TWI779442B - Intelligent charging system and method - Google Patents

Abstract

The purpose of the present invention is to improve the CC-CV charging procedure programed in the traditional charge apparatus, which may cause the battery voltage rising too fast at the beginning stage of charging and reduce the operational duration of the battery. Therefore, the present invention proposes a novel intelligent charging system and method, the method includes the steps of: the control module for controlling the operation of the system; the power conversion module converts the input AC power into the electricity required by the system; the temperature detection module which detects the temperature of the battery and adjust the amount of the charging current. Further, the pre-charging module which is connected to the control module, an optimized parameters are programmed in the control module for pre-charging while the battery voltage V_b is less than a predetermined value.

Description

Smart Charging System and Method

The present invention relates to a smart charging system and method, more specifically, to optimize the charging steps and conditions when charging a battery, and improve the charging efficiency and battery life of the charging system and method.

In recent years, as the research and development of chargers for electric vehicles has progressed towards miniaturization and light weight, it is less difficult to establish charging bases, the conversion efficiency during charging is high, and the charging speed has also been greatly improved. In the current market, lithium battery chargers used for electric vehicles generally adopt the constant current-constant voltage (Constant Current-Constant Voltage, CC-CV) charging method. When charging the battery, when the upper limit of the charging voltage is reached, it will be converted to a constant voltage and current limiting method, and the charging current will be gradually reduced while keeping the charging voltage constant, and the charging process will be completed when the charging current drops sufficiently.

However, the above charging methods have three possible disadvantages: one is that when the battery is in a low-voltage state, a high current is used for charging at the beginning, so that the voltage of the battery rises too fast during the pre-charging stage, and it is easy to cause a violent internal reaction of the battery Out of control occurs, causing the temperature to rise rapidly, reducing battery life or even causing accidents such as fire and explosion; the second is that during the pre-charging phase, the battery is in a low-voltage condition, because the input current of the conventional charger is through current-limiting Resistor control, the voltage at both ends of the current-limiting resistor will change with the battery voltage, so the charging current will be too large at the beginning, and the voltage will rise during the charging process, so that the pre-charging current changes greatly. The conventional charger lacks the above phenomenon. The control mechanism, and because the current-limiting resistor must bear high power loss, it is necessary to choose a resistor with a higher rated power, which has a large heat loss, which is not conducive to the design of a miniaturized charger, and also greatly affects the battery life. . Finally, the third disadvantage is that the traditional constant current and then constant voltage charging method does not consider the impact of charging temperature on the battery. If the ambient temperature changes, but the charging current remains constant, it will affect the charging efficiency. When the capacity of the battery declines due to repeated charging, if the battery is charged with the original rated current, the higher current will further shorten the service life of the battery.

Taking the above-mentioned charging method of constant current and then constant voltage as an example, Chinese Patent Publication No. CN102009595A proposes a management procedure for electric vehicle lithium batteries, which includes monitoring the parameter changes of each lithium battery in real time through an independent control chip, and in this In the charging process of Figures 3 and 4 of '595, the technical characteristics of charging steps such as conventional trickle charging, constant current charging, and constant voltage charging are discussed. But as mentioned above, in the process of constant current charging and constant voltage charging, the battery is at a low voltage, and the sudden input charging current may make the initial chemical reaction inside the battery too fast, even if the trickle charging step is added to the conventional technology, In an attempt to improve the problem that the voltage of the battery rises too fast during the pre-charging phase, but the trickle charging in stages may make the input current unstable, and at the same time make the battery withstand multiple current pulses. In the current electric vehicle While the battery cost is still high, it still has limited help in improving battery life.

Therefore, based on the traditional chargers still have the above deficiencies, especially the large amount of charging current variation in the pre-charging stage, which is not conducive to the miniaturization, safety, charging efficiency and battery life of the charger, so the existing charging methods and charging There is still room for further improvement.

Therefore, in order to solve the above problems, the present invention proposes a smart charging system, the system architecture of which includes: a control module (Micro Control Unit, MCU), used to control the operation of the system; a power conversion module, coupled to the control module , and convert the input alternating current (AC) into the power required by the system; switch module, switch the power required for charging; pre-charge module, coupled with the control module, when the total capacity of the battery is less than the total capacity of the battery 5%, that is, the state of charge (SOC: State-Of-Charge) of the battery, or when the battery voltage V _b is less than the first preset range of the upper limit of the battery voltage, the battery is first pre-loaded with a current of 0.01C-0.5C. Charging; and, the voltage detection module detects the battery voltage V _b of the battery and the output voltage _Vipre of the power conversion module, and feeds the detected results into the control module. Wherein, the C, generally referred to as C-rate, is a ratio unit used to indicate the magnitude of the current during charging and discharging of the battery.

