperature prediction model is developed to forecast battery surface temperature rise stemming from measured internal and external RTD temperature signatures.

title: A kind of high performance all solid lithium ion battery and preparation method thereof
abstract: The present invention discloses a kind of high performance all solid lithium ion battery and preparation method thereof, the all solid lithium ion battery preparation method of the present invention solves the problems, such as to contact firmly between electrolyte and electrode interface, improve the activation degree of electrolyte and electrode material, reduce activation polarization, it will be apparent that reduce the internal resistance of cell;The polymer dielectric of lithium superionic conductors modification improves the transmission rate of lithium ion through whole all solid lithium ion battery system, improves the rate charge discharge ability of all solid lithium ion battery;It is binding agent that positive and negative plate coating, which has used the high molecular polymer same with electrolyte phase, shortens the diffusion road warp of lithium ion, and the capacity for being conducive to active material plays, and significantly improves battery specific energy, up to 763Wh/Kg;High molecular polymer has relaxed the uneven discharge and recharge of negative metal lithium at the same time, it is suppressed that the growth of lithium crystallization, improves service life, can be recycled more than 1000 times.

title: The Structure Optimization of Lithium ion Battery Pack Based on Fluid solid Conjugate Thermodynamic Analysis
abstract: To effectively improve the discharging efficiency and the cycle period, the thermodynamic analysis and the heat dissipation structure optimization are conducted on the lithium iron battery pack. The internal resistance characteristics of the battery are experimented, and the change of internal resistance at different discharge rate and ambient temperature is measured. The three dimensional thermal effect model of the battery is established, and the simulation analysis of thermoelectric coupling is carried out by using MSMD model in FLUENT. The simulation results are compared with the experimental results to verify the validity of the model. By the Ansys Workbench software, the three dimensional model are established based on the conjugate thermal transfer phenomenon. Based on the fluid solid conjugate heat transfer mechanism, the influence of the airflow channel spacing and air inlet angle on the temperature distribution of the battery pack is analyzed, thus optimizing the heat dissipation structure. By studying the effect of the air flow rate and its temperature on the temperature distribution of the battery pack, the optimized heat dissipation structure can achieve the best performance.

title: The polarization characteristics of lithium ion batteries under cyclic charge and discharge
abstract: A high fidelity electrochemical thermal coupling was established to study the polarization characteristics of power lithium ion battery under cycle charge and discharge. The lithium manganese oxide lithium ion battery was selected to study under cyclic conditions including polarization voltage characteristics, and the polarization internal resistance characteristics of the power lithium ion battery under cyclic conditions were analyzed via the Hybrid Pulse Power Test (HPPC) The results show that for different working conditions, the polarization voltage difference of the power lithium ion battery is mainly affected by the change in polarization internal resistance. A higher charge discharge rate, lower ambient temperatures, and more cycles lead to a greater polarization internal resistance of the battery. Meanwhile, the ohmic polarization internal resistance and the concentration polarization internal resistance of the power lithium ion battery both exhibit different characteristics under different working condition. In addition, the internal resistance of the ohmic polarization is not affected by the change in current, but it is significantly affected by the change in ambient temperature. Therefore, the ohmic polarization voltage reacts rapidly with changes in the charge/discharge state of the battery; the change of the internal resistance of the concentration polarization is relatively slow.

title: Relationship between the crystal structures of LiMn1.5Ni0.5O4 and LiMn1.5Ni0.45Fe0.05O4 and their internal resistances as cathode materials for lithium ion batteries
abstract: It has been reported that the partial substitution of Fe for Ni in LiMn1.5Ni0.5O4 improves the rate capability of batteries wherein it is used as a cathode material. To understand the mechanism of this improvement, LiMn1.5Ni0.5O4 and LiMn1.5Ni0.45Fe0.05O4 samples were prepared to compare their crystal structures and the internal resistances of batteries fabricated using them. Electrochemical measurements showed that resistance of LiMn1.5Ni0.45Fe0.05O4 to the diffusion of Li+ ions into bulk is lower than that for LiMn1.5Ni0.5O4. The crystal structures of LiMn1.5Ni0.5O4 and LiMn1.5Ni0.45Fe0.05O4 were examined by neutron diffraction and transmission electron microscopy. The mass percentage of the ordered P4332 phase in LiMn1.5Ni0.45Fe0.05O4 was found to be smaller than that in LiMn1.5Ni0.5O4, and the coexistence of an ordered P4332 phase and a disordered Fd3 \overline{3} $m phase leads to the formation of boundaries in the primary particles of the samples. From these results, it was proposed that the reason for the internal resistance improvement was that the boundaries between the P4332 and Fd3 \overline{3} $m phase impeded the diffusion of Li+ ions. Therefore, LiMn1.5Ni0.45Fe0.05O4 exhibited lower internal resistance because it contained a lower amount of P4332 phase and consequently, a lower occurrence of boundaries.

title: Assessment of All Solid State Lithium Ion Batteries
abstract: All solid state lithium ion batteries (ASSBs) are considered as next generation energy storage systems. A model might be very useful, which describes all contributions to the internal cell resistance, enables an optimization of the cell design, and calculates the performance of an open choice of cell architectures. A newly developed one dimensional model for ASSBs is presented, based on a design concept which employs the use of composite electrodes. The internal cell resistance is calculated by linking two phase transmission line models representing the composite electrodes with an ohmic resistance representing the solid electrolyte (separator) Thereby, electrical parameters, i.e. ionic and electronic conductivity, electrochemical parameters, i.e. charge transfer resistance at interfaces and lithium solid state diffusion, and microstructure parameters, i.e. electrode thickness, particle size, interface area, phase composition and tortuosity, are considered as the most important material and design parameters. Subsequently, discharge curves are simulated, and energy and power density characteristics of all solid state cell architectures are calculated. These model calculations are discussed and compared with experimental data from literature for a high power LiCoO2 Li10GeP2S12/Li10GeP2S12/Li4Ti5O12 Li10GeP2S12 cell.

title: Mg2+ W6+ co doped Li2ZnTi3O8 anode with outstanding room, high and low temperature electrochemical performance for lithium ion batteries
abstract: Li2ZnTi3O8 (LZTO) co doped with Mg2+ W6+ (LM6ZTW3O) has been successfully prepared by a facile one step solid state route. A co doping strategy improves ionic conductivity, reduces transfer resistance, internal resistance and polarization, stabilizes the structure of LZTO and enables the LM6ZTW3O electrode to have a good electrical contact. The co doped LZTO exhibits excellent electrochemical performance at room, high and low temperatures. At 1 A g 1, 94.7% of the capacity for the 2nd cycle is kept at room temperature after 400 cycles. At 2 A g 1, there is no capacity decay at the 300th cycle at room temperature. Even at 3 A g 1, 177.9 mA h g 1 is kept at the 120th cycle. At 55 degC, 88.3% of the capacity for the 2nd cycle is obtained at 1 A g 1. At 0 degC, 192.9 mA h g 1 is still obtained at 0.6 A g 1 for the 60th cycle, and there is no capacity decay for 200 and 300 cycles at 0.2 and 0.5 A g 1, respectively.

title: Preparation and Electrochemical Performance of Mg2 Doped Li4Ti5O12 Anode Materials for Lithium Ion Batteries
abstract: Spinel Li4Ti5O12 (LTO) doped with Mg2+ was synthesized by solid phase reaction method. The Mg2+ doping quantity was 3% 6% 9% and 12% respectively. The structure and electrochemical performance of the prepared LTO composites were investigated by X ray diffraction (XRD) Scanning Electron Microscopy (SEM) Electrochemical Impedance Spectroscopy (EIS) and galvanostatic charge discharge tests. It was found that the doped Mg ion did not change the structure of Li4Ti5O12, and it was evenly distributed around Li4Ti5O12. When Mg2+ doping quantity increased from 3% to 12% the internal resistance and charge transfer resistance of the composite both decreased. The first discharge specific capacity of 6% Mg2+ doped LTO composite was 168 mAh/g, which was close to the theoretical capacity of pure lithium titanate (175 mAh/g) and the capacity retention rate was 98% after 100 cycles.

title: High performance all solid state lithium ion battery and preparation method thereof
abstract: The invention discloses a high performance all solid state lithium ion battery and a preparation method thereof. The preparation method of the all solid state lithium ion battery solves the problem of hard contact between an electrolyte and an electrode interface, improves the activation degree of the electrolyte and an electrode material, reduces electrochemical polarization and obviously reduces the internal resistance of the battery. A lithium superionic conductor modified polymer electrolyte penetrates through an overall all solid state lithium ion battery system, improves the transmission rate of lithium ions and improves the high rate charge discharge capability of the all solid state lithium ion battery. A high molecular polymer which is the same as the electrolyte is utilized for coating a positive plate and a negative plate as a binder, so that the diffusion path of the lithium ions is shortened; capacity development of active materials is facilitated; the specific energy of the battery is significantly improved and reaches 763Wh/Kg; meanwhile, uneven charging and discharging of a negative lithium metal are alleviated by the high molecular polymer; growth of lithium crystal is inhibited; the service lifetime is prolonged; and the high performance all solid state lithium ion battery can be recycled over 1,000 times.