CN114628763A - Lithium battery grouping method for reducing parallel connection circulation current and bias current - Google Patents
Lithium battery grouping method for reducing parallel connection circulation current and bias current Download PDFInfo
- Publication number
- CN114628763A CN114628763A CN202210211041.XA CN202210211041A CN114628763A CN 114628763 A CN114628763 A CN 114628763A CN 202210211041 A CN202210211041 A CN 202210211041A CN 114628763 A CN114628763 A CN 114628763A
- Authority
- CN
- China
- Prior art keywords
- lithium battery
- parallel
- current
- lithium
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/04—Construction or manufacture in general
- H01M10/0404—Machines for assembling batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
- H01M50/507—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing comprising an arrangement of two or more busbars within a container structure, e.g. busbar modules
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/50—Current conducting connections for cells or batteries
- H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
- H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a lithium battery grouping method for reducing parallel loop current and bias current, which comprises the following steps: s1, carrying out series-parallel connection on lithium batteries to establish a series-parallel circuit model; s2, establishing a grouped circuit according to the obtained series-parallel circuit model, including: the single lithium battery or the serial parts of a plurality of lithium batteries in the model are connected by adopting a confluence piece, and the parallel connection in the model is welded by adopting a voltage-sharing connecting line. The lithium battery pack provided by the invention is beneficial to prolonging the service life, the charging and discharging efficiency and the safety of the lithium battery pack.
Description
Technical Field
The invention relates to the technical field of new energy lithium battery application, in particular to a lithium battery grouping method for reducing parallel circulation and bias current.
Background
With the rapid development of lithium battery technology, lithium batteries are beginning to be applied in industries such as new energy vehicles and energy storage on a large scale. In order to improve the energy storage capacity of the lithium battery pack, a method of connecting single lithium batteries in series and in parallel is commonly adopted in the industry to improve the voltage and current capacity of the lithium battery pack. In practical use, the grouping method can cause circulation and bias current between the parallel single lithium batteries. Due to the existence of circulation and bias current, particularly circulation with large amplitude, reactive charge-discharge circulation, electric quantity loss and heat collection among the parallel single lithium batteries can be caused, so that the problems of the lithium battery pack, such as the reduction of service life, the reduction of charge-discharge efficiency, the reduction of safety and the like, are caused.
In the prior art, a processing method aiming at the problems of the lithium battery pack, such as the reduction of the service life, the reduction of the charging and discharging efficiency, the reduction of the safety and the like, caused by the bias current and the circulation generated by the parallel connection of the single lithium batteries in the lithium battery pack and the inconsistency of the capacity, the internal resistance temperature and the like is a passive intervention method. Specifically, when the BMS in the lithium battery pack finds that the capacity and the voltage are inconsistent, active or passive equalization is carried out, and the inconsistent phenomenon is forcibly eliminated. The disadvantage is that the generation of bias current and circulation current cannot be fundamentally prevented or eliminated, so that the generation of inconsistency cannot be prevented or eliminated; the second disadvantage is that the equalization treatment, especially the passive equalization treatment, causes electric quantity loss and heat aggregation; the third disadvantage is that equalization treatment, especially active equalization treatment of large current, can cause the inconsistency of SoH of the lithium battery to be aggravated and the service life of the lithium battery pack to be reduced.
Disclosure of Invention
Aiming at the defects, the invention adopts an active prevention method to prevent the occurrence of circulation and bias current between the lithium batteries connected in parallel and improve the consistency of the capacity, the internal resistance and the temperature between the lithium batteries connected in parallel in the lithium battery pack, thereby solving the problems from the root. The invention aims to provide a lithium battery grouping method for reducing parallel circulation and bias current.
The purpose of the invention is realized by adopting the following technical scheme:
the invention provides a lithium battery grouping method for reducing parallel loop current and bias current, which comprises the following steps:
s1, carrying out series-parallel connection on lithium batteries to establish a series-parallel circuit model;
s2, establishing a grouped circuit according to the obtained series-parallel circuit model, including: the single lithium battery or the serial parts of a plurality of lithium batteries in the model are connected by adopting a bus sheet, and the parallel connection in the model is welded by adopting a voltage-sharing connecting line.