Based on the above, in one embodiment of the present invention, the voltage detection module can be installed between the primary side and the secondary side and the switching module, and between the battery and the switching module, respectively for different circuit areas in the smart charging system Take a voltage measurement.

According to the content of the present invention, when the smart charging system is in the above-mentioned pre-charging stage, the formula of the pre-charging current is I _ipre =(V _ipre -V _b )/R _precharge . Among them, V _ipre -V _b =△V means that the voltage difference between the two ends of the pre-charging module in the first preset range is a preset parameter, and _Vipre represents the input voltage of the pre-charging module (that is, the output voltage of the power conversion module ), the output voltage formula is V _ipre =V _b +△V, V _b represents the battery voltage, and R _precharge represents a precharge current limiting resistor parameter, which can be adjusted according to the required power or application conditions, because it is a resistor , as long as the output voltage of the power conversion module is controlled to maintain a fixed voltage difference (△V) across the resistor, the output current can be controlled to stabilize the current input to the battery during charging.

According to the content of the present invention, the smart charging system includes a temperature detection module, which detects the temperature of the battery, and feeds the detected temperature to the control module, so that the control module can adjust the size of the pre-charging current to avoid internal battery damage. Heating up too fast can cause accidents.

According to the content of the present invention, the smart charging system includes a current detection module to detect the charging current I _b output by the battery.

According to the content of the present invention, the smart charging system includes a feedback module, and the control module outputs a control signal I _REF and V _REF according to the battery voltage V _b . In one embodiment of the present invention, the feedback module is coupled to the current detection module and the voltage detection module, and the above signals are respectively corresponding to the reference signals I _REF and V _REF of the charging current and the battery voltage, and correct and control the output The electric power, so that the intelligent charging system can stabilize the charging voltage and charging current of the battery in each charging stage.

In order to solve the problem of the traditional charging method, the present invention proposes a smart charging method, the method flow includes: measuring the battery voltage V _b by the voltage detection module, feeding the measurement result to the control module, and the control module according to the battery voltage The measurement result of V _b determines what stage the battery is in; when the battery voltage V _b is in the first preset range, the control module determines that it is in the pre-charging stage, and the battery needs to be charged with a current of 0.01C-0.5C Charging; when the battery voltage _Vb is in the second preset range, the control module determines that it is in the constant current stage, and the battery needs to be charged with a fixed current; when the battery voltage _Vb is in the third preset range, the control module determines that In the constant voltage stage, a charging voltage corresponding to a fixed voltage needs to be set to charge the battery; when the battery current I _b drops to an end condition, the control module determines that the charging is completed, and stops charging the battery. Wherein, the first preset range is 7%-70% of the battery voltage upper limit (the voltage when the battery is fully charged).

According to the content of the present invention, the method flow of the smart charging method further includes using the temperature detection module to confirm the connection status of the battery and measure the temperature of the battery. In one embodiment of the present invention, it can be provided in the form of a thermistor, and whether the voltage detection module can detect the voltage of the battery, if it is greater than a preset temperature value, it will not be charged.

100:Smart charging system

101: Control module

103:Power conversion module

103a: rectification unit

105: Pre-charging module

107:Voltage detection module

109:Temperature detection module

111: battery

115: Current detection module

117: switch module

113:Feedback module

400: Smart pre-charging method

S1-S7: Method flow

The following detailed description of the present invention and the schematic diagram of the embodiment should make the present invention more fully understood; however, it should be understood that this is only used as a reference for understanding the application of the present invention, rather than limiting the present invention to a specific implementation Among the examples.

Figure 1 illustrates the system architecture of the smart charging system.

FIG. 2 further illustrates the detailed system architecture of the smart charging system in the embodiment of the present invention.

FIG. 3 shows the power curves of each charging stage when the smart charging system and method are used for charging.

FIG. 4 illustrates the method flow of the smart precharge method.

The present invention will be described in detail with preferred embodiments and viewpoints. The following description provides specific implementation details of the present invention so that readers can fully understand the implementation of these embodiments. However, those skilled in the art will understand that the present invention may be practiced without these details. In addition, the present invention can also be used and implemented through other specific embodiments, and the details described in this specification can also be applied based on different needs, and various modifications or changes can be made without departing from the spirit of the present invention . The present invention will be described with preferred embodiments and viewpoints. Such descriptions are to explain the structure of the present invention, and are only used for illustration rather than to limit the patent scope of the present invention. Terms used in the following description are to be interpreted in the broadest reasonable manner even when used in conjunction with a detailed description of a particular embodiment of the invention. In addition, it should be noted that For, the intelligent charging system and method described in the present invention can preferably be applied to the charging application of lithium batteries, but those skilled in the art in the field of the present invention can also modify and apply to other types of batteries according to the common knowledge in the field , Such as hydrocarbon batteries, nickel-cadmium batteries, nickel-hydrogen batteries, etc., which are also only used to illustrate but not limit the scope of the patent application of the present invention.

