Method and equipment for rapid charging of accumulators

The invention relates to a method and apparatus for Charging a rechargeable battery.

Electrochemical storage batteries such as nickel-cadmium Akkumulato ren that for mains-independent operation of a plurality of Gerä th example of video cameras, cordless phones, find boring or portable computers use, be after a successful discharge date of the exchange of power grid connectable chargers voltage a rectification and make transformation, with a kon constants DC a maximum thickness of 1 Amp're again charged. The required charging times be several Hours. The consequent downtime of accumulator powered devices are very disturbing in many cases. in addition is that the batteries due to electrochemical Pro lose processes with time performance when not be fully discharged at each use, thereby recharging in ever shorter intervals is necessary.

The invention is therefore based on the object, a possible ability of charging a battery in a matter of minutes to accomplish.

The object is a method for charging a like dissolved deraufladbaren accumulator, the invention as is characterized in that the accumulator with a pul amount end-organizing DC with a few Amp're DC averaging and also some Amp're Betra ing amplitude of the current pulses is fed.

The charging a battery with a more Amp're Betra ing current is according to the manufacturer's instructions for accumulators not actually allowed because this destruction by would enter an excessive heating of the battery. This applies both for nickel-cadmium batteries as well as for Metal hydride storage batteries. Tests have now but überra ingly shown that when a pulsed charging current of some amperes strength this actually expected Zer disorder of the accumulator does not occur. It occurs in comparison for charging with conventional devices, on the contrary a very much slighter warming to the accumulator. The case be due to the high amperage recoverable load times only about 5 minutes. The inventive method creates Thus one way to discharge a battery that so within a very short time to recharge and operation the video camera, drill or the like again continued enforce. The current pulses can thus more or less rectangular shape exhibit. In addition, the pulse duration and the time Spacing of the pulses to be adjusted to different To load types of batteries. Advantageously, can the maximum current <b>6</b> to <b>8th</b> Amp're and minimal amperage <b>3</b> to <b>4</b> be Amp're. When charging a nickel-cadmium accumulator can take place before the pulse duration preferably be from a few seconds and the time interval of pulses in the order of 100 ms are. Also at Charging a very heat sensitive metal hydride accumulators sector has proven to be before a pulse duration of a few seconds geous proved, the time interval of pulses may be a few seconds. Further advantages result, if before recharging the battery by pulsed Entla dung, in which the accumulator, a current of 1 to 1.5 Amp're is removed, is discharged to a minimum voltage. By this pre-discharge, the fatigue effect described above with frequent, partially discharging the battery, the in The literature describes as a memory effect, again undone and the full performance of the battery mulators are restored. Brand new or extended Currently not used accumulators are not immediately operational. It has been found that there may be appropriate, before charging these accumulators these by current pulses of an amplitude of 1 to 1.5 Amp're and a time and a time interval of a few mils liseconds to load or unload, the loading and unloading can also be carried out several times. After that can the actual charging process be initiated.

The inventive device for charging a back rechargeable battery powers the battery on their Terminals with a pulsating direct current with a DC average and a pulse amplitude of some Amperes and has for this purpose at least one pulse generator. The pulse duration and the interval of the pulses can Attending adjustable. It is expedient here if the Pulse rate and pulse amplitude between normal market practice Accumulators tuned values ​​by means of a switch are switchable. Also, a further pulse generator for be provided generating a pulse-like discharge current to be the aforementioned memory effect for the batteries again side can. Also, the provision of a Konstantstromquel le to maintain the accumulator pressure is possible. Thus, the automatic unloading of unused Akkumula tors be counteracted. The accumulator is this to connected use to the device according to the invention and each of the constant current source with a charging current ver ensures as soon as the voltage a at the Akkumulatorklemmen certain threshold below.

The apparatus may also include means for adjusting the having voltage at the terminals of the accumulator, to the device for storage batteries with different be able to use voltage values. Further, control equipment for automatic activation of the discharge and Loads and their duration in dependence on the Akkumula be provided generator voltage. Thus, for example, auto cally at first for a few minutes, a discharge of the accumulators tors before the automatic insertion of the charging carry out. The application range of the device can still be increased by the fact that they either via a power supply to the AC power or a 12 volt car battery may be connected.

Below are exemplified by the novel Method charging currents generated as well as a preferred Ausfüh tion for an inventive device on the basis of Drawing explained.

Show it:

<b>Fig.</b> 1 the time course of a charging current for a nickel-cadmium battery;

<b>Fig.</b> 2 shows the time course of a charging current for a metal hydride battery;

<b>Fig.</b> 3 shows the time course of a Entladestro mes for a secondary battery;

<b>Fig.</b> 4 shows the time course of a charging current in preparation for the charging of a fa brikneuen or long unused Pc kumulators;

<b>Fig.</b> 5 is a block diagram of an apparatus for Charging a battery.