In one embodiment, the equalizer is made of nickel-plated steel strip, nickel-plated steel wire, nickel-plated copper strip, nickel-plated aluminum strip, or the like.
In one embodiment, the proportionality coefficient of the equalizing line resistance and the direct-current internal resistance of the lithium battery is k, and the formula is as follows:
k＝Rca/Rc
wherein R iscaIs a voltage equalizing line resistor, RcThe direct current internal resistance of the lithium battery.
In one embodiment, the value range of the proportionality coefficient k between the voltage-equalizing line resistor and the direct-current internal resistance of the lithium battery is as follows: [0,1000].
In one embodiment, the junction between the current collector and the voltage equalizer is completed by an integrally formed processing technology.
In one embodiment, the lithium battery busbar and the equalizing line are processed in a split mode, and the connection is completed through a processing and assembling process of combined welding and installation.
In one embodiment, lithium batteries are connected in series and parallel to form a series-parallel circuit model, wherein the series-parallel circuit model comprises one or more parallel lithium battery groups, and the positive electrode and the negative electrode of each lithium battery in each parallel lithium battery group are connected in parallel; a plurality of lithium battery parallel groups are connected in series to form a series-parallel circuit model.
In one embodiment, the positive electrode or the negative electrode of each lithium battery in each lithium battery parallel group is connected by a voltage-sharing connecting wire.
In one embodiment, in the parallel group of lithium batteries, the positive electrode of the nth lithium battery is connected with the negative electrode of the nth lithium battery in the previous parallel group of lithium batteries; the negative electrode of the nth lithium battery is connected with the positive electrode of the nth lithium battery in the next parallel group of lithium batteries.
In one embodiment, the lithium battery in the series-parallel circuit model is equivalent to an equivalent model in which a voltage source and an internal resistance are connected in series;
in one embodiment, an external equivalent circuit model of a lithium battery includes: lithium batteryRated capacity C of the poolcapEquilibrium electromotive force EMF of lithium battery, hysteresis voltage V of lithium batteryhResidual electric quantity V of lithium batterySOCRated capacity C of lithium batterycapCurrent I flowing through the lithium batteryBAnd voltage VBAdjustable inductance LhOhmic internal resistance R of lithium batteryΩOhmic polarization internal resistance R of lithium batterysElectrochemical polarization internal resistance R of lithium batterymConcentration difference polarization internal resistance R of lithium batteryfOhmic polarization capacitance C of lithium batterySElectrochemical polarization capacitance C of lithium batterymConcentration difference polarization capacitance C of lithium batteryf；
Wherein the voltage V of the lithium batteryBThe positive electrode is connected with concentration difference polarization internal resistance RfElectrochemical polarization internal resistance RmOhmic polarization internal resistance RsOhmic internal resistance RΩHysteresis voltage VhAnd balancing the electromotive force EMF with the voltage V of the lithium batteryBThe negative electrode of (1) is connected; wherein the concentration difference polarizes the capacitance CfPolarization internal resistance R with concentration differencefParallel, electrochemically polarized capacitance CmAnd electrochemical polarization internal resistance RmParallel ohmic polarized capacitor CSAnd ohmic polarization internal resistance RsParallel connection;
wherein rated capacity CcapPositive electrode and residual electric quantity VSOCThe anode is connected with the voltage V of the lithium batteryBThe negative electrode of (1) is connected; current IBTo rated capacity CcapParallel adjustable inductance LhPositive pole and voltage VhThe anode is connected with the voltage V of the lithium batteryBIs connected to the negative electrode of the anode, and the current beta IBAnd an adjustable inductance LhAre connected in parallel.
