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CN113922338A - Battery overcurrent protection circuit - Google Patents

Battery overcurrent protection circuit Download PDF

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Publication number
CN113922338A
CN113922338A CN202111202181.2A CN202111202181A CN113922338A CN 113922338 A CN113922338 A CN 113922338A CN 202111202181 A CN202111202181 A CN 202111202181A CN 113922338 A CN113922338 A CN 113922338A
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China
Prior art keywords
control module
mos
battery pack
main control
battery
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CN202111202181.2A
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Chinese (zh)
Inventor
韦晓宇
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Dongguan Antai Electronic Technology Co ltd
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Dongguan Antai Electronic Technology Co ltd
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Priority to CN202111202181.2A priority Critical patent/CN113922338A/en
Publication of CN113922338A publication Critical patent/CN113922338A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/18—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for batteries; for accumulators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0046—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electric energy storage systems, e.g. batteries or capacitors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/04—Cutting off the power supply under fault conditions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00304—Overcurrent protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)
  • Protection Of Static Devices (AREA)

Abstract

The present disclosure relates to a battery overcurrent protection circuit, including: a main control module; the cut-off protection module is connected among the battery pack, an external power supply and a load; the cut-off protection module comprises an MOS tube group, the MOS tube group comprises a plurality of MOS tubes, the sources of the MOS tubes are connected in common, the drains of the MOS tubes are connected in common, the MOS tubes are in a parallel connection structure, and the signal output end of the main control module is connected with the grids of the MOS tubes; the sampling detection module comprises a current detection unit, the current detection unit is electrically connected with the cut-off protection module, and the signal output end of the current detection unit is connected with the signal input end of the main control module and used for detecting and obtaining the working current I. The cut-off protection module adopts a multi-MOS tube parallel structure, and has the advantages of high response speed, good expandability, good reliability and durability, small volume, light weight, low power consumption and low component cost.

