TWI473387B - Capacitor active balancing device with high-voltage differential and method thereof - Google Patents

Description

High-voltage differential capacitor active balancing device and method thereof

The invention relates to a capacitor active balancing device and a method thereof, in particular to a high-voltage differential capacitor active balancing capable of charging an energy storage element with a voltage difference of at least two battery cells in series, and performing energy transfer by the energy storage element. Apparatus and method therefor.

In recent years, with the popularization and vigorous development of secondary batteries (also known as rechargeable batteries), the field of application has also increased relatively, such as: hybrid electric vehicles, fuel cell vehicles, electric vehicles, etc. . However, since the battery is susceptible to various environmental factors, the loss is accelerated. Therefore, how to improve the battery life has become one of the problems that various manufacturers are eager to solve.

Generally, a battery is composed of a plurality of battery cells in series. Since the material properties of the battery cells cannot be completely the same, the battery may be overcharged or overdischarged during charging and discharging, thereby affecting the use of the battery. life. To avoid this, battery balancing techniques can be utilized to adjust the energy of each cell to simultaneously reach the cutoff voltage while charging. At present, battery balance is roughly divided into active balance and passive balance, and active balance is most noticed because of low energy loss and low heat generation. In the active balance, there are common capacitive balance and inductive balance. The former is light in weight and low in efficiency, while the latter is heavy and efficient. Therefore, inductive balance can be said to be the current mainstream, but in the case of weight considerations, the importance of capacitive balance can not be ignored.

At present, in the capacitive balancing technology, some manufacturers propose to control any pair of switches (ie, two pairs of switches connecting the positive and negative poles of any one battery unit) with programmable control logic to balance the capacitance and the battery unit. The voltage and the freedom to control the time the switch is turned on. However, the above method is only for the voltage balance of a single battery unit and a capacitor, so the problem of poor battery balance efficiency cannot be effectively solved.

In summary, it can be seen that in the prior art, there has been a problem of poor balance efficiency of the battery with capacitive balance for a long time, so it is necessary to propose an improved technical means to solve this problem.

In view of the problems of the prior art, the present invention discloses a high voltage differential capacitive active balancing device and a method thereof.

The high-voltage differential capacitor active balancing device disclosed in the present invention comprises: a battery unit, a switch control unit and an energy storage unit. Wherein, the N battery cells are connected in series to form a battery string for storing and providing electrical energy, wherein the N is a positive integer not less than the value "2"; the switch control unit is electrically connected to the battery string for use in the first state Switching the electrical connection with the battery string to form a power supply string of K battery cells in series, and switching the electrical connection with the battery string in the second state to form a charging string of L battery cells, the K and L being positive An integer and N≧K≧2, K-1≧L≧1; the energy storage unit is electrically connected to the switch control unit for receiving and storing the power of the power supply string in the first state, and outputting the storage in the second state. The power of the unit can be used to charge the charging string.

As for the high-voltage differential capacitor active balancing method of the present invention, the steps include: providing N battery cells in series to form a battery string, the battery string storing and providing electrical energy, wherein N is a positive integer not less than the value "2"; When the control unit is in the first state, the electrical connection with the battery string is switched to form a power supply string of K battery cells in series, and the power supply string outputs power to the energy storage unit for storage, where K is a positive integer and N≧ K≧2; when the switch control unit is in the second state, switching electrical connection with the battery string to form a charging string of L battery cells, and the energy storage unit outputs power to the charging string to charge the charging string, Where L is a positive integer and K-1≧L≧1.

The apparatus and method disclosed by the present invention are as above, and the difference from the prior art is that the present invention charges the energy storage unit in the case of a high voltage difference by connecting a plurality of battery cells in series, and the power storage unit has a lower power amount. The battery cells are discharged to complete energy transfer and battery balancing.

Through the above technical means, the present invention can achieve the technical effect of improving the efficiency of battery balance.

