AA cell

A number of manufacturers started commercial production of nickel—MH cells in 1991 (31—35). The initial products are "AA"-size, "Sub-C", and "C -size cells constmcted in a fashion similar to small sealed nickel —cadmium cells. Table 6 compares the Ovonics experimental cell and a similar sized nickel—cadmium cell. Ovonics also deUvered experimental electric vehicle cells, 22 A-h size, for testing. The charge—discharge of "AA" cells produced in Japan (Matsushita) are compared in Figure 22. 

An advanced Li—Mn02 battery under the trade name MoHceh has been developed by MoH Energy Ltd. (49). The cell has a nominal voltage of 3 V, allowing replacement of two NiCd cells with one MoHceh, hence significantly reducing battery pack size and volume. Production "AA" cells demonstrate a nominal capacity of 600 mAh for an energy density of 100 Wh/kg. Cycle life for this cell is reported to be typically 200 cycles (50). 

Figure 4. Discharge characteristics of RAM AA cells when cycled at 20 °C. The cells are discharged for 4 h per day at 4 Q, and charged overnight with a constant voltage charger at 1.7 V.

Figure 5. Performance of RAM AA cells as a function of the depth of discharge (DOD) recharging is done after each discharge. For an explanation of these example, see the text.

Figure 8. Low-cost diode-overflow charger for four RAM AA cells [30,351.

Figure 9. In a Motorola-type cellular phone handset, the six AA cells in series are protected by reversal-limiting diodes, and the overflow at 1.7 V is determined by the six red LEDs [38],...

The connection of AA-size cells in parallel can replace larger cells (e.g., D-size cells). Four AA cells fit into a D-size can, and six AA-cells are in equivalent weight to a D-cell [27]. The utilization of the Mn02 cathode is considerably improved because the cathode thickness is only 2 mm in a AA cell, but 5 mm in a D-cell. The internal resistance is also lower by a factor of 4 to 6. Figure 11 depicts a 5 PxlO S bundle battery five AA cells in parallel = 1 bundle, 10 bundles in series make a (nominal) 12 V battery. It is used as the power source for a transmitter/receiver service. A typical load profile is 2 A for 1 min, 0.33 A for 9 min average load, 0.5 A per bundle or 0.1 A per cell service, about 15 h. Smaller bundle batteries (with 2x9 cells) are very suitable for notebook-computers 18 AA cells weight 0.36 kg, and the total initial capacity is 32 Wh. 

Figure 7. Relationship between FOM of AA cells, lithium cycling efficiency (Eff) on stainless steel, and PC content in 1 mol L 1 - LiAsFfl - EC/PC.

Figure 7 shows the FOM of an AA cell and the PC content in EC/PC binary mixed-solvent electrolytes. With an increase in PC content, the lithium cycling efficiency (Eff) obtained with Li cycling on a stainless steel substrate increases. However, the FOM of the AA cell reaches its maximum value at EC/PC=1 9 [82], This result arises from the interaction between EC and the a-V205-P205 cathode. 

V2O5-P205 (95 5, molar ratio) cathode and a lithium anode (Li/a-V205 cell) [1]. In this section, we describe safety test results for AA Li/a- V2Os cells. The AA cell we fabricated has a pressure vent, a Polyswitch (PS, Raychem Co., thermal and current fuse) and is composed of a spirally wound cathode sheet, a metallic Li-based anode sheet and a polyethylene (PE) separator [87]. 

Figure 44. Voltage profile of overcharged Li/LiJV[n02 AA cells containing different substituted ferrocenes as redox additives in 1.0 M LiAsFe/EC/PC (A) reference (B) fer-rocenyl ketone (C) dimethylaminomethyFerrocene (D) ferrocene (E) n-butylferrocene. (Reproduced with permission from ref 429 (Figure 6). Copyright 1992 The Electrochemical Society.)...

The effect of these ferrocene-based additives on overcharge protection is shown in Figure 44, where AA cells based on lithium, LhMn02, and electrolytes with or without additives were overcharged. In the absence of these redox shuttles (A), the cell voltage continues to rise, indicating the occurrence of major irreversible decompositions within the cell whereas the presence of shuttle agents (B—E) locks the cell potential in the vicinity of their redox potentials... 

Recently Nagarajan et al. characterized three different commercial AA cells and compared the... 

BID, Binding (covalent) to DNA, Chinese hamster ovary AAS cells + NT 43 Leuratti eta/. (1993)... 

Cells are manufactured in AAA, AA, C and D sizes, with the AA cell being the most common. The demand for AAA cells is now increasing rapidly. 

Table 6.1 Comparison of AA-cell characteristics (by permission of Rayovac)...

To simplify the designation of dimensions, some well-established cells are given codes - e.g. the cylindrical AA-cell is known simply as R6. 

Agents that can be used to raise low blood glucose include the hormone glucagon, a peptide secreted by the aa-cells of the Islets of Langerhans in the pancreas, that physiogically... 

AA cells, MCHC = 5.9mM, pH 7.07. The inflection frequency of each dispersion curve is indicated by arrows along the horizontal axis. After Ref. 13. 

Figure 26. Comparison of the discharge of 1 D size cell and a parallel array of 6 AA cells.

Figure 27. Comparison of the polarisation and the internal resistance of 1 D and 6 AA cells.

Figure 28. Relationship of capacity versus current for 1 D cell (1) and an array off 6 AA cells (2).

Figure 30. Total service hours comparison between PAM and RAM AA cells on 10 2 continuous deep discharge to 0.9 V.

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