Description

Battery overcurrent protection circuit
Technical Field
The disclosure relates to the technical field of battery overcurrent protection, in particular to a battery overcurrent protection circuit.
Background
The over-current protection of the lithium battery is very important for the service life of the battery, especially for the driving safety and the spontaneous combustion prevention of the electric automobile. When the current exceeds the allowable value in the working process of the battery, if the working current cannot be cut off in time, the temperature of the battery is rapidly increased, the damage life of the battery is shortened if the temperature is light, and fire or even explosion can be caused if the temperature is heavy. At present, the traditional lithium battery overcurrent protection circuit is connected between a battery pack and an external power supply/load, the overcurrent protection circuit generally adopts a relay as a cut-off element, and when the working current of the circuit overflows, namely the working current is greater than a preset current threshold value, a controller controls the relay to be disconnected, so that the battery pack and the external power supply/load are disconnected, the charging and discharging actions of the battery pack are interrupted, and the overcurrent protection of a lithium battery is further realized. The use of relays as the cut-off elements has the following drawbacks:
firstly, the relay has long response time and slow action execution, and a phenomenon that a circuit cannot be cut off in time possibly occurs, so that certain potential safety hazards exist;
secondly, in the on-off action of the relay, the contact position is abraded due to collision, in the long-time use process, the contact abrasion phenomenon is gradually serious, the contact abrasion can possibly cause the relay to be incapable of normally realizing the on-off control function, the reliability is poor, electric arcs can be generated when the contacts collide, the electric arcs can possibly cause ignition, and certain safety hidden dangers exist;
thirdly, noise is generated in the on-off action of the relay, so that the working noise of the lithium battery is large, and the overcurrent protection circuit of the relay is adopted, so that the defects of large size, heavy weight, high power consumption and high component cost commonly exist.
In summary, in the conventional over-current protection circuit for a lithium battery, since a relay is used as a cut-off element, there are disadvantages of long response time, poor reliability, large size, and the like.
Disclosure of Invention
In order to solve the problems of the prior art, the present disclosure is directed to a battery overcurrent protection circuit. The cut-off protection module adopts a multi-MOS tube parallel structure, and has the advantages of high response speed, good expandability, good reliability and durability, small volume, light weight, low power consumption and low component cost.
The disclosed battery overcurrent protection circuit includes:
a main control module;
the cut-off protection module is connected among the battery pack, an external power supply and a load; the cut-off protection module comprises an MOS tube group, the MOS tube group comprises a plurality of MOS tubes, the source electrodes of the MOS tubes are connected in common, the drain electrodes of the MOS tubes are connected in common, the MOS tubes are in a parallel connection structure, and the signal output end of the main control module is connected with the grid electrodes of the MOS tubes;
the sampling detection module comprises a current detection unit, the current detection unit is electrically connected with the cut-off protection module, and the signal output end of the current detection unit is connected with the signal input end of the main control module and is used for detecting and obtaining a working current I;
when the working current I is less than or equal to a preset current threshold ImaxWhen the battery pack is powered on, the main control module continuously outputs a conducting signal to the grid electrode of the MOS tube, and the MOS tube is conducted to enable the battery pack to be powered on to work;
when the working current I is larger than a preset current threshold ImaxAnd when the power supply is switched off, the main control module stops outputting a conducting signal to the grid electrode of the MOS tube, and the MOS tube is switched off to cut off the power supply of the battery pack.
Preferably, the number of the MOS transistors is n, and n is calculated according to the following formula:
Figure BDA0003304975120000021
(n is rounded up);
wherein, IeIndicates the normal operating current, I, of the battery packe' represents rated current of the MOS tube, k represents reserved margin, and k satisfies 0<k<1。
Preferably, the margin k is 15%.
Preferably, the operating current I is calculated by:
is detected by the current detection unitThe working currents of t MOS tubes in the MOS tube group are sequentially marked as I1、I2...ItThe working current I is calculated according to the following formula:
Figure BDA0003304975120000022
preferably, t is 3.
Preferably, the number of the MOS tube groups is multiple groups, and the multiple groups of the MOS tube groups are connected in parallel.
Preferably, the cut-off protection module further comprises:
and the fuse is connected with the MOS tube group in series.
Preferably, the battery overcurrent protection circuit further includes:
the charging control module is connected between an external power supply and a battery pack, and a signal output end of the main control module is connected with an enabling end of the charging control module;
and the discharge control module is connected between the battery pack and the load, and the signal output end of the main control module is connected with the enabling end of the discharge control module.
Preferably, the sampling detection module further comprises:
the voltage detection unit is electrically connected with the battery pack and used for detecting the voltage of the battery pack, and the signal output end of the voltage detection unit is connected with the signal input end of the main control module;
the temperature detection unit is arranged at the battery pack and used for detecting the temperature of the battery pack, and the signal output end of the temperature detection unit is connected with the signal input end of the main control module.
Preferably, the main control module comprises an MCU.
The battery overcurrent protection circuit has the advantages that:
