CN215552564U

CN215552564U - Secondary protection device for lithium battery of electric vehicle

Info

Publication number: CN215552564U
Application number: CN202122262401.2U
Authority: CN
Inventors: 潘赞明
Original assignee: Hangzhou Jisu Electronics Co ltd
Current assignee: Hangzhou Jisu Electronics Co ltd
Priority date: 2021-09-17
Filing date: 2021-09-17
Publication date: 2022-01-18
Anticipated expiration: 2031-09-17

Abstract

The utility model belongs to the technical field of battery protection, and discloses a secondary protection device for a lithium battery of an electric vehicle, which comprises a primary protection circuit and a secondary protection circuit which are connected in series with an output main circuit, wherein the secondary protection circuit comprises an MCU chip, a relay connected in series with the primary protection circuit main circuit, and a power control circuit connected in series between the relay and the MCU, and one control end pin of the relay is connected with a 12V power supply. According to the utility model, through adding the secondary relay protection device, one path of relay is added in the output main loop, and the singlechip controls the secondary protection of the relay through the logic circuit, so that the problem that the charging and discharging of the battery cannot be protected due to the breakdown, direct connection and failure of the charging and discharging MOS tube is solved, the potential hazard of overcharge or ignition is prevented, and the secondary protection circuit has the advantages of simple structure, small volume, strong practicability, low cost, easiness in popularization and obvious practical and economic benefits.

Description

Secondary protection device for lithium battery of electric vehicle

Technical Field

The utility model belongs to the technical field of battery protection, and particularly relates to a secondary protection device for a lithium battery of an electric vehicle.

Background

The conventional power system of the electric vehicle mainly uses a lithium battery as a power battery, and the lithium battery is provided with a fixed charging and discharging voltage platform, so that safety accidents such as ignition and explosion of the lithium battery caused by excessive charging can be caused if the lithium battery is directly used without a protection plate, and the power battery of the electric vehicle applied to the lithium battery must be provided with the corresponding protection plate.

The electric motor car lithium battery protection board on the market at present divides into two types, hardware board and software board, and what the hardware board adopted is battery protection IC, and the hardware protection circuit who builds protects the group battery, and this scheme is with low costs, and it is relatively poor to be applied to lithium iron phosphate and the ternary battery protection on the reliability.

On the basis of a single chip microcomputer, the software board controls the on-off of the MOS tube through an IC embedded software program to control the output to be switched off, the PCB board is provided with an IC, an MOS switch, a precision resistor, an NTC and the like and has the functions of overcharge protection, overdischarge protection, overcurrent protection, over-temperature protection, short-circuit protection and the like, and if the lithium battery pack is abnormal, the IC controls the on-off of the charge-discharge MOS tube to realize the cut-off output of the battery pack, so that the equipment is protected and the use is safe.

However, in the practical application process, due to the inconsistency of the components, the breakdown is straight, the MOS tube cannot be turned off due to the inconsistency of the MOS tube, the output circuit of the lithium battery cannot be turned off due to the failure of the control circuit, and the hidden danger of ignition or explosion occurs in the use process, particularly the charging process of the battery pack.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems and provides a secondary protection device for a lithium battery of an electric vehicle, which has the advantage of secondary protection of the lithium battery.

In order to achieve the purpose, the utility model provides the following technical scheme: the utility model provides an electric motor car lithium cell secondary protection device, is including establishing ties in the one-level protection circuit and the secondary protection circuit of output major loop, the secondary protection circuit is including the MCU chip, establishes ties in the relay of one-level protection circuit major loop to and the power control circuit of establishing ties between relay and MCU, one of them control end pin of relay inserts the 12V power.

As a preferred technical scheme of the utility model, the power control circuit is composed of a Darlington tube and a current-limiting resistor, the base electrode of the Darlington tube is connected with the I/O port of the MCU through a current-limiting resistor, the emitting electrode of the Darlington tube is grounded, the collector electrode of the Darlington tube is connected with the pin at the other control end of the relay, when the primary protection circuit works normally, the MCU outputs high level to the base electrode of the Darlington tube, so that the Darlington tube is in an amplifying state, the relay coil is controlled to be electrified normally, the relay coil is electrified to close the switch, the main loop of the primary protection circuit is in a normal conduction state, when the MOS tube of the primary protection circuit is broken down and the primary protection circuit fails, the MCU outputs a low level to the base electrode of the Darlington tube, the Darlington tube is cut off, then the relay is turned off, and the primary protection circuit is turned off to lead the main output circuit to be turned off.

As a preferred technical scheme of the utility model, the power control circuit is composed of a photoelectric coupler and a current-limiting resistor, the base of the photoelectric coupler is connected with an I/O port of the MCU through the current-limiting resistor, the emitter of the photoelectric coupler and the cathode of the light-emitting diode are both grounded, the collector of the photoelectric coupler is connected with the other control end pin of the relay, when the primary protection circuit works normally, the MCU outputs high level to the base of the photoelectric coupler, so that the photoelectric coupler works normally, a relay coil circuit connected with the photoelectric coupler is conducted, the relay coil is electrified to close the switch, then the main loop of the primary protection circuit is in a normal conduction state, when the MOS tube of the primary protection circuit is broken down, the primary protection circuit fails, and the MCU outputs low level to the base of the photoelectric coupler, so that the light-emitting diode of the photoelectric coupler does not emit light, then the phototriode is cut off, the coil of the relay is not electrified, then the relay switch is turned off, and the primary protection circuit is turned off to lead the main output circuit to be turned off.

