TW202010173A - Charging circuit - Google Patents

Abstract

A charging circuit configured for charging a battery and including a constant current charging circuit, a detection circuit, a constant voltage charging circuit and a control circuit is provided. The constant current charging circuit is configured to charge the battery by a predetermined current value within a first period. The detection circuit is configured to measure a voltage raising value of the battery before and after the constant current charging circuit starts to charge the batter within the first period. The control circuit is configured to determine whether the battery has degraded according to the voltage raising value. The control circuit configures the constant voltage charging circuit to charge the battery by a first voltage level within a second period when the control circuit determines the battery has not degraded. The control circuit configures the constant voltage charging circuit to charge the battery by a second voltage level within the second period when the control circuit determines the battery has degraded. The second voltage level is less than the first voltage level, and the second period is later than the first period.

Description

Charging circuit

The invention relates to a battery charging method, and in particular to a charging circuit that can delay the aging of the battery.

With the development of technology, all kinds of portable electronic devices, such as tablet computers, laptop computers, and smart phones, have become indispensable in modern life. Missing tools. These portable electronic devices are equipped with batteries, so that users can use these portable electronic devices in an environment where there is no commercial power supply. In general, as the number of uses and time increase, the aging of the battery will cause the battery's power storage capacity to gradually deteriorate.

However, the conventional charging circuit does not adjust the battery charging method as the battery ages. When the battery ages, if the battery is still charged in the same way, it will cause the metal ions inside the battery to dilute and accumulate on the separator in the battery. When the amount of accumulated metal ions is sufficient, the separator used to isolate the positive and negative electrodes in the battery may be pierced by the dendrite structure formed by the accumulation of metal ions, which may cause the battery to expand and damage, or even fire and explode. Based on this, how to delay the aging of the battery and improve the safety of the battery is actually one of the topics of concern to those skilled in the art.

In view of this, the present invention provides a charging circuit that can estimate the aging degree of the battery to adjust the charging method, thereby delaying the aging phenomenon of the battery and improving the safety of the battery.

An embodiment of the present invention provides a charging circuit configured to charge a battery, and includes a constant current charging circuit, a detection circuit, a constant voltage charging circuit, and a control circuit. The constant current charging circuit is configured to charge the battery in the first period with a preset current value. The detection circuit is configured to measure the voltage rise value of the battery before and after charging when the constant current charging circuit starts charging the battery in the first period. The control circuit determines whether the battery has deteriorated according to the voltage rise value. When the control circuit determines that the battery is not aging, the control circuit sets a constant voltage charging circuit to charge the battery in the second period with the first voltage value. When the control circuit determines that the battery is aging, the control circuit sets the constant voltage charging circuit to charge the battery in the second period with the second voltage value. The second voltage value is smaller than the first voltage value, and the second time period is later than the first time period.

Based on the above, the above embodiment can estimate the aging degree of the battery according to the voltage increase range when the battery starts charging, and adjust the charging method to delay the aging of the battery and extend the service life of the battery, thereby improving the safety of the battery.

In order to make the above-mentioned features and advantages of the present invention more obvious and understandable, the embodiments are specifically described below in conjunction with the accompanying drawings for detailed description as follows.

FIG. 1 is a functional block diagram of a charging circuit 100 according to an embodiment of the invention. The charging circuit 100 is configured to be electrically connected to a power source 180 to charge the battery 190. The charging circuit 100 and the battery 190 may be separately or integratedly installed in various electronic devices (not shown) such as a notebook computer, a tablet computer, a smart phone, a digital camera, a personal digital assistant (PDA), or a game console. The battery 190 is used to supply power required by the electronic device, and may include one or more battery cells to provide appropriate voltage and current output. The power supply 180 can adopt direct current or alternating current according to different setting considerations. For example, the power supply 180 can be a commercial power provided by a general outlet.

In the embodiment of FIG. 1, the resistance 191 and the capacitance 192 are simplified as an equivalent model of the battery 190, so as to explain the battery aging phenomenon. The aging referred to in this specification refers to the phenomenon that the amount of power that the battery can store or provide can decrease due to factors such as the number of charging, the time of use, or the method of charging. However, even if the battery 190 is equivalent to a more complicated model, the following description can still be used to understand the phenomenon of battery aging. In the embodiment of FIG. 1, the capacitor 192 has an open circuit voltage Voc, the resistor 191 has a resistance value R, and the resistance value R increases as the battery ages. When the battery 190 has not started charging, the voltage difference across the battery 190 is the open circuit voltage Voc (regardless of the voltage drop of the resistor 191); when the charging circuit 100 charges the battery 190 with a charging current Ic with a current value of I _charge , the battery The voltage difference across 190 is the open circuit voltage Voc plus the current value I _charge times the resistance value R, which is Voc+I _charge *R. Since the resistance value R increases as the battery ages, the charging circuit 100 can determine whether the battery is ageing according to the voltage difference I _charge *R between the two ends of the battery 190 before and after starting charging.

