CN108134414B - Modular equalization circuit and equalization mode thereof - Google Patents
Modular equalization circuit and equalization mode thereof Download PDFInfo
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- CN108134414B CN108134414B CN201711298800.6A CN201711298800A CN108134414B CN 108134414 B CN108134414 B CN 108134414B CN 201711298800 A CN201711298800 A CN 201711298800A CN 108134414 B CN108134414 B CN 108134414B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
- H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
- B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
- B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
- B60L58/22—Balancing the charge of battery modules
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
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- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention discloses a modular equalization circuit and an equalization mode thereof, which are used for solving the problems of high power loss, a plurality of equalization devices, large size and high cost of an equalization circuit in a series battery pack equalization topology in the prior art. The battery pack balancing device comprises a battery module, a balancing circuit and a controller, wherein the controller is connected with the balancing circuit and controls the balancing circuit to balance the battery module; the equalizing circuit comprises a bottom equalizing circuit and a top equalizing circuit; the top equalization circuit comprises N top single-pole double-throw switches connected in series, and the top LC series circuit is connected in series. The invention realizes zero flow switching of the switch device, reduces the switching loss of the switch device, increases the balance path through modular balance, is easy to expand, and is suitable for a battery management system of an energy storage device in an electric automobile or an energy storage power station.
Description
Technical Field
The invention relates to the field of batteries, in particular to a modular equalization circuit and an equalization mode thereof.
Background
With the increasingly worsening of air quality and the gradually scarcity of petroleum resources, new energy vehicles, especially pure electric vehicles, become development hot spots of various automobile companies in the world today. The power battery pack is used as a key part of the electric automobile, and has great influence on the dynamic property, the economy and the safety of the whole automobile. After a plurality of charge and discharge cycles, the distribution of the residual capacity of each battery cell is approximately different, and overcharge and overdischarge phenomena are easy to occur if the residual capacity of each battery cell is not balanced. Therefore, in practical use, the service life of the battery pack is seriously influenced, and even the potential safety hazard of overheating and fire catching exists.
The existing lithium ion battery pack balance control method can be divided into two categories, namely an energy dissipation type and an energy non-dissipation type according to the energy consumption condition of a circuit in the balance process; the dissipation type is that a shunt resistor is connected in parallel outside each single battery, the energy of the battery module with higher residual capacity is consumed through the resistor by controlling the corresponding switch device, the method wastes the energy, a large amount of heat is generated in the balancing process, and the load of battery thermal management is increased. The non-dissipative type achieves energy transfer through a DC-DC circuit external to the battery. The balance function is classified into charge balance, discharge balance, and dynamic balance. The charge equalization refers to equalization in the charging process, generally, equalization is started when the voltage of a battery pack monomer reaches a set value, and overcharge is prevented by reducing charge current; the discharge balance refers to balance in a discharge process, and prevents over-discharge by supplementing energy to the battery cells with low residual energy; the dynamic equalization mode combines the advantages of charge equalization and discharge equalization, and means equalization of the battery pack in the whole charge and discharge process.
In the prior art, the balancing topology of the series battery pack has the problems of high power loss, a plurality of balancing devices, large size of a balancing circuit and high cost.
Disclosure of Invention
Aiming at the defects of the prior art, the modular equalization circuit is provided for solving the problems of high power loss, more equalization devices, large size and high cost of the equalization circuit in the equalization topology of the series battery pack in the prior art; the equalizing circuit and the equalizing mode thereof can realize zero current at the moment of switching on and switching off the switch, thereby greatly reducing the switch loss, improving the equalizing efficiency, reducing the power loss and reducing the equalizing devices.
A modularized equalization circuit comprises a battery module, an equalization circuit and a controller, wherein the controller is connected with the equalization circuit and controls the equalization circuit to equalize the battery module; the equalizing circuit comprises a bottom equalizing circuit and a top equalizing circuit;
the bottom equalization circuit is formed by connecting N bottom equalization modules Qi (i is 1,2,3 … N) in series, each bottom equalization module Qi comprises 1 battery module Mi, 4 bottom single-pole double-throw switches Si (i is 1,2,3,4) connected in series, and 3 bottom LC series circuits Ci-Li (i is 1,2,3) connected in series; each single-pole double-throw switch Si comprises three terminals Si _ a, Si _ b, Si _ c (i ═ 1,2,3, 4); si _ a and Si _ b are respectively a first static terminal and a second static terminal, and Si _ c is a selection terminal; the battery module Mi is formed by connecting 4 batteries Bi (i is 1,2,3,4) in series;
si _ c selects to contact with Si _ a or Si _ b according to the control signal; the first static terminal Si _ a (i ═ 1,2,3,4) is connected to the positive pole of the battery Bi (i ═ 1,2,3,4), and the second static terminal Si _ b is connected to the negative pole of the battery Bi; one end of the capacitor Ci is connected with the selection terminal Si _ c, and the other end of the capacitor Ci is connected with the inductor Li; one end of an inductor Li is connected with Ci, and the other end of the inductor Li is connected with a capacitor C (i +1) and a selection terminal S (i +1) _ C;
the top-layer balancing circuit comprises N battery modules Mi (i is 1,2, … N) connected in series, N top-layer single-pole double-throw switches Smi (i is 1,2, … N) connected in series, and N-1 top-layer LC series circuits Cmi-Lmi (i is 1), … and Cmi-Lmi (i is N-1) connected in series, and is used for balancing among the battery modules Mi, the top-layer LC series circuits are connected in series, and each top-layer LC series circuit is arranged among the top-layer single-pole double-throw switches Smi; each top single-pole double-throw switch Smi comprises three terminals Smi _ a, Smi _ b and Smi _ c; the terminals Smi _ a and Smi _ b are respectively a first static terminal and a second static terminal, and Smi _ c is a selection terminal; smi _ c selects to contact Smi _ a or Smi _ b according to the control signal; smi _ a is connected with the positive electrode of the battery module Mi, Smi _ b is connected with the negative electrode of the battery module Mi, one end of a capacitor Cmi is connected with Smi _ c, and the other end of the capacitor Cmi is connected with an inductor Lmi; one end of the inductor Lmi is connected with the capacitor Cmi, and the other end of the inductor Lmi is connected with the capacitor Cm (i +1) and the selection terminal Sm (i +1) _ c; sm (i +1) _ a is connected with the positive electrode of the battery module M (i +1), Sm (i +1) _ b is connected with the negative electrode of the battery module M (i +1) and Smi _ a, and the negative electrode of the battery module M (i +1) is connected with the positive electrode of the battery module Mi;
the terminal Smi _ b is connected with Si _ b (i is 1) of the bottom equalization module Qi, and Smi _ a is connected with Si _ a (i is 4) of the bottom equalization module Qi; sm (i +1) _ b is connected with Si _ b (i ═ 1) of the bottom equalization module Q (i +1), and Sm (i +1) _ a is connected with Si _ a (i ═ 4) of the bottom equalization module Q (i + 1); si _ a (i ═ 4) of the bottom equalization module Qi is connected to Si _ b (i ═ 1) of the bottom equalization module Q (i + 1);
the bottom LC series circuit and the top LC series circuit are both formed by connecting an inductor L and a capacitor C in series; the N battery modules Mi (i is 1,2,3 … N) of the bottom equalization circuit are connected in series and used for equalization among the battery cells in the battery modules Mi;
the battery modules Mi (i is 1,2,3 … N) of the bottom equalization circuit are N, each battery module Mi is formed by connecting 4 single batteries Bi (i is 1,2,3,4) in series and serves as a main body to be equalized, the N battery modules Mi are connected in series and then connected into the bottom equalization circuit to form a bottom equalization module Qi (i is 1,2,3 … N), and the bottom equalization module Qi (i is 1,2,3 … N) is connected in series and then connected into the top equalization circuit;
the bottom equalization circuit and the top equalization circuit both adopt the same equalization circuit based on an LC series circuit;
the LC series circuit is formed by connecting a capacitor C and an inductor L in series and works in a quasi-resonance state; the switching devices in all the equalization circuits are connected with the controller, and the controller controls the energy transfer by controlling the on-off of the switching devices, so that the equalization of the battery pack is realized; the LC series circuit presents a quasi-resonance characteristic in the working process, and the current flowing into or out of the capacitor changes from zero at the moment of switching the state of the single-pole double-throw switch, so that the switching noise and EMI (electro-magnetic interference) are reduced to provide the working quality of the circuit;
the duty ratio of a control signal of the single-pole double-throw switch is 50% so as to ensure that the inductive current is reduced to zero at each switching moment; the controller is connected with all the single-pole double-throw switches in the equalizing circuit, the energy transfer is controlled by controlling the on-off of the single-pole double-throw switches, the equalization of the battery pack is realized, the on-off frequency fs of the single-pole double-throw switches controlled by the controller is determined by lumped parameters R, L, C in the equalizing circuit, the LC series circuit is ensured to work in a quasi-resonance state, the current of the LC series circuit is reduced to zero at each switching moment, the switching loss is reduced, the equalizing efficiency is improved, and the equalizing time is shortened; the controller sends out PWM signals, after the switch is thrown to be high, the switch is controlled to be thrown to be low after a half PWM period, the on-off of the switch device is completed in the PWM period, and the LC series circuit works in a quasi-resonance state.
Further, the bottom single-pole double-throw switch Si and the top single-pole double-throw switch Smi are both composed of two series MOSFET tubes, the source S of the first MOSFET tube is connected with the drain D of the second MOSFET tube, each MOSFET tube is internally provided with an anti-parallel diode, the drain D of the first MOSFET tube is a first static terminal Si _ a of the single-pole double-throw switch Si, the source S of the second MOSFET tube is a second static terminal Si _ b of the single-pole double-throw switch Si, and the connection point of the two MOSFET tubes is a selection terminal Si _ c of the single-pole double-throw switch Si; the grid G of the first MOSFET and the grid G of the second MOSFET are respectively connected with a controller, and the controller controls Si _ c to be connected with Si _ a or Si _ b;
the top single-pole double-throw switch Smi and the bottom single-pole double-throw switch Si are connected in the same mode, and the top single-pole double-throw switch Smi is provided with a first static terminal Smi _ a, a second static terminal Smi _ b and a selection terminal Smi _ c.
Further, the first unit of the bottom equalization module Qi is formed by connecting a capacitor Ci (i ═ 1) in series with an inductor Li (i ═ 1), one end of the capacitor Ci (i ═ 1) is connected with a selection terminal Si _ c (i ═ 1) of a bottom single-pole double-throw switch Si (i ═ 1), and the other end of the capacitor Ci (i ═ 1) is connected with the inductor Li (i ═ 1); the other end of the inductor Li (i ═ 1) far from the capacitor Ci (i ═ 1) is connected with the capacitor Ci (i ═ 2) and a selection terminal Si _ c (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2); a second static contact single-son Si _ b (i ═ 1) of the bottom layer single-pole double-throw switch Si (i ═ 1) is connected with the negative electrode of the battery Bi (i ═ 1), and a first static contact terminal Si _ a (i ═ 1) of the bottom layer single-pole double-throw switch Si (i ═ 1) is connected with the positive electrode of the battery Bi (i ═ 1) and a second static contact single-son Si _ b (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2);
the second unit of the bottom equalization module Qi is formed by connecting a capacitor Ci (i ═ 2) and an inductor Li (i ═ 2) in series, one end of the capacitor Ci (i ═ 2) is connected with a selection terminal Si _ c (i ═ 2) and the inductor Li (i ═ 1), and the other end of the capacitor Ci (i ═ 2) is connected with the inductor Li (i ═ 2); the other end of the inductor Li (i ═ 2) remote from the capacitor Ci (i ═ 2) is connected to the selection terminal Si _ c (i ═ 3) and the capacitor Ci (i ═ 3); a second static contact single-son Si _ b (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2) is connected with the negative electrode of the battery Bi (i ═ 2), and a first static contact terminal Si _ a (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2) is connected with the positive electrode of the battery Bi (i ═ 2) and the second static contact single-son Si _ b (i ═ 3) of the bottom layer single-pole double-throw switch Si (i ═ 3);
the third unit of the bottom equalization module Qi is formed by connecting a capacitor Ci (i ═ 3) and an inductor Li (i ═ 3) in series, one end of the capacitor Ci (i ═ 3) is connected with the selection terminal Si _ c (i ═ 3) and the inductor Li (i ═ 2), and the other end of the capacitor Ci (i ═ 3) is connected with the inductor Li (i ═ 3); the other end of the inductor Li (i ═ 3) remote from the capacitor Ci (i ═ 3) is connected to a selection terminal Si _ c (i ═ 4); a second static contact single-pole-double-throw (i-4) of the bottom layer single-pole-double-throw switch Si (i-4) is connected with the negative electrode of the battery Bi (i-4), and a first static contact terminal Si _ a (i-4) is connected with the positive electrode of the battery Bi (i-4); the second static contact unit Si _ b (i ═ 3) is connected with the negative electrode of the battery Bi (i ═ 3), and the first static contact terminal Si _ a (i ═ 3) is connected with the positive electrode of the battery Bi (i ═ 3);
the selective terminals Sic of all the bottom single-pole double-throw switches Si are respectively connected with the controller;
the controller sends a control signal to the single-pole double-throw switch Si, and the control signal is used for controlling connection of Si _ c and Si _ a or Si _ b; the driving signals of the two MOSFET tubes are a pair of complementary unipolar rectangular wave signals.
The notation (i +1) in the text is a number, and (i +1) indicates the value i plus 1; the symbol (N-1) is a number and (N-1) represents the value N minus 1.
An equalizing method of a modularized equalizing circuit comprises the following steps:
the 4 bottom single-pole double-throw switches Si of the bottom equalization module Qi are all controlled by a controller to throw high, namely Si _ c of any switch is connected with Si _ a, 3 bottom LC series circuits Ci-Li are coupled to a battery B (i +1) corresponding to an upper position and connected in parallel, each bottom LC series circuit Ci-Li and the battery B (i +1) connected in parallel carry out energy exchange, and the bottom LC series circuits Ci-Li are charged or discharged to the battery B (i + 1);
the 4 bottom single-pole double-throw switches Si of the bottom equalization module Qi are all controlled by a controller to be thrown low, namely Si _ c of any switch is connected with Si _ b, 3 bottom LC series circuits Ci-Li are coupled to batteries Bi corresponding to the current position and connected in parallel, each LC series circuit Ci-Li exchanges energy with the batteries Bi connected in parallel, and the LC series circuits Ci-Li are charged or discharged to the batteries Bi;
repeatedly throwing all the switches high and low, and the time intervals are the same each time, so that the voltage of all the batteries Bi tends to be consistent, the internal balance effect of the battery module Mi is realized, and the internal battery balance of the battery module Mi is realized by the bottom layer balancing module Qi;
when voltage inconsistency occurs among the battery modules Mi, in the top-layer balancing circuit, the controller controls the N top-layer single-pole double-throw switches Smi (i is 1,2,3 … N) to be thrown high or low repeatedly, time intervals at each time are the same, voltage of all the battery modules Mi tends to be consistent, a specific working method is the same as a balancing method among the bottom-layer batteries Bi, and voltage balancing among the battery modules Mi is achieved.
Further, an equalizing method of the modularized equalizing circuit comprises the following steps:
firstly, when 4 bottom single-pole double-throw switches Si are all controlled by the controller to throw high, i.e. Si _ c of any switch is connected to Si _ a, 3 bottom LC series circuits Ci-Li are coupled to and connected in parallel with the battery B (i +1) corresponding to the previous bit, specifically, the bottom LC series circuits Ci-Li (i ═ 1) are connected in parallel with the battery Bi (i ═ 2), Ci-Li (i ═ 2) are connected in parallel with the battery Bi (i ═ 3), Ci-Li (i ═ 3) are connected in parallel with the battery Bi (i ═ 4), and then each bottom LC series circuit Ci-Li exchanges energy with the battery B (i +1) connected in parallel therewith, and the bottom LC series circuits Ci-Li are either charged or discharged to the previous battery B (i + 1);
then, when the 4 bottom single-pole double-throw switches Si are controlled to be thrown low by the controller, that is, Si _ c of any switch is connected to Si _ b, 3 bottom LC series circuits Ci-Li are coupled to the battery Bi corresponding to the current position in parallel, the bottom LC series circuit Ci-Li (i ═ 1) is connected to the battery Bi (i ═ 1) in parallel, Ci-Li (i ═ 2) is connected to the battery Bi (i ═ 2) in parallel, and Ci-Li (i ═ 3) is connected to the battery Bi (i ═ 3) in parallel, and each LC series circuit Ci-Li exchanges energy with the battery Bi connected in parallel, and the LC series circuits Ci-Li are either charged or discharged to the battery Bi;
repeatedly throwing all the switches to be high and low, and the time intervals are the same each time; the voltage of all the batteries tends to be consistent, and the effect of battery equalization is realized;
during the alternating switching, the energy of the high-voltage battery can be transferred to the low-voltage battery; when the voltage of battery Bi (i ═ 3) is higher than the voltage of battery Bi (i ═ 1), charge will flow from the battery pack Bi (i ═ 2) -Bi (i ═ 3) to the capacitances Ci (i ═ 1) and Ci (i ═ 2); in the balancing process, under the working state that the switch of the bottom balancing module is thrown low, equal charges are released from the capacitors Ci (i is equal to 1) and Ci (i is equal to 2) to the battery pack Bi (i is equal to 1) -Bi (i is equal to 2); the charge amount flowing into and out of the battery Bi (i-2) is the same in the whole process of charge transfer, and the charge is actually directly transferred from the battery Bi (i-3) to the battery Bi (i-1);
similarly, when the voltage of the battery Bi (i ═ 1) is higher than that of the battery Bi (i ═ 3), when two operating states of the bottom equalization module switch high and the bottom equalization module switch low are alternately performed in the equalization process, the charge is transferred from the battery Bi (i ═ 1) to the battery Bi (i ═ 3) through the capacitors Ci (i ═ 1) and Ci (i ═ 2); the two capacitors Ci (i ═ 1) and Ci (i ═ 2) provide a path between the batteries Bi (i ═ 1) and Bi (i ═ 3) that can be used to transfer charge directly; the capacitor Ci (i ═ 1) provides a direct charge transfer path between the batteries Bi (i ═ 1) and Bi (i ═ 2); the capacitor Ci (i-2) provides a direct charge transfer path between the batteries Bi (i-2) and Bi (i-3); the capacitor Ci (i-4) provides a direct charge transfer path between the batteries Bi (i-3) and Bi (i-4); a path for directly transferring charge is arranged between every two batteries;
when voltage inconsistency occurs among the battery modules Mi, the specific working principle and the specific working method of the battery modules Mi are the same as those of the balancing method among the bottom layer batteries Bi, and the balancing is realized through the balancing among the bottom layer batteries Bi.
The invention has the beneficial effects that: by using the LC series circuit working in the quasi-coordinated state to balance the batteries, the circuit current is 0 when the switch is switched, the problem of high power loss of the series battery pack balancing topology in the prior art is solved, balancing devices are reduced, and the volume and the cost of the balancing circuit are reduced.
The invention realizes the zero-point current switching of the switch device, reduces the switching loss of the switch device, increases the balance path through modular balance and is easy to expand. The invention improves the phenomenon of unbalance of the series battery pack and is suitable for the battery management system of the energy storage device in the electric automobile or the energy storage power station.
Drawings
Fig. 1 is a schematic diagram of a conventional battery pack equalization circuit structure;
FIG. 2 is a circuit schematic of an embodiment of the present invention;
FIG. 3 is a schematic diagram of a top level equalization circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a bottom level equalization module Qi according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a single pole, double throw switch according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of the switch throw height of the bottom equalization module during equalization in accordance with an embodiment of the present invention;
fig. 7 is a schematic diagram of the low throw of the switches of the bottom equalization module during equalization according to an embodiment of the present invention.
Detailed Description
For further understanding of the features and technical means of the present invention, as well as the specific objects and functions attained by the present invention, the present invention will be described in further detail with reference to the accompanying drawings and detailed description.
Referring to fig. 1 to 7, in combination with an embodiment of the present invention, the embodiment includes a battery module, an equalizing circuit, and a controller, where the controller is connected to the equalizing circuit and controls the equalizing circuit to equalize the battery module; the equalization circuit comprises a bottom equalization circuit and a top equalization circuit.
The bottom layer balancing module Qi comprises 4 bottom layer single-pole double-throw switches Si (i is 1,2,3,4) and 3 bottom layer LC series circuits, and is used for balancing the battery cells in the battery module Mi; the top-layer equalization circuit comprises N top-layer single-pole double-throw switches Smi (i is 1,2,3, … N) and (N-1) top-layer LC series circuits which are used for equalization among the battery modules Mi, the LC series circuits are mutually connected in series, and each LC series circuit is arranged among the single-pole double-throw switches; in the specific implementation process, whether the intermediate equalization circuit is set or not is mainly determined according to actual needs, specifically, the intermediate equalization circuit is determined according to the number of the batteries needing equalization, and if the number of the batteries needing equalization is small, the intermediate equalization circuit is not set. In a specific embodiment, M is 4 is a number that is relatively necessary in practice, and if the value of M is too small, the total number of necessary LC series circuits is too large, and if M is too large, the number of cells is large, and the equalization time is too long.
The conventional battery pack equalization circuit described in fig. 1 uses a capacitor for energy transfer, and has no advantage of 0 switching circuit current in the quasi-resonance state of the LC series circuit.
In the invention, the controller is connected with all switches in the equalizing circuit, the energy transfer can be controlled by controlling the on-off of the switching elements, the equalization of the battery pack is realized, the on-off frequency fs of the switches controlled by the controller is determined by lumped parameters R, L, C in the equalizing circuit, and the LC series circuit is ensured to work in a quasi-resonance state. Specifically, the controller sends out a PWM signal, after the switch is thrown high, the switch is controlled to be thrown low after a half PWM period, and the on-off of the switch device is completed in the PWM period, so that the LC series circuit works in a quasi-resonance state.
Further, in an embodiment, the balancing circuit includes a bottom balancing circuit and a top balancing circuit, and includes N series battery modules Mi, N bottom balancing modules Qi, 1 top balancing circuit, and 1 controller. Each battery module Mi contains 4 cells. Each bottom equalization module Qi comprises 4 bottom single-pole double-throw switches Si, 3 bottom LC series circuits. The top equalization circuit comprises N top single-pole double-throw switches Smi and (N-1) top LC series circuits. Each LC series circuit operates in a quasi-resonant state, reducing switching noise and electromagnetic interference (EMI).
The balance circuit realizes zero flow switching of the switch device, reduces the switching loss of the switch device, increases a balance path through modular balance, and is easy to expand. The invention improves the phenomenon of unbalance of the series battery pack and is suitable for the battery management system of the energy storage device in the electric automobile or the energy storage power station.
The equalizing circuit comprises bottom equalizing circuit, top layer equalizing circuit, and bottom equalizing circuit comprises N bottom equalizing module Qi (i 1,2,3 … N) series connection, and N bottom equalizing module Qi is responsible for the equilibrium between the battery monomer in battery module Mi, and 1 top layer equalizing circuit is responsible for the equilibrium between the battery module Mi, and when battery pack battery (battery module Mi) difference reached equalizing circuit operating requirement, each equalizing circuit began work. The switching devices in all the equalization circuits are connected with the controller, and the controller controls the energy transfer by controlling the on-off of the switching devices, so that the equalization of the battery pack is realized.
The bottom equalization circuit and the top equalization circuit both adopt the same equalization circuit based on an LC series circuit (LC series quasi-resonant circuit).
The bottom equalization module Qi comprises 4 batteries B1, B2, B3 and B4, 4 bottom single-pole double-throw switches S1, S2, S3 and S4, and 3 bottom LC series circuits C1-L1, C2-L2 and C3-L3. Each of the bottom single-pole double-throw switches Si includes three terminals Si _ a, Si _ b, and Si _ c (i ═ 1,2,3, and 4). Si _ a and Si _ b are the first static terminal and the second static terminal, and Si _ c is the select terminal. Si _ c selects contact with Si _ a or Si _ b according to the control signal. Si _ a is connected to the positive pole of battery Bi and Si _ b is connected to the negative pole of battery Bi. One end of the capacitor Ci is connected to the Si _ c, and the other end of the capacitor Ci is connected to the inductor Li; one end of the inductor Li is connected with Ci, and the other end of the inductor Li is connected with C (i +1) and S (i +1) _ C.
As shown in FIG. 3, the top equalization circuit comprises N battery modules M1, M2, … and MN, N top single-pole double-throw switches Sm1, Sm2, … and SmN, and (N-1) top LC series circuits Cm1-Lm1, … and Cm (N-1) -Lm (N-1). Wherein each top single-pole double-throw switch Smi comprises three terminals Smi _ a, Smi _ b, Smi _ c, wherein i is an integer greater than or equal to 1 and less than or equal to N. Smi _ a, Smi _ b, respectively, are first and second static terminals, Smi _ c select terminals. Smi _ c selects to contact Smi _ a or Smi _ b according to the control signal. Smi _ a is connected to the positive pole of the battery module Mi and Smi _ b is connected to the negative pole of the battery module Mi. The capacitor Cmi is connected to Smi _ c at one end and to the inductor Lmi at the other end. One end of the inductor Lmi is connected to the capacitor Cmi, and the other end is connected to the capacitors Cm (i +1) and Sm (i +1) _ c.
The notation (i +1) in the text is a number, and (i +1) indicates the value i plus 1; the symbol (N-1) is a number and (N-1) represents the value N minus 1.
The LC series circuit (LC series quasi-resonance circuit) is formed by connecting a capacitor C and an inductor L in series and works in a quasi-resonance state. Switching frequency f of equalizing circuitsThe LC series circuit is ensured to work in a quasi-resonant state according to the lumped parameter R, L, C in the equalization circuit, the current of the LC series circuit is reduced to zero at each switching moment, the switching loss is reduced, the equalization efficiency is improved, and the equalization time is reduced. The duty cycle of the control signal for the single pole double throw switch should be 50% to ensure that the inductor current is reduced to zero at each switching instant.
The batteries in the series battery module Mi (battery pack) may be secondary batteries, including any one of lithium ion batteries, lead acid batteries, super capacitors, or nickel metal hydride batteries.
In one embodiment, the single-pole double-throw switch is described with reference to fig. 5: an ith single pole double throw switch Si comprising: the first MOSFET and the second MOSFET take an N-channel device as an example; the source S of the first MOSFET is connected with the drain D of the second MOSFET, and each MOSFET has an anti-parallel diode. The drain D of the first MOSFET is a first contact terminal Si _ a of the single-pole double-throw switch Si, the source S of the second MOSFET is a second contact single Si _ b of the Si, and the connection point of the two MOSFETs is a selection terminal Si _ c of the Si. And the grids G of the two MOSFET tubes are respectively connected with a controller.
Further, in one embodiment, as shown in fig. 4, each bottom equalization module Qi includes: 1 battery module Mi, the battery module Mi (battery pack) is composed of 4 batteries B1, B2, B3, B4 connected in series, 4 bottom single-pole double-throw switches S1, S2, S3, S4 connected in series, 3 bottom LC series circuits C1-L1, C2-L2, C3-L3 connected in series, each bottom single-pole double-throw switch Si switch includes three terminals Si _ a, Si _ B, Si _ C (i ═ 1,2,3, 4); si _ a and Si _ b are respectively a first static terminal and a second static terminal, and Si _ c is a selection terminal;
the first unit of the bottom equalization module Qi is formed by connecting a capacitor C1 and an inductor L1(C1-L1) in series, one end of the capacitor C1 is connected with a selection terminal S1_ C of a bottom single-pole double-throw switch S1, and the other end of the capacitor C1 is connected with the inductor L1; the other end of the inductor L1, which is far away from the capacitor C1, is connected with the capacitor C2 and a selection terminal S2_ C of the bottom single-pole double-throw switch S2; the second static contact single S1_ B of the bottom single-pole double-throw switch S1 is connected with the negative electrode of the battery B1, and the first static contact terminal S1_ a of the bottom single-pole double-throw switch S1 is connected with the positive electrode of the battery B1 and the second static contact single S2_ B of the bottom single-pole double-throw switch S2;
the second unit of the bottom equalization module Qi is formed by connecting a capacitor C2 and an inductor L2(C2-L2) in series, one end of the capacitor C2 is connected with a selection terminal S2_ C and an inductor L1, and the other end of the capacitor C2 is connected with the inductor L2; the other end of the inductor L2, which is far away from the capacitor C2, is connected with the selection terminal S3_ C and the capacitor C3; the second static contact single S2_ B of the bottom single-pole double-throw switch S2 is connected with the negative electrode of the battery B2, and the first static contact terminal S2_ a of the bottom single-pole double-throw switch S2 is connected with the positive electrode of the battery B2 and the second static contact single S3_ B of the bottom single-pole double-throw switch S3;
the third unit of the bottom equalization module Qi is formed by connecting a capacitor C3 and an inductor L3(C3-L3) in series, one end of the capacitor C3 is connected with a selection terminal S3_ C and an inductor L2, and the other end of the capacitor C3 is connected with the inductor L3; the other end of the inductor L3 far away from the capacitor C3 is connected with a selection terminal S4_ C; the second static contact single S4_ B of the bottom single-pole double-throw switch S4 is connected with the negative electrode of the battery B4, and the first static contact terminal S4_ a is connected with the positive electrode of the battery B4; the second static contact unit S3_ B is connected with the negative electrode of the battery B3, and the first static contact terminal S3_ a is connected with the positive electrode of the battery B3;
and the selection terminals Sic of all the bottom single-pole double-throw switches Si are respectively connected with the controller.
The controller sends a control signal to the single-pole double-throw switch Si for controlling the connection of Si _ c and Si _ a or Si _ b. The driving signals of the two MOSFET tubes are a pair of complementary unipolar rectangular wave signals.
When the MOSFET is selected to have different channels, the effect of the single-pole double-throw switch can also be achieved, and the details are not repeated here.
The energy storage advantages and principles of the LC series circuit during equalization are described below.
The LC series circuit (LC series equalization circuit) exhibits quasi-resonant characteristics during operation. With this circuit design, the current flowing into or out of the capacitor will change from zero at the instant the single pole double throw switch row switches state, thereby helping to reduce switching noise and EMI to provide a quality of operation for the circuit. In addition, in the implementation process, the selected inductor 106 may be a conventional small-sized inductor, which does not cause the equalization circuit to have an excessively large size.
The circuit voltage equalization process is described below. Take the first battery module M1 and the bottom equalization module Q1 as an example.
First, referring to fig. 6, when 4 bottom single-pole double-throw switches Si are all controlled by the controller to throw high (i.e. Si _ C of any switch is connected to Si _ a), 3 bottom LC series circuits Ci-Li are coupled to the battery B (i +1) corresponding to the previous bit and connected in parallel, specifically, the bottom LC series circuit C1-L1 is connected in parallel to the battery B2, C2-L2 is connected in parallel to the battery B3, and C3-L3 is connected in parallel to the battery B4, so that each bottom LC series circuit Ci-Li exchanges energy with the battery B (i +1) connected in parallel thereto, and the bottom LC series circuit Ci-Li is either charged or discharged to the previous battery B (i + 1).
Then, referring to fig. 7, when the 4 bottom single-pole double-throw switches Si are controlled to be thrown low by the controller (i.e. Si _ C of any switch is connected to Si _ B), 3 bottom LC series circuits Ci-Li are coupled to the battery Bi corresponding to the current position in parallel, specifically, the bottom LC series circuits C1-L1 are connected in parallel to the battery B1, C2-L2 are connected in parallel to the battery B2, and C3-L3 is connected in parallel to the battery B3, so that each LC series circuit Ci-Li exchanges energy with the battery Bi connected in parallel thereto, and the LC series circuits Ci-Li are either charged or discharged to the battery Bi.
All switches are repeatedly thrown high and low with the same time interval each time. The method can realize that all the battery voltages tend to be consistent, and realize the effect of battery equalization.
During the above-described alternate switching, the energy of the high-voltage battery can be transferred to the low-voltage battery. For example, when the voltage of battery B3 is higher than the voltage of battery B1, in the operating state as shown in fig. 6, charge will flow from battery B2-B3 to capacitors C1 and C2; further, the equalization circuit switches to the operating state shown in fig. 7, and an equal amount of charge is discharged from the capacitors C1 and C2 to the battery packs B1-B2. The amount of charge flowing into and out of cell B2 is the same throughout the charge transfer process, i.e., charge is actually transferred directly from cell B3 to cell B1; similarly, when the voltage of battery B1 is higher than the voltage of battery B3, charge is transferred from battery B1 to battery B3 through capacitors C1 and C2 when the two operating states shown in fig. 6 and 7 are alternated. This effectively means that the two capacitors C1 and C2 provide a path between the batteries B1 and B3 that can be used to transfer charge directly. Similarly, capacitor C1 provides a direct charge transfer path between batteries B1 and B2. Capacitor C2 provides a direct charge transfer path between batteries B2 and B3. Capacitor C4 provides a direct charge transfer path between batteries B3 and B4. And so on. That is, there is a path for direct transfer of charge between every two cells.
When voltage inconsistency occurs between the battery modules Mi, the specific working principle and the specific working method of the battery modules Mi are the same as those of the balancing method between the bottom layer batteries Bi, and the balancing method between the bottom layer batteries Bi is known. Are not described in detail.
The series battery pack is formed by connecting N battery modules Mi in series, and each battery module Mi is formed by connecting 4 single batteries in series. The N bottom equalization modules Qi are responsible for equalization among the battery monomers in the battery module Mi, the 1 top equalization circuit is responsible for equalization among the battery modules Mi, and when the battery difference of the battery modules Mi (battery pack) reaches the working requirement of the equalization circuits, the equalization circuits start to work. The switching devices in all the equalization circuits are connected with a controller (control circuit), and the energy transfer is controlled by controlling the on-off of the switching devices, so that the equalization of the battery pack is realized. The bottom equalization circuit and the top equalization circuit both adopt the same equalization circuit based on the LC series quasi-resonance circuit.
In the specific implementation process, due to the characteristics of the circuit, the expansion of the equalization circuit can be easily realized, and the number of the equalization modules at the bottom layer can be increased or the number of the single batteries in the battery module can be directly increased. The voltage of the battery monomer can be measured, and then the on-off of the corresponding switch is controlled in a targeted mode, so that the balancing efficiency is improved.
The above-mentioned embodiments only express one embodiment of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (5)
1. A modularized equalizing circuit is characterized by comprising a battery module, an equalizing circuit and a controller, wherein the controller is connected with the equalizing circuit and controls the equalizing circuit to equalize the battery module;
the equalizing circuit comprises a bottom equalizing circuit and a top equalizing circuit;
the bottom equalization circuit is formed by connecting N bottom equalization modules Qi (i is 1,2,3 … N) in series, each bottom equalization module Qi comprises 1 battery module Mi, 4 bottom single-pole double-throw switches Si (i is 1,2,3,4) connected in series, and 3 bottom LC series circuits Ci-Li (i is 1,2,3) connected in series; each single-pole double-throw switch Si comprises three terminals Si _ a, Si _ b, Si _ c (i ═ 1,2,3, 4); si _ a and Si _ b are respectively a first static terminal and a second static terminal, and Si _ c is a selection terminal; the battery module Mi is formed by connecting 4 batteries Bi (i is 1,2,3,4) in series;
si _ c selects to contact with Si _ a or Si _ b according to the control signal; the first static terminal Si _ a (i ═ 1,2,3,4) is connected to the positive pole of the battery Bi (i ═ 1,2,3,4), and the second static terminal Si _ b is connected to the negative pole of the battery Bi; one end of the capacitor Ci is connected with the selection terminal Si _ c, and the other end of the capacitor Ci is connected with the inductor Li; one end of an inductor Li is connected with Ci, and the other end of the inductor Li is connected with a capacitor C (i +1) and a selection terminal S (i +1) _ C;
the top-layer balancing circuit comprises N battery modules Mi (i is 1,2, … N) connected in series, N top-layer single-pole double-throw switches Smi (i is 1,2, … N) connected in series, and N-1 top-layer LC series circuits Cmi-Lmi (i is 1), … and Cmi-Lmi (i is N-1) connected in series, and is used for balancing among the battery modules Mi, the top-layer LC series circuits are connected in series, and each top-layer LC series circuit is arranged among the top-layer single-pole double-throw switches Smi; each top single-pole double-throw switch Smi comprises three terminals Smi _ a, Smi _ b and Smi _ c; the terminals Smi _ a and Smi _ b are respectively a first static terminal and a second static terminal, and Smi _ c is a selection terminal; smi _ c selects to contact Smi _ a or Smi _ b according to the control signal; smi _ a is connected with the positive electrode of the battery module Mi, Smi _ b is connected with the negative electrode of the battery module Mi, one end of a capacitor Cmi is connected with Smi _ c, and the other end of the capacitor Cmi is connected with an inductor Lmi; one end of the inductor Lmi is connected with the capacitor Cmi, and the other end of the inductor Lmi is connected with the capacitor Cm (i +1) and the selection terminal Sm (i +1) _ c; sm (i +1) _ a is connected with the positive electrode of the battery module M (i +1), Sm (i +1) _ b is connected with the negative electrode of the battery module M (i +1) and Smi _ a, and the negative electrode of the battery module M (i +1) is connected with the positive electrode of the battery module Mi;
the terminal Smi _ b is connected with Si _ b (i is 1) of the bottom equalization module Qi, and Smi _ a is connected with Si _ a (i is 4) of the bottom equalization module Qi; sm (i +1) _ b is connected with Si _ b (i ═ 1) of the bottom equalization module Q (i +1), and Sm (i +1) _ a is connected with Si _ a (i ═ 4) of the bottom equalization module Q (i + 1); si _ a (i ═ 4) of the bottom equalization module Qi is connected to Si _ b (i ═ 1) of the bottom equalization module Q (i + 1);
the bottom LC series circuit and the top LC series circuit are both formed by connecting an inductor L and a capacitor C in series; the N battery modules Mi (i is 1,2,3 … N) of the bottom equalization circuit are connected in series and used for equalization among the battery cells in the battery modules Mi;
the battery modules Mi (i is 1,2,3 … N) of the bottom equalization circuit are N, each battery module Mi is formed by connecting 4 single batteries Bi (i is 1,2,3,4) in series and serves as a main body to be equalized, the N battery modules Mi are connected in series and then connected into the bottom equalization circuit to form a bottom equalization module Qi (i is 1,2,3 … N), and the bottom equalization module Qi (i is 1,2,3 … N) is connected in series and then connected into the top equalization circuit;
the bottom equalization circuit and the top equalization circuit both adopt the same equalization circuit based on an LC series circuit;
the LC series circuit is formed by connecting a capacitor C and an inductor L in series and works in a quasi-resonance state; the switching devices in all the equalization circuits are connected with the controller, and the controller controls the energy transfer by controlling the on-off of the switching devices, so that the equalization of the battery pack is realized; the LC series circuit presents a quasi-resonance characteristic in the working process, and the current flowing into or out of the capacitor changes from zero at the moment of switching the state of the single-pole double-throw switch, so that the switching noise and EMI (electro-magnetic interference) are reduced to provide the working quality of the circuit;
the duty ratio of a control signal of the single-pole double-throw switch is 50% so as to ensure that the inductive current is reduced to zero at each switching moment; the controller is connected with all the single-pole double-throw switches in the equalizing circuit, the energy transfer is controlled by controlling the on-off of the single-pole double-throw switches, the equalization of the battery pack is realized, the on-off frequency fs of the single-pole double-throw switches controlled by the controller is determined by lumped parameters R, L, C in the equalizing circuit, the LC series circuit is ensured to work in a quasi-resonance state, the current of the LC series circuit is reduced to zero at each switching moment, the switching loss is reduced, the equalizing efficiency is improved, and the equalizing time is shortened; the controller sends out PWM signals, after the switch is thrown to be high, the switch is controlled to be thrown to be low after a half PWM period, the on-off of the switch device is completed in the PWM period, and the LC series circuit works in a quasi-resonance state.
