CN205509600U - Novel double -deck balanced control of lithium cell group device - Google Patents

Abstract

The embodiment of the utility model discloses novel double -deck balanced control of lithium cell group device, including battery status observation circuit, battery management controller and the balanced control circuit who connects gradually, the battery status observation circuit will be monitored data transmission and given the battery management controller, the battery management controller will data are sent control signal and are given after carrying out algorithm analysis balanced control circuit realizes energy in the lithium cell group between battery cell is balanced. And simultaneously, balanced control circuit includes bottom inductance equalizer circuit and top layer electric capacity equalizer circuit, bottom inductance equalizer circuit, be used for the energy transduction between lithium cell inter block battery cell, top layer electric capacity equalizer circuit, be used for the equilibrium between the lithium cell inter block cell, this embodiment adopts upper and lower layer equalizer circuit coordinated actions, realizes between two wantonly battery cell in the lithium cell group and the developments transfer of energy between cell, has improved entire system's balanced efficiency.

Description

A new type of double-layer balance control device for lithium battery pack

technical field

The utility model relates to the technical field of equalization of battery packs, in particular to a novel double-layer equalization control device for lithium battery packs.

Background technique

In order to solve the problems faced by countries all over the world, such as energy crisis and environmental pollution, new energy vehicles have emerged under this background. Among them, electric vehicles have the advantages of low noise, less waste heat, simple structure, and convenient use and maintenance. The advantages of the series have attracted people's attention. However, the voltage and capacity of the single cells of lithium battery packs cannot meet people's performance requirements for electric vehicles at all, so they need to be connected in series to form battery packs to provide energy for electric vehicles.

However, the inconsistency between single cells in lithium battery packs still exists widely, and there are differences in various parameters of lithium batteries in the production process. Inconsistent. With the increase in the number of charging and discharging of lithium batteries in actual operation, as well as the influence of various factors such as temperature and self-discharge, these differences will continue to expand, making the performance differences between lithium battery cells more and more large, resulting in The phenomenon of overcharge and overdischarge of a single battery, the attenuation speed of each single battery in the battery pack is inconsistent, the capacity of the lithium battery pack in series is determined by the capacity of the lowest single battery in the group, so once a certain battery is deeply discharged, the entire The battery pack has to stop working. Similarly, once a certain battery is overcharged, the charging process will be stopped immediately, resulting in a sharp shortening of the battery pack's service life.

In order to realize the output voltage balance of each lithium battery in the lithium battery pack, in the prior art, resistors are usually connected in parallel on the single cells in the battery pack to consume energy or voltage balance is achieved by controlling multiple switches through relays. However, there are problems of energy waste and poor heat dissipation in the way of parallel resistors; the use of relay network equalization technology requires the secondary winding of the transformer to charge each single battery separately, and the consistency of the secondary winding needs to be strictly controlled, but the inductance winding Consistency is very difficult to control, and the equalization efficiency is low. It is not suitable for fast equalization during high-current charging. When the voltage difference between adjacent batteries is small, the equalization time will be very long.

Utility model content

The embodiment of the utility model provides a novel lithium battery pack double-layer equalization control device to solve the problems of low equalization precision and low efficiency in the voltage equalization mode in the prior art.

In order to solve the above technical problems, the embodiment of the utility model discloses the following technical solutions:

The embodiment of the utility model provides a novel lithium battery pack double-layer balance control device, including a battery state monitoring circuit, a battery management controller and a balance control circuit, wherein:

The input terminal of the battery state monitoring circuit is connected to the lithium battery pack, and is used to collect the cell voltage data of each single cell in the lithium battery pack and the unit voltage data of each battery cell. The unit is formed by connecting two or more single cells in series;

The input end of the battery management controller is connected to the output end of the battery state monitoring circuit, and is used to output a pulse signal to control the power switch in the equalization control circuit according to the cell voltage data and the cell voltage data Tube on and off;

The input terminal of the balance control circuit is connected to the output terminal of the battery management controller, and the output terminal is connected to the single battery and the battery unit, and is used to switch on or off the corresponding battery cell according to the pulse signal. charging or discharging circuit;

The equalization control circuit includes a bottom-layer inductance equalization circuit and a top-layer capacitance equalization circuit, the bottom-layer inductance equalization circuit is connected with the single cells, and is used to equalize the voltage between the single cells, and the top-layer capacitive equalization circuit is connected with the single cells. The battery cells are connected to balance the voltage between the battery cells.