FIG. 2 is a detailed functional block diagram of an embodiment of the charging circuit 100 in FIG. 1. In this embodiment, the charging circuit 100 includes a control circuit 210, a detection circuit 220, a constant current charging circuit 230, and a constant voltage charging circuit 240. The control circuit 210 sets a constant current charging circuit 230 to charge the battery 190 with a preset current value. The detection circuit 220 is used to detect the voltage rise across the battery 190 when the battery 190 starts to be charged. The control circuit 210 determines whether the battery is aging according to the voltage rise value at both ends of the battery 190, and accordingly sets a constant voltage charging circuit 240 to charge the battery 190 with different voltage values to delay the aging of the battery 190.

FIG. 3 is a flowchart of an embodiment of charging performed by the charging circuit 100 of FIG. 2. The operation of the charging circuit 100 will be described below with reference to FIGS. 1 to 3.

In step S310, the control circuit 210 sets the constant current charging circuit 230 to charge the battery 190 within a first period with a preset current value. In addition, the control circuit 210 sets the detection circuit 220 to measure a voltage rise value of the battery 190 before and after charging when the constant current charging circuit 230 starts to charge the battery 190.

In step S320, the control circuit 210 determines whether the battery 190 has deteriorated according to the voltage increase value. When the control circuit 210 determines that the battery 190 is not degraded, it proceeds to step S330. When the control circuit 210 determines that the battery 190 has deteriorated, it proceeds to step S340.

In step S330, when the battery 190 is not aging, the control circuit 210 sets the constant voltage charging circuit 240 to charge the battery 190 with a first voltage value in the second period, which is later than the first period. For example, when the battery 190 is a lithium battery, the first voltage value can be set to 4.2 volts. In addition, the switching point between the first period and the second period can be set according to the attributes of the battery 190. For example, if the battery 190 is an unaged lithium battery, it can be set that when the detection circuit 220 measures the voltage difference across the battery 190 as 4.2 volts, the control circuit 210 uses the preset by the constant current charging circuit 230 in the first period The charging operation of the battery 190 with the current value is changed to use the constant voltage charging circuit 240 to charge the battery 190 with the first voltage value in the second period.

In step S340, when the battery 190 has deteriorated, the control circuit 210 sets the constant voltage charging circuit 240 to charge the battery 190 with a second voltage value in the second period, which is later than the first period, and The second voltage value is less than the first voltage value. For example, when the battery 190 is a lithium battery, the first voltage value can be set to 4.2 volts, and the second voltage value can be set to 4.1 volts. In an embodiment, the switching point of the first period and the second period may be set according to the attributes of the battery 190 in step S330. In another embodiment, the switching point between the first time period and the second time period can be set according to the properties of the battery 190 and the aging degree of the battery 190, so that the detection circuit 220 measures the voltage difference between the two ends of the battery 190 When reaching a lower 4.1 volts (4.2 volts lower than the voltage difference in step S330), the control circuit 210 changes the charging operation of the battery 190 by the constant current charging circuit 230 using the preset current value in the first period to use The constant voltage charging circuit 240 uses the second voltage value to charge the battery 190 during the second period.

In steps S310 and S320, the recording method of the voltage rise value and the judgment method of the control circuit 210 may be various suitable methods according to different design considerations. In one embodiment, the control circuit 210 compares the voltage rise value with a threshold to determine whether the battery is aging. For example, when the voltage rise value is greater than a first threshold, the control circuit 210 determines that the battery 190 has aged, and sets the constant voltage charging circuit 240 to charge the battery 190 in the second period with the second voltage value. In another embodiment, the control circuit 210 compares the voltage rise value with multiple thresholds to determine the aging degree of the battery. For example, when the voltage rise value is greater than a first threshold, the control circuit 210 determines that the battery 190 has aged, and sets the constant voltage charging circuit 240 to charge the battery 190 in the second period with the second voltage value. In addition, when the voltage rise value is greater than a second threshold, the control circuit 210 determines that the battery 190 has aged, and sets the constant voltage charging circuit 240 to charge the battery 190 with the third voltage value in the second period. And the second threshold is larger than the first threshold, and the third voltage value is smaller than the second voltage value. That is, as the number of charging cycles increases and the aging of the battery 190 intensifies, the control circuit 210 may set the constant voltage charging circuit 240 to charge the battery 190 at a lower and lower voltage value during the second period.