The invention has the beneficial effects that: the invention provides a grouping method for reducing parallel connection circulation and bias current for grouping lithium battery packs. The method adopts the shunt principle of the parallel circuit to control the circulation and bias current between the parallel single lithium batteries, can effectively reduce the circulation and bias current between the parallel single lithium batteries while ensuring the voltage balance of the parallel single lithium batteries, controls the circulation to the extent of having no influence on the service life of the lithium batteries, reduces the electric quantity loss, reduces heat aggregation, improves the consistency of the capacity, the internal resistance and the temperature between the parallel lithium batteries, thereby improving the service life, the safety and the charging and discharging efficiency of the lithium battery pack.
Drawings
The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be obtained on the basis of the following drawings without inventive effort.
FIG. 1 is a schematic diagram of an accurate equivalent circuit model of a lithium battery according to the present invention;
FIG. 2 is a simplified equivalent circuit diagram of a lithium battery according to the present invention;
FIG. 3 is a schematic diagram of a parallel equivalent circuit of a lithium battery according to the present invention;
FIG. 4 is a schematic diagram of a series-parallel equivalent circuit of a lithium battery according to the present invention;
FIG. 5 is a schematic diagram of a current bias phenomenon of a parallel lithium battery according to the present invention;
FIG. 6 is a schematic diagram illustrating the generation of the circulation phenomenon according to the present invention;
FIG. 7 is a schematic diagram of the system of the present invention;
FIG. 8 is a schematic view of an exemplary combination of the present invention;
FIG. 9 is a schematic diagram of the voltage equalizing line and the voltage equalizing effect of the present invention;
FIG. 10 is a schematic diagram of the system connection of the present invention;
FIG. 11 is a schematic view of an integrated structure of the equalizing line and the bus bar according to the present invention;
FIG. 12 is a schematic view of a process for assembling an equalizing line and a bus bar according to the present invention.
Detailed Description
The invention is further described in connection with the following application scenarios.
The design idea of the invention comprises:
1. lithium battery equivalent circuit model
The method has the advantages that the accurate model of the lithium battery can be built by integrating the factors such as terminal voltage, working current, SoC, temperature, internal resistance, electromotive force and SoH of the lithium battery, the model of the lithium battery is built as shown in figure 1, the model of the lithium battery belongs to an external characteristic model, the equivalent model has strong practicability, various states of the lithium battery in the working process can be estimated through the built model, and therefore model basis can be provided for management control of various lithium batteries.
The potential characteristic and the impedance characteristic are comprehensively considered, and when bias current and circulation current of the lithium batteries connected in parallel are analyzed, an equivalent model formed by connecting a voltage source and internal resistance in series is adopted, as shown in fig. 2.
According to the above analysis, the parallel equivalent circuit diagram of the lithium battery is shown in fig. 3.
An equivalent circuit diagram of series-parallel connection of lithium batteries is shown in fig. 4.
2. Bias and circulation flow analysis
According to Thevenin's theorem, it is equivalent to a single lithium battery as a voltage source and its internal resistance connected in series. From a voltage point of view, the internal resistance can be understood as an additional load in series with the load, which has a voltage dividing effect with the load. This means that the higher the internal resistance, the lower the voltage across the load. The internal resistance increases the resistance value in the whole circuit and reduces the current output by the power supply. For external loads, the output power of the power supply is actually reduced, i.e., the load capacity of the power supply is reduced. Since the internal resistance is equivalent to the resistance connected in series in the circuit, the current output by the power supply also flows through the internal resistance, a voltage drop is formed on the internal resistance, the power consumed by the internal resistance is ineffective and harmful for the power supply, and the generated heat causes the temperature inside the power supply to rise and even causes the power supply to be damaged.
For a plurality of parallel lithium batteries, when the internal resistances of the parallel lithium batteries are inconsistent in the application process, the lithium batteries with small internal resistances will flow larger current for the lithium batteries connected in parallel, as shown in fig. 5, the lithium batteries V1 to V6 represent batteries with smaller internal resistances, and more current will flow.
When the internal resistances of the lithium batteries are inconsistent in the application process, for the lithium batteries connected in parallel, a bias current phenomenon that the lithium batteries with small internal resistances flow larger current will occur, and when a large current flows (especially when the SoC is low), a circulation current phenomenon is generated at the same time, that is, circulation currents of mutual charging and discharging of the lithium batteries connected in parallel will occur, as shown in fig. 6.
