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CN113315207B - Split-type balanced charge and discharge protection method and system based on lithium ion battery - Google Patents

Split-type balanced charge and discharge protection method and system based on lithium ion battery Download PDF

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Publication number
CN113315207B
CN113315207B CN202110659515.2A CN202110659515A CN113315207B CN 113315207 B CN113315207 B CN 113315207B CN 202110659515 A CN202110659515 A CN 202110659515A CN 113315207 B CN113315207 B CN 113315207B
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China
Prior art keywords
battery
temperature
single battery
discharge
charge
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CN113315207A (en
Inventor
栗欢欢
徐桐
王亚平
江浩斌
袁朝春
陈龙
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Jiangsu University
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Jiangsu University
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00309Overheat or overtemperature protection
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014Circuits for equalisation of charge between batteries
    • H02J7/0016Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00302Overcharge protection
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00306Overdischarge protection
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0068Battery or charger load switching, e.g. concurrent charging and load supply
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007Regulation of charging or discharging current or voltage
    • H02J7/007188Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
    • H02J7/007192Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
    • H02J7/007194Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature of the battery
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

The invention provides a split-flow type balanced charge and discharge protection method and system based on a lithium ion battery, comprising the following steps: sampling the temperature of the single battery in the charging and discharging process; judging the temperature of each single battery of the series battery pack according to the sampling result, and carrying out normal charging or normal discharging when the temperature sampling value of the single battery is smaller than the temperature failure threshold value; when the single battery is excessively discharged, the temperature sampling value is larger than the temperature failure threshold value, and the single battery is shunted to prevent the single battery from being excessively discharged; when the single battery is overcharged, the temperature sampling value is larger than the temperature failure threshold value, and the single battery is bypassed through breakdown of the voltage stabilizing diode. When the single battery fails or the capacity is seriously reduced, the series battery pack can timely shunt the single battery, and the single battery is prevented from overdischarging; when the single battery is charged to reach rated capacity, the serial battery pack can bypass the single battery in time, so that the single battery is prevented from being overcharged, and the service life of the battery is prevented from being damaged.

Description

Split-type balanced charge and discharge protection method and system based on lithium ion battery
Technical Field
The invention belongs to the technical field of battery charge and discharge protection, and particularly relates to a split-flow type balanced charge and discharge protection method and system based on a lithium ion battery.
Background
The power battery is a power source of the new energy automobile, and the safety of the power battery directly determines the popularization and application degree of the new energy automobile. The lithium ion battery has high energy density and meanwhile has insufficient safety, and safety accidents caused by the lithium ion battery characterized by thermal runaway occur. When lithium ion batteries are connected in series, the capacity of each battery is often different, so that when the batteries are charged and discharged, overcharge and overdischarge of part of the batteries are often caused, and certain potential safety hazards exist.
Disclosure of Invention
Aiming at the technical problems, the invention provides a split-type balanced charge-discharge protection method and system based on a lithium ion battery, which solve the problem that when a single battery fails or the capacity is seriously reduced, a series battery pack can split the single battery in time to prevent the single battery from overdischarging; when the single battery is charged to reach rated capacity, the serial battery pack can bypass the single battery in time, so that the single battery is prevented from being overcharged, the service life of the battery is damaged, and the capacity of the battery pack can still be maintained to be in an ideal state when the single battery is invalid or reaches the rated capacity. The invention simplifies the charge and discharge protection circuit by using the active and passive equalization method, reduces the cost and has better protection effect.
