Patent Application
20190341784
This application is based upon and claims priority of Taiwan Patent Application No. 107114959, filed on May 3, 2018, the contents being incorporated herein by reference.
The present application relates to a battery charging system, and in particular, to a battery charging system capable of adjusting a charging current according to an internal resistance value of a battery.
Rechargeable batteries are commonly used in portable devices. For example, in notebook computers, mobile phones, and tablet computers, applications thereof can be seen. Currently, some rechargeable batteries can already withstand a high charging current, to support fast charging.
For example, fast charging can be achieved if a relatively high charging current is applied to a battery, thereby improving convenience in use. However, if a relatively high charging current is applied to the battery, aging of the battery may be accelerated. If an aging degree of the battery already reaches a predetermined level, a relatively high charging current is still applied thereto, an overall service life of the battery will be shortened.
To avoid shortening of a service life of a battery, a relatively low charging current maybe applied to the battery to perform charging at a general speed. This can avoid excessively rapid aging of the battery and extend a battery life, but may lead to excessively slow charging and inconvenience a user.
In view of the foregoing engineering problem that it is difficult to balance a charging speed and a battery aging speed, the following embodiments provide a solution.
According to an embodiment, a battery charging system is provided, and includes a control unit, a charging unit, and a measurement unit. The control unit is configured to generate and output a control signal. The charging unit is coupled to the control unit and a battery, where the charging unit is configured to receive the control signal, generate a charging current according to the control signal, and output the charging current to charge the battery. The measurement unit is coupled to the battery and the control unit, and configured to measure a battery voltage output by the battery, and output a measurement signal to the control unit, where the measurement signal corresponds to the battery voltage.
According to an embodiment, a battery charging method is provided, and is applied to a battery charging system. The battery charging system includes a control unit, a charging unit, and a measurement unit. The method includes: generating, by the control unit, a control signal; receiving, by the charging unit, the control signal, and outputting a charging current to a battery according to the control signal; outputting, by the battery, a battery voltage to the measurement unit; and outputting, by the measurement unit, a measurement signal to the control unit, where the measurement signal corresponds to the battery voltage.
According to the battery charging system and the battery charging method provided by the embodiments, an engineering effect of balancing a charging speed for a battery and avoidance of excessively rapid aging of the battery can be achieved.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
According to this embodiment, the control unit 110 may obtain an internal resistance value Rb of the battery BAT according to the measurement signal Sb, and the control unit 110 may set the control signal Sc according to the obtained internal resistance value Rb. For example, if the control unit 110 learns through calculation that an internal resistance value Rb of the battery BAT does not reach a predetermined value, indicating that an aging degree of a cell of the battery BAT is not severe, the control unit 110 may set a control signal Sc to increase or not reduce the charging current Ic output by the charging unit 120. On the contrary, if the control unit 110 learns through calculation that an internal resistance value Rb of the battery BAT already reaches a predetermined value, indicating that an aging degree of a cell of the battery BAT already reaches a predetermined degree, the control unit 110 may set a control signal Sc to reduce or no increase the charging current Ic output by the charging unit 120. Another example is provided below for description.
As shown in
In
A time period T3 may correspond to a predetermined cycle of the oscillation waveform of the charging current Ic, for example, a cycle of the curved line 210 from a valley to a valley, or a cycle of the curved line 210 from a peak to a peak. In the time period T3, the charging current Ic has a maximum current value Imax and a minimum current value Imin, and the battery voltage Vb has a maximum voltage value Vmax and a minimum voltage value Vmin. The internal resistance value Rb of the battery BAT may be obtained according to the maximum voltage value Vmax, the minimum voltage value Vmin, the maximum current value Imax, and the minimum current value Imin, and for example, may be represented as Rb=f(Imax,Imin,Vmax,Vmin), and f( ) herein may be a function expression.
According to another embodiment, the internal resistance value Rb may be directly proportional to a quotient of a difference between the maximum voltage value Vmax and the minimum voltage value Vmin and a difference between the maximum current value Imax and the minimum current value Imin. In other words, the internal resistance value Rb may be represented as Rb∝((Vmax−Vmin)/(Imax−Imin). For example, the internal resistance value Rb may be obtained by using the following mathematical equation: Rb=(Vmax−Vmin)/(Imax−Imin).
