CN110707769A - Battery charging method and control unit - Google Patents

Abstract

The invention relates to a method for charging a battery (2) by means of an electrical energy source (3) and to a control unit (5), in which a charging period ( _Qs ) and a time period ( _ts ) are selected, in which The electrical energy source (3) distributes a control unit (5) that controls the energy source (3) or the pulse generator (4), wherein the control unit (5) controls the energy source (3) or the pulse generator (4) such that a charge pulse (LP) is generated within the time period (t _S ) to charge the battery (2) within the charge period (Q _S ), wherein the charge pulse (LP) has at least A pulse (P) and a pulse pause (PP), in which the method continues until a predetermined stop condition is reached.

Description

Battery charging method and control unit

technical field

The present invention relates to a method and a control unit for charging a battery.

Background technique

Currently, batteries, such as lithium-ion batteries, are charged at higher and higher currents so that the charging time can be kept constant as the capacity increases. Here, charging is performed with a constant current until the end-of-charge voltage is reached, and then the current is decreased while the voltage is kept constant. Due to the low charging current, this CV phase requires a long charging time. This method is also known as the CC/CV method (Constant Current/Constant Voltage) and is described as prior art in DE 10 2010 051 016 A1.

Furthermore, charging methods are known which use current in the form of charging pulses. A method is known from US2013/0026976A1 in which the charging pulse has a positive pulse and a pulse pause and a discharge pulse, wherein during the pulse pause the current can be greater than or equal to zero. Depending on the voltage of the battery, reduce the length of the pulse. Here, it is also provided that the height of the discharge pulse is reduced. If the voltage on the battery exceeds the threshold, the method is terminated. Here, the time period of the charging pulse decreases towards the end. In an alternative embodiment, only the pulse off time is extended by the shortening of the pulse time. Finally, an embodiment is also disclosed in which the discharge pulse is surrounded by two pulse pauses. The last method is also known from US 5,481,174 A.

The pulse charging method has the potential to significantly shorten the charging time.

SUMMARY OF THE INVENTION

The technical problem underlying the present invention is to further improve the method for charging the battery and to provide a control unit suitable for this.

The solution to this technical problem results from a method with the features of claim 1 and a control unit with the features of claim 9 . Further advantageous embodiments of the invention emerge from the subclaims.

In this case, the battery is charged by means of an electrical energy source, wherein a charging period and a time period are selected, wherein a control unit that controls the energy source or the pulse generator is assigned to the electrical energy source, wherein the control unit controls the energy source or the pulse generator such that in all A charging pulse is generated within the time period in order to charge the battery during the charging period, wherein the charging pulse has at least one pulse and a pulse pause, wherein the method is continued until a predetermined termination condition is reached. The basic idea of the invention is not to force charging at the highest possible current for as long as possible, but to achieve a very economical, but fast charging by trying to schedule a certain charging continuously within the stated time period part. Preferably, the charging pulse has exactly one pulse.

Here, the charging current in the pulse pause can be set to be greater than or equal to zero. The advantage of having the charging current greater than zero in the pulse pause is that it is not erroneously inferred that the charging is paused.

Additionally or alternatively, discharge pulses can be provided in pulse pauses, as is known from the prior art.

In another embodiment, the gradient of the rise or fall of the pulse is limited to a predetermined value, for example to 20 A/s.

In another embodiment, the charging period is reduced when the pulse reaches the time period or exceeds a predetermined maximum charging time.

Conversely, when the pulse is shorter than the predetermined minimum charging time, the charging segment is increased.

In one embodiment, the predetermined termination condition is a limit value of the state of charge of the battery, wherein the limit value is at least SOC=80%, preferably greater than/equal to 85% and particularly preferably greater than/equal to 90%.

In another embodiment, the characteristic curves for the maximum current, maximum voltage and temperature of the battery are taken into account in the control unit.

The control unit for controlling the electrical energy source or the pulse generator to generate the charging pulses for charging the battery is designed to control the electrical energy source or the pulse generator so that the charging pulses are generated so as to generate a pre-charged pulse for a predetermined time period. For a given charging segment, wherein the charging pulse has at least one pulse and a pulse pause, the control unit is further configured to generate the charging pulse until a predetermined stop condition is reached.

With regard to possible further configurations of the control unit, reference is made to the aforementioned embodiments with regard to the method.

Description of drawings

The present invention is explained in more detail below with reference to preferred embodiments. in:

Figure 1 shows a schematic block diagram of an apparatus for charging a battery,

Figure 2 shows the charging pulse in the first embodiment,

Figure 3 shows the charging pulse in the second embodiment,

Figure 4 shows the charging pulse in the third embodiment,

Fig. 5 shows the charging pulse in the fourth embodiment,

Figure 6 shows a charging pulse sequence with reduced charging segments,

Figure 7 shows a charge pulse sequence with increasing charge segments, and

FIG. 8 shows an exemplary charge pulse sequence.