The purpose of the present invention is to hope to improve the charging mode of constant current and then constant voltage (CC-CV) commonly adopted in traditional chargers. When a fixed current is adopted at the beginning, it is easy to cause the battery voltage to rise too fast, and the detract from battery life or even cause accidents. At the same time, in the pre-charging stage, the voltage across the current-limiting resistor will change with the battery voltage, so the charging current is too high at the beginning. Therefore, if the size of the current-limiting resistor is fixed, the current-limiting resistor will suffer higher power loss. , so a resistor with a higher rated power must be selected, and the heat loss is large, which is not conducive to the design of a miniaturized charger. Charging may make the input current unstable, and at the same time make the battery withstand multiple current pulses. Therefore, the smart charging system and method proposed in the present invention, by further optimizing the structure of the traditional charging system, and the pre-charging stage and the constant current stage , constant voltage stage and other judging conditions during each charging stage to solve the above-mentioned problems of battery life and safety in the traditional charger, and its detailed technical means will be detailed as follows.

To achieve the above purpose, please refer to Fig. 1, the present invention proposes a smart charging system (100), its system architecture includes: a control module (101), used to control the operation of the system; a power conversion module (103), coupled Connect the control module (101), and convert the input alternating current into the power required by the system; the switching module (117), switch the power required for charging; the pre-charging module (105), coupled with the control module ( 101), when the power of the battery (111) is less than 5% of the total capacity, or the battery voltage _Vb is less than the first preset range of its upper limit, firstly pre-charge the battery with a charging current of 0.01C-0.5C; And, output voltage _Vipre of the voltage module (103), and feed the detection result into the control module (101). Wherein, the first preset range is 7%-70% of the upper limit of the battery voltage _{Vb (} the voltage when the battery is fully charged); the second preset range is 70-97% of the upper limit of the battery voltage Vb. %; the third preset range is above 97% of the upper limit of the battery voltage V _b .

In addition, in the present invention, the control module (101) is a microcontroller (Micro Control Unit, MCU) integrating a central processing unit, a memory, a timer/counter, and various input and output interfaces, It is integrated and operated in a generally known manner to provide computing resources for the charging program of the smart charging system (100) and coordinate with the processing program. In the viewpoint of the present invention, the control module (101) can be single or multiple, so as to include a single or multiple microcontrollers, so that it can provide an integrated system for each component in the system according to the needs of use. control, or when it is necessary to enhance or split the function of a certain component, it can be controlled by a dedicated microcontroller. For example, in an embodiment of the present invention, an integrated control module (101) may be used to control the operation of the entire smart charging system (100), or the feedback module (113) may also have a separate control module ( 101), so that it contains two microprocessors to control. It should be noted that the above are only preferred embodiments of the present invention, and those skilled in the art will know that other system components may also include a single microcontroller after reading this specification.

Wherein, according to an embodiment of the present invention, the switching module (117) receives the control signal from the control module (101) according to the needs of each charging stage of the battery (111), switches the charging circuit required by the battery, and determines The power conversion module (103) directly provides the power required for charging, or indirectly provides the power required for the pre-charging stage through the pre-charging module (105). For example, when the battery voltage V _b of the battery (111) is lower than the first preset range of its upper limit, the charging circuit will be switched through the switching module (117), so that the pre-charging module (105) can first use 0.01 The charging current of C-0.5C precharges the battery (111) until the battery voltage _Vb is out of the first preset range.

Please refer to FIG. 2, which further illustrates that in the present invention, the smart charging system (100) includes a temperature detection module (109), which detects the temperature of the battery (111) to adjust the pre-charging voltage and The size of the pre-charge current. In one embodiment of the present invention, the formula used for the precharge voltage is: V _ipre = V _b + △ V + V (t); where V _ipr represents the output voltage of the power conversion module (103), and V _b represents the battery Voltage, ΔV represents the first preset range The voltage difference between the two ends of the pre-charging module is a preset parameter, V(t) is a correction function of temperature, so that the smart charging system (100) can The battery (111) is maintained in the range of 0.01C-0.5C pre-charging current. In a preferred embodiment of the present invention, when the temperature of the battery (111) is -10°C-45°C, the preferred correction value range of V(t) is 0-5V (Volt), so that the battery ( 111) The internal chemical reaction is not too intense, which reduces the calorific value of the smart charging system (100), increases the adjustment space of charging voltage and charging current in each charging stage, and does not cause temperature rise during charging Too fast will affect the service life of the battery (111). At the same time, an optimal balance can be obtained between charging speed and service life, and the goal of miniaturization of charging can also be achieved.