The technical scheme of the invention is as follows: a split-flow type balanced charge-discharge protection method based on a lithium ion battery comprises the following steps:
Step S1, performing a charge-discharge test on a lithium battery sample to obtain time domain voltage data U (T), time domain current data I (T) and time domain surface temperature data T (T) in the charge-discharge process of the lithium battery sample, and setting a temperature failure threshold;
step S2, sampling the temperature of the single battery in the charging and discharging process of the step S1;
S3, judging the temperature of each single battery of the series battery pack according to the sampling result of the step 2, and carrying out normal charging or normal discharging when the temperature sampling value of the single battery is smaller than a temperature failure threshold value; when the single battery is excessively discharged, and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the over-discharge temperature failure threshold, the single battery is split, and the over-discharge of the single battery is prevented; when the single battery is overcharged and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the overcharged temperature failure threshold, the voltage-stabilizing diode is broken down to bypass the single battery.
In the above scheme, the normal discharge includes the following steps:
Step S41: connecting all the single batteries of the series battery pack in series;
step S42: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S43: according to the sampling result of the step S42, adjusting the discharge voltage of the series battery pack;
step S44: when any single battery discharges to reach a temperature failure threshold, a logic switch of the single battery is opened through a control circuit to shunt the single battery;
step S45: and repeating the steps S42-S45 until all the single batteries of the series battery pack reach the discharge temperature threshold value, and completing the discharge.
In the above scheme, the normal charging includes the following steps:
step S51: connecting all the single batteries of the series battery pack in series;
step S52: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
Step S53: according to the sampling result of the step S52, the charging voltage and the charging current of the series battery pack are adjusted;
Step S54: when any single battery is charged to reach a temperature failure threshold, the voltage at two ends of the battery breaks down the zener diode to cause bypass of the single battery;
step S55: and repeating the steps S52-S55 until all the single batteries of the series battery pack reach the charging temperature threshold value, and completing charging.
In the above scheme, according to the sampling result in step S1, a temperature failure threshold is set, a cell with a cell temperature less than the temperature failure threshold is defined as a normal capacity cell, and a cell with a cell temperature greater than the temperature failure threshold is defined as an abnormal capacity cell.
In the above scheme, the overdischarge of the unit cells includes the steps of:
step S61: connecting all the single batteries of the series battery pack in series;
Step S62: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S63: if the temperature of the single battery is greater than the temperature failure threshold, judging that the battery is an abnormal capacity battery;
Step S64: the logic switch is opened for the abnormal capacity battery, the battery is shunted, and meanwhile, the discharge voltage of the battery is adjusted, so that the damage to the single battery is reduced;
step S65: and repeating the steps S61-S65 until all the single batteries reach the discharge temperature threshold value.
In the above scheme, the overcharge of the single battery includes the steps of:
step S71: connecting all the single batteries of the series battery pack in series;
step S72: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S73: connecting a zener diode in a circuit in a reverse manner;
step S74: when the single battery reaches a charging threshold or a temperature failure threshold, the voltage at the two ends of the battery breaks down the voltage stabilizing diodes connected in parallel at the two ends of the battery, so that the single battery is bypassed.
Step S75: and repeating the steps S71-S75 until all the single batteries reach the charging threshold or reach the normal capacity.
In the scheme, the method further comprises the verification step of analog simulation: the circuit is simplified, software is used for simulating the short circuit of the battery pack during discharging, an additional parallel resistor and an electronic switch which are connected with the battery in parallel are introduced to protect the circuit, and the voltages of different batteries and corresponding battery currents under different battery charging and discharging multiplying powers are obtained according to simulation results, and the battery charge states under different charging and discharging multiplying powers are obtained.
Further, the verification of the analog simulation includes the following steps:
Step S81: simplifying a split-flow type balanced charge-discharge protection circuit of the lithium ion battery, and arranging a series battery pack comprising two single batteries;
Step S82: setting a zero-dimensional model in software, selecting a lumped battery, and setting parameters of the battery;
Step S83: parameter setting is carried out on the simplified circuit, and modeling is carried out on the simplified circuit;
step S84: simulating to obtain voltages of different batteries, corresponding battery currents of different batteries and charge states of different charge and discharge multiplying powers;
Step S85: according to the simulation result: the voltage of different batteries, the corresponding battery currents of different batteries, the charge states of different charge and discharge multiplying powers and the influence of the shunt resistance on the single battery in the complete discharge state are compared;
Step S86: analysis results in improving the damage of the overdischarge of the single battery to the battery capacity under the condition of adding the shunt resistor.
