TWI661647B - A Fast Balancing Circuit for Battery - Google Patents

Abstract

The invention relates to a battery quick balancing circuit, which includes a plurality of battery cells, a transformer, a plurality of first and second switching switches, and a control unit, wherein the plurality of battery cells are connected in series with each other; the transformer has two sides of a live wire and a ground. Each line is provided with a diode and a switch to control the side as the primary side or the secondary side. The plurality of first and second switching connections connect the plurality of battery cells and the two sides of the transformer, and the selective switching corresponds to the battery. The unit is connected to the corresponding side of the transformer, and the control unit is connected to the two changeover switches and the first and second changeover switches on the transformer to control the plurality of battery units connected to the corresponding side of the transformer, thereby controlling the battery units to charge each other. Discharge to achieve the effect of fast charge balance, and has the advantages of simplified circuit, reduced volume and improved balance efficiency.

Description

Battery fast balancing circuit

The invention relates to a battery balancing circuit, in particular to a battery fast balancing circuit capable of controlling battery cells to charge and discharge each other.

In recent years, batteries have been widely used in various types of electrical equipment, such as electric vehicles, mobile power supplies, and notebook computers. However, the voltage of a single battery is limited and cannot meet the needs of high-voltage applications. Therefore, in order to achieve the voltage required for each type of load, multiple batteries will be connected in series to improve the voltage supply equipment. During the charging process of the series battery pack, each battery has internal resistance, chemical characteristics, and manufacturing differences. The difference. It will lead to uneven charging and the possibility of overcharging, which will shorten the battery life or damage the battery. Therefore, the existing battery pack will be equipped with a battery balancing circuit to balance the charging of each battery cell in the battery pack. Discharge.

Existing battery balancing circuits can be divided into passive battery balancing circuits, transformer battery balancing circuits, inductive battery balancing circuits, capacitive battery balancing circuits, and uniform charge battery balancing circuits, which are briefly described below.

Passive battery balancing circuit is a passive battery balancing circuit composed of multiple sets of resistors and switches. The principle of its circuit operation is to separately control the on-time of the switch, shunt the current flowing into the battery to the resistor, reduce the current flowing into the battery, and achieve the effect of battery balance. Because this method consumes more energy from higher voltage batteries through resistance, special attention must be paid to the resistance value of the resistance, A long equilibration time results in poor efficiency and thermal energy. This will have a greater impact on the safety and performance of the circuit.

Transformer-type battery balancing circuit is a transformer-type battery balancing circuit composed of a transformer and a switch. It mainly transfers the energy of the battery pack from the primary side of the transformer to the secondary side, and controls the corresponding switch of the lower voltage battery to achieve battery balance. As a result, in this type of circuit, the magnetic coupling of the windings of the transformer must be the same. Therefore, the winding and design of the transformer are difficult, which will increase the circuit cost and volume and control the complexity.

Inductive battery balancing circuit is an inductive battery balancing circuit composed of multiple sets of inductors and switches. It mainly adjusts the energy stored in the inductor by controlling the on period of the switch, and the energy is transferred to the lower voltage battery through the switch to reach the battery. For the effect of balance, this method must transfer energy layer by layer through multiple sets of inductors. It cannot directly transfer the energy of the higher voltage battery to the lower voltage battery, so the balance time is longer and the efficiency is poor.

Capacitive battery balancing circuit is a capacitive battery balancing circuit composed of multiple sets of capacitors and switches. The excess power is stored in the capacitor through switch switching, or the energy in the capacitor is transferred to a lower voltage battery. The balancing time is longer. And the efficiency is poor.

Equal-charge battery balance circuit is an equal-charge battery balance circuit composed of multiple sets of converters. The principle of circuit operation is that each set of converters controls the conduction ratio of its switches to avoid uneven battery power or overcharging. Achieving the effect of battery balance, but this method requires multiple sets of converters, which will increase the circuit cost, volume, and control difficulty, and cannot meet the requirements of small size, low cost, and easy control.

Although the existing battery balancing circuit has various technical solutions, there are still unsatisfactory aspects in cost, balancing time, and circuit complexity.