The embodiments of the present invention will be described in detail below with reference to the drawings and embodiments, so that the application of the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.

Before describing the high-voltage differential capacitor active balancing device and method thereof disclosed in the present invention, the terminology defined by the present invention will be described first. The battery string according to the present invention refers to N battery cells connected in series (also referred to as Is a battery cell), where N is a positive integer not less than the value "2", such as: "2", "3", "4", etc.; and the power supply string refers to the series K a battery unit for charging the energy storage unit, the charging string refers to L battery cells connected in series for receiving and storing electrical energy from the energy storage unit, wherein K and L are positive integers and N≧K ≧2, K-1≧L≧1, for example, assuming that N is the value "3", then K is the value "3" or "2", and L is the value "2" or "1". In general, in most cases, the power of the battery unit as the power supply string is higher than the average, but it does not exclude the case where the power supply string contains a battery unit having a lower average battery.

The high-voltage differential active-balance device of the present invention will be further described below with reference to the drawings. Please refer to FIG. 1 and FIG. 1 is a system block diagram of a high-voltage differential capacitive active balancing device of the present invention, including: a battery The unit 10, the switch control unit 20 and the energy storage unit 30. Wherein, N battery cells 10 are connected in series to form a battery string 100 for storing and providing electrical energy, wherein N is a positive integer not less than the value "2", such as: "2", "3", "4", .... .. and so on. Since the battery string 100 has been described in the above-mentioned self-defined nouns, it will not be repeated here.

The switch control unit 20 is electrically connected to the battery string 100 for switching the electrical connection with the battery string 100 in the first state to form a power supply string (not shown) of the series K battery cells. One state refers to a state in which the electric energy of the battery unit 10 is to be moved to the energy storage unit 30, and when the electric energy is to be moved, it can be determined according to the amount of electric energy of each of the battery cells 10. In addition, in the second state, the electrical connection manner of the switch control unit 20 and the battery string 100 is switched to form a charging string (not shown) of the L battery cells 10, where K and L are positive integers and N ≧K≧2, K-1≧L≧1, the second state refers to a state in which the electric energy of the energy storage unit 30 is to be transferred from the energy storage unit 30 to the charging string. For example, assuming N is the value "4" and K is the value "2", the number L of battery cells 10 of the charging string is the value "1" (ie: "2-1≧L≧1"); N is the value "4", and K is the value "3". The number of the battery cells 10 of the charging string is "2" or "1", and the number of the battery cells 10 is determined to be "2" or "1". It is determined according to the amount of electric energy of the battery unit 10, for example, if the battery unit 10 with the lowest electric energy is to be charged, the number of the battery units 10 of the charging string is "1", or the battery unit 10 is required to be low for all electric energy. When charging, the number of battery cells 10 of the charging string is "2". In practical implementation, the switch control unit 20 can be composed of a microcontroller (microcontroller) and a plurality of switches. The battery unit 10 with less power than the average battery unit 10 may also be connected in series with other battery units 10 to provide a power supply string, and the power is more average. It is also possible for the battery unit 10 to be connected in series with other battery units 10 as a charging string. The switch may be a Metal-Oxide-Semiconductor FET (MOSFET), and after the controller determines the first state or the second state, the controller controls whether the switch is turned on or not to enable The battery unit 10 and the energy storage unit 30 form a suitable charge and discharge circuit. In general, since the residual power of each battery unit 10 changes at any time, the switch control unit 20 will alternate between the first state and the second state, and the battery cells 10 as the power supply string and the charging string and the number thereof will also follow Change. The manner in which the power supply string and the charging string are formed by the switch control unit 20 will be described in detail later with reference to the drawings.