By adopting a branch current method, an equation set is respectively listed for a node and a loop by applying Kirchhoff Current Law (KCL) and voltage law, and each branch current is solved. Taking discharge as an example, IB is the module external discharge current, I1 is the 1 st series branch discharge current, I2 is the 2 nd series branch discharge current, I3 is the 3 rd series branch discharge current, I4 is the 4 th series branch discharge current, In is the nth series branch discharge current, I1a, I1b are the circulating current and the bias current of batteries V1 and V2, and the following conclusions can be drawn through calculation and simulation data:
1)IB＝I1+I2+I3+I4+···+In
2) the branch circuit currents I1, I2 and I3 … In are related to the voltage and the internal resistance of each single lithium battery of the branch circuit.
3) The higher the internal resistance of the single lithium battery of the branch circuit is, the lower the output current of the branch circuit is.
4) The current of the single loop among the branches is related to the voltage difference of the single lithium battery.
Based on the above concept, the current limiting design principle of the present invention is as follows:
in order to eliminate or reduce the circulation and bias current between the parallel lithium batteries, the design of the invention starts from the aspects of reducing the total pressure difference between the parallel branches, reducing the monomer voltage difference of the adjacent equipotential lithium batteries of the parallel branches, reducing the ratio of the internal resistance and the balanced current-limiting resistance, and the like, wherein the system schematic diagram of the invention is shown in fig. 7.
The traditional combination modes include a mode of serial-to-parallel connection first, a mode of serial-to-parallel connection first and a mode of serial-to-parallel connection and serial-to-parallel mixed connection, and as shown in fig. 8, different combination modes have advantages and disadvantages respectively.
The combination mode of the invention is developed on the basis of series-parallel mixed connection, and effectively solves the problem of bias current circulation generated by the traditional mixed connection. Different from the traditional mixed connection mode, the traditional serial-parallel mixed connection mode has no equalizing line. The key factor of the balanced current limiting is the proportional relation between the resistance value of the voltage equalizing line and the internal resistance value of the lithium battery, which is determined by the parameters of the material, the line diameter and the like of the voltage equalizing line. The parallel connection in the module is welded by adopting voltage-sharing connecting wires, so that the module plays a role in balancing and limiting current, and the proportional coefficient of the resistivity of the voltage-sharing wires and the internal resistance of the lithium battery is k as shown in figure 9. On the other hand, the voltage balance between the modules is also considered in the design of the standardized module, and a voltage balance interface is added, so that the consistency of the voltage and the total pressure of the battery monomer between the modules connected in parallel can be effectively guaranteed.
The system connection diagram is shown in fig. 10.
Based on the design principle, the application specifically provides a lithium battery grouping method for reducing parallel connection loop current and bias current, which comprises the following steps:
1) the lithium battery is equivalent to synthesize the factors of terminal voltage, working current, SoC, temperature, internal resistance, electromotive force, SoH and the like of the lithium battery, and an external characteristic model of the lithium battery is established, wherein the external characteristic model of the lithium battery is mainly used for obtaining the parameters of the terminal voltage, the working current and the internal resistance. Various states of the lithium battery in the working process are estimated, so that model basis can be provided for various lithium battery management control. The terminal voltage is the object of voltage equalization of the equalizing line, and the terminal voltage is ensured to be equal. The working current is the evaluation basis of the current limiting effect, and is mainly collected and evaluated by a matched BMS. The internal resistance parameters are mainly the basis for selecting materials and wire diameters of the voltage-sharing wires.