<b>Fig.</b> 1 shows a typical charging current for a nickel Cadmi to accumulator. The current I₁ is a pulsating direct current, whose current strength in the example between 3 Amp're shown and 6 Amp're varies. pulses<b>10</b> the current I₁ exhibit approximately rectangular shape and have a duration of 2.5 td₁ Seconds. The time interval between the individual ta₁ pulses <b>10</b> the current I₁ in the example shown 100 ms. The maximum current I_max1 So must for each very short periods of time to the minimum value I_min1 lowered be to the destruction of the battery due to excessive prevent warming.

<b>Fig.</b> 2 shows the <b>Fig.</b> 1 corresponding current-time diagram a charging current <b>12</b> for a metal hydride battery. Also Here, the charging current <b>12</b> a pulsating direct current, which Thickness between a minimum value I_min2 = 4 and a Amp're maximum current value I_max2 = 8 amperes varies. The duration of the impulse <b>11</b> the current <b>12</b> is shown in Example 2 Seconds, while the time interval between a ta₂ individual pulses <b>11</b> case 6 seconds, so much is greater than for nickel-cadmium accumulators. This contributes the larger the heat sensitivity of metal hydride Akkumulato ren bill. Nevertheless, even when charging Metallhy hydride batteries with the <b>Fig.</b> 2 corresponding charge accessing current running load times of about 5 minutes.

In <b>Fig.</b> 3 is a discharge current <b>13</b> to eliminate the memory Effect shown in its time course. The current strength fluctuates here also pulsed between -1 Amp're and -1.5 Amp're. The time interval of each td₃ In pulse <b>13</b> is a few milliseconds. To activate a brand new or a long time unused battery is a discharge of the battery to the power <b>13</b> after <b>Fig.</b> 3 fast pulsed charging with the in <b>Fig.</b> 4 shown current profile <b>14</b> performed. The pulse duration td₄ the current <b>14</b> is about 2.5 ms, and the time from stood ta₄ of pulses <b>14</b> about 10 ms. It may also be substituted multiple discharge and charge cycles in accordance with the current profiles <b>13</b> and <b>14</b> be made.

In <b>Fig.</b> 5 is a typical structure of an apparatus for He generation of battery-charging and discharging in accordance with the <b>Fig.</b> 1-4 shown. The device indicates connection jam <b>20</b>. <b>30</b> a vibrant for an accumulator DC from to its generating a pulse generator <b>21</b> in front is seen. The pulse generator<b>21</b> depending on the position of switch <b>22</b> a charging pulse <b>23</b> along with varying generate time intervals of the individual pulses. By Flipping the switch can hereby for example between a charging current Ii by <b>Fig.</b> 1 for a nickel-cadmium battery simulator and a charging current <b>12</b> according to <b>Fig.</b> 2 for a metal hydride battery can be selected. In addition, the pulse Gene generator <b>21</b> a pulse <b>24</b> to generate a current for prepara th charging of brand new or long unused Accumulators in accordance with the current <b>14</b> in <b>Fig.</b> 4 taken. From a subsequent changeover <b>25</b> Either the charging pulse <b>23</b> or the precharge pulse <b>24</b> to a power stage <b>26</b> and from there to the positive terminal <b>20</b> the device gege ben. The control of the relay<b>25</b> takes place via a one direction <b>27</b>That also to the positive terminal <b>20</b> of the Apparatus is connected and a drop in the voltage at the Accumulator detects. If the load pulse<b>23</b> from relay <b>25</b> switched through, a first light emitting diode D1 at the lights Device for indicating the charging on. The device also has a discharge performance level <b>28</b> , which provide if the positive terminal <b>20</b> connected to the device is and the battery will discharge before charging, to eliminate the memory effect. The discharging stage<b>28</b> becomes from an oscillator <b>29</b>Equipped with a switch <b>31</b> actuated is, and a control signal from a device <b>36</b> for Kon trol the voltage drop during discharge of the battery receives, driven. During the discharging lights a light emitting diode D2 to the apparatus. To maintain the Charge of an unused battery, the device In addition, a constant-current source <b>32</b> on which a Einrich tion <b>33</b> is activated, unless the oscillator <b>29</b> a indicates deliberate discharge and means <b>34</b> to Detecting the voltage at the battery sagging this Voltage below a certain threshold signals. The Kon cur- rent source <b>32</b> is doing as well as the switching of the relay <b>25</b> for switching the Vorladepulses <b>24</b> by the facility <b>27</b> by a timer <b>35</b> driven, the insbesonde re the duration of the precharge state pretends. When the constant power source <b>32</b> is enabled, an LED will light D3 pre direction on. To the amplitude of the pulsating current kon stant to maintain, is a voltage regulator <b>37</b> provided. The whole device is a power supply unit <b>38</b> to the change electricity network or connected to a 12-volt car battery.