In view of the shortcomings of the existing battery balancing circuit with complicated circuits and poor balancing efficiency, the present invention proposes a fast battery balancing circuit, which can reduce the circuit complexity and improve the balancing efficiency.

The technical means adopted to achieve the above purpose is to make the battery fast balancing circuit include: a plurality of battery cells, which are connected in series with each other; a transformer, each of which has a live line, a ground line and a neutral line on two sides, The live wire is reversely connected to a diode, the live wire on the other side is connected to a diode in turn, and the ground wires on the two sides are respectively connected to two switching switches. The plurality of first switching switches are connected to a part of the battery cells in the plurality of battery cells and The neutral line, live line, and ground wire on one side of the transformer are connected to the switch, and the selectable switching corresponding battery unit is connected to the corresponding side of the transformer; the plurality of second switching switches are connected to another part of the plurality of battery cells and the battery cell. The other side of the transformer is connected to the switch on the neutral line, live line and ground. Selective switching corresponds to the battery unit connected to the corresponding side of the transformer. A control unit is connected to the two switches on the transformer and the first and second switches. The switch is connected to control the plurality of battery cells to be connected to the corresponding side of the transformer.

The above-mentioned invention uses the switch on the ground wire on the two sides of the transformer to determine whether it is the primary or secondary side. When the switch on this side is turned on, the corresponding battery unit will be connected to the corresponding side through the first or second switch. Neutral and ground, this side is used as the primary side, the battery unit is discharged, the other side needs to maintain the switch off, as the secondary side, the corresponding battery unit is connected to this secondary through the first or second switch The live line and neutral line on the side charge the battery unit. During this process, the charging status of each battery unit can be detected through the control unit, and the switch on the transformer and the first and second switch can be controlled to control the power. The purpose of a fuller battery cell is to charge a less powerful battery cell.

The above-mentioned circuit of the present invention only uses a group of transformers with two diodes and two switching switches, and each battery unit also requires only two switching switches. Therefore, compared with the existing battery balancing circuit, an inductor, a capacitor, or multiple transformers are required. , Relay, etc., the invention can reduce the circuit volume, reduce the complexity of the circuit and reduce the hardware cost, and will not increase the time required for balancing due to the time delay caused by the charge and discharge of the capacitor.

10‧‧‧Transformer

20‧‧‧Control unit

30‧‧‧Filter circuit

V _B1 ~ V _Bn ‧‧‧Battery unit

S ₁ , S ₂ ‧‧‧ switch

D ₁ , D ₂ ‧‧‧ Diode

S _{a_0} ~ S _{a_n-1} ‧‧‧The first switch

S _{b_1} ~ S _{b_n} ‧‧‧Second switch

[Fig. 1] A schematic circuit diagram of the present invention.

[Figures 2 to 5]: Schematic diagrams of current in various use states of Figure 1.

In order to understand the technical features and practical effects of the present invention in detail, and can be implemented in accordance with the contents of the description, the preferred embodiment shown in the drawings is further described in detail as follows.

Please refer to FIG. 1. The battery rapid balancing circuit of the present invention includes: a plurality of battery cells V _B1 to V _Bn connected in series with each other; a transformer 10 having a live line, a ground line, and a neutral line on each of two sides, one of which The live wire on one side is reversely connected to a diode D ₁ , the live wire on the other side is connected to a diode D ₂ on the other side, and the ground wires on the two sides are respectively connected to two switching switches S ₁ and S ₂ ; a plurality of first switching switches ( S _{a_0} ~ S _{a_n-1} ), are connected to a part of the plurality of battery cells and the switch of the neutral line, live line and ground on one side of the transformer, and the selective switching corresponding battery unit is connected to the corresponding side of the transformer ; The second plurality of switching switches (S _{b_1} ~ S _{b_n} ) are connected to another part of the plurality of battery cells and the other side of the transformer neutral line, live line and ground line, and selectably switch the corresponding battery. The unit is connected to the corresponding side of the transformer; a control unit 20 is connected to two changeover switches on the transformer and the first and second changeover switches to control the plurality of battery units to be connected to the corresponding side of the transformer.