Preferably, the underlying inductance equalization circuit is composed of a plurality of identical inductance equalization subcircuits, and the inductance equalization subcircuit includes an energy storage inductance L, a degaussing resistor R, an NMOS transistor and a PMOS transistor, wherein:

The NMOS transistor is connected across the two ends of the first single battery, the PMOS transistor is connected across the two ends of the second single battery, and the first single battery and the second single battery are two adjacent battery;

One end of the energy storage inductor L is connected between the NMOS transistor and the PMOS transistor, and the other end is connected between the first single cell and the second single cell;

The degaussing resistor R is connected in parallel with the energy storage inductance L;

An electric field effect diode is connected in parallel with the NMOS transistor and the PMOS transistor respectively.

Preferably, the top layer capacitance balancing circuit includes an energy storage capacitor, a first MOS transistor and a second MOS transistor, wherein:

One side of the energy storage capacitor is connected to the positive pole of the battery unit through the first MOS transistor, and the other side is connected to the negative pole of the battery unit through the second MOS transistor.

Preferably, the top-layer capacitance balancing circuit further includes a first balancing resistor and a second balancing resistor, wherein:

The first balancing resistor is connected in series between the first MOS transistor and the positive pole of the battery unit, and the second balancing resistor is connected in series between the second MOS transistor and the negative pole of the battery unit.

Preferably, the device further includes a battery protection circuit, wherein:

The input end of the battery protection circuit is connected to the battery management controller, and the output end is connected to the lithium battery pack.

Preferably, the inductance value of the energy storage inductor L is 8-12 μH.

Preferably, the resistance value of the degaussing resistor R is 15-25 kΩ.

Preferably, the capacitance value of the energy storage capacitor is 450-550 μF.

Preferably, the resistance values of the first balancing resistor and the second balancing resistor are both 1-3 kΩ.

It can be seen from the above technical solutions that a new double-layer balance control device for a lithium battery pack provided by the embodiment of the present invention includes a battery state monitoring circuit, a battery management controller and a balance control circuit connected in sequence, and the battery state monitoring circuit will The monitoring data is sent to the battery management controller, and the battery management controller analyzes the data with an algorithm, and then sends a control signal to the equalization control circuit to realize the energy balance between the single cells in the lithium battery pack. Precisely balanced.

The equalization control circuit includes a bottom-layer inductance equalization circuit and a top-layer capacitance equalization circuit. The bottom-layer inductance equalization circuit uses inductance as an energy transfer medium to realize energy transfer between single cells in the lithium battery pack; the top-layer capacitance equalization circuit On the top of the circuit, the flying capacitor is used as the balancing medium to realize the balancing between the battery cells in the lithium battery pack. This embodiment simplifies the overall structure of the system, thereby greatly reducing the implementation cost. At the same time, this embodiment adopts the upper and lower layer equalization The coordinated action of the circuit realizes the dynamic transfer of energy between any two cells of the lithium battery pack and between battery cells, which improves the equilibrium efficiency of the entire system.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art In other words, other drawings can also be obtained from these drawings under the premise of not paying creative work.

Fig. 1 is a schematic diagram of the basic structure of a novel lithium battery pack double-layer equalization control device provided by the embodiment of the present invention;

Fig. 2 is a schematic diagram of the basic structure of an equalization control circuit provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of the basic structure of the bottom inductance equalization circuit in FIG. 2;

FIG. 4 is a schematic diagram of the basic structure of the top-layer capacitive equalization circuit in FIG. 2 .

detailed description

In order to enable those skilled in the art to better understand the technical solution in the utility model, the technical solution in the utility model embodiment will be clearly and completely described below in conjunction with the accompanying drawings in the utility model embodiment. Obviously, The described embodiments are only some of the embodiments of the present utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

Referring to Fig. 1, it is a schematic diagram of the basic structure of a new double-layer balance control device for a lithium battery pack provided by an embodiment of the present invention, which is used for voltage balance control in a lithium battery pack, and the lithium battery pack can also be composed of several batteries The units are formed in series, and each battery unit includes three single cells connected in series. Of course, the battery unit can also be formed by connecting two or more single cells in series.

The balance control device includes a battery state monitoring circuit 1, a battery management controller 2, a balance control circuit 3, a battery protection circuit 4 and a power supply system 5, wherein the battery management controller 2 includes a data processing chip, a data acquisition interface, a GIPO data Interface and PWM signal output interface, the data processing chip adopts STM32F103C8T6 chip.

The input terminal of the battery state monitoring circuit 1 is connected to the lithium battery pack, and is used for collecting the single voltage data of each single battery in the lithium battery pack and the unit voltage data of the battery cells, and balancing Current and battery temperature data during charging and discharging.