1. the cutting-off protection module comprises an MOS tube group, wherein the MOS tube group comprises a plurality of MOS tubes connected in parallel, and each MOS tube group is an independent module, so that the cutting-off protection module is integrally of a modular structure, the number of the arranged modules can be selected according to actual condition requirements and working current grades, the expandability is good, the cutting-off protection module is more flexible and convenient to use, and the maintenance and the replacement of the cutting-off protection module are more convenient;
2. according to the battery pack, the MOS tube is used as a cutting-off element, the response speed of the MOS tube is higher, the current can be cut off quickly and timely, the heat productivity of the battery pack is reduced, the service life of the battery pack is prolonged, and meanwhile, the safety of the battery pack is ensured;
3. the MOS tube disclosed by the invention does not have a contact collision action during on-off control, does not generate contact abrasion, has better durability, can keep a stable on-off control function in a long-time use process, and has better reliability; meanwhile, electric arcs generated by contact collision can be avoided, and potential safety hazards in the working process of the battery are reduced;
4. the MOS tube has no noise in the on-off action process, can reduce the working noise of the lithium battery, and meanwhile, the MOS tube group has small circuit component size and high integration level, so that the cut-off protection module has small size and light weight, which is beneficial to the miniaturization design of the battery;
5. the utility model discloses a cut off protection module still is equipped with the fuse, forms "dual fail-safe" through fuse and MOS nest of tubes, and accessible fuse fuses under overcurrent overheat environment when MOS nest of tubes became invalid, and then cuts off the circuit connection between group battery and the external power source/load, can play reliable and stable overcurrent protection effect.
Drawings
Fig. 1 is a schematic diagram of a battery overcurrent protection circuit according to the present disclosure;
fig. 2 is a logic diagram of the determination of the battery overcurrent protection circuit according to the present disclosure.
Description of reference numerals: the method comprises the following steps of 1-battery pack, 2-main control module, 3-cut-off protection module, 4-sampling detection module, 5-external power supply and 6-load.
Detailed Description
As shown in fig. 1, the battery overcurrent protection circuit according to the present disclosure is used in combination with a battery pack 1, where the battery pack 1 is a battery pack 1 of a common lithium battery, and is mainly used for storing and outputting electric energy.
The battery overcurrent protection circuit includes:
the main control module 2, the main control module 2 is mainly used for controlling the cut-off protection module 3 to execute a cut-off action to protect the battery pack 1 when the overcurrent occurs, and is also responsible for controlling the charge and discharge actions of the battery pack 1.
The protection module 3 is cut off, and the protection module 3 is connected between the battery pack 1 and an external power supply 5 (usually, commercial power), that is, the circuit communication between the battery pack 1 and the external power supply 5 is controlled by switching on or off the protection module 3 itself, when the protection module 3 is switched on, the battery pack 1 is switched on with the external power supply 5, the external power supply 5 can supply electric energy to the battery pack 1, and the battery pack 1 performs a charging action.
The cut-off protection module 3 is also connected between the battery pack 1 and the load 6, that is, the circuit communication between the battery pack 1 and the load 6 is controlled by the on and off of the cut-off protection module 3, when the cut-off protection module 3 is switched on, the battery pack 1 is switched on with the load 6, the battery pack 1 can transmit electric energy to the load 6, and the battery pack 1 performs a discharging action.
Cut off protection module 3 and specifically include MOS nest of tubes, MOS nest of tubes includes a plurality of MOS pipes, the source pole of a plurality of MOS pipes connects altogether, the drain electrode connects altogether, a plurality of MOS pipes connect to be modular structure, the structure of a plurality of MOS pipes connect can share the heavy current that group battery 1 during operation produced jointly by a plurality of MOS pipes, can satisfy the user demand of heavy current lithium cell, can set up the quantity of MOS pipe in a flexible way according to the electric current size of group battery 1 during operation, make this open extensive applicability who cuts off protection module 3 extensive. The single MOS battery pack is a module, a source electrode common contact and a drain electrode common contact are led out of pins outwards so as to be convenient for wiring, the source electrode common contact is connected to one end close to an external power supply 5, the drain electrode common contact is connected to one end close to a load 6, and the current input and output ends of the lithium battery pack 1 are electrically connected with the drain electrode common contact.
The signal output end of the main control module 2 is connected with the gates of the MOS transistors, more specifically, one of the signal output ends of the main control module 2 is simultaneously connected with the gates of all the MOS transistors, the main control module 2 synchronously outputs a conducting signal to all the MOS transistors through the signal output end, when the conducting signal is input to the gate of the MOS transistor, the source and the drain of the MOS transistor are conducted, so that the two ends of the MOS transistor are conducted, that is, the protection module 3 is switched off, otherwise, when no signal is input to the gate of the MOS transistor, the source and the drain are switched off, and the protection module 3 is switched off.