Rapid cell balancing circuit described above, in the two side of the transformer 10, wherein a side of the firing line connected to a corresponding cathode of diode D _1, the anode of the diode line D ₁ and the handover of the ground side of the switch S ₁ and the corresponding part of the first battery cell switch (S _{a_1,} S _{a_3} ....) connection, Firewire other side connected to the anode of a corresponding diode D _2, the cathode of the diode D ₂ of the system It is connected with the switch S ₂ of the ground wire on the side and a part of the second switch (S _{b_1} , S _{b_3} ...) Corresponding to the battery unit.

In this way, the switching switches S1 and S2 of the ground wire on the two sides of the transformer 10 can be used as the primary or secondary side. When the switching switch on this side is turned on, the corresponding battery unit will be connected through the first or second switching switch. To the neutral and ground wires of the corresponding side, this side is used as the primary side, the battery unit is discharged, and the other side needs to keep the switch off. As the secondary side, the corresponding battery unit is passed through the first or second switch The live line and neutral line connected to this secondary side are used to charge the battery unit, which will be further explained below.

In this embodiment, the plurality of battery cells are divided into an odd array and an even array. The anodes and cathodes of the odd-numbered battery cells V _B1 , V _B3, ... are passed through the plurality of first switching switches (S _{a_0} ~ S _{a_n -1} ) is connected to the corresponding side of the transformer 10, and the even group is connected to the corresponding side of the transformer 10 through the plurality of second switching switches ( _{Sb_1} ~ _{Sb_n} ).

The battery rapid balancing circuit of the present invention uses the switches S ₁ and S ₂ on the two sides of the transformer to control the side as a primary side or a secondary side (that is, charge or discharge), and through the plurality of first and second switching switches (S _{a_0} ~ S _{a_n-1} , S _{b_1} ~ S _{b_n} ) Select the corresponding battery cell for charging or discharging. For example, when the battery cell with the maximum power in the odd array is to be switched to the battery cell with the lowest power in the dual array, the transformer is switched. corresponding to the odd switches switch S ₁ is turned on the side of the corresponding even numbered side of the switch S ₂ is turned off, and turns on the first switch corresponding to the maximum capacity of the battery cell and the corresponding minimum charge of the battery cells of the second switch, The maximum power battery unit is charged through the transformer to charge the minimum power battery unit, which is described in detail below with reference to the drawings.

Please refer to FIG. 2 for further cooperation. This is a state of use of the present invention. When the first battery cell V _{B1 of the} odd array has the largest power and the last battery cell V _{Bn of the} even array has the smallest power, the control unit 20 will switch the transformer. 10 The switch S ₁ corresponding to the odd array is turned on, and the first switch S _{a_0} , S _{a_1} corresponding to the first battery cell V _B1 of the odd array is switched, and the second switch S _{b_n} corresponding to the last battery cell V _{Bn is even} . _-1 and S _{b_n are} turned on, so that the anode and cathode of the first battery cell VB1 are connected to the neutral and ground of the primary side of the transformer 10, and the anode and cathode of the last battery cell V _Bn are connected to the secondary side of the transformer 10 And the neutral line, so that the first battery cell V _B1 of the odd array and the last battery cell V _Bn of the dual array are charged.

Please refer to FIG. 3 for further cooperation. When the charging capacities of the two battery cells are balanced, the second switch S _{b_n-1 of the} charged battery cell V _Bn (the last battery cell of the even array) will be turned off first. S _{b_n} and the switch S _{2 of the} transformer 10. At this time, the battery unit V _B1 , which was originally connected to the neutral and ground wires of the transformer 10, will be connected to the neutral and live wires of the transformer 10 to make the transformer 10 Demagnetization is performed to recover excess electric energy in the transformer to the battery unit V _B1 , and the essential diode of the secondary-side switch S ₂ can prevent energy transmission to the secondary-side rechargeable battery during demagnetization.