As described above, after calculating the internal resistance value Rb of the battery BAT, the control unit 110 may monitor whether the internal resistance value Rb is excessively high, to correspondingly set a control signal Sc. Table 1 is a table, in this embodiment, recorded after a battery voltage Vb and a charging current Ic are monitored in four cycles of a curved line 210, and an internal resistance value Rb is calculated in real time.
Table 1 is merely an example. In this embodiment, it is not limited to monitoring only four cycles. For example, if in the time period T2, 20 cycles of the current waveform of the charging current Ic are included, the 20 cycles can be also monitored in Table 1. Numerals in Table 1 are merely used as examples to explain the principle of an application, and are not intended to limit this embodiment of the present application or a measured result. Based on the foregoing content, if a calculated internal resistance value Rb already reaches a predetermined value, indicating that aging of the cell of the battery BAT already reaches a predetermined degree, the control signal Sc can be adjusted, to enable the charging current Ic to maintain a relatively low value, or is reduced from a high current value. The predetermined value may be, for example (but is not limited to), 80 mΩ, or may be set according to a battery model and a test result.
Table 2 is a table, in this embodiment, of a description of an operation of the control unit 110 setting a control signal Sc according to an obtained internal resistance value Rb calculated by the control unit 110.
In Table 2, the first current value may be, for example, a standard charging current value or a charging current value lower than the standard charging current value, and the second current value may be, for example, a fast charging current value, where the first current value may be lower than the second current value.
According to an embodiment, in the time period T2, a change frequency of the waveform of the charging current Ic may not be excessively high. In other words, a cycle corresponding to the time period T3 may not be excessively short. If the cycle of the current waveform of the charging current Ic is excessively short, a change of the battery voltage Vb cannot easily reflect a status of embedding ions into the cell. This may cause reduction of precision of the internal resistance value Rb calculated by the control unit 110. If a battery of a common notebook computer is used as an example, the cycle of the current waveform corresponding to the time period T3 may be (but is not limited to) 10 seconds. An appropriate cycle of the current waveform may be adjusted and set according to a test result.
According to an embodiment, in
If in a cycle in the time period T33, an internal resistance value Rb of the control unit 110 already reaches a predetermined value, indicating that in consideration of an aging degree of the battery BAT, the charging current Ic should be reduced, to slow down the aging. Therefore, in a time period T34, the average current value of the charging current Ic is adjusted to approximately 1.5 amperes. If in a subsequent cycle in the time period T34, an internal resistance value Rb of the control unit 110 already reaches a predetermined value, indicating that in consideration of an aging degree of the battery BAT, the charging current Ic should be further reduced. Therefore, in a time period T35, the average current value of the charging current Ic is controlled to be approximately 1.5 amperes.
In
In addition, in
Step 410: A control unit 110 generates a control signal Sc.
Step 415: A charging unit 120 receives the control signal Sc and outputs a charging current Ic to a battery BAT according to the control signal Sc.
Step 420: The battery BAT outputs a battery voltage Vb to a measurement unit 130.
Step 425: The measurement unit 130 outputs a measurement signal Sb to the control unit 110, where the measurement signal Sb corresponds to the battery voltage Vb.
Step 430: The control unit 110 obtains an internal resistance value Rb of the battery according to the measurement signal Sb.
Step 435: The control unit 110 sets a control signal Sc according to the internal resistance value Rb.
In the step 430, a process of calculating the internal resistance value Rb is described above, and therefore, is not described again. In the step 435, the internal resistance value Rb does not reach a predetermined value, the control signal Sc may be set to increase the charging current Ic, or not to reduce the charging current Ic (if the charging current Ic is originally a high current). If the internal resistance value Rb already reaches a predetermined value, the control signal Sc can be set to reduce the charging current Ic, or not to increase the charging current Ic (if the charging current Ic is originally a low current). According to this embodiment, the steps 410 to 435 may be cyclically performed, and after the step 435 is performed, the method may be performed again starting from the step 410 according to a requirement.
It can be learned based on the above that by using the battery charging system and method provided in the embodiments, an appropriate charging current may be input dynamically and in real time according to an internal resistance value and an aging status of a battery, in each period during use of the battery. Therefore, fast charging and avoidance of shortening of a service life of the battery can be balanced, to help alleviate an engineering problem in the art.
The foregoing descriptions are merely preferred embodiments in the present application, and equivalent changes and modifications made according to the claims of the present application should all fall within the scope of the present application.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 107114959 | May 2018 | TW | national |