According to a general equivalent model, an external characteristic model of the lithium battery is shown in fig. 1, and in one scenario, the external equivalent circuit model of the lithium battery comprises: rated capacity C of lithium batterycapEquilibrium electromotive force EMF of lithium battery, and hysteresis voltage V of lithium batteryhResidual electric quantity V of lithium batterySOCRated capacity C of lithium batterycapCurrent I flowing through the lithium batteryBAnd voltage VBAdjustable inductance LhOhmic internal resistance R of lithium batteryΩOhmic polarization internal resistance R of lithium batterysElectrochemical polarization internal resistance R of lithium batterymConcentration difference polarization internal resistance R of lithium batteryfOhmic polarization capacitance C of lithium batterySElectrochemical polarization capacitance C of lithium batterymConcentration difference polarization capacitance C of lithium batteryf；
Wherein the voltage V of the lithium batteryBThe positive electrode is connected with concentration difference polarization internal resistance RfElectrochemical polarization internal resistance RmOhmic polarization internal resistance RsOhmic internal resistance RΩHysteresis voltage VhAnd balancing the electromotive force EMF with the voltage V of the lithium batteryBThe negative electrode of (1) is connected; wherein the concentration difference polarizes the capacitance CfPolarization internal resistance R with concentration differencefParallel, electrochemically polarized capacitance CmAnd electrochemical polarization internal resistance RmParallel ohmic polarization capacitance CSAnd ohmic polarization internal resistance RsParallel connection;
wherein rated capacity CcapPositive electrode and residual electric quantity VSOCThe anode is connected with the voltage V of the lithium batteryBThe negative electrode of (1) is connected; current IBTo rated capacity CcapParallel adjustable inductance LhPositive pole and voltage VfhThe anode is connected with the voltage V of the lithium batteryBIs connected to the negative electrode of the anode, and the current beta IBAnd an adjustable inductance LhAnd (4) connecting in parallel.
Wherein, CcapEMF is the equilibrium electromotive force, V, of the lithium batteryhThe OCV of a lithium battery is composed of EMF and VhComposition, the voltage of EMF is controlled by the SoC (V) of lithium batterySOC) Control of (V)hVoltage of the lithium battery SoC (V)SoC) And VfhAnd (4) controlling. Rated capacity of lithium battery CcapThe current flowing through the lithium battery is IBVoltage V across itSoCRepresenting the remaining capacity SoC of the battery. Adjustable inductor L for current flowinghIs subjected to a current I flowing through the lithium batteryBControl of voltage V across itfhIndicating hysteresis voltage V of lithium batteryhWhether discharging hysteresis or charging hysteresis. Hysteresis voltage V of lithium batteryhDirection receiver VfhThe size value is controlled by SoC, i.e. by CcapVoltage V acrossSoCAnd (4) controlling. RΩOhmic internal resistance, R, of lithium batteriessOhmic polarization internal resistance, R, of lithium batterymIs the electrochemical polarization internal resistance, R, of a lithium batteryfThe concentration difference polarization internal resistance of the lithium battery, CSBeing lithium batteriesOhmic polarization capacitance, CmIs the electrochemical polarization capacitance of a lithium battery, CfThe concentration difference polarization capacitance of the lithium battery.
2) The series-parallel connection of the lithium batteries is equivalent to a series-parallel connection circuit model formed by a voltage source and a resistor in series, as shown in fig. 4, wherein V1, V2 and V3 … Vn are equivalent voltages of the lithium batteries, R1, R2 and R3 … Rn are equivalent internal resistances of the lithium batteries, and R1a, R2a and R3a … Rna are connected group contact resistors.
The equivalent internal resistance is the internal resistance of the lithium battery in the previous external characteristic model of the lithium battery and is the basis for selecting materials and wire diameters of the equalizing wires.
The group contact resistance is measured according to the connection mode used in the actual lithium battery production process. The group contact resistance influences the calculation result of the resistance of the voltage equalizing wire, and the conversion relation in practical engineering is Rca＝k×Rc-ReWherein R iscaIs a voltage equalizing line resistor, RcIs the equivalent internal resistance, R, of the lithium batteryeIs the internal resistance of the contacts in groups.
3) The modules are connected in parallel and welded by adopting voltage-sharing connecting wires, so that the effects of balancing and limiting current are achieved, voltage balancing among the modules is also considered in the design of the standardized modules, a voltage balancing interface is added, and the consistency of the voltage and the total pressure of the battery monomer among the modules connected in parallel can be effectively guaranteed.