The sampling detection module 4, the sampling detection module 4 includes the current detection unit, the current detection unit with cut off protection module 3 electricity and be connected, the current detection unit adopt conventional current detection circuit can, its sense terminal is connected with cut off protection module 3 electricity, the signal output part of current detection unit connects the signal input part of host system 2 for in inputing the detected signal of current detection unit to host system 2. More specifically, the detection end of the detection circuit is electrically connected with one MOS tube of the MOS tube group and is used for detecting the internal current value of one MOS tube. The number of the current detection circuits can be multiple groups, and the current detection circuits are used for respectively detecting the internal current values of the multiple MOS tubes and calculating the total current at the two ends of the cut-off protection module 3, namely the working current I in the working circuit of the lithium battery according to the multiple groups of internal current values.
As shown in fig. 2, the main control module 2 calculates and obtains a real-time working current I of the battery pack 1 according to a real-time detection result of the current detection unit, and compares the obtained working current I with a preset current threshold ImaxComparing the values, wherein the current threshold value ImaxThe design can be made according to the maximum current that can be borne by the battery pack 1, the wires and other components, subject to that the components are not burned out, but are not overheated.
When the working current I is less than or equal to the preset current threshold ImaxWhen the current in the circuit is normal, the main control module 2 judges that the battery pack 1 normally works, the output end of the main control module 2 continuously outputs a conducting signal to the grids of all the MOS tubes to conduct the MOS tubes, so that the cut-off protection module 3 is conducted, at the moment, the battery pack 1 is in a conducting state with the external power supply 5/load 6, and the battery pack 1 can execute charging and discharging actions when being electrified.
When the working current isI is greater than a predetermined current threshold ImaxWhen the current in the circuit is over-current, the main control module 2 judges that the battery pack 1 works abnormally, the main control module 2 stops outputting a conducting signal to the grid electrode of the MOS tube at the moment, no signal is input to the grid electrode of the MOS tube, the MOS tube is turned off to turn off the cut-off protection module 3, the battery pack 1 is in a cut-off state with the external power supply 5/load 6 at the moment, and the battery pack 1 is powered off to stop executing charging and discharging actions.
The cutting-off protection module 3 comprises an MOS tube group, the MOS tube group comprises a plurality of MOS tubes connected in parallel, and each MOS tube group is an independent module, so that the cutting-off protection module 3 is integrally of a modular structure, the number of the set modules can be selected according to actual condition requirements and working current grades, the expandability is good, the use is more flexible and convenient, and the maintenance and the replacement of the cutting-off protection module 3 are more convenient;
according to the battery pack 1, the MOS tube is used as a cutting-off element, the response speed of the MOS tube is higher, the current can be cut off quickly and timely, the heat productivity of the battery pack 1 is reduced, the service life of the battery pack 1 is prolonged, and the safety of the battery pack 1 is ensured;
the MOS tube disclosed by the invention does not have a contact collision action during on-off control, does not generate contact abrasion, has better durability, can keep a stable on-off control function in a long-time use process, and has better reliability; meanwhile, electric arcs generated by contact point collision can be avoided, and potential safety hazards in the working process of the battery are reduced;
the MOS pipe of this disclosure is at the noiseless production of break-make action in-process, can reduce the working noise of lithium cell, and MOS nest of tubes circuit part is small simultaneously, the integrated level is high for cut off protection module 3 small, light in weight, this miniaturized design that is favorable to the battery, the MOS pipe still has the advantage that the low power dissipation is with low costs with the part in addition.
Further, in this embodiment, the number of the MOS transistors is n, and n is calculated according to the following formula:
Figure BDA0003304975120000061
(n is rounded up);
wherein, IeIndicating electricityNormal operating current, I, of battery pack 1e' represents rated current of the MOS tube, k represents reserved margin, and k satisfies 0<k<1；
Because a plurality of MOS transistors in the MOS transistor group are in a parallel connection structure, and the operating current of the battery pack 1 is divided equally by the plurality of MOS transistors, the number of MOS transistors needs to be determined according to the normal operating current of the battery pack 1 (i.e., the current in the circuit when the battery pack 1 operates normally), and the rated current of the selected MOS transistor, so as to reasonably determine the number of MOS transistors, so that the number of MOS transistors is appropriate, thereby avoiding the waste of components when the number is too large, and the phenomenon of the over-current burning of the MOS transistors when the number is too small. Furthermore, during specific circuit design, a certain margin k needs to be reserved to avoid the MOS transistor from being burnt out due to overcurrent, so that the reliability and stability of the protection module 3 are better.
More specifically, the margin k is 15% so that the number of the MOS transistors is appropriate, and both the redundancy of the number of the MOS transistors and the burning-out of a single MOS transistor due to overcurrent can be avoided.
Further, in the present embodiment, the operating current I is calculated as follows:
detecting the working current of t MOS tubes in the MOS tube group through the current detection unit, and sequentially marking as I1、I2...ItThe working current I is calculated according to the following formula:
Figure BDA0003304975120000062
the working current I represents a current in a circuit when the battery pack 1 operates, that is, currents at two ends of the protection cutoff module 3, and since the MOS tube group of the protection cutoff module 3 is a structure in which a plurality of MOS tubes are connected in parallel, in order to make calculation of the working current I accurate, the calculation method described above is adopted, t of the MOS tubes are selected, the working currents (that is, internal circulating currents) of the selected t MOS tubes are detected by a current detection unit, more specifically, t may be 3, the working current values of the t MOS tubes are added and then divided by t, that is, a mean value of the working currents of the selected t MOS tubes is obtained, and then according to characteristics of the connected structure, the obtained mean value is multiplied by the number n of the MOS tubes, that is, the currents at two ends of the protection cutoff module 3, that is, the required working current I, can be obtained.