The input end of the battery management controller 2 is connected to the output end of the battery state monitoring circuit 1, and is used to output a PWM pulse signal to control the equalization control circuit according to the cell voltage data and the cell voltage data 3. The on-off of the power switch tube realizes the energy balance between the single battery and the battery unit. At the same time, according to the cell voltage data, current and battery temperature data, the on-off of the power switch in the battery protection circuit 4 is controlled to protect the lithium battery pack from overcharging, overdischarging, and overheating protection, wherein, The battery protection circuit 4 is connected with the battery management controller 2 through a GPIO interface.

At the same time, the battery state monitoring circuit 1 and the battery management controller 2 are also connected to a power supply system 5, and the input end of the power supply system 5 is connected to the lithium battery pack for providing power for the lithium battery pack through the lithium battery pack. The battery state monitoring circuit 1 and the battery management controller 2 provide electric energy, which can reduce the volume of the double-layer balance control device compared with using an additional power supply for power supply.

The input terminal of the balance control circuit 3 is connected to the output terminal of the battery management controller 2, and the output terminal is connected to the single battery and the battery unit, and is used to switch on or off according to the pulse signal. Open the corresponding charging or discharging circuit.

As shown in Figure 2, the equalization control circuit 3 includes a bottom inductance equalization circuit and a top capacitive equalization circuit, the bottom inductance equalization circuit is connected with the single battery for equalizing the single battery in the battery unit the voltage between the cells; the top-layer capacitor balancing circuit is connected to the battery cells and is used to balance the voltage between the battery cells.

As shown in FIG. 3 , the underlying inductance equalization circuit is composed of a plurality of identical inductance equalization subcircuits, and the inductance equalization subcircuit includes an energy storage inductance L, a degaussing resistor R, an NMOS transistor and a PMOS transistor. In this embodiment, one of the inductance equalization sub-circuits is taken as an example to introduce the bottom inductance equalization circuit in detail.

The inductance equalization sub-circuit includes an energy storage inductance L ₁ , a degaussing resistor R ₁ , an NMOS transistor M _1-a and a PMOS transistor M _1-b . The NMOS transistor M _1-a is connected across the two ends of the first unit battery B ₂ , the PMOS transistor M _1-b is connected across the two ends of the second unit battery B ₁ , and the first unit The battery B ₂ and the second unit battery B ₁ are two adjacent batteries; one end of the energy storage inductor L ₁ is connected between the NMOS transistor M _1-a and the PMOS transistor M _1-b , The other end is connected to the first unit battery B ₂ and the second unit battery B ₁ ; the degaussing resistor R ₁ is connected in parallel with the energy storage inductance L ₁ for switching the energy storage inductance L ₁ The remaining stored energy is consumed in the resistor; the NMOS transistor M _1-a and the PMOS transistor M _1-b are respectively connected in parallel with a power field effect diode D _1-a and D _1-b . In this embodiment, the inductance value of the energy storage inductor L ₁ is 8-12 μH, and the resistance value of the degaussing resistor R ₁ is 15-25 kΩ, but the values are not limited to the above range.

The two electric field effect MOS transistors M _1-a and M _1-b cooperate with each other to control the on-off of the balanced charging circuit of the adjacent first single battery B ₂ and the second single battery B ₁ ; The power field effect diodes D _1-a and D _1-b constitute a balanced discharge circuit.

Assuming that the voltage of the second unit battery B1 detected by the battery state monitoring circuit ₁ is greater _than the voltage of the first unit battery B2, that is, VB1>VB2, the battery management controller 2 passes The control signal turns on the PMOS transistor M _1-b , because the voltage difference across the second single battery B ₁ causes a current to be generated in the loop, but due to the inductive reactance property of the inductor L ₁ , the current cannot reach the maximum instantaneously , but a slow rising process, so that the magnetic flux _of the inductance L1 increases continuously, and the energy is accumulated. The whole process realizes the energy transfer _of the second single battery B1 to the inductance L1. When the discharge cut _- off time is reached, , the battery management controller 2 controls the PMOS transistor M _1-b to disconnect the second unit battery B ₁ , but because a large amount of magnetic flux is stored in the inductor L ₁ , the current cannot drop to zero instantaneously , so the voltage generated at its two ends breaks down the diode D _{1_a} to form a loop to charge the first single battery B ₂ , so as to achieve a preliminary balance of energy between the two single batteries.

On the contrary, if the voltage of the second unit battery B1 detected by the battery state monitoring circuit ₁ is lower _than the voltage of the first unit battery B2, that is, VB1<VB2, the battery management controller 2 The NMOS transistor M1 _-a is turned on by a control signal.

In this embodiment, the bottom inductance equalization circuit uses inductance as the energy transfer medium to realize the energy transfer between the single cells in the battery unit, and the topological current transfer path is bidirectional, which can realize top-down or bottom-up Two-way transfer of energy is realized between two adjacent energy storage battery cells, and multiple adjacent battery pairs in the battery cells can be charged and discharged at the same time, so as to shorten the equalization time and improve the equalization efficiency. The circuit topology is easy Realization, low energy consumption, suitable for voltage balance of energy storage battery packs with few monomers. At the same time, the operation of each inductance equalization sub-circuit is not affected by the main circuit current, so it can work at any stage such as charging, discharging or shelving of the battery pack.

As shown in FIG. 2, the top-layer capacitance balancing circuit includes an energy storage capacitor C, a plurality of first MOS transistors and a plurality of second MOS transistors, and one side of the energy storage capacitor C passes through the first MOS transistors respectively. It is connected to the positive pole of the battery unit, and the other side is respectively connected to the negative pole of the battery unit through the second MOS tube, wherein the first MOS tube and the second MOS tube can be of the same type MOS tube. In order to protect the energy storage capacitor C, the top capacitor equalization circuit further includes a plurality of first equalization resistors and a plurality of second equalization resistors, and the first equalization resistors are connected in series between the first MOS tube and the battery unit The second balancing resistor is connected in series between the second MOS tube and the negative electrode of the battery cell, wherein the first balancing resistor and the second balancing resistor can be of the same type. In this embodiment, the capacitance value of the energy storage capacitor C is 450-550 μF, and the resistance values of the first balancing resistor and the second balancing resistor are both 1-3 kΩ, but are not limited to the range of values.

In this embodiment, the two capacitor equalization sub-circuits are taken as examples to introduce the top layer capacitor equalization circuit in detail. As shown in FIG. 4 , one side of the energy storage capacitor C is connected to the positive electrode of the first battery unit M 1 through the first MOS transistor S ₁ and the first resistor R ₀₁ , and the other side is respectively connected to the positive electrode of the first battery unit M ₁ through the The second MOS transistor S ₂ and the second resistor R ₀₂ are connected to the negative electrode of the first battery unit M ₁ ; at the same time, one side of the energy storage capacitor C passes through the first MOS transistor S ₅ and The first resistor R ₀₅ is connected to the positive pole of the third battery unit M3, and the other side is connected to the negative pole of the third battery unit M3 through the second MOS transistor S ₆ and the second resistor R ₀₆ respectively.

Assuming that the battery state monitoring circuit 1 detects that the voltage of the first battery unit M1 is greater _than the voltage of the third battery unit M3, that is, VM1>VM3, the battery management controller 2 makes the battery The MOS switches S1 and S2 are turned _on , the _first battery unit M1 charges the energy storage capacitor C, and when the discharge cut _- off time is reached, the battery management controller 2 uses a control signal to make the MOS switch S1 and _S2 are disconnected, and the MOS switches S5 and S6 are turned _on , so that the energy storage capacitor C transfers energy to the third battery unit M3, so as to realize energy balance among the battery units. Accompanied by the periodic charging and discharging of the energy storage capacitor C, the voltage balance between the battery cells M1 and M3 is realized, so as to realize the energy balance among the battery cells again.

In this embodiment, the top-level equalization circuit is equalized by flying capacitors. This equalization technology can realize direct point-to-point energy transfer, has a short equalization path and high efficiency, and is suitable for use as a top-level equalizer of the equalization system. When the system detects that the balance between battery cells needs to be turned on, the inter-cell mode is turned on, and the current battery cell that needs to be balanced is judged, and the MOS switch is controlled to be turned on or off through the output control signal, so that through the cycle of the capacitor Sexual switching realizes the point-to-point transfer of energy from the energy storage battery unit with the highest voltage to the battery unit with the lowest voltage.

Using the double-layer balance control device provided in this embodiment, when the battery state monitoring circuit 1 and the battery management controller 2 detect and analyze that it is necessary to turn on the bottom balance, that is, the balance between the single cells in the battery unit When the voltage difference is greater than the first preset threshold, the bottom layer inductance equalization circuit is turned on; the detection is continued at intervals, and when the voltage difference between the single cells in the battery unit is smaller than the first preset threshold, the bottom layer is turned off The inductance equalization circuit then detects whether the top level equalization needs to be turned on, that is, whether the voltage difference between the battery cells is greater than the second preset threshold. When it is detected and analyzed that the battery cells need to be balanced, that is, when the voltage difference between the battery cells is greater than the second preset threshold, the top-level equalization circuit is turned on, so as to realize the energy balance between the battery cells in the entire lithium battery pack. balanced.

