NOVELTY - A lithium ion battery comprises a cathode (3), an anode (2), and an electrolyte layer (4) between the cathode and anode, to constitute a cell element. The electrolyte layer includes an arrangement of insulating particles (4a) with several interstitial spaces between the particles, and electrolytes (4b) occupying at least some of the interstitial spaces. The insulating particles comprise olefin resins or inorganic oxides.    USE - To form a battery assembly useful in a vehicle, particularly as a power supply for a drive train of the vehicle (claimed) e.g. hybrid electric vehicle, fuel-cell vehicle and electric vehicle, and useful as a fuel-cell.    ADVANTAGE - The use of insulating particles in the electrolyte layer, makes the electrolyte layer much thinner than the minimum thickness of the polyolefin film used as electrolyte layer in conventional battery cell elements. Therefore, the gap between the electrodes can be reduced, and the volume of the pores between the particles can be increased compared to the conventional polyolefin film. Hence, the power output of the battery can be increased, and necessary energy can be derived even during recharging and discharging with a large current. The insulating particles also function as a separator to maintain the gap between the electrodes so that the facing anode and cathode do not come into contact. The thickness of the electrolyte layer is less than or equal to10 microns. The lithium ion battery exhibits increased cell voltage, high energy density and high output, and hence can be used in various applications, particularly in the power trains of vehicles.    DETAILED DESCRIPTION - The insulating particles are placed between the cathode and anode, so that facing sides of the cathode and anode do not contact each other. The lithium ions can be inserted into and removed from the cathode and the anode, through the electrolyte layer. The electrolyte layer is preferably a solid electrolyte layer. An INDEPENDENT CLAIM is included for manufacturing the battery by applying insulating particles and electrolytic polymer to form the electrolyte layer, and layering the electrolyte layer between the cathode and anode.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified cross-sectional view representing cell layer structure of a lithium ion battery.    collector (1)    anode (2)    cathode (3)    electrolyte layer (4)    insulating particles (4a)    electrolytes. (4b)