The system for realizing the split-type balanced charge-discharge protection method based on the lithium ion battery comprises a temperature sampling module, a voltage-stabilizing diode module, a shunt resistance module, a charge-discharge module, an electronic switch group, a charge/discharge change-over switch and a control module;
The control module is respectively connected with the single temperature sampling module, the electronic switch group, the charge/discharge change-over switch and the charge/discharge module;
the temperature sampling module is connected with the series battery pack and is used for sampling the temperature of the single batteries in the series battery pack;
The charge/discharge change-over switch is arranged between the charge/discharge module and the temperature sampling module and is used for switching charge or discharge of the series battery pack;
the electronic switch group comprises a plurality of electronic switches and is used for shunting the single battery;
the voltage stabilizing diode module is connected with the single battery in parallel and is used for bypassing the single battery;
The control module is used for controlling the closing of any electronic switch of the electronic switch group, the closing of the charge/discharge change-over switch and the charging and discharging of the charge/discharge module; the control module is also used for judging whether the single batteries in the series battery pack fail or not and bypassing the failed single batteries.
In the above scheme, the charging and discharging module comprises a charging DC-DC and a discharging DC-DC.
Compared with the prior art, the invention has the beneficial effects that: when the capacity of a single battery in the battery pack reaches rated capacity, the voltage stabilizing diode short-circuits the single battery; when the single battery fails or the capacity is seriously attenuated in the battery pack, the series battery pack can timely shunt the single battery, prevent the single battery from overdischarging, effectively isolate and damage the single battery and avoid the whole battery from failing; when the capacities of the monomers in the battery packs are greatly different, the invention can effectively utilize the energy of the whole battery pack, and avoid that the whole battery pack is limited by the monomer with the minimum capacity; the method can carry out supplementary charging on the lagging monomer, and has the effect similar to the prior balancing technology; the energy-saving type solar energy generating device has the advantages of no passive energy consumption element, small energy loss and high efficiency. By performing analog simulation on the circuit, the damage of the overdischarge of the single battery to the battery capacity can be greatly improved under the condition of adding the shunt resistor through analysis. The invention simplifies the charge and discharge protection circuit by using the active and passive equalization method, reduces the cost and has better protection effect.
Drawings
FIG. 1 is a diagram of an exemplary circuit configuration of an embodiment of the present invention;
FIG. 2 is a flow chart of the operation process of an embodiment of the present invention;
FIG. 3 is a simplified circuit diagram of an embodiment of the present invention;
FIG. 4 is a graph of the battery voltage and voltmeter measurements of a lumped battery in accordance with an embodiment of the invention;
Fig. 5 shows the state of charge of the battery at different charge/discharge rates according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
Fig. 1 shows a preferred embodiment of the split-type balanced charge-discharge protection method based on a lithium ion battery, which includes the following steps:
Step S1, performing a charge-discharge test on a lithium battery sample to obtain time domain voltage data U (T), time domain current data I (T) and time domain surface temperature data T (T) in the charge-discharge process of the lithium battery sample, and setting a temperature failure threshold;
step S2, sampling the temperature of the single battery in the charging and discharging process of the step S1;
S3, judging the temperature of each single battery of the series battery pack according to the sampling result of the step 2, and carrying out normal charging or normal discharging when the temperature sampling value of the single battery is smaller than a temperature failure threshold value; when the single battery is excessively discharged, and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the over-discharge temperature failure threshold, the single battery is split, and the over-discharge of the single battery is prevented; when the single battery is overcharged and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the overcharged temperature failure threshold, the voltage-stabilizing diode is broken down to bypass the single battery.