In one embodiment, the equalizer is made of nickel-plated steel strip, nickel-plated steel wire, nickel-plated copper strip, nickel-plated aluminum strip, or the like.
In one embodiment, the proportionality coefficient of the voltage equalizing line resistance and the direct current internal resistance of the lithium battery is k, and the formula is as follows:
k＝Rca/Rc
wherein R iscaIs a voltage equalizing line resistor, RcThe direct current internal resistance of the lithium battery.
In one embodiment, the value range of the proportionality coefficient k between the voltage-equalizing line resistor and the direct-current internal resistance of the lithium battery is as follows: [0,1000].
In one embodiment, the junction between the bus bars (rows) and the voltage-sharing lines is completed by an integrated process, as shown in fig. 11.
In one embodiment, the busbar and the equalizing line of the lithium battery are connected by adopting a processing and assembling process of split processing and combined welding installation, as shown in fig. 12. The lithium battery bus bar is an electrical connection component required when lithium batteries are connected in series, in parallel and in a mixed manner, and plays a role in conducting electricity and connecting electricity, as shown in fig. 12.
The invention has the following beneficial effects and advantages:
1) the grouping method for reducing parallel circulation and bias current for grouping the lithium battery packs and the implementation circuit thereof can effectively reduce circulation and bias current between the parallel single lithium batteries, control the circulation current to the extent of having no influence on the service life of the lithium batteries, and are superior to the existing common lithium battery grouping technology in the aspect of the whole service life of the lithium battery packs.
2) The grouping method for reducing parallel circulation and bias current for grouping the lithium battery packs and the implementation circuit thereof can effectively reduce circulation and bias current among the parallel single lithium batteries, reduce heat aggregation, and improve the consistency of capacity, internal resistance and temperature among the parallel lithium batteries.
3) The grouping method for reducing parallel circulation and bias current for grouping the lithium battery packs and the implementation circuit thereof can effectively reduce circulation and bias current between the parallel single lithium batteries, reduce electric quantity loss and heat loss, improve the consistency of capacity, internal resistance and temperature between the parallel lithium batteries, and are superior to the existing common lithium battery grouping technology in the aspect of charging and discharging efficiency of the lithium battery packs.
4) The grouping method for reducing parallel connection circulation and bias current for grouping lithium battery packs and the implementation circuit thereof have low requirements on the initial capacity consistency and the rate consistency of the single lithium battery, so that the cost of the single lithium battery and the manufacturing equipment is superior to that of the single lithium battery and the manufacturing equipment of a general grouping technology.
5) The grouping method for reducing parallel connection circulation and bias current for grouping lithium battery packs and the implementation circuit thereof effectively prolong the whole service life of the lithium battery packs, and are superior to the conventional common lithium battery grouping technology in the aspects of comprehensive use cost and environmental benefit.
6) The grouping method for reducing parallel connection circulation and bias current for grouping the lithium battery PACKs and the implementation circuit thereof have obvious economic benefits in the aspects of manufacturing and using cost of lithium battery PACKs; the method has great social benefit in the aspects of improving the application safety of the lithium battery and protecting the environment.
Compared with the prior art, the method disclosed by the invention has the advantages that the consistency of the capacity, the internal resistance and the temperature among the lithium batteries connected in parallel in the lithium battery pack is improved by controlling the circulation current and the bias current among the lithium batteries connected in parallel, and the method belongs to an active prevention method. On one hand, the active prevention design is mainly used for preventing the occurrence of bias current and circulation current, instead of passively repairing the bias current and the circulation current by using methods such as reuse equalization and the like, and the safety of the system is improved. On the other hand, the problems of energy loss and service life loss of the lithium battery pack caused by the traditional balancing method are avoided, and the effect is obvious in the aspects of prolonging the service life and improving the charging and discharging efficiency of the lithium battery pack.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be analyzed by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (6)
1. A lithium battery grouping method for reducing parallel connection circulation current and bias current is characterized by comprising the following steps:
s1, establishing a series-parallel circuit model by series-parallel connection of lithium batteries;
s2, establishing a grouped circuit according to the obtained series-parallel circuit model, including: the single lithium battery or the serial parts of a plurality of lithium batteries in the model are connected by adopting a bus sheet, and the parallel connection in the model is welded by adopting a voltage-sharing connecting line.