The multi-MOS tube parallel connection structure has the advantages that the working current I is convenient to calculate, the calculation result is accurate through the working current I calculated in the mode, and the overcurrent protection control process of the battery is facilitated.
Further, in this embodiment, the quantity of MOS nest of tubes is the multiunit, multiunit MOS nest of tubes connects, every group MOS nest of tubes is an solitary module, the source electrode of each MOS nest of tubes is connected altogether, the drain electrode is connected altogether, make and be the structure of connecting between each MOS nest of tubes, in concrete embodiment, can be according to the MOS pipe quantity commonly used, the MOS nest of tubes of multiple specification (MOS pipe quantity is different) is formed in the processing, when protection module 3 is cut off in the assembly like this, just can select the MOS nest of tubes of required specification for use in a flexible way according to the demand to install, make this disclosed battery overcurrent protection circuit scalability good, it is convenient nimble more during the assembly.
Further, in this embodiment, the cut-off protection module 3 further includes:
the fuse, the fuse concatenates with the MOS nest of tubes, and when the fuse fusing, cutting off protection module 3 is the off-state, forms "dual fail-safe" through fuse and MOS nest of tubes, and accessible fuse fuses under overcurrent overheat environment when the MOS nest of tubes became invalid, and then cuts off the circuit connection between group battery 1 and external power source 5/load 6, can play reliable and stable overcurrent protection effect.
Further, in this embodiment, the battery overcurrent protection circuit further includes:
the charging control module is connected between an external power supply 5 and the battery pack 1, and the signal output end of the main control module 2 is connected with the enabling end of the charging control module; specifically, the charging control module comprises conventional charging control circuit and two switch triodes, the signal output part of main control module 2 is connected to charging control circuit one end, the other end is connected to the base of two switch triodes, the collecting electrode and the projecting electrode of two switch triodes are connected to the connecting circuit between external power supply 5 and group battery 1, when main control module 2 outwards exports the drive signal that charges, two switch triodes switch on, make group battery 1 switch-on external power supply 5 charge.
And the discharge control module is connected between the battery pack 1 and the load 6, and the signal output end of the main control module 2 is connected with the enabling end of the discharge control module. Specifically, the discharge control module is composed of a conventional discharge control circuit and two switching triodes, one end of the discharge control circuit is connected with the signal output end of the main control module 2, the other end of the discharge control circuit is connected with the base electrodes of the two switching triodes, the collector electrodes and the emitter electrodes of the two switching triodes are connected to the connecting circuit between the load 6 and the battery pack 1, and when the main control module 2 outputs a discharge driving signal outwards, the two switching triodes are conducted, so that the battery pack 1 is connected with the load 6 to discharge.
The charging control module and the discharging control module can be matched with the main control module 2 to stably control the charging and discharging actions of the battery pack 1, and have simple structure and low component cost.
Further, in this embodiment, the sampling detection module 4 further includes:
the voltage detection unit is a conventional voltage detection circuit, the voltage detection unit is electrically connected with the battery pack 1 and is used for detecting the voltage of the battery pack 1, and the signal output end of the voltage detection unit is connected with the signal input end of the main control module 2. More specifically, the voltage detection unit is connected to the input/output end of the battery pack 1 to detect the voltage of the battery pack 1 in real time, and further determine the power storage state of the battery pack 1, when the voltage of the battery pack 1 rises to a certain value, the main control module 2 determines that the charging of the battery pack 1 is completed, and controls the battery pack 1 to stop charging through the charging control module.
Temperature detecting element, thermistor temperature detection circuit can be chooseed for use to temperature detecting element, also can choose for use the temperature sensor circuit that integrates, temperature detecting element sets up the temperature that is used for detecting group battery 1 in group battery 1 department, the signal output part of temperature detecting element connects main control module 2's signal input part, main control module 2 receives temperature detecting element's detected signal, discern the conversion with the signal, then the temperature of accessible external display equipment to group battery 1 department shows, so that grasp the running state of battery better.
Further, in this embodiment, the main control module 2 includes an MCU (micro controller Unit), which has the advantages of small size, fast operation and low energy consumption, and is suitable for being used as a control element of the main control module 2 of this embodiment.
In the description of the present disclosure, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience in describing and simplifying the disclosure, and in the absence of a contrary explanation, these directional terms are not intended to indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present disclosure.
Various other modifications and changes may be made by those skilled in the art based on the above teachings and concepts, and all such modifications and changes are intended to fall within the scope of the claims of this disclosure.