The normal discharge includes the steps of:
Step S41: connecting all the single batteries of the series battery pack in series;
step S42: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S43: according to the sampling result of the step S42, adjusting the discharge voltage of the series battery pack;
step S44: when any single battery discharges to reach a temperature failure threshold, a logic switch of the single battery is opened through a control circuit to shunt the single battery;
step S45: and repeating the steps S42-S45 until all the single batteries of the series battery pack reach the discharge temperature threshold value, and completing the discharge.
The normal charging includes the steps of:
step S51: connecting all the single batteries of the series battery pack in series;
step S52: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
Step S53: according to the sampling result of the step S52, the charging voltage and the charging current of the series battery pack are adjusted;
Step S54: when any single battery is charged to reach a temperature failure threshold, the voltage at two ends of the battery breaks down the zener diode to cause bypass of the single battery;
step S55: and repeating the steps S52-S55 until all the single batteries of the series battery pack reach the charging temperature threshold value, and completing charging.
And according to the sampling result of the step S1, setting a temperature failure threshold, defining a single battery with the single battery temperature smaller than the temperature failure threshold as a normal capacity battery, and defining a single battery with the single battery temperature larger than the temperature failure threshold as an abnormal capacity battery.
The overdischarge of the unit cells includes the steps of:
step S61: connecting all the single batteries of the series battery pack in series;
Step S62: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S63: if the temperature of the single battery is greater than the temperature failure threshold, judging that the battery is an abnormal capacity battery;
Step S64: the logic switch is opened for the abnormal capacity battery, the battery is shunted, and meanwhile, the discharge voltage of the battery is adjusted, so that the damage to the single battery is reduced;
step S65: and repeating the steps S61-S65 until all the single batteries reach the discharge temperature threshold value.
The overcharge of the single battery includes the steps of:
step S71: connecting all the single batteries of the series battery pack in series;
step S72: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
Step S73: selecting a proper voltage stabilizing diode, and connecting the voltage stabilizing diode in a circuit in a reverse mode;
step S74: when the single battery reaches a charging threshold or a temperature failure threshold, the voltage at the two ends of the battery breaks down the voltage stabilizing diodes connected in parallel at the two ends of the battery, so that the single battery is bypassed.
Step S75: and repeating the steps S71-S75 until all the single batteries reach the charging threshold or reach the normal capacity.
The method further comprises the step of verifying the analog simulation: the circuit is simplified, the Comsol software is used for simulating the short circuit of the simulated battery pack during discharging, an additional parallel resistor and an electronic switch which are connected with the battery in parallel are introduced for protecting the circuit, and the voltages of different batteries and the corresponding battery currents under different battery charge and discharge multiplying powers and the battery charge states under different charge and discharge multiplying powers are obtained according to the simulation result.
The verification of the simulation comprises the following steps:
Step S81: simplifying a split-flow type balanced charge-discharge protection circuit of the lithium ion battery, and arranging a series battery pack comprising two single batteries;
Step S82: setting a zero-dimensional model in the Comsol software, selecting a lumped battery, and setting parameters of the battery;
Step S83: parameter setting is carried out on the simplified circuit, so that the battery in the simplified circuit discharges in a 2-second configuration, and modeling is carried out on the simplified circuit;
step S84: simulating to obtain voltages of different batteries, corresponding battery currents of different batteries and charge states of different charge and discharge multiplying powers;
Step S85: according to the simulation result: the voltage of different batteries, the corresponding battery currents of different batteries, the charge states of different charge and discharge multiplying powers and the influence of the shunt resistance on the single battery in the complete discharge state are compared;
step S86: the analysis results show that the damage of the overdischarge of the single battery to the battery capacity can be greatly improved under the condition of adding the shunt resistor.