The energy storage unit 30 is electrically connected to the switch control unit 20 for receiving and storing the power of the power supply string in the first state, that is, the power supply string formed when the switch control unit 20 is in the first state, There is a high voltage difference between the energy storage units 30, and therefore, the power supply string charges the energy storage unit 30. In addition, in the second state, since the switch control unit 20 has completed switching and forms a charging string, the power of the charging string is low, and the energy storage unit 30 outputs electric energy to the charging string for charging. So far, the flow of the electric energy of any two or more battery cells 10 (ie, the power supply string) by the energy storage unit 30 to the battery unit 10 (ie, the charging string) having lower electric energy is completed, thereby achieving active balance. In particular, the energy storage unit 30 includes at least one capacitive element for storing and supplying electrical energy. Even the capacitive element is further connected in series with a resistive element to form an “RC circuit”, and the resistive element can be a capacitor equivalent resistor or a common resistor. The switch resistance, the internal resistance of the battery, or a combination thereof, and the response time (Response time) can be set by adjusting the resistance value and the capacitance value of the resistor element and the capacitor element in series.

Next, please refer to "Fig. 2", which is a flow chart of a method for actively balancing a high-voltage differential capacitor according to the present invention. The steps include: providing N battery cells 10 in series to form a battery string 100, the battery string 100 storing and providing electrical energy, wherein N is a positive integer not less than the value "2" (step 210); when the switch control unit 20 is in the first state, switching electrical connection with the battery string 100 to form a series of K battery cells a power supply string of 10, the power supply string outputs power to the energy storage unit 30 for storage, wherein K is a positive integer and N≧K≧2 (step 220); when the switch control unit 20 is in the second state, switching with the battery string Electrically coupled to form a charging string of L battery cells 10, the energy storage unit 30 outputs electrical energy to a charging string to charge the charging string, where L is a positive integer and K-1≧L≧1 (step 230) . Through the above steps, the energy storage unit 30 can be charged by connecting a plurality of battery cells 10 in a high voltage difference, and the battery unit 10 having a lower power can be discharged by the energy storage unit 30 to complete the energy transfer and the battery. balance.

The following is a description of the following examples in conjunction with "3D" to "7B". Please refer to "3" and "3" for a circuit diagram of a high-voltage differential active-balance device. As mentioned above, the switch control unit 20 can switch between different electrical connection modes. In practical implementation, the switch control unit 20 is composed of a plurality of switches, such as: "SW _0A ~ SW _NA " and "SW _0B ~ SW _NB " and The controller 21 controls these switches. Adjusting the electrical connection manner of the battery string 100 and the energy storage unit 30 by turning on or off (ie, breaking or short-circuiting) of the switches, so that some of the switches are turned on to connect at least one of the battery cells 10 And the energy storage unit 30 forms a loop (also referred to as a charge and discharge loop). Next, the manner in which the power supply string and the charging string are formed by the switch control unit 20 will be described with reference to the drawings.

As shown in "Fig. 4", "Fig. 4" is a schematic diagram of a circuit for forming a power supply string by applying the present invention. As mentioned above, the switch control unit 20 switches the electrical connection mode in the first state to form a power supply string of the K battery cells 10 in series. In the "fourth diagram", the power supply string 101 is composed of a plurality of battery cells 10 ( That is, "battery unit 2" to "battery unit N" is composed by switching the switches "SW _1A " and "SW _NA " short, and switching the switch "SW _1B " to "down", and the switch "SW" _NB ” switches to “up”. In this way, the power supply string 101 can be formed and form a loop with the energy storage unit 30 (as indicated by the black bold lines), and because of the high voltage difference between the power supply string 101 and the energy storage unit 30, the power can be quickly supplied. The power of the string 101 is transferred to the energy storage unit 30. In addition, the capacitive element 31 included in the energy storage unit 30 and its series-connected resistive element 32 also form an RC circuit as shown in FIG. 4 to provide a user with the resistance value and the capacitive element of the resistive element 32. The capacitance value of 31 changes the reaction time. In practical implementation, the charging time of the energy storage unit 30 is greater than or equal to "0.3 RC", and the discharge time of the energy storage unit 30 to the charging string 102 is also greater than or equal to "0.3 RC".