2. The method for grouping lithium batteries with reduced parallel circulating currents and reduced bias currents as claimed in claim 1, wherein the voltage equalizer is made of nickel-plated steel strip, nickel-plated steel wire, nickel-plated copper strip, nickel-plated aluminum strip, or the like.
3. The method for grouping lithium batteries with reduced parallel circulating current and reduced bias current as claimed in claim 1, wherein the proportional coefficient of the resistance of the voltage-sharing line to the direct-current internal resistance of the lithium batteries is k, and the formula is as follows:
k＝Rca/Rc
wherein R iscaIs a voltage equalizing line resistor, RcDirect current internal resistance of the lithium battery is obtained;
the value range of the proportional coefficient k of the voltage-sharing line resistance and the direct-current internal resistance of the lithium battery is as follows: [0,1000].
4. The method for grouping the lithium batteries for reducing the parallel connection loop current and the bias current as claimed in claim 1, wherein the lithium battery collector plate and the voltage equalizing line are connected by adopting an integrally-formed processing technology; or
The lithium battery confluence piece and the equalizing line are processed in a split mode, and the connection is completed through the processing and assembling process of combined welding installation.
5. The method for grouping lithium batteries with reduced parallel circulating current and reduced bias current as claimed in claim 1, wherein the lithium batteries are connected in series and parallel to establish a series-parallel circuit model, wherein the series-parallel circuit model comprises one or more parallel groups of lithium batteries, and the positive electrode and the negative electrode of each lithium battery in each parallel group of lithium batteries are connected in parallel; a plurality of lithium battery parallel groups are connected in series to form a series-parallel circuit model.
6. The method for grouping lithium batteries with reduced parallel circulating current and reduced bias current as claimed in claim 5, wherein in the parallel group of lithium batteries, the positive electrode of the nth lithium battery is connected with the negative electrode of the nth lithium battery in the previous parallel group of lithium batteries; the negative electrode of the nth lithium battery is connected with the positive electrode of the nth lithium battery in the next parallel group of lithium batteries.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210211041.XA CN114628763A (en) | 2022-03-03 | 2022-03-03 | Lithium battery grouping method for reducing parallel connection circulation current and bias current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210211041.XA CN114628763A (en) | 2022-03-03 | 2022-03-03 | Lithium battery grouping method for reducing parallel connection circulation current and bias current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114628763A true CN114628763A (en) | 2022-06-14 |
Family
ID=81899900
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210211041.XA Pending CN114628763A (en) | 2022-03-03 | 2022-03-03 | Lithium battery grouping method for reducing parallel connection circulation current and bias current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114628763A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102022121213A1 (en) | 2022-08-23 | 2024-02-29 | Bayerische Motoren Werke Aktiengesellschaft | High-voltage energy storage device with a detection device for detecting a short circuit in a storage cell |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060177734A1 (en) * | 2005-02-04 | 2006-08-10 | Li-Ho Yao | Battery assembly |
| CN102263300A (en) * | 2010-05-31 | 2011-11-30 | 比亚迪股份有限公司 | On-vehicle power battery module |
| CN102355040A (en) * | 2011-10-19 | 2012-02-15 | 北京四方继保自动化股份有限公司 | Converter modular design and control method matched with battery grouping application |
| CN105720220A (en) * | 2016-04-18 | 2016-06-29 | 力帆实业(集团)股份有限公司 | Power battery of electric automobile |
| CN110299493A (en) * | 2019-07-25 | 2019-10-01 | 河南豫清新能源产业有限公司 | A kind of lithium battery pack grouping method |