Wherein, the first preset threshold and the second preset threshold can be set according to actual needs, which are not limited in this embodiment.

In this embodiment, the bottom layer inductance equalization circuit and the top layer capacitance equalization circuit perform data transmission in real time through the CAN bus, and the upper and lower layer equalization circuits coordinate actions without interfering with each other, so that the energy of any two single cells in the battery pack can be directly or Compared with single-layer equalization, this solution can quickly realize the dynamic transfer of energy between lithium battery packs and improve the equalization efficiency of the entire system.

At the same time, the balance control device can use a low-power, low-cost single-chip microcomputer, and a complex programmable logic device. With software control, it can not only realize real-time monitoring of battery voltage, current and other data, but also realize charging and sampling data. Accurate sampling and control.

It should be noted that in this article, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these No such actual relationship or order exists between entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only specific implementation methods of the present utility model, so that those skilled in the art can understand or realize the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A novel lithium battery pack double-layer equalization control device for a lithium battery pack, characterized in that it includes a battery state monitoring circuit, a battery management controller and an equalization control circuit, wherein: The input terminal of the battery state monitoring circuit is connected to the lithium battery pack, and is used to collect the cell voltage data of each single cell in the lithium battery pack and the unit voltage data of each battery cell. The unit is formed by connecting two or more single cells in series; The input end of the battery management controller is connected to the output end of the battery state monitoring circuit, and is used to output a pulse signal to control the power switch in the equalization control circuit according to the cell voltage data and the cell voltage data Tube on and off; The input terminal of the balance control circuit is connected to the output terminal of the battery management controller, and the output terminal is connected to the single battery and the battery unit, and is used to switch on or off the corresponding battery cell according to the pulse signal. charging or discharging circuit; The equalization control circuit includes a bottom-layer inductance equalization circuit and a top-layer capacitance equalization circuit, the bottom-layer inductance equalization circuit is connected with the single cells, and is used to equalize the voltage between the single cells, and the top-layer capacitive equalization circuit is connected with the single cells. The battery cells are connected to balance the voltage between the battery cells. 2. The novel lithium battery pack double-layer equalization control device according to claim 1, wherein the bottom-layer inductance equalization circuit is composed of a plurality of identical inductance equalization sub-circuits, and the inductance equalization sub-circuit includes an energy storage inductance L, degaussing resistor R, NMOS tube and PMOS tube, where: The NMOS transistor is connected across the two ends of the first single battery, the PMOS transistor is connected across the two ends of the second single battery, and the first single battery and the second single battery are two adjacent battery; One end of the energy storage inductor L is connected between the NMOS transistor and the PMOS transistor, and the other end is connected between the first single cell and the second single cell; The degaussing resistor R is connected in parallel with the energy storage inductance L; An electric field effect diode is connected in parallel with the NMOS transistor and the PMOS transistor respectively. 3. The novel lithium battery pack double-layer equalization control device according to claim 1, wherein the top-layer capacitor equalization circuit includes an energy storage capacitor, a first MOS transistor, and a second MOS transistor, wherein: One side of the energy storage capacitor is connected to the positive pole of the battery unit through the first MOS transistor, and the other side is connected to the negative pole of the battery unit through the second MOS transistor. 4. The novel lithium battery pack double-layer equalization control device according to claim 3, wherein the top-layer capacitance equalization circuit further includes a first equalization resistor and a second equalization resistor, wherein: The first balancing resistor is connected in series between the first MOS transistor and the positive pole of the battery unit, and the second balancing resistor is connected in series between the second MOS transistor and the negative pole of the battery unit. 5. The new lithium battery pack double-layer balance control device according to claim 1, characterized in that the device also includes a battery protection circuit, wherein: The input end of the battery protection circuit is connected to the battery management controller, and the output end is connected to the lithium battery pack. 6. The novel lithium battery pack double-layer balance control device according to claim 2, characterized in that the inductance value of the energy storage inductor L is 8-12 μH. 7. The novel lithium battery pack double-layer balance control device according to claim 2, characterized in that the resistance of the degaussing resistor R is 15-25 kΩ. 8. The novel lithium battery pack double-layer equalization control device according to claim 3, characterized in that the capacitance value of the energy storage capacitor is 450-550 μF. 9 . The novel lithium battery pack double-layer balance control device according to claim 4 , wherein the resistance values of the first balance resistor and the second balance resistor are both 1-3 kΩ.