Please refer to "Figure 5" for illustration. Figure 5 is a schematic diagram of a circuit for forming a charging string by applying the present invention. When the energy storage unit 30 completes charging in the first state, it will be converted from the first state to the second state. At this time, the switch control unit 20 shorts the switches "SW _0A " and "SW _1A ", and will switch "SW _1B " _. Switch to "up" and switch "SW _0B " to "down". In this way, the charging string 102 can be formed and form a loop with the energy storage unit 30 (as indicated by the black bold lines). At this time, the energy storage unit 30 will be the battery unit 10 for the lower power (ie, the battery unit). 1") to charge.

Please refer to FIG. 6 for a schematic diagram of a circuit diagram of another embodiment of the switch control unit of the present invention. In actual implementation, the power supply string 101 and the charging string 102 can also be formed by the switch control unit 201 as illustrated in FIG. In particular, in this example, the switch control unit 201 has a plurality of switches SW _NA and SW _NB , and a part of the battery cells 10 in the battery string 100 form a loop with the energy storage unit 30 by the switch control unit 201. Only one of the switches SW _NA can be turned on, and only one of the switches SW _NB can be turned on.

Although the present invention describes the circuits of the switch control units (20 and 201) by way of the above-mentioned "figure 5" and "figure 6", the present invention is not limited thereto, and in practice, any can be used in N. The power supply string 101 forming the K battery cells 10 in series and the charging string 102 forming the L battery cells in the battery unit 10 do not deviate from the application scope of the present invention, wherein N is a positive integer not less than the value "2", K And L is a positive integer and N≧K≧2, K-1≧L≧1.

Next, please refer to "7A" and "7B", "7A" and "7B" are schematic diagrams of voltage and current waveforms of the present invention and conventional capacitor balance. First, "Picture 7A" is a application case of a lithium battery, in which the waveform of the solid line portion is the voltage across the energy storage unit 30 of the present invention, and the dotted line portion is the cross-voltage of the capacitor of the conventional capacitor balance, from "7A". It can be clearly seen that the cross pressure between the two has a significant difference (greater than 10N times). In addition, in the "Fig. 7B", the waveform of the solid line portion is the charge and discharge current of the energy storage unit 30, and the dotted line portion is the charge and discharge current of the capacitor of the conventional capacitor balance, which can also be obtained from "Fig. 7B". It is clear that the present invention and the conventional capacitance balance have significant differences (greater than 10M times) in the amount of moving power. The moved charge is equal to the current integral and depends on the voltage difference between the energy storage unit 30 and the power supply string 101 or the charge string 102. In particular, the above M refers to a value obtained by subtracting K from L. When the value of K and L subtracted is "1", M is a value of "1", so the present invention is more than ten times the amount of moving power ( 10*1=10)Traditional efficiency, but when the value of K and L subtraction is “2”, since the value of M is “2”, the transfer power will be greater than twenty times (10*2=20). Efficiency... and so on. In addition, since the waveform amplitude of the present invention is larger than the conventional capacitance balance, the electric quantity is more easily quantized and controllable.

In summary, it can be seen that the difference between the present invention and the prior art is that the energy storage unit 30 is charged in the case of a high voltage difference by connecting a plurality of battery cells 10 in series, and the battery cells having a lower power amount are stored by the energy storage unit 30. The discharge is performed to complete the energy transfer and the battery balance, and the technical problems of the prior art can be solved by the technical means, thereby achieving the technical effect of improving the efficiency of the battery balance.

While the present invention has been described above in the foregoing embodiments, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of patent protection shall be subject to the definition of the scope of the patent application attached to this specification.