Claims (10)

1. A battery overcurrent protection circuit, comprising:
a main control module;
the cut-off protection module is connected among the battery pack, an external power supply and a load; the cut-off protection module comprises an MOS tube group, the MOS tube group comprises a plurality of MOS tubes, the sources of the MOS tubes are connected in common, the drains of the MOS tubes are connected in common, the MOS tubes are in a parallel connection structure, and the signal output end of the main control module is connected with the grids of the MOS tubes;
the sampling detection module comprises a current detection unit, the current detection unit is electrically connected with the cut-off protection module, and the signal output end of the current detection unit is connected with the signal input end of the main control module and is used for detecting and obtaining a working current I;
when the working current I is less than or equal to a preset current threshold ImaxWhen the battery pack is powered on, the main control module continuously outputs a conducting signal to the grid electrode of the MOS tube, and the MOS tube is conducted to enable the battery pack to be powered on to work;
when the working current I is larger than a preset current threshold ImaxAnd when the power supply is switched off, the main control module stops outputting a conducting signal to the grid electrode of the MOS tube, and the MOS tube is switched off to cut off the power supply of the battery pack.
2. The battery overcurrent protection circuit of claim 1, wherein the number of the MOS transistors is n, and n is calculated according to the following formula:
Figure FDA0003304975110000011
(n is rounded up);
wherein, IeIndicates the normal operating current, I, of the battery packe' represents rated current of the MOS tube, k represents reserved margin, and k satisfies 0<k<1。
3. The battery overcurrent protection circuit of claim 2, wherein the margin k is 15%.
4. The battery overcurrent protection circuit of claim 2, wherein the operating current I is calculated by:
detecting the working current of t MOS tubes in the MOS tube group through the current detection unit, and sequentially marking as I1、I2...ItThe working current I is calculated according to the following formula:
Figure FDA0003304975110000012
5. the battery overcurrent protection circuit of claim 4, wherein t is 3.
6. The battery overcurrent protection circuit according to claim 4, wherein the number of the MOS tube sets is plural, and the plural MOS tube sets are connected in parallel.
7. The battery overcurrent protection circuit of claim 1, wherein the trip protection module further comprises:
and the fuse is connected with the MOS tube group in series.
8. The battery overcurrent protection circuit of claim 1, further comprising:
the charging control module is connected between an external power supply and a battery pack, and a signal output end of the main control module is connected with an enabling end of the charging control module;
and the discharge control module is connected between the battery pack and the load, and the signal output end of the main control module is connected with the enabling end of the discharge control module.
9. The battery overcurrent protection circuit of claim 8, wherein the sampling detection module further comprises:
the voltage detection unit is electrically connected with the battery pack and used for detecting the voltage of the battery pack, and the signal output end of the voltage detection unit is connected with the signal input end of the main control module;
the temperature detection unit is arranged at the battery pack and used for detecting the temperature of the battery pack, and the signal output end of the temperature detection unit is connected with the signal input end of the main control module.
10. The battery overcurrent protection circuit of claim 1, wherein the main control module comprises an MCU.
CN202111202181.2A 2021-10-15 2021-10-15 Battery overcurrent protection circuit Pending CN113922338A (en)

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Citations (4)

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Publication number Priority date Publication date Assignee Title
US20100072950A1 (en) * 2008-09-25 2010-03-25 Yoshinao Tatebayashi Assembled battery system
CN106655107A (en) * 2017-01-20 2017-05-10 深圳市木村机电有限公司 High power lithium battery protector
CN108063428A (en) * 2017-09-23 2018-05-22 华为技术有限公司 A kind of apparatus for protecting power supply and the terminal using described device
CN209658953U (en) * 2019-04-30 2019-11-19 苏州杰跃飞电子科技有限公司 Series-connected cell group power module

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Publication number Priority date Publication date Assignee Title
US20100072950A1 (en) * 2008-09-25 2010-03-25 Yoshinao Tatebayashi Assembled battery system
CN106655107A (en) * 2017-01-20 2017-05-10 深圳市木村机电有限公司 High power lithium battery protector
CN108063428A (en) * 2017-09-23 2018-05-22 华为技术有限公司 A kind of apparatus for protecting power supply and the terminal using described device
CN209658953U (en) * 2019-04-30 2019-11-19 苏州杰跃飞电子科技有限公司 Series-connected cell group power module

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Application publication date: 20220111