HEM HOME


The future battery electric vehicle (BEV)

Concept presentation by Anton Bech.

23.april 2003


>>    Why BEV
>>    Vehicle concepts
>>    Drive train
>>    Type of battery
>>    What to recommend
>>    Battery unit
>>    Battery interface in the car
>>    Electrical structure in the car
>>    Infrastructure
>>    Battery ownership
>>    How to get started
>>    For further discussion


- emission Battery electric vehicles have the best energy performance

- They use half the energy compared with hydrocarbon propelled cars

- They use 3-4 times less energy than fuel cell cars

- They are zero emission vehicles (ZEV)


Vehicle concepts

- Ordinary serial cars converted with an electrical drive train and battery

- Vehicles designed to be electrical


Drive train

- The electrical engine can be a AC or DC engine.
The AC engine has the benefit of being service free.
The DC engine offers better torque performance and efficiency, but requires maintenance for the brushes

- The battery can be one of many electrochemical possibilities.
Lead acid is relatively heavy and do not accept deep discharging.
NiCd have worked well in the past, but shall be out phased due to toxic material.
NiMH is working well and have better performance than NiCd with 70Wh/kg.
Other battery types are also subject to be used if the energy density is better than i.e. 50Wh/kg


Type of battery

Lead acid is relatively heavy and do not accept deep discharging. Energy density is 35Wh/kg

NiCd have worked well in the past, but shall be out phased due to toxic material. Energy density is 50Wh/kg

NiMH has proven performance in EV´s. They accept uncompleted charging/discharging better than NiCd. Energy density is 70Wh/kg

Lithium ion is high performing, but there is problems with calendar life and safety concerns due to the organic electrolyte. Energy density is 140Wh/kg

Zink-sodium requires hot battery and the technology is new and not proven. Energy density is expected to be app. 120Wh/kg


What to recommend

The car frame can be from a serial car or special designed. People like the existing car frames and they are the results of many years development.
New car frames give a very high up front cost.
Converted serial cars is ok in particular as long as the serial size is too small to bear the cost of making new frames
The drive train can well be a DC engine as the performance is good and the maintenance is low
The battery choice is today the NiMH, as it has proven performance and is commercial available.


Battery unit

The batteries should be in one or more battery boxes, which is attached to the car from below. The battery box should be in a standard format, so it can be used in various cars. Each box could be with 120V and 50-60Ah. Such box could be app. 0.8x0.4x0.2m and with a weight of app. 100-120kg

The battery unit contains a computer, which inform the car computer about the energy status and controllers the charging together with the charger in the car or an extern charger.
The batteries in the box can be changed to other types, when more suitable batteries are available
The box should be insulated and contain a thermal management. This allow the batteries to stay “warm” from own heat when used in winter periods and prevent overheating in summer.
The battery units can be made by all manufactures (OVONIC, SAFT, PANASONIC, etc)
It do not have to be of a specific chemistry

The battery unit is not a part of the car, hence the car manufacture do not have to sell the battery as a part of the deal. See. Dias 11.


Battery interface in the car

The car can have 1, 2 or more battery boxes depending on the frame size and power specification.
The battery box is vertical lifted onto a mating plate under the car. This plate have a locking device, which secure the box to the car. Power pins and communication pins are connected at the same time
The car battery plate includes a jack, so the battery box can be set on the floor or lifted up by the car itself

Battery change can be done in the garage or on any plane surfaces.
The car sink the battery box to the ground and release it. Roll the car till it is in position over the new battery box. Let the car hoist the box in position. The battery box can also be slated out and the box replaced without moving the car

This feature allow battery to be changed in minutes and changed batteries can be charged outside the car. Fleet cars can be “fully charged” in minutes. It also make it possible to have service stations along the road side, where the batteries can be swapped. Used batteries can be charged stationary and ready for use 1 hour later.


Electrical structure in the car

The car has a battery charger, which can deliver power to the batteries. It is a 1 phase 230V 10/15 Amps charger (2.3-3.5kW), but can as option be extended to 3 phase 230/400V 15A (10.5 kW)
The car has a socket for rapid charging from an external energy sources
The motor controller collect power from the batteries. If there is 2 boxes, the controller collect the current from each box with respect to the batteries energy status. The batteries can be with different capacity and chemistry, hence the current output from each must be differentiated to discharge the batteries with respect to their capacity
The energy meter in the car get information from the battery boxes about their status and display the average of the remaining energy to the driver.



An electric car do need an infrastructure as well as petrol cars needs petrol filling stations

There is a need for access to electric power on public parking lots. It can be just a 1 phase 230V 16A blue CEE sockets at some of the parking boxes. The fee for power can be paid by a ticket for the connection
3 phase 230/400V 16A at motorway cafeterias and restaurants
Battery change facilities at the petrol filling stations and highway service centres
1 phase 230V 16A blue CEE sockets 1-3 km before highway service centres along the motorway for emergency charging only


Battery ownership

Battery modules can be owned in various ways as the battery isn't a part of the car itself

Owned by the car holder. The battery package is bought and is property of the car owner. The energy capacity, the brand and the chemistry is the owners choice
The battery can be leased from a battery companies, who offers these services. This could well be the oil companies like Shell, Statoil, Elf etc, which already have the service stations along the roads. The leasing can be in two ways:
1) Battery, which is hold by the car owner
2) Battery, which is swapped and belong to a battery pool. The discharged battery will be swapped to fully charged when the user need it during distant travels and the battery will not return to the same user again

Batteries, which is owned or hold by the car owner, can also be swapped during distant travels, but will in such cases be reclaimed by the owner i.e. on the return travel, where he swap back to his own battery, which in the mean time has been charged.


How to get started

The car manufactures, the battery makers and the service companies must agree on how to operate. Which norm shall be fix for the battery package. How shall the infrastructure and the ownership be. Etc
The car makers make their cars fitted for the solution
The consumers buy the car, then buy or lease the battery from the “battery company”. To start with the swapping facilities will not be in place before the density of cars in the region has come to a size, where it make sense to offer such service

This solution do not have up front a high investment cost, as the infrastructure can be gradually extended

The Presentation is available in Power Point

For further discussion

Eng. Anton Bech


                   HEM HOME