The system for realizing the split-type balanced charge-discharge protection method based on the lithium ion battery comprises a temperature sampling module, a voltage-stabilizing diode module, a shunt resistance module, a charge-discharge module, an electronic switch group, a charge/discharge change-over switch and a control module;
The control module is respectively connected with the single temperature sampling module, the electronic switch group, the charge/discharge change-over switch and the charge/discharge module;
the temperature sampling module is connected with the series battery pack and is used for sampling the temperature of the single batteries in the series battery pack;
The charge/discharge change-over switch is arranged between the charge/discharge module and the temperature sampling module and is used for switching charge or discharge of the series battery pack;
the electronic switch group comprises a plurality of electronic switches and is used for shunting the single battery;
the voltage stabilizing diode module is connected with the single battery in parallel and is used for bypassing the single battery;
The control module is used for controlling the closing of any electronic switch of the electronic switch group, the closing of the charge/discharge change-over switch and the charging and discharging of the charge/discharge module; the control module is also used for judging whether the single batteries in the series battery pack fail or not and bypassing the failed single batteries.
The charging and discharging module comprises a charging DC-DC circuit and a discharging DC-DC circuit. The control module is a control circuit.
According to this embodiment, preferably, as shown in the circuit configuration diagram of fig. 1, the batteries 1 to n are n battery cells, SW1 to SWn are electronic switches, and the electronic switches are controlled single pole single throw switches. The battery pack is connected with the discharging DC-DC circuit or the charging DC-DC circuit, and is switched by a charging/discharging change-over switch, and the change-over switch is controlled by a control circuit. The discharging DC-DC circuit has its input connected to the battery and its output connected to the external load, and features that the voltage output to the load is maintained unchanged and the output voltage and current can be regulated by the control circuit. The input end of the charging DC-DC circuit is connected with an external charging input, and the output end is connected with the battery pack. The circuit is provided with a single battery temperature sampling circuit for sampling the temperature of each battery single battery. The temperature sampling information is sent to the control circuit. The control circuit outputs SW1-SWn electronic switch control signals, discharging DC-DC output voltage, current control signals, charging DC-DC charging voltage and charging/discharging switching control signals.
The working process of this embodiment is shown in fig. 2, where the charge/discharge is started, and the control circuit controls the battery pack to enter the following procedure according to the battery pack state and the charge/discharge requirement. The judging source of the battery pack state is the current value or the historical value of parameters such as the single voltage, the capacity, the internal resistance, the temperature and the like acquired by the control circuit.
1. Charging: the application conditions are as follows: the difference of the parameters of each single cell in the battery pack is small, and the capacity is basically not attenuated.
And after the charge-discharge switch is turned on, the battery pack is controlled to be charged. And adjusting the charging limiting voltage of the charging DC-DC to the charging voltage corresponding to the whole group of batteries, and monitoring the capacity of each single body in real time by the control circuit through the single body temperature sampling circuit in the charging process. When the control circuit judges that a certain single battery reaches a charging temperature threshold (such as that the temperature reaches a charging cut-off temperature) according to the temperature of the single battery, the voltage at two ends of the battery reaches the breakdown voltage of the voltage stabilizing diode, the voltage stabilizing diode breaks down, and charging current flows from the diode to the next single battery, so that capacity attenuation caused by overcharging of the single battery is prevented, meanwhile, the output charging voltage of the charging DC-DC is controlled to be adjusted to be (n-1) x Vi, the battery pack is continuously charged, when m single batteries are bypassed, the output charging voltage of the charging DC-DC is adjusted to be (n-m) x Vi, until all the single batteries are fully charged, wherein n is the total number of the single batteries in the battery pack, and Vi is the voltage of the ith battery in the battery pack.
2. Discharging: the application conditions are as follows: the difference of the parameters of each single cell in the battery pack is small, and the capacity is basically not attenuated.