| CN110303940A (en) * | 2019-07-31 | 2019-10-08 | 河南豫清新能源产业有限公司 | A kind of box-like lithium battery BMS system production method of group of networks |
| CN209947926U (en) * | 2019-06-23 | 2020-01-14 | 成都精锐环科技有限公司 | Parallel storage battery pack system based on combined circulation cut-off device |
| CN214099824U (en) * | 2021-01-19 | 2021-08-31 | 河南利威新能源科技有限公司 | Bus bar and battery module using same |
| CN114024101A (en) * | 2021-11-10 | 2022-02-08 | 张国庆 | Battery pack with small bias current and easy detection of each battery cell |
-
2022
- 2022-03-03 CN CN202210211041.XA patent/CN114628763A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060177734A1 (en) * | 2005-02-04 | 2006-08-10 | Li-Ho Yao | Battery assembly |
| CN102263300A (en) * | 2010-05-31 | 2011-11-30 | 比亚迪股份有限公司 | On-vehicle power battery module |
| CN102355040A (en) * | 2011-10-19 | 2012-02-15 | 北京四方继保自动化股份有限公司 | Converter modular design and control method matched with battery grouping application |
| CN105720220A (en) * | 2016-04-18 | 2016-06-29 | 力帆实业(集团)股份有限公司 | Power battery of electric automobile |
| CN209947926U (en) * | 2019-06-23 | 2020-01-14 | 成都精锐环科技有限公司 | Parallel storage battery pack system based on combined circulation cut-off device |
| CN110299493A (en) * | 2019-07-25 | 2019-10-01 | 河南豫清新能源产业有限公司 | A kind of lithium battery pack grouping method |
| CN110303940A (en) * | 2019-07-31 | 2019-10-08 | 河南豫清新能源产业有限公司 | A kind of box-like lithium battery BMS system production method of group of networks |
| CN214099824U (en) * | 2021-01-19 | 2021-08-31 | 河南利威新能源科技有限公司 | Bus bar and battery module using same |
| CN114024101A (en) * | 2021-11-10 | 2022-02-08 | 张国庆 | Battery pack with small bias current and easy detection of each battery cell |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102022121213A1 (en) | 2022-08-23 | 2024-02-29 | Bayerische Motoren Werke Aktiengesellschaft | High-voltage energy storage device with a detection device for detecting a short circuit in a storage cell |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103163464B (en) | The detection method of battery core in power brick | |
| EP4027444A1 (en) | Battery pack, method and vehicle | |
| CN106824831A (en) | A kind of manufacture method of the motive-power battery for improving lithium ion battery uniformity | |
| Susanna et al. | Comparison of simple battery model and thevenin battery model for SOC estimation based on OCV method | |
| CN210607350U (en) | Lithium battery system device | |
| Kim et al. | A multicell battery system design for electric and plug-in hybrid electric vehicles | |
| CN207753126U (en) | A kind of lithium battery management system | |
| CN114628763A (en) | Lithium battery grouping method for reducing parallel connection circulation current and bias current | |
| CN106786909B (en) | A kind of equalising control device in groups and control method of energy storage liquid metal cell | |
| CN102769316B (en) | Battery selective equalization method | |
| CN110865307A (en) | Battery module complementary energy detection method | |
| CN213181939U (en) | Lithium battery parameter acquisition circuit | |
| CN101944582A (en) | Novel stack battery connection method | |
| Chen et al. | Performance of inconsistency in lithium-ion battery packs for battery energy storage systems | |
| CN108918948B (en) | Method for extracting generated current in power battery | |
| CN115436833B (en) | Energy storage system and SOC correction method thereof | |
| CN218383214U (en) | Detection system of battery module | |
| CN108923084B (en) | Method for testing current distribution of polar plate of polar group | |
| CN107255786A (en) | A kind of ferric phosphate lithium cell LOC models | |
| CN116699447A (en) | Detection circuit and detection system of battery module | |
| Pathiyil et al. | Battery model for Hybrid Electric Vehicle corrected for self-discharge and internal resistance | |
| CN112462274A (en) | Battery self-discharge effect-based method for diagnosing short-circuit fault in grouped batteries | |
| CN114388993A (en) | High-safety power battery module | |
| CN113595221A (en) | Composite power supply module and composite power supply equalization system | |
| Li et al. | High-accuracy parameters identification of non-linear electrical model for high-energy lithium-ion capacitor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |