Among: E is the accumulator cell idling terminal voltage, RM is the starting motor armature resistance, RB is the accumulator cell 内阻, RL is the line resistance.
Because RM, RB, RL extremely low, the starting current is extremely big. For example with 12V, the 45Ah accumulator cell starts installs 1.9 litres diesel engines instantaneous the automobiles, the accumulator cell voltage falls in the start from 12.6V to approximately 3.6V! Start process accumulator cell voltage waveform like chart 1; The start instant electric current reaches 550A, approximately for accumulator cell 12C discharge ratio! Start process accumulator cell current waveform like chart 2, (electric current sensor electric current/voltage transformation ratio: 100A/V). Although the vehicle with the accumulator cell is the start special-purpose accumulator cell, may the high percentage electric discharge, but may see in chart 1, time 10 time of above high percentage electric discharge accumulator cell performance changes very much badly, moreover, the so high percentage electric discharge to the accumulator cell damage also is extremely obvious. The start process voltage fierce change also is the greatly strengthened electronmagetic interference, may create the electrical equipment "to fall the electricity", forces the electrical equipment to start the process after the generator to finish on again electricity, computer in this process extremely easy dying machine. Therefore, regardless of or improves the automobile from the improvement automobile electrical equipment electromagnetic environment the start performance and the accumulator cell performance, lengthens the service life to consider, improves the automobile power source in the start process performance is necessary.




The question solution may enlarge the accumulator cell the capacity, but needs to increase very many, causes the volume to increase, this certainly is not the good solution. Are parallel the super capacitor and the accumulator cell may solve this problem well.

2 super capacitors principles and characteristic
2.1 super capacitors principles
The super capacitor is one kind of electric capacity may reach several thousand farads the electric capacity enormous capacitors. According to the capacitor principle, the electric capacity is decided to the electrode between is away from and the electrode surface area, in order to obtain the so great electric capacity, the super capacitor reduces between as far as possible the electrode the distance, the increase electrode surface area. Has used 双电�?the principle and the activated charcoal porous electrode for this, super capacitor structure like chart 3. 双电�?the medium exerts voltage when the capacitor two electrodes, in approaches the electrode on the dielectric medium contact surface to produce with the electrode carries the electric charge opposite electric charge and is fettered on the medium contact surface, forms in fact capacitor two electrodes, like chart 4, very obvious, two electrodes distances are extremely small, only several nanometer, simultaneously the activated charcoal porous electrode may obtain the enormous electrode surface area, may amount to the 200m2/ gram. Thus this kind of structure super capacitor has the enormous electric capacity and may save the very big static electricity energy. Speaking of the stored energy, super capacitor this characteristic is situated between traditional between the capacitor and the battery.
When between two pole plates the electric potential is lower than the electrolyte the oxidation reduction electrode potential, on the electrolyte contact surface the electric charge cannot be separated from the electrolyte, the super capacitor for the normal work condition (usually is below 3V), when the capacitor beginnings and ends voltage surpasses the electrolyte the oxidation reduction electrode potential, the electrolyte will decompose, will be the abnormal condition. Because along with super conductive discharge, on negative plate electric charge by external circuit 泄放, on electrolyte contact surface electric charge response reduction. From this may see: The super capacitor sufficient electric discharge process throughout is the physical process, does not have the chemical reaction. Therefore the performance is stable, with using the chemical reaction accumulator cell is different.


2.2 main characteristics
Although the super capacitor energy density is the accumulator cell 5% perhaps are less, but this energy storage way may apply in the traditional accumulator cell deficiency and the short-time high-peak current. Compares the battery to say that, this kind of super capacitor has following several superiority:
The electric capacity big, the super capacitor uses the active carbon powder and the activated charcoal textile fiber takes the polarizable electrode, with electrolyte contact area big increase, according to electric capacity formula, two pole plates surface areas bigger, then the electric capacity is bigger. Therefore, the common 双电�?capacity of condenser is very easy to surpass 1F, its appearance caused the cable telegram vessel the capacity scope suddenly to jump 3 ~ 4 magnitudes, at present the monomer super capacitor maximum electric capacity may reach 5000F.
Sufficient electric discharge life very long, may reach 500,000 times, or 90,000 hours, but the accumulator cell sufficient electric discharge life is very difficult to surpass 1,000 time; May provide the very high discharging current, if the 2700F super capacitor fixed discharging current is not lower than 950A, the electric discharge peak value electric current may reach 1680A, the common accumulator cell usually cannot have the so high discharging current, some high discharging currents accumulator cells the service life which will flow off in the so high electric discharge electricity greatly reduce.
May dozens of seconds to several minute in rapid charge rates, but the accumulator cell will fill the electricity in the so short time will be extremely dangerous perhaps is nearly impossible.
May in the very wide temperature range the normal work (-40 �? ~ +70 �?, but the accumulator cell very difficultly especially maybe under the low temperature environment works in the high temperature; The super capacitor uses the material is the security and non-toxic, but the lead-acid battery, the nickel cadmium accumulator cell has the toxicity; Moreover, the super capacitor may wilfully parallel use increases the electric capacity, after if adopts presses the measure, but also may connect the use.

3 super capacitors and the accumulator cell combinations improvement automobile starts the performance
3.1 electricity performance improvement




Uses the super capacitor and the accumulator cell is parallel when starts the process voltage waveform like chart 5, current waveform like chart 6. With chart 1, chart 2 compares the start instantaneous voltage to drop from only uses when the accumulator cell 3.2V promotes 7.2V; The starting current enhances from 560A to 1200A; The start instant power source output enhances from 2kW to 8.7kW; The start process steady voltage enhances 9.4V from 7V; The start process steady electric current enhances 440A from 280A; The start process power source steady output enhances from 2.44kW to 4.12kW.
3.2 starts performance improvement
The super capacitor and the accumulator cell parallel application may enhance the locomotive the start performance, the super electric capacity (450F/16.2V) with 12V, the 45Ah accumulator cell parallel start installs 1.9 litres diesel engines the automobiles, in 10 Celsius degree-hour of steady starts, although in this kind of situation, when does not connect the super capacitor, the accumulator cell also may start, but uses the super capacitor and the accumulator cell parallel time starting motor speed and the performance extremely is all good. As a result of the power source output enhancement, the start speed by only uses when the accumulator cell start speed 300rpm, increases 450rpm; Especially in enhances the automobile in the cold season starting performance (higher starting moment) on, the super capacitor is extremely significant, in below zero 20 Celsius degree-hour, because the accumulator cell performance greatly drops, is very possible not to be able normally to start or must to start many times can be successful, when the super capacitor and the accumulator cell are parallel then only needs a time of ignition. Its merit is extremely obvious.
3.3 pair of accumulator cells applications condition improvement
When the super capacitor and the accumulator cell are parallel, because the super capacitor equivalent series resistance (ESR) far is lower than the accumulator cell 内阻, therefore, electric current provides in start instantaneous 1200A in the starting current 800A by the super capacitor, the accumulator cell only provides 400A the electric current. Obviously is lower than only uses the accumulator cell 560A, effectively reduced the battery plate polarization, prevented the accumulator cell 内阻 rise enable the start process the steady voltage to obtain the enhancement. Most main is the battery plate polarization reduces not only is advantageous to lengthens the accumulator cell the service life, moreover also may eliminate the frequent start to the accumulator cell life influence.