And after the charge-discharge switch is turned on, the battery pack is controlled to be discharged. And adjusting the discharge limiting voltage of the discharge DC-DC to be the discharge voltage corresponding to the whole group of batteries, and monitoring the capacity of each single body in real time by the control circuit through the single body temperature sampling circuit in the discharge process. When the control circuit judges that a certain single battery reaches a discharge temperature threshold value (such as that the temperature reaches a discharge cutoff temperature) according to the single battery temperature, the attenuation speed of the individual single battery is obvious, when the single battery is excessively discharged, the temperature of the single battery is gradually increased, at the moment, the temperature of the single battery is monitored in real time through the temperature sampling circuit, and when the control circuit judges that the certain single battery reaches a charge temperature threshold value (such as that the temperature reaches the charge cutoff temperature) according to the single battery temperature, the control circuit controls an electronic switch corresponding to the single battery to shunt the single battery, so that the attenuation of capacity brought by the excessive discharge of the single battery is prevented. The voltage at two ends of the battery reaches the breakdown voltage of the voltage stabilizing diode, the voltage stabilizing diode is broken down, the single battery is bypassed, meanwhile, the output charging voltage of the charging DC-DC is controlled to be adjusted to (n-1) Vi, the battery pack is continuously charged, when m single batteries are bypassed, the output charging voltage of the charging DC-DC is adjusted to be (n-m) Vi until all the single batteries are fully charged, wherein n is the total number of the single batteries in the battery pack, and Vi is the voltage of the ith battery in the battery pack.
The working process of the embodiment is shown in fig. 3, fig. 3 is a simplified circuit diagram of the embodiment, and when the batteries are integrated into the battery unit, additional circuit components can be added to handle balance and overcharge/discharge protection among the batteries. A small circuit (2 s configuration discharge) is defined consisting of two lithium ion batteries in series. After a period of operation, one of the cells begins to discharge at a higher rate due to internal shorting, causing uneven cell discharge/balancing, ultimately resulting in overdischarge. To mitigate the risk of overdischarge, the circuit is modified by introducing an additional parallel resistor and electronic switch in parallel with the battery.
The operation of this example is shown in fig. 4, where fig. 4 is a graph of the cell voltage and voltmeter measurements for a lumped cell, showing the voltage of the various cells in operation, and the voltmeter voltage when operated in series without and with a shunt. Simulation results as shown in fig. 4, show a sharp drop in the respective voltages of the respective batteries at the time of triggering the event of monitoring the SOC level, and the batteries begin to discharge through the respective parallel resistors connected in parallel to the batteries. When the potential drop of the single battery is 0V, the single battery does not drop any more, so that the battery is effectively protected from being damaged; the series circuit without the shunt causes the voltage drop of-8V due to overdischarge of the battery, which causes great damage to the capacity of the single battery.
The working process of the embodiment is shown in fig. 5, and fig. 5 shows the states of charge of the battery under different charge and discharge rates. For the series circuit without the shunt, as can be seen from the simulation result of fig. 5, the capacity of one battery is seriously reduced and overdischarged, and the other battery is not completely discharged, so that the battery pack is in a state of 'being used up and being finished up', and further, the performances of all the single batteries in the battery pack are greatly different, and a certain potential safety hazard exists. For the series circuit provided with the current divider, after discharging operation, the final charge states of the two batteries are 0, so that complete discharging is realized, and the voltage deviation of the battery cells is kept within an expected range, thereby ensuring that each battery cell is kept in the same state during normal use, and effectively protecting the battery cells.
It should be understood that although the present disclosure has been described in terms of various embodiments, not every embodiment is provided with a separate technical solution, and this description is for clarity only, and those skilled in the art should consider the disclosure as a whole, and the technical solutions in the various embodiments may be combined appropriately to form other embodiments that will be understood by those skilled in the art.
The above list of detailed descriptions is only specific to practical embodiments of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent embodiments or modifications that do not depart from the spirit of the present invention should be included in the scope of the present invention.