According to the content of the present invention, the smart charging system (100) includes a feedback module (113), coupled to the current detection module (115). Wherein, in one embodiment of the present invention, please refer to FIG. 2, between the Primary side, the Secondary side and the switch module (117), there is also a voltage detection module (107), coupled to the feedback module ( 113), so that the smart charging system (100) can control the charging of the power conversion module (103) through the control module (101) according to the battery voltage V _b and the charging current I _b in each charging stage The voltage follows the battery voltage V _b + △ V, so that the charging voltage is fixed and will not change too much with the power disturbance of the external input power conversion module (103). The detection module (109) detects the temperature of the battery to adjust the charging current, taking into account the charging efficiency and life of the battery (111). In one embodiment of the present invention, taking the pre-charging stage as an example, in Fig. 2-3, the control module (101) respectively outputs analog reference signals I _REF and V _REF , and the reference signals correspond to the pre-charging phase respectively. stage, the reference value of _charging current and _charging voltage, so that the feedback module (113) can obtain an error signal ( _Comp ) or It is called the feedback compensation signal, to control the output voltage of the power conversion module (103), stabilize the level of the pre-charge voltage _Vipre , so that it can charge the battery (111) at a stable and slow rate during the pre-charge phase , and after the battery voltage _Vb reaches a predetermined condition, it will switch to the constant current stage. Wherein, it should be noted that, as described in the above-mentioned embodiments, the reference signals I _REF and V _REF in analog form output by the control module (101) are not limited to the reference signals during the pre-charging stage, the control module (101) (101) also stores reference values for each charging stage such as the constant current stage and the constant voltage stage, so that the smart charging system (100) can stably adjust the charging voltage and charge according to the charging status of the battery (111) at any stage. The size of the current can effectively prolong the service life of the battery (111) even if the battery (111) is in poor health.

According to an embodiment of the present invention, the above-mentioned power conversion module (103) includes a rectification unit (103a) to convert the power input from the outside from AC power to required DC power. The above-mentioned AC-DC conversion can be but not limited to full-wave rectification or half-wave rectification. At the same time, the rectification unit (103a) smoothes the output DC power, improves the power factor, and reduces harmonic distortion, so as to further improve the smart charging system (100 ) power supply quality.

Please refer to Fig. 4, in order to solve the problem of the traditional charging method, the present invention proposes a smart charging method (400), the method process includes: in the process (S2), measure the battery voltage by the voltage detection module (107) V _b , feed the measurement result to the control module (101), and the control module (101) judges the state of the battery (111) according to the measurement result of the battery voltage V _b ; in the process (S4) , when the battery voltage _Vb is in the first preset range, the control module (101) determines that it is a pre-charging stage, and the battery (111) needs to be charged with a charging current of 0.01C-0.5C; in the process (S5), When the battery voltage _Vb is in the second preset range, the control module (101) determines that it is in the constant current stage, and the battery (111) needs to be charged with a fixed charging current; in the process (S6), when the battery voltage When V _b is in the third preset range, the control module (101) determines that it is a constant voltage stage, and needs to set a charging current corresponding to a fixed charging voltage to charge the battery (111); in the process (S7), When the battery voltage _Vb reaches an end condition, the control module (101) determines that the charging is completed, and stops charging the battery (111). Among them, the first preset range is 7%-70% of the upper limit of the battery voltage (referring to the voltage when the power is fully charged); the second preset range is 70%-97% of the upper limit of the battery voltage; the third preset range , which is more than 97% of the upper limit of the battery voltage.

According to an embodiment of the present invention, in the smart charging method ( 400 ), in the process ( S2 ), when the detected battery voltage V _b is below the first preset range, no charging is performed. Take a general commercially available lithium battery as an example, when its power capacity is fully charged, its battery voltage V _b is about 4.2V (take the rated voltage of a single battery of 4.2V as an example, in general applications, multiple batteries will be connected in series) , and when its power capacity is exhausted, its battery voltage V _b is about 3V, so when the first preset range is below (the size of the battery voltage V _b is about 0.03V at this time), it means that the lithium battery at this time There may be damage, failure, or abnormality in its connection, so it is not charged in the process (S2) to avoid accidents.