10. . . Battery unit

20. . . Switch control unit

twenty one. . . Controller

30. . . Energy storage unit

31. . . Capacitive component

32. . . Resistance element

100. . . Battery string

101. . . Power supply string

102. . . Charging string

201. . . Switch control unit

Step 210 provides N battery cells connected in series to form a battery string, the battery string stores and supplies electrical energy, where N is a positive integer not less than the value 2

Step 220: When a switch array is in a first state, switching electrical connection with the battery string to form a power supply string of K battery cells in series, the power supply string outputting power to an energy storage unit for storage, where K Is a positive integer and N≧K≧2

Step 230: When the switch array is in a second state, switching electrical connection with the battery string to form a charging string of L battery cells, the energy storage unit outputs power to the charging string to charge the charging string , where L is a positive integer and K-1≧L≧1

1 is a block diagram of a system of a high-voltage differential capacitor active balancing device of the present invention.

FIG. 2 is a flow chart of a method for actively balancing a high voltage differential capacitor according to the present invention.

Figure 3 is a circuit diagram of a high-voltage differential capacitor active balancing device.

Figure 4 is a schematic diagram of a circuit for forming a power supply string by applying the present invention.

Figure 5 is a schematic diagram of a circuit for forming a charging string using the present invention.

Figure 6 is a circuit diagram showing another embodiment of the switch control unit of the present invention.

7A and 7B are schematic diagrams showing a comparison of voltage and current waveforms of the present invention and conventional capacitors.

10. . . Battery unit

20. . . Switch control unit

30. . . Energy storage unit

100. . . Battery string

Claims (10)

A high-voltage differential capacitor active balancing device, comprising: N battery cells, wherein the N battery cells are connected in series to form a battery string for storing and supplying electrical energy, wherein N is a positive integer not less than a value of 2; a control unit, the switch control unit is electrically connected to the battery string, for switching a electrical connection with the battery string in a first state to form a power supply string of the series K battery cells, and in a second state Switching electrically connected to the battery string to form a charging string of L battery cells, wherein K and L are positive integers and N≧K≧2, K-1≧L≧1; and an energy storage unit, The energy storage unit is electrically connected to the switch control unit, configured to receive and store the power of the power supply string in the first state, and output the power of the energy storage unit to the power string in the second state Charge it. The high-voltage differential capacitor active balancing device according to claim 1, wherein the energy storage unit comprises at least one capacitive element. The high-voltage differential capacitor active balancing device according to claim 2, wherein the capacitor element is connected in series with a resistor element, which is a capacitor equivalent resistor, a common resistor, a switch resistor, a battery internal resistance or a combination thereof. . The high-voltage differential type capacitor active balancing device according to claim 3, wherein the resistive element and the capacitive element provide an adjustment resistance value and a capacitance value to change a reaction time. The high-voltage differential capacitor active balancing device according to claim 1, wherein the switch control unit comprises a plurality of switches and a controller for controlling the switches. The high-voltage differential capacitor active balancing device according to claim 5, wherein a part of the switches are turned on to connect at least one of the battery strings and the energy storage unit to form a loop. A high-voltage differential capacitor active balancing method includes the steps of: providing N battery cells in series to form a battery string, the battery string storing and providing electrical energy, wherein N is a positive integer not less than a value of 2; when a switch control unit is in a In the first state, the electrical connection with the battery string is switched to form a power supply string of K battery cells in series, and the power supply string outputs power to an energy storage unit for storage, where K is a positive integer and N≧K≧ 2; and when the switch control unit is in a second state, switching electrical connection with the battery string to form a charging string of L battery cells, the energy storage unit outputs power to the charging string to the charging string Charging is performed, where L is a positive integer and K-1 ≧ L ≧ 1. The high-voltage differential capacitor active balancing method according to claim 7, wherein the energy storage unit comprises at least one capacitive element. The high-voltage differential capacitor active balancing method according to claim 8 , wherein the capacitor component is connected in series with a resistor component, wherein the resistor component is a capacitor equivalent resistor, a common resistor, a switch resistor, a battery internal resistance or a combination thereof. . The high voltage difference capacitor active balancing method according to claim 9, wherein the resistor element and the capacitor element provide an adjustment resistance value and a capacitance value to change a reaction time.