Claims (10)

1. The split-type balanced charge-discharge protection system based on the lithium ion battery is characterized by comprising a temperature sampling module, a voltage-stabilizing diode module, a split-flow resistor module of a splitter, a charge-discharge module, an electronic switch group, a charge/discharge change-over switch and a control module;
The control module is respectively connected with the single temperature sampling module, the electronic switch group, the charge/discharge change-over switch and the charge/discharge module;
the temperature sampling module is connected with the series battery pack and is used for sampling the temperature of the single batteries in the series battery pack;
The charge/discharge change-over switch is arranged between the charge/discharge module and the temperature sampling module and is used for switching charge or discharge of the series battery pack;
the electronic switch group comprises a plurality of electronic switches and is used for shunting the single battery;
the voltage stabilizing diode module is connected with the single battery in parallel and is used for bypassing the single battery;
The control module is used for controlling the closing of any electronic switch of the electronic switch group, the closing of the charge/discharge change-over switch and the charging and discharging of the charge/discharge module; the control module is also used for judging whether the single batteries in the series battery pack fail or not and bypassing the failed single batteries; judging the temperature of each single battery of the series battery pack, and carrying out normal charging or normal discharging when the temperature sampling value of the single battery is smaller than a temperature failure threshold value; when the single battery is excessively discharged, and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the over-discharge temperature failure threshold, the single battery is split, and the over-discharge of the single battery is prevented; when the single battery is overcharged and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the overcharged temperature failure threshold, the voltage-stabilizing diode is broken down to bypass the single battery.
2. The lithium ion battery based shunt balanced charge-discharge protection system of claim 1, wherein the charge-discharge module comprises a charge DC-DC and a discharge DC-DC.
3. A method for implementing the lithium ion battery-based split-flow balanced charge-discharge protection system of claim 1 or 2, comprising the steps of:
Step S1, performing a charge-discharge test on a lithium battery sample to obtain time domain voltage data U (T), time domain current data I (T) and time domain surface temperature data T (T) in the charge-discharge process of the lithium battery sample, and setting a temperature failure threshold;
step S2, sampling the temperature of the single battery in the charging and discharging process of the step S1;
S3, judging the temperature of each single battery of the series battery pack according to the sampling result of the step 2, and carrying out normal charging or normal discharging when the temperature sampling value of the single battery is smaller than a temperature failure threshold value; when the single battery is excessively discharged, and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the over-discharge temperature failure threshold, the single battery is split, and the over-discharge of the single battery is prevented; when the single battery is overcharged and the temperature sampling value is larger than the temperature failure threshold, namely the single battery reaches the overcharged temperature failure threshold, the voltage-stabilizing diode is broken down to bypass the single battery.
4. A method of a lithium ion battery shunt balanced charge and discharge protection system according to claim 3, wherein said normal discharge comprises the steps of:
Step S41: connecting all the single batteries of the series battery pack in series;
step S42: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S43: according to the sampling result of the step S42, adjusting the discharge voltage of the series battery pack;
step S44: when any single battery discharges to reach a temperature failure threshold, a logic switch of the single battery is opened through a control circuit to shunt the single battery;
step S45: and repeating the steps S42-S45 until all the single batteries of the series battery pack reach the discharge temperature threshold value, and completing the discharge.
5. The method of lithium ion battery shunt balanced charge-discharge protection system according to claim 3, wherein the normal charging comprises the steps of:
step S51: connecting all the single batteries of the series battery pack in series;
step S52: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
Step S53: according to the sampling result of the step S52, the charging voltage and the charging current of the series battery pack are adjusted;
Step S54: when any single battery is charged to reach a temperature failure threshold, the voltage at two ends of the battery breaks down the zener diode to cause bypass of the single battery;
step S55: and repeating the steps S52-S55 until all the single batteries of the series battery pack reach the charging temperature threshold value, and completing charging.
