Bulk resistivity

Because a length of metal associated with the connector contact is ordinarily in the path between the contact end to which a wire is terminated and the contact interface, its resistance (bulk resistance) must be added to contact resistance when considering the connector as a circuit element. This overall resistance is sometimes erroneously called contact resistance. 

See 2-3.1. Electrical conduction through solids takes place both through the bulk material and over the surface. In most cases surfaces have different physical and chemical properties than the bulk, for example due to contamination or moisture. Volume and surface resistivity can be separately measured for solid materials such as antistatic plastic sheet. Powders represent a special case since although both surface and bulk conduction occur, their contributions cannot be individually measured and the volume or bulk resistivity of a powder includes surface effects. 

When coke breeze is tamped down the correct pressure to aim for is approximately 15 Nm" This will ensure integrity of the groundbed whilst in operation, remembering that it will be reducing in volume by chemical oxidation. A pressure of this magnitude will reduce the initial bulk resistivity of the coke. 

A value of Rqb for an SEI lOnm thick can be estimated from its values for CPE and CSE by assuming that these solid electrolytes consist of nanometer-sized particles. Thus the expected value for / GB at 30 °C for a lOnm SEI is in the range 10-lOOQcm2, i.e., it cannot be neglected. In some cases it may be larger than the ionic (bulk) resistance of the SEI. This calculation leads us to the conclusion that 7 GB and CGB must be included in the equivalent circuits of the SEI, for both metallic lithium and for LixC6 electrodes. The equivalent circuit for a mosaic-type... 

Polymers are inherent insulators and have a high surface and bulk electrical resistance. Reduction of the surface and bulk resistivity is achieved by ... 

In accordance with this model, the current path is made through the contact resistance external collector - volume collectors (Rki), then goes through many other resistances, such as bulk resistance of the conductive particles (Rvi) and the contact resistance between the conductive particles in the volume of the electrode (Rci) at the end, there is contact resistance between the conductive particles and active mass particles (Rmi). 

For powders and granular solids, there are two types of antistatic agents surface- and volume-active additives. Surface-active agents, which increase the surface conductivity of individual particles, are effective because triboelectric charge is always situated on the surfaces of individual particles. Most if not all surface-active agents are hygroscopic and thus attract a thin film of water to the surface it is this moisture that is responsible forthe increased surface conduction (van Drumpt, 1991). The effective bulk resistivity of the particles % -may be estimated by assuming that the particles are spherical and of radius R (Jones, 1995). 

All of the films grown showed p-type conduction regardless of the reactor type, Cu/In ratio, or morphology. It was reported that S-rich material shows p-type conduction61,62 and that the Cu-on-In antisite (Cuin) in Cu-rich films is expected to be the major acceptor for p-type conduction.47 The bulk resistivities ranged from O.lQ-cm to 30Q-cm Cu-rich films generally had lower resistivity than In-rich films. 

However, there seems to be some disagreements on the exact influence of anode composition on the cell/anode bulk resistance. While Kawada et al. [42] indicated that cell bulk resistance also reached minimum when the Ni content was 40 vol% (Figure 2.12), Koide et al. [25] showed that as the Ni content increased, cell bulk resistance decreased continuously, and cell maximum power output also increased (Figure 2.13). 

A resistance Rv due to the sum of the ohmic contact resistance, the silicon bulk resistance and in part to the electrolyte resistance. 

Through assumptions and the use of values for known resistances of the materials used in the apparatus, the actual bulk resistance of the DL material could be calculated. This resistance was then used so that the electrical conductivity could be solved. Nitta and colleagues noted that the in-plane conductivities of the DL materials were a linear fxmction of the compressed thickness (i.e., the conductivity increased when the thickness decreased with increased compression pressure). This resulted from a decrease in thickness that led to a loss of porosity in the DL materials and higher contact between fibers. 

Fig. 10.12 Expected complex plane impedance diagram for an electrolyte with one mobile species which is contacted by two non-blocking metal electrodes, e.g. Ag/Ag Rblj/Ag. is the bulk resistance of the electrolyte and R is the charge transfer resistance for the Ag/Ag Rbls interface.

One of the major causes of the distorted behaviour seen when rough electrodes are used is due to the fact that different parts of the interface have different bulk resistance pathways to them, in some cases causing transmission line type behaviour. 

The latter authors used anode and cathode symmetrical cells in EIS analysis in order to simplify the complication that often arises from asymmetrical half-cells so that the contributions from anode/ electrolyte and cathode/electrolyte interfaces could be isolated, and consequently, the temperature-dependences of these components could be established. This is an extension of their earlier work, in which the overall impedances of full lithium ion cells were studied and Ret was identified as the controlling factor. As Figure 68 shows, for each of the two interfaces, Ra dominates the overall impedance in the symmetrical cells as in a full lithium ion cell, indicating that, even at room temperature, the electrodic reaction kinetics at both the cathode and anode surfaces dictate the overall lithium ion chemistry. At lower temperature, this determining role of Ra becomes more pronounced, as Figure 69c shows, in which relative resistance , defined as the ratio of a certain resistance at a specific temperature to that at 20 °C, is used to compare the temperature-dependences of bulk resistance (i b), surface layer resistance Rsi), and i ct- For the convenience of comparison, the temperature-dependence of the ion conductivity measured for the bulk electrolyte is also included in Figure 69 as a benchmark. Apparently, both and Rsi vary with temperature at a similar pace to what ion conductivity adopts, as expected, but a significant deviation was observed in the temperature dependence of R below —10 °C. Thus, one... 

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