2. A modular equalization circuit according to claim 1, characterized in that the bottom spdt switch Si and the top spdt switch Smi are both formed by two MOSFET tubes connected in series, the source S of the first MOSFET tube is connected to the drain D of the second MOSFET tube, each MOSFET tube has an anti-parallel diode, the drain D of the first MOSFET tube is the first static terminal Si _ a of the spdt switch Si, the source S of the second MOSFET tube is the second static terminal Si _ b of the spdt switch Si, and the connection point of the two MOSFET tubes is the select terminal Si _ c of the spdt switch Si; the grid G of the first MOSFET and the grid G of the second MOSFET are respectively connected with a controller, and the controller controls Si _ c to be connected with Si _ a or Si _ b;
the top single-pole double-throw switch Smi and the bottom single-pole double-throw switch Si are connected in the same mode, and the top single-pole double-throw switch Smi is provided with a first static terminal Smi _ a, a second static terminal Smi _ b and a selection terminal Smi _ c.
3. A modular equalization circuit as claimed in claim 1, characterized in that the first unit of the bottom equalization module Qi is formed by a capacitor Ci (i-1) connected in series with an inductor Li (i-1), one end of the capacitor Ci (i-1) being connected to a selection terminal Si _ c (i-1) of a bottom single-pole double-throw switch Si (i-1), and the other end of the capacitor Ci (i-1) being connected to the inductor Li (i-1); the other end of the inductor Li (i ═ 1) far from the capacitor Ci (i ═ 1) is connected with the capacitor Ci (i ═ 2) and a selection terminal Si _ c (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2); a second static contact single-son Si _ b (i ═ 1) of the bottom layer single-pole double-throw switch Si (i ═ 1) is connected with the negative electrode of the battery Bi (i ═ 1), and a first static contact terminal Si _ a (i ═ 1) of the bottom layer single-pole double-throw switch Si (i ═ 1) is connected with the positive electrode of the battery Bi (i ═ 1) and a second static contact single-son Si _ b (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2);
the second unit of the bottom equalization module Qi is formed by connecting a capacitor Ci (i ═ 2) and an inductor Li (i ═ 2) in series, one end of the capacitor Ci (i ═ 2) is connected with a selection terminal Si _ c (i ═ 2) and the inductor Li (i ═ 1), and the other end of the capacitor Ci (i ═ 2) is connected with the inductor Li (i ═ 2); the other end of the inductor Li (i ═ 2) remote from the capacitor Ci (i ═ 2) is connected to the selection terminal Si _ c (i ═ 3) and the capacitor Ci (i ═ 3); a second static contact single-son Si _ b (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2) is connected with the negative electrode of the battery Bi (i ═ 2), and a first static contact terminal Si _ a (i ═ 2) of the bottom layer single-pole double-throw switch Si (i ═ 2) is connected with the positive electrode of the battery Bi (i ═ 2) and the second static contact single-son Si _ b (i ═ 3) of the bottom layer single-pole double-throw switch Si (i ═ 3);
the third unit of the bottom equalization module Qi is formed by connecting a capacitor Ci (i ═ 3) and an inductor Li (i ═ 3) in series, one end of the capacitor Ci (i ═ 3) is connected with the selection terminal Si _ c (i ═ 3) and the inductor Li (i ═ 2), and the other end of the capacitor Ci (i ═ 3) is connected with the inductor Li (i ═ 3); the other end of the inductor Li (i ═ 3) remote from the capacitor Ci (i ═ 3) is connected to a selection terminal Si _ c (i ═ 4); a second static contact single-pole-double-throw (i-4) of the bottom layer single-pole-double-throw switch Si (i-4) is connected with the negative electrode of the battery Bi (i-4), and a first static contact terminal Si _ a (i-4) is connected with the positive electrode of the battery Bi (i-4); the second static contact unit Si _ b (i ═ 3) is connected with the negative electrode of the battery Bi (i ═ 3), and the first static contact terminal Si _ a (i ═ 3) is connected with the positive electrode of the battery Bi (i ═ 3);
the selective terminals Sic of all the bottom single-pole double-throw switches Si are respectively connected with the controller;
the controller sends a control signal to the single-pole double-throw switch Si, and the control signal is used for controlling connection of Si _ c and Si _ a or Si _ b; the driving signals of the two MOSFET tubes are a pair of complementary unipolar rectangular wave signals.
4. A method for equalizing a modular equalization circuit according to any of claims 1 to 3, characterized in that the method comprises the following steps:
the 4 bottom single-pole double-throw switches Si of the bottom equalization module Qi are all controlled by a controller to throw high, namely Si _ c of any switch is connected with Si _ a, 3 bottom LC series circuits Ci-Li are coupled to a battery B (i +1) corresponding to an upper position and connected in parallel, each bottom LC series circuit Ci-Li and the battery B (i +1) connected in parallel carry out energy exchange, and the bottom LC series circuits Ci-Li are charged or discharged to the battery B (i + 1);
the 4 bottom single-pole double-throw switches Si of the bottom equalization module Qi are all controlled by a controller to be thrown low, namely Si _ c of any switch is connected with Si _ b, 3 bottom LC series circuits Ci-Li are coupled to batteries Bi corresponding to the current position and connected in parallel, each LC series circuit Ci-Li exchanges energy with the batteries Bi connected in parallel, and the LC series circuits Ci-Li are charged or discharged to the batteries Bi;
repeatedly throwing all the switches high and low, and the time intervals are the same each time, so that the voltage of all the batteries Bi tends to be consistent, the internal balance effect of the battery module Mi is realized, and the internal battery balance of the battery module Mi is realized by the bottom layer balancing module Qi;
when voltage inconsistency occurs among the battery modules Mi, in the top-layer balancing circuit, the controller controls the N top-layer single-pole double-throw switches Smi (i is 1,2,3 … N) to be thrown high or low repeatedly, time intervals at each time are the same, voltage of all the battery modules Mi tends to be consistent, a specific working method is the same as a balancing method among the bottom-layer batteries Bi, and voltage balancing among the battery modules Mi is achieved.
5. The equalizing method for a modular equalizing circuit according to claim 4, characterized in that the method is as follows:
firstly, when 4 bottom single-pole double-throw switches Si are all controlled by the controller to throw high, i.e. Si _ c of any switch is connected to Si _ a, 3 bottom LC series circuits Ci-Li are coupled to and connected in parallel with the battery B (i +1) corresponding to the previous bit, specifically, the bottom LC series circuits Ci-Li (i ═ 1) are connected in parallel with the battery Bi (i ═ 2), Ci-Li (i ═ 2) are connected in parallel with the battery Bi (i ═ 3), Ci-Li (i ═ 3) are connected in parallel with the battery Bi (i ═ 4), and then each bottom LC series circuit Ci-Li exchanges energy with the battery B (i +1) connected in parallel therewith, and the bottom LC series circuits Ci-Li are either charged or discharged to the previous battery B (i + 1);
then, when the 4 bottom single-pole double-throw switches Si are controlled to be thrown low by the controller, that is, Si _ c of any switch is connected to Si _ b, 3 bottom LC series circuits Ci-Li are coupled to the battery Bi corresponding to the current position in parallel, the bottom LC series circuit Ci-Li (i ═ 1) is connected to the battery Bi (i ═ 1) in parallel, Ci-Li (i ═ 2) is connected to the battery Bi (i ═ 2) in parallel, and Ci-Li (i ═ 3) is connected to the battery Bi (i ═ 3) in parallel, and each LC series circuit Ci-Li exchanges energy with the battery Bi connected in parallel, and the LC series circuits Ci-Li are either charged or discharged to the battery Bi;
repeatedly throwing all the switches to be high and low, and the time intervals are the same each time; the voltage of all the batteries tends to be consistent, and the effect of battery equalization is realized;
during the alternating switching, the energy of the high-voltage battery can be transferred to the low-voltage battery; when the voltage of battery Bi (i ═ 3) is higher than the voltage of battery Bi (i ═ 1), charge will flow from the battery pack Bi (i ═ 2) -Bi (i ═ 3) to the capacitances Ci (i ═ 1) and Ci (i ═ 2); in the balancing process, under the working state that the switch of the bottom balancing module is thrown low, equal charges are released from the capacitors Ci (i is equal to 1) and Ci (i is equal to 2) to the battery pack Bi (i is equal to 1) -Bi (i is equal to 2); the charge amount flowing into and out of the battery Bi (i-2) is the same in the whole process of charge transfer, and the charge is actually directly transferred from the battery Bi (i-3) to the battery Bi (i-1);
similarly, when the voltage of the battery Bi (i ═ 1) is higher than that of the battery Bi (i ═ 3), when two operating states of the bottom equalization module switch high and the bottom equalization module switch low are alternately performed in the equalization process, the charge is transferred from the battery Bi (i ═ 1) to the battery Bi (i ═ 3) through the capacitors Ci (i ═ 1) and Ci (i ═ 2); the two capacitors Ci (i ═ 1) and Ci (i ═ 2) provide a path between the batteries Bi (i ═ 1) and Bi (i ═ 3) that can be used to transfer charge directly; the capacitor Ci (i ═ 1) provides a direct charge transfer path between the batteries Bi (i ═ 1) and Bi (i ═ 2); the capacitor Ci (i-2) provides a direct charge transfer path between the batteries Bi (i-2) and Bi (i-3); the capacitor Ci (i-4) provides a direct charge transfer path between the batteries Bi (i-3) and Bi (i-4); a path for directly transferring charge is arranged between every two batteries;
when voltage inconsistency occurs among the battery modules Mi, the specific working principle and the specific working method of the battery modules Mi are the same as those of the balancing method among the bottom layer batteries Bi, and the balancing is realized through the balancing among the bottom layer batteries Bi.
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| CN110707783B (en) * | 2019-10-31 | 2023-01-17 | 上海科技大学 | Compound level battery equalizer circuit based on LLC and Buck-Boost |
| CN111204259A (en) * | 2020-02-26 | 2020-05-29 | 潍柴动力股份有限公司 | Battery equalization circuit and battery management method |
| IL276933A (en) * | 2020-08-25 | 2022-03-01 | Irp Nexus Group Ltd | Advanced battery management system (bms) for charge equalization of serially connected electrical storage cells |
| CN113162159B (en) * | 2021-04-07 | 2022-07-26 | 华南理工大学 | Improved Cell-to-Cell battery equalization circuit based on LC resonance circuit and implementation method |
| CN113315202A (en) * | 2021-06-07 | 2021-08-27 | 傲普(上海)新能源有限公司 | Battery pack equalization circuit and control method thereof |
| CN113725975B (en) * | 2021-09-03 | 2023-09-26 | 傲普(上海)新能源有限公司 | Double-layer capacitance resistance battery equalization circuit |
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| CN204118209U (en) * | 2014-06-25 | 2015-01-21 | 太原奥深华电气设备制造有限公司 | Series battery feasible type capacitive equalizer |
| CN105576719B (en) * | 2014-10-08 | 2018-12-11 | 香港理工大学 | A kind of voltage balance circuit |
| CN105609887B (en) * | 2016-01-08 | 2018-06-26 | 南京航空航天大学 | Layer-stepping equalizing circuit system and mixing control method based on series battery |
| CN106786880B (en) * | 2016-12-21 | 2023-06-20 | 华南理工大学 | Novel layering equalization circuit |
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2017
- 2017-12-08 CN CN201711298800.6A patent/CN108134414B/en active Active
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