The expected shortage of fossil fuels, ecological problems, climate concerns and resulting pollution restrictions are likely to increase the demand for electrically powered transportation means, further also referred to as vehicles, in the near future.
In contrast to the existing and well functioning petrol supply system, new challenges will advance out of this, since in contrast to petrol tanks, the storages for electrical energy, further also referred to by the common terms energy cell, battery or accumulator, are expensive, have a limited lifetime and require careful handling. Especially in the present state of development, in particular much longer time is needed for the regeneration of such a storage than for the refilling of a fuel tank of similar energy content. Another important drawback is the limited range, achievable with battery powered vehicles as the stored energy per weight ratio of such storages is much lower than the one of fossil fuel, whereby a desired low weight of the accumulators does result in a limited range of activity of such a vehicle which can be overcome without regeneration or exchange of the storage.
The vehicles can be expected to be dominated by wheelers comparable to the presently used passenger cars, but also other transportation means such as lorries, trucks, tractors, public buses, scooters, motorcycles, electrically powered bikes, crates, coaches or even construction machineries can in the future be equipped with electrical propulsions and therefore the herein described method and unit is also applicable on those.
To manage the consumption of energy and range of mobility of the vehicles many, more or less sophisticated, methods and means that can be implemented into the vehicles are known in the prior art. Many of them involve the task of vehicle navigation similar to the navigation devices as included in fuel powered vehicles.
The words storage, battery or energy cell represent means, which are movable and capable of supplying electrical energy. This comprises advanced technologies such as liquid batteries as e.g. presented in US 2007/0154814, energy cells which are rechargeable by exchange of electrolytes or liquid electrodes e.g. similar to the “liquid battery” presented in MIT's technology review magazine, No. 10, March/April 2009.
The storages can in general be primary cells as well as secondary cells, which signify that they do not necessarily need to be rechargeable or regeneratable. They can as well just be exchangeable, replaceable or even consumable just once, with their remains disposable after usage. Therefore, the words storage, battery, energy cell, and accumulator are used in a synonymous way to describe those means.
The document JP 10170293 concerns the search of an optimum leading route to the destination, by considering the charge of an on-vehicle battery on the basis of road map data which contains information on charging stations. A GPS receiver receives a GPS signal from a satellite and detects the present position, moving direction and moving velocity of the vehicle. A memory stores road map data which includes information on the charging station such as its position and a residual capacity of an on-vehicle battery is measured. A controller searches an optimum leading route to the destination and displays the present position and the leading route on a road map to guide a driver.
From the Japanese patent application JP 2006112932, a navigation system for an electric vehicle which can perform total time forecasting to a destination, including the charging time for a vehicle-mounted battery, is known. In addition, the system is also capable of providing information on restaurant locations, tourist spots, leisure facilities, or the like in the vicinity of charging facilities. This is done by the navigation system for the electric vehicle which comprises a display, an input section, a battery management section for measuring a remaining amount of the vehicle-mounted battery and a database section which stores position, information on charging performance and map information of the charging facilities.
An analysis section calculates charging time at the charging facility on the basis of the remaining amount of the vehicle-mounted battery, the energy consumption of the electric vehicle, the distance from the present position to the charging facility and the distance from the charging facility to the destination. The time of arrival at the destination, including the charging time calculated by the analysis section, is displayed on the display section.
The document JP 1012802 discloses a system to prevent a battery-driven vehicle from stopping due to the consumption of the remaining capacity of a battery during travelling by an alternation of the destination to a charging position, when the battery voltage arrives at a predetermined value. Therein a separate distance between the present travelling position of the battery-driven vehicle and a charging position for charging the battery is detected and a battery voltage allowable value according to the separate distance signals is set. On the other hand, when the fact is detected that the remaining capacity of the battery arrives at a predetermined battery voltage allowable value, the designation is altered to a position instructed by a destination setter and a travel controller outputs a command for the vehicle to travel to the charging position.
The therein presented method of changing the target of travel to a charging location when the battery level drops below a certain threshold might be acceptable if the recharging of the energy storage can be done within short time or the vehicle is of a kind such as an autonomous electrical lawn mower, but it is not desirable for personal transportation and time consuming regeneration or charging processes, since the unpredictability of the system and the thereof resulting unknown time of travel and stopovers would for sure not be accepted by a driver in many cases.
The publication DE 10 2008 017556 presents a navigation unit of a hydrid vehicle which records a charge-possible point and the history of travelling conditions near the charge-possible point. If a destination point on an optimum route is the charge-possible point, the navigation unit determines a continuous section where the electrically powered travelling is possible up to the charge-possible point, based on the history through state of a charge management plan preparation processing. The changing over between the hydrid powered and the electrically powered travelling is done according to this determination while travelling.
Involving the recorded history of the travelling conditions on the chosen route, as presented in DE 10 2008 017556, allows an increase of the accuracy of the expected range that is achievable with the remaining charge of the battery.
To overcome the drawback of the long regeneration or charging time, an exchange of the whole battery-package is a known solution, wherein the battery packages are charged at dedicated reconditioning locations for regeneration, similar to today's filling stations. The publication WO 2009/039454 discloses an electric vehicle network comprising such battery exchange stations.
The vehicles will in this case drop off the whole battery package at the reconditioning station and replace it with another, most likely, but not necessarily, one with a higher energy content than the previous one. The dropped off battery will be recharged at the location and then be put to another vehicle's disposal. The stopover time can thereby be reduced to the time needed for the replacement of the battery, which can, in fact, be even shorter than the time needed to fuel a state of the art car.
It is also a known concept to recondition the storage by an exchange of only some parts of the battery like some electrolytes or electrodes, which are then regenerated (or charged) at reconditioning stations instead of an exchange of the whole battery package. Thereby the longish charging can be done at those stations and the time needed for reconditioning is reduced to e.g. pumping out the used, liquid electrolyte and pumping in the reconditioned one, whereby times similar to those of petrol fuelling stops can be achieved.
Beside those dedicated public stations, also regeneration by sockets at public or private parking lots is possible, since electricity can be easily supplied without much effort by the often already present electrical networks.
But still, especially in case of longer distances, where the energy contained in one fully charged battery is not sufficient to reach the desired target, dedicated charge or exchange stations have to be considered in the planning of the best route or path of travel.
The stock of fully or partially charged batteries at such a station can only be limited and a single location can easily run out of charged batteries, while other batteries are lying around, unused for quite a while, at some other locations.
Therefore, a management of the usage of those regenerative storages and also of the availability of reconditioning stations and the stock and regeneration of the exchangeable storages is one of the challenges to overcome when the introduction of a wide-spread system for electrical transportation means for private, public and/or business use should be achieved.
The resources of storages are a limited set, which entities can be associated to transportation means or reconditioning stations. Although in a global view their number is sufficient to power the complete set of vehicles presently on the road, there can likely be a shortage of storages or a queue for regeneration slots (storages and regeneration slots are further also referred to as resources) in one area, while in another area there is a huge stock of storages or lots of unused regeneration slots.
This results in a demand to manage the assignment or allocation of the energy cells to optimize their usage and avoid shortages. This can also be expressed as management of the assignment of transportation means to reconditioning stations, since the batteries or energy cells can in general either be seen as associated to a transportation means or a reconditioning station, where they are consumed, charged or stocked.