Please refer to FIG. 4 further. On the contrary, when the battery cells V _B1 of the odd array are charged by the battery cells V Bn of the even array, the switch S2 on the corresponding side of the transformer 10 can be turned on, and the corresponding battery cells V _Bn , V can be turned on. The first and second switching switches (S _{a_0} ~ S _{a_n-1} , S _{b_1} ~ S _{b_n} ) of _B1 . At this time, the anode and cathode of the battery cell V _Bn corresponding to the even group will be connected to the ground and middle of the transformer 10 respectively. The neutral line is used as the primary side. The anode and cathode of the battery cell V _B1 on the secondary side will be connected to the neutral and live wires of the transformer 10 respectively. V _Bn charges the battery cell V _B1 on the secondary side (that is, the odd array) through the transformer.

Please refer to FIG. 5 again. Similarly, when the power of the two battery cells tends to be balanced, the first changeover switch (S _{a_0} ~ S _{a_n-1} ) of the charged battery unit V _B1 and the changeover switch of the transformer 10 may be turned off first. S ₂ makes the anode and cathode of the battery cell originally used for charging connected to the live and neutral wires of the transformer 10, respectively, so as to recover the excess power of the transformer.

In order to further improve the stability of the balancing process of the battery, the voltage and current output from the converter to the battery can be filtered to reduce the ripple of the voltage and current output from the converter to the battery, which can further make the live and neutral wires on the two sides of the transformer The neutral line and the ground line are each connected to a filtering circuit 30, and are connected to the first and second switching switches of the corresponding battery unit through the filtering circuit.

With the above technology, the battery fast balancing circuit of the present invention has the following effects: it can directly charge and discharge the odd and even battery cells, without the need for other energy storage elements such as capacitors and inductors, to achieve the function of fast balancing and Can reduce the time required for balancing, and has higher efficiency.

Only one set of transformers and several transfer switches are needed to achieve the purpose, which can greatly reduce the complexity and volume of the circuit and reduce the cost.

The circuit of the present invention can adopt an electronic circuit, which avoids the problems of the limitation of the number of mechanical switches and the large volume.

It has the function of transmitting energy in both directions and has the function of electrical isolation.

It also has the function of automatic demagnetization, which can reduce the excitation current to 0 before the start of each switching cycle.

Because the battery quick balancing circuit of the present invention is provided with a filter circuit, the battery energy can be further stored in the filter circuit when the transformer is demagnetized, which can prevent the problem that the input energy of the converter is insufficient or unstable due to the switching of the switch. .

The above description is only the preferred embodiments of the present invention, and is not intended to limit the scope of the rights claimed by the present invention. Any other equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included in the present invention. Within the scope of patent application.

Claims (3)

A battery quick balancing circuit includes: a plurality of battery cells connected in series with each other; a transformer having two live wires, a ground wire, and a neutral wire on each of two sides, and one of the live wires is reversely connected to a diode The live wire on the other side is connected to a diode in turn, and the ground wires on the two sides are connected to two transfer switches respectively; the first plurality of transfer switches are connected to a part of the plurality of battery cells and a neutral line on the transformer side. , The live wire and the ground wire are connected to the switch, and the selective switching corresponds to the corresponding battery unit connected to the corresponding side of the transformer; the plurality of second switching switches are connected to another part of the plurality of battery cells and the neutral line on the other side of the transformer , Switch on the live and ground wires, and select the corresponding battery unit to connect to the corresponding side of the transformer; a control unit connected to the two switches on the transformer and the first and second plural switches to control The plurality of battery cells are connected to the corresponding side of the transformer. The battery quick balancing circuit according to claim 1, wherein the two sides of the transformer are connected to the cathode of the corresponding diode, and the anode of the diode is connected to the grounding switch on the side and A part of the first switch corresponding to the battery unit is connected, and the other side of the live wire is connected to the anode of the corresponding diode. The cathode of the diode is connected to the ground wire on the side and the second switch of the part corresponding to the battery unit. Switch connection. The battery quick balancing circuit according to claim 1 or 2, each of the live line, neutral line and ground line on the two sides of the transformer is connected to a filter circuit, and the first and second switching between the filter circuit and the corresponding battery unit is performed. Switch connection.