6. The method of claim 3, wherein a temperature failure threshold is set according to the sampling result in the step S1, a cell with a cell temperature less than the temperature failure threshold is defined as a normal capacity cell, and a cell with a cell temperature greater than the temperature failure threshold is defined as an abnormal capacity cell.
7. The method of lithium ion battery based split-flow balanced charge-discharge protection system of claim 6, wherein the overdischarging of the battery cells comprises the steps of:
step S61: connecting all the single batteries of the series battery pack in series;
Step S62: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S63: if the temperature of the single battery is greater than the temperature failure threshold, judging that the battery is an abnormal capacity battery;
Step S64: the logic switch is opened for the abnormal capacity battery, the battery is shunted, and meanwhile, the discharge voltage of the battery is adjusted, so that the damage to the single battery is reduced;
step S65: and repeating the steps S61-S65 until all the single batteries reach the discharge temperature threshold value.
8. The method of lithium ion battery based split-flow balanced charge-discharge protection system of claim 6, wherein the cell overcharge comprises the steps of:
step S71: connecting all the single batteries of the series battery pack in series;
step S72: sampling the current, the single battery voltage and the temperature of the single battery of the series battery pack in real time;
step S73: connecting a zener diode in a circuit in a reverse manner;
step S74: when the single battery reaches a charging threshold or a temperature failure threshold, the voltage at the two ends of the battery breaks down the voltage stabilizing diodes connected in parallel at the two ends of the battery, so that a bypass of the single battery is caused;
Step S75: and repeating the steps S71-S75 until all the single batteries reach the charging threshold or reach the normal capacity.
9. The method of a split-flow balanced charge-discharge protection system based on a lithium ion battery according to claim 6, further comprising the step of verifying the simulated simulation: the circuit is simplified, software is used for simulating the short circuit of the battery pack during discharging, an additional parallel resistor and an electronic switch which are connected with the battery in parallel are introduced to protect the circuit, and the voltages of different batteries and corresponding battery currents under different battery charging and discharging multiplying powers are obtained according to simulation results, and the battery charge states under different charging and discharging multiplying powers are obtained.
10. The method of lithium ion battery shunt balanced charge and discharge protection system according to claim 9, wherein the verification of the analog simulation comprises the steps of:
Step S81: simplifying a split-flow type balanced charge-discharge protection circuit of the lithium ion battery, and arranging a series battery pack comprising two single batteries;
Step S82: setting a zero-dimensional model in software, selecting a lumped battery, and setting parameters of the battery;
Step S83: parameter setting is carried out on the simplified circuit, and modeling is carried out on the simplified circuit;
step S84: simulating to obtain voltages of different batteries, corresponding battery currents of different batteries and charge states of different charge and discharge multiplying powers;
Step S85: according to the simulation result: the voltage of different batteries, the corresponding battery currents of different batteries, the charge states of different charge and discharge multiplying powers and the influence of the shunt resistance on the single battery in the complete discharge state are compared;
Step S86: analysis results in improving the damage of the overdischarge of the single battery to the battery capacity under the condition of adding the shunt resistor.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102376979A (en) * 2010-08-13 2012-03-14 周金平 Charge-discharge automatically equalized lithium-ion power battery series battery pack
CN111355282A (en) * 2020-03-30 2020-06-30 中国电建集团成都勘测设计研究院有限公司 Charging and discharging protection method and system for series battery pack

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102780210A (en) * 2012-07-20 2012-11-14 吴讯驰 Battery pack charging and discharging protector
CN103607001A (en) * 2013-11-04 2014-02-26 江苏嘉钰新能源技术有限公司 Battery shunt equalization method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102376979A (en) * 2010-08-13 2012-03-14 周金平 Charge-discharge automatically equalized lithium-ion power battery series battery pack
CN111355282A (en) * 2020-03-30 2020-06-30 中国电建集团成都勘测设计研究院有限公司 Charging and discharging protection method and system for series battery pack

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