Compared with the prior art, the utility model has the following beneficial effects:

according to the utility model, a secondary relay protection device is added on the original basis of the lithium battery protection board of the electric vehicle, one path of relay is added in an output main loop, and the singlechip controls the secondary protection of the relay through a logic circuit, so that the problem that the charging and discharging of the battery cannot be protected due to the breakdown, direct connection and failure of a charging and discharging MOS tube is solved, the potential hazard of overcharge or ignition is prevented, and the secondary protection circuit has the advantages of simple structure, small volume, strong practicability, low cost, easiness in popularization and obvious practical and economic benefits.

Drawings

FIG. 1 is a circuit diagram of a second embodiment of a secondary protection device according to the present invention;

FIG. 2 is a circuit diagram of a second embodiment of the secondary protection device of the present invention;

in the figure: 1. a primary protection circuit; 2. and a secondary protection circuit.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 2, the present invention provides a secondary protection device for a lithium battery of an electric vehicle, which comprises a primary protection circuit 1 and a secondary protection circuit 2 connected in series with an output main circuit, wherein the secondary protection circuit 2 comprises an MCU chip, a relay connected in series with the main circuit of the primary protection circuit 1, and a power control circuit connected in series between the relay and the MCU, and one control terminal pin of the relay is connected to a 12V power supply.

FIG. 1 is a circuit diagram of a first embodiment of the two-stage protection circuit of the present invention, in which the power control circuit is composed of a Darlington transistor and a current-limiting resistor, the base of the Darlington transistor is connected to the I/O port of the MCU through the current-limiting resistor, the emitter of the Darlington transistor is grounded, the collector of the Darlington transistor is connected to the other control terminal pin of the relay, when the primary protection circuit 1 works normally, the MCU outputs high level to the base electrode of the Darlington tube, so that the Darlington tube is in an amplifying state, the relay coil is controlled to be normally electrified, the relay coil is electrified to close the switch, the main loop of the primary protection circuit 1 is in a normal conducting state, when the MOS tube of the primary protection circuit 1 is broken down, the primary protection circuit 1 fails, the MCU outputs a low level to the base electrode of the Darlington tube, the Darlington tube is cut off, then the relay is turned off, and the primary protection circuit 1 is turned off to lead the main output loop to be turned off.

FIG. 2 is a circuit diagram of a second embodiment of the secondary protection circuit of the present invention, in which the power control circuit is composed of a photoelectric coupler and a current-limiting resistor, the base of the photoelectric coupler is connected to the I/O port of the MCU through the current-limiting resistor, the emitter of the photoelectric coupler and the cathode of the light-emitting diode are both grounded, the collector of the photoelectric coupler is connected to the other control terminal pin of the relay, when the primary protection circuit 1 is working normally, the MCU outputs a high level to the base of the photoelectric coupler, so that the photoelectric coupler is working normally, the relay coil circuit connected to the photoelectric coupler is turned on, the relay coil is charged to close the switch, so the main circuit of the primary protection circuit 1 is in a normal conduction state, when the MOS transistor of the primary protection circuit 1 is broken down, the primary protection circuit 1 is disabled, and the MCU outputs a low level to the base of the photoelectric coupler, the light emitting diode of the photoelectric coupler does not emit light, so that the phototriode is cut off, the coil of the relay is not electrified, the relay switch is turned off, and the primary protection circuit 1 is turned off to turn off the main output loop.

The working principle and the using process of the utility model are as follows:

the secondary protection circuit of the electric vehicle management system is in an electrified use state, the secondary protection circuit is conducted by default, when the primary protection fails, the secondary protection control circuit acts to actively disconnect the main power circuit, and the purpose of secondary protection of a battery pack is achieved;

specifically, the secondary protection circuit is composed of a power control circuit, the power control circuit comprises two components, one is controlled by a Darlington tube formed by connecting triodes in series, the other is directly realized by a photoelectric coupler, the working principle of the two components is basically the same, after the primary protection circuit 1 fails, an MCU (microprogrammed control unit) can lower the level of an I/O (input/output) port connected with the secondary protection circuit 2, the phototriode of the Darlington tube or the photoelectric coupler is cut off, and a relay is turned off, so that a main output circuit is turned off, and the secondary protection effect is realized.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides an electric motor car lithium cell secondary protection device, is including establishing ties in output primary circuit's one-level protection circuit (1) and secondary protection circuit (2), its characterized in that: the secondary protection circuit (2) comprises an MCU chip, a relay connected in series with a main loop of the primary protection circuit (1), and a power control circuit connected in series between the relay and the MCU, wherein one control end pin of the relay is connected into a 12V power supply.

2. The secondary protection device for the lithium battery of the electric vehicle as claimed in claim 1, wherein: the power control circuit is composed of a Darlington tube and a current-limiting resistor, the base of the Darlington tube is connected with an I/O port of the MCU through the current-limiting resistor, the emitting electrode of the Darlington tube is grounded, and the collecting electrode of the Darlington tube is connected with the other control end pin of the relay.

3. The secondary protection device for the lithium battery of the electric vehicle as claimed in claim 1, wherein: the power control circuit is composed of a photoelectric coupler and a current-limiting resistor, the base of the photoelectric coupler is connected with an I/O port of the MCU through the current-limiting resistor, the emitter of the photoelectric coupler and the cathode of the light-emitting diode are both grounded, and the collector of the photoelectric coupler is connected with the other control end pin of the relay.