In another embodiment, the control circuit 210 compares the voltage rise value with the previously stored voltage rise stored value to determine whether the battery is aging. For example, the voltage rise stored value may be one or more preset values, the voltage rise value measured by the detection circuit 220 in the previous time, or a value generated after calculation based on the voltage rise values measured in the previous few times . When a rise difference between the voltage rise value and the voltage rise stored value is greater than a first difference, the control circuit 210 determines that the battery 190 has aged, and sets the constant voltage charging circuit 240 to match the second voltage value in the second period The battery 190 is charged. In another embodiment, when a rise difference between the voltage rise value and the voltage rise stored value is greater than a first difference value, the control circuit 210 determines that the battery 190 has deteriorated, and sets the constant voltage charging circuit 240 to the second The voltage value charges the battery during the second period. In addition, when the rising difference is greater than a second difference, the control circuit 210 determines that the battery 190 has deteriorated, and sets the constant voltage charging circuit 240 to charge the battery 190 in the second period with the fourth voltage value. And the second difference is greater than the first difference, and the fourth voltage value is less than the second voltage value.

In the above embodiment, the first period and the second period may be set at the same charging operation, or may be set at different charging operations. In one embodiment, when the control circuit 210 determines that the battery 190 is aging, after the constant current charging operation of this charging is completed, the lower voltage is used to perform the constant voltage charging operation. In another embodiment, when the control circuit 210 determines that the battery 190 is aging, after the constant current charging operation of this charging is completed, the constant voltage charging operation is still performed using the previously set voltage value; and the constant current charging is performed at the next charging After the operation is completed, the lower voltage is used for constant voltage charging operation. In addition, when the control circuit 210 determines that the battery 190 has deteriorated, the constant current charging circuit 230 may also be set to perform a constant current charging operation at a lower current, and use a lower voltage to perform the constant voltage charging operation.

The detection circuit 220 and the control circuit 210 can be implemented by a combination of hardware, firmware, and/or software. For example, the detection circuit 220 and the control circuit 210 may be implemented by an integrated circuit, or may be implemented by using one or more controllers and their firmware.

In summary, in the above embodiment, the aging degree of the battery can be evaluated according to the voltage increase value before and after the battery is charged to determine whether to lower the charging voltage of the battery 190 during the constant voltage charging period. Decreasing the charging voltage applied to the battery for charging according to the evaluated battery aging degree can delay the battery aging speed and extend the battery life.

Although the present invention has been disclosed as above with examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be subject to the scope defined in the appended patent application.

100‧‧‧Charge circuit 190‧‧‧Battery 191‧‧‧Resistance 192‧‧‧Capacitance 180‧‧‧Power supply Voc‧‧‧Open circuit voltage Ic‧‧‧Charge current 210‧‧‧Control circuit 220‧‧‧Detection Circuit 230‧‧‧Constant current charging circuit 240‧‧‧Constant voltage charging circuit S310～S340‧‧‧Step

FIG. 1 is a functional block diagram of a charging circuit according to an embodiment of the invention. FIG. 2 is a detailed functional block diagram of an embodiment of the charging circuit in FIG. 1. FIG. 3 is a flowchart of an embodiment of charging performed by the charging circuit of FIG. 2.

100‧‧‧charging circuit

190‧‧‧ battery

191‧‧‧Resistance

192‧‧‧capacitor

180‧‧‧Power

Voc‧‧‧Open circuit voltage

Ic‧‧‧Charging current

Claims (5)

A charging circuit configured to charge a battery, including: a certain current charging circuit, configured to charge the battery at a first period with a preset current value; a detection circuit, configured to charge the battery The constant current charging circuit measures a voltage rise value of the battery before and after charging in the first period of time; a certain voltage charging circuit; and a control circuit, based on the voltage rise value to determine whether the battery has been charged Aging; when the control circuit judges that the battery is not aging, the control circuit sets the constant voltage charging circuit to charge the battery with a first voltage value in a second period; when the control circuit judges that the battery is aging, the control The circuit sets the constant-voltage charging circuit to charge the battery with a second voltage value during the second time period, wherein the second voltage value is less than the first voltage value, and the second time period is later than the first time period. The charging circuit as described in item 1 of the patent application scope, wherein when the voltage rise value is greater than a first threshold, the control circuit determines that the battery has deteriorated, and sets the constant voltage charging circuit to use the second voltage value in the The battery is charged during the second period. The charging circuit as described in item 2 of the patent application scope, wherein when the voltage rise value is greater than a second threshold, the control circuit determines that the battery has deteriorated, and sets the constant voltage charging circuit to a third voltage value The battery is charged in the second period; the second threshold is greater than the first threshold; and the third voltage value is less than the second voltage value. The charging circuit as described in item 1 of the patent application range, wherein the control circuit determines the battery when a rise difference between the voltage rise value and a previously stored voltage rise stored value is greater than a first difference value It is aging, and the constant voltage charging circuit is set to charge the battery in the second period with the second voltage value. The charging circuit as described in item 4 of the patent application range, wherein when the rise difference is greater than a second difference, the control circuit determines that the battery has deteriorated and sets the constant voltage charging circuit to a fourth voltage value The battery is charged in the second period; the second difference is greater than the first difference; and the fourth voltage value is less than the second voltage value.

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