According to the content of the present invention, the smart charging method (400) includes a process (S1), confirming the connection status of the battery (111) through the temperature detection module (190), and measuring the temperature of the battery (111), when it is greater than a temperature preset When the value is set, or when the rate of temperature rise is greater than a temperature gradient, it will not be charged. In addition, if the smart charging method (400) is in the process (S4), that is, when the battery (111) is in the pre-charging stage, the charging formulas used for the pre-charging voltage and the pre-charging current are: V _ipre = V _b + ΔV +V(t); I _ipre =(V _ipre -V _b )/R _precharge ; wherein, V(t) is a correction function related to temperature. , in another embodiment of the present invention, when the temperature of the battery (111) is -10°C-45°C, the preferred correction value range of V(t) is 0-5V (Volt), so that the battery (111 ) of the battery voltage V _b is that when the charging voltage is in the first preset range, it can match the temperature condition detected by the temperature detection module (190), and control the output of the power conversion unit (103) according to this process, so as to achieve the cost The invention hopes to control the purpose of stable pre-charging current.

The above descriptions are preferred embodiments of the present invention. Those skilled in the art should be able to understand that it is used to illustrate the present invention, but not to limit the scope of patent rights claimed by the present invention. The scope of its patent protection shall depend on the scope of the appended patent application and its equivalent fields. Anyone who is familiar with the technology in this field, without departing from the spirit or scope of this patent, changes or modifications are all equivalent changes or designs completed under the spirit disclosed by the present invention, and should be included in the scope of the following patent application Inside.

100:Smart charging system

101: Control module

103:Power conversion module

103a: rectification unit

105: Pre-charging module

107:Voltage detection module

109:Temperature detection module

111: battery

115: Current detection module

117: switch module

113:Feedback module

Claims (10)

A smart charging system, the structure of which includes: at least one control module to control the operation of the system; a power conversion module coupled to the control module to provide power for system operation; a voltage detection module to detect the battery voltage V _b , and feed it into the at least one control module; and, a pre-charging module, when the battery voltage V _b is less than a first preset range of its upper limit, a charging current of 0.01C-0.5C is used Precharge, where the precharge voltage adopts the charging formula V _ipre =V _b +△V+V(t) and the precharge current adopts the charging formula I _ipre =(V _ipre -V _b )/R _precharge , V(t) is A correction function related to temperature, R _precharge is a precharge current limiting resistor parameter. The smart charging system according to claim 1, wherein the first preset range is 7%-70% of the upper limit of the battery voltage _Vb . The smart charging system as described in claim 1 further includes a temperature detection module to confirm the connection of the battery and measure the temperature of the battery. When the temperature is greater than a preset value, the battery will not be charged. The smart charging system as described in claim 3 further includes a feedback module coupled to the voltage detection module, so that the system can control and stabilize the charging voltage to follow the battery voltage V _b + △ through the control module V; wherein, the stable condition of the charging voltage further includes the battery temperature measured by the temperature detection module. The smart charging system as described in claim 4, wherein when the battery voltage V _b is less than the first preset range, the magnitude of the pre-charge voltage V _ipre is the sum of the battery voltage V _b + ΔV and a correction function, the The correction function is a function of battery temperature. In the smart charging system according to claim 5, when the battery temperature is -10°C-45°C, the value range of the correction function is 0V-5V. A smart charging method includes the following process: a voltage detection module measures the battery voltage V _b , and a control module judges the condition of the battery according to the battery voltage V _b ; when the battery voltage V _b is in a first preset range , the control module executes the pre-charging phase and charges the battery with a charging current of 0.01C-0.5C, wherein the pre-charging voltage adopts the charging formula V _ipre =V _b +△V+V(t) and the pre-charging current adopts the charging The formula I _ipre =(V _ipre -V _b )/R _precharge , V(t) is a correction function related to temperature, R _precharge is a parameter of a pre-charge current limiting resistor; when the battery voltage V _b is at a second pre-charge When setting the range, the control module executes the constant current stage; wherein, the second preset range is 70%-97% of the upper limit of the battery voltage. The smart charging method as claimed in item 7, wherein the first preset range is 7%-70% of the upper limit of the battery voltage. The smart charging method according to claim 7, wherein when the battery voltage V _b is less than the first preset range, the magnitude of the pre-charge voltage V _ipre is the sum of the battery voltage V _b + ΔV and a correction function, the The correction function is a function of battery temperature. The smart charging method according to claim 9, wherein when the battery temperature is -10°C-45°C, the value range of the correction function is 0V-5V.

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