Detailed ways

A block diagram of a device 1 for charging a battery 2 is shown schematically in FIG. 1 . The device 1 has an electrical energy source 3 , a pulse generator 4 and a control unit 5 . The electrical energy source 3 can be a direct current or an alternating voltage source, wherein the pulse generator 4 is designed to convert the electrical energy of the energy source 3 into charging pulses LP. The control unit 5 has an input unit through which inputs such as the charging period Q _S and the time period t _S can be input. Furthermore, the control unit 5 obtains data such as voltage and temperature from the battery 2 . In addition, a characteristic curve of current I, voltage V and temperature T is stored in control unit 5 , from which the maximum permissible current I at specific temperatures and voltages of battery 2 is derived. Finally, the minimum charging time _tlade,min and the maximum charging time _tlade,max are also stored. Here, the time period t _S remains the same for all charging pulses LP. The charging segment also remains constant with a few exceptions (more on this later with reference to Figures 6 and 7), where the ratio of pulses to pulse _pauses is dynamically controlled over the charging segment QS, which is explained in more detail. In this case, the pulse generator 4 can also be integrated into the energy source 3 .

First, some possible implementations of the charging pulse LP should be explained in more detail with reference to FIGS. 2 to 5 . Here, a first possible embodiment of the charging pulse LP is shown in FIG. 2 . The charging pulse LP consists of a pulse P and a pulse pause PP, wherein the time period _tS of the charging pulse LP consists of a charging time _tlade and a pause time _tPP . In summary, in the time period _tS , the battery 2 is charged in the charging period _QS . In the example shown, the charging current I in the pulse pause PP is greater than zero, so that part of the charging segment Q _S also charges the battery 2 in the pulse pause PP. Obviously, Q _S is the integral of the charging pulse LP. It should be noted here that the current I _max of the pulse P is preferably selected as the maximum possible current under the current ambient conditions (U, T, SOC) of the battery 2 . For example, the current I _max may be 200A.

An alternative charging pulse LP is shown in FIG. 3 , wherein the difference from the charging pulse LP according to FIG. 2 is that the current intensity I in the pulse pause PP is zero.

In FIG. 4 , a discharge pulse EP is additionally provided in the pulse pause PP. The discharge pulse can also be placed at the end of the charge pulse LP or within the pulse pause PP. As shown, the current intensity I of the pulse pause PP may be greater than or equal to zero.

The charging pulse LP is shown in FIG. 5, where the pulse rise and fall are limited. It should be noted here that this embodiment can also be combined with other charging pulses LP. For example, the magnitude of the gradient is limited to 20A/s.

FIG. 6 now shows the situation in which the charging segment Q _S has to be reduced because the maximum charging time _tlade,max has been exceeded. Accordingly, the control unit 5 reduces the charging segment Q _S to Q _S ′ for the next charging pulse LP, so that the maximum charging time _tlade,max is no longer exceeded.

The case of raising the charging segment Q _S to Q _S ′ is shown in FIG. 7 because the minimum charging time _tlade,min is below. Alternatively, in such a case, the current intensity of the pulses P can also be reduced.

An exemplary pulse sequence is shown in FIG. 8 where the charging segment Q _S is held constant. If the amperage I must be reduced due to the ambient conditions of the battery 2 (eg U, T and/or SOC), the charging time _tlade is correspondingly extended and the pulse pause PP is shortened.

Then, when an abort condition (eg, SOC = 90%) is reached, the method is terminated.

Claims (9)

1. A method for charging a battery (2) by means of an electrical energy source (3), wherein a charging section (Q) is selected_S) And time period (t)_S) Wherein a control unit (5) controlling the energy source (3) or the pulse generator (4) is assigned to the electrical energy source (3), wherein the control unit (5) controls the energy source (3) or the pulse generator (4) such that during the time period (t)_S) Generating a charging pulse (LP) internally in order to charge the section (Q)_S) Charging the battery (2), wherein the charging pulse (LP) has at least one pulse (P) and a Pulse Pause (PP), wherein the method is continued until a predefined pause condition is reached.

2. Method according to claim 1, characterized in that in said Pulse Pause (PP) a charging current is set which is greater than zero or equal to zero.

3. Method according to claim 1 or 2, characterized in that a discharge pulse (EP) is provided in the Pulse Pause (PP).

4. Method according to any of the preceding claims, characterized in that the gradient of the pulse rise or fall is limited to a predefined value.

5. Method according to any of the preceding claims, characterized in that when said pulse (P) reaches said time period (t)_S) Or exceeds a predetermined maximum charging time (t)_lade，max) While decreasing said charging section (Q)_S）。

6. Method according to any of the preceding claims, characterized in that a minimum charging time (t) is predefined_lade，min) Wherein when said pulse (P) is shorter than a minimum charging time (t)_lade，min) While increasing the charging section (Q)_S）。

7. Method according to any of the preceding claims, characterized in that the suspension condition is a limit value for the state of charge of the battery (2), wherein the limit value is at least SOC = 80%.

8. Method according to any of the preceding claims, characterized in that the characteristic curves for the maximum current (I), the maximum voltage (U) and the temperature (T) of the battery (2) are taken into account in the control unit (5).

9. A control unit (5) for controlling an electrical energy source (3) or a pulse generator (4) to generate charging pulses (LP) for charging a battery (2), wherein the control unit (5) is designed to control the energy source (3) or the pulse generator (4) such that the charging pulses (LP) are generated in order to charge the battery for a predetermined period of time (t)_S) Generating a predetermined charging section (Q) in_S) Wherein the charging pulse (LP) has at least one pulse (P) and a Pulse Pause (PP), wherein the control unit (5) is further designed to generate the charging pulse (LP) until a predefined pause condition is reached.

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