CN111751744A - Insulation monitoring circuit and monitoring method for lithium battery pack - Google Patents
Insulation monitoring circuit and monitoring method for lithium battery pack Download PDFInfo
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- CN111751744A CN111751744A CN202010612859.3A CN202010612859A CN111751744A CN 111751744 A CN111751744 A CN 111751744A CN 202010612859 A CN202010612859 A CN 202010612859A CN 111751744 A CN111751744 A CN 111751744A
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- insulation resistance
- battery cluster
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- 238000009413 insulation Methods 0.000 title claims abstract description 73
- 238000012544 monitoring process Methods 0.000 title claims abstract description 31
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 13
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 13
- 238000000034 method Methods 0.000 title claims abstract description 9
- 238000005070 sampling Methods 0.000 claims abstract description 16
- 238000001514 detection method Methods 0.000 claims abstract description 15
- 238000010586 diagram Methods 0.000 description 4
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/385—Arrangements for measuring battery or accumulator variables
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/025—Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
Abstract
An insulation monitoring circuit and a monitoring method of a lithium battery pack comprise a battery cluster, a voltage detection module, a sampling operational amplifier circuit, a digital processing module, a fault alarm module, a switch, equivalent insulation impedance and a plurality of resistors; the positive electrode and the negative electrode of the battery cluster are respectively connected with two resistors; the battery cluster is connected with equivalent insulation resistance, the equivalent insulation resistance is divided into two paths, one path is grounded, and the other path and the negative electrode of the battery cluster are respectively connected with a voltage detection module, a sampling operational amplifier circuit, a digital processing module and a fault alarm module in sequence; and a switch is arranged between one resistor on the positive side of the battery cluster and the equivalent insulation resistance, and between one resistor on the negative side of the battery cluster and the equivalent insulation resistance. The invention has low cost and simple realization.
Description
Technical Field
The invention belongs to the technical field of battery insulation monitoring, and particularly relates to an insulation monitoring circuit and an insulation monitoring method for a lithium battery pack.
Background
A Battery Management System (BMS) is a link between a Battery and a user, and a primary object is a secondary Battery. The secondary battery has some disadvantages such as a small amount of stored energy, a short life, a problem of series-parallel use, safety in use, difficulty in estimating the amount of electricity of the battery, etc. The performance of the battery is complex and the characteristics of different types of batteries vary widely. A Battery Management System (BMS) is mainly to improve the utilization rate of a battery, prevent overcharge and overdischarge of the battery, extend the life span of the battery, and monitor the state of the battery.
The current battery management system does not have an insulation monitoring function generally, can not detect the change of the insulation condition of the battery pack in real time and dynamically, and is not beneficial to the safe use of the battery box.
Disclosure of Invention
The invention aims to provide an insulation monitoring circuit and an insulation monitoring method for a lithium battery pack, so as to solve the problems.
In order to achieve the purpose, the invention adopts the following technical scheme:
an insulation monitoring circuit of a lithium battery pack comprises a battery cluster, a voltage detection module, a sampling operational amplifier circuit, a digital processing module, a fault alarm module, a switch, equivalent insulation impedance and a plurality of resistors; the positive electrode and the negative electrode of the battery cluster are respectively connected with two resistors; the battery cluster is connected with equivalent insulation resistance, the equivalent insulation resistance is divided into two paths, one path is grounded, and the other path and the negative electrode of the battery cluster are respectively connected with a voltage detection module, a sampling operational amplifier circuit, a digital processing module and a fault alarm module in sequence; and a switch is arranged between one resistor on the positive side of the battery cluster and the equivalent insulation resistance, and between one resistor on the negative side of the battery cluster and the equivalent insulation resistance.
Furthermore, the battery cluster consists of a plurality of batteries which are connected in series to form a battery string, and the plurality of batteries are connected in series to form the battery cluster; the insulation resistance of each battery to the case is RsnpnAnd finally, adding the equivalent insulation resistance Ri to the insulation resistance of all the batteries.
Further, the resistors are a resistor R1, a resistor R2, a resistor R3 and a resistor R4; the two resistors on the positive side of the battery cluster are a resistor R1 and a resistor R3, and the two resistors on the negative side of the battery cluster are a resistor R2 and a resistor R4; the resistance values of R3 and R4 are far smaller than the resistance values of R1 and R2; the switches are respectively arranged on the side surfaces of the resistor R3 and the resistor R4.
Further, the resistor R3 and the resistor R4 are switched by the switch S1 and the switch S2.
Further, a monitoring method of an insulation monitoring circuit of a lithium battery pack comprises the following steps:
step 1, after the processor starts the self-checking function, firstly closing S1 and opening S2 to obtain that Earth has a voltage sampling value of UE1 for the negative pole of the battery, and a voltage sampling value of the positive pole of the battery is UBAT +, and an equation formula one can be listed according to the node current:
step 3, listing the equivalent insulation resistance of the whole battery box body to obtain a formula III:
Rs1p1+Rs1p2+......+Rs1pn+Rs1p1+Rs1p2+......+Rs2pn+Rs2p1+Rs2p2+......+Rsnpn＝Ri(formula three);
step 4, solving the equations with the first, second and third formulas to obtain an equivalent insulation resistance value formula IV as follows:
step 5, comparing the result of the formula IV with a protection threshold value set in a program so as to judge whether the battery box body has insulation fault;
step 6: after the processor processes the monitoring signals, if insulation monitoring faults exist, the processor transmits the insulation monitoring fault signals to the host computer so as to remind relevant workers to check.
Compared with the prior art, the invention has the following technical effects:
according to the invention, through the change-over switch and the matching of sampling feedback signals, the insulation detection of the battery box body can be effectively and reliably realized through the calculation of an internal formula of the processor;
according to the invention, through the cyclic processing of the processor, the insulation detection of the battery box body can be effectively realized in real time;
the invention mainly comprises S1, S2 and two groups of resistors, and has low cost and simple realization.
Drawings
FIG. 1 is an equivalent diagram of the insulation resistance detection of the battery according to the present invention.
FIG. 2 is a schematic diagram of an equivalent switch mode for detecting insulation resistance of a battery according to the present invention.
Fig. 3 is a schematic diagram of the insulation resistance detection switch mode of the battery according to the present invention.
FIG. 4 is a flow chart of the insulation monitoring software of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
referring to fig. 1 to 4, an insulation monitoring circuit of a lithium battery pack includes a battery cluster, a voltage detection module, a sampling operational amplifier circuit, a digital processing module, a fault alarm module, a switch, an equivalent insulation resistance, and a plurality of resistors; the positive electrode and the negative electrode of the battery cluster are respectively connected with two resistors; the battery cluster is connected with equivalent insulation resistance, the equivalent insulation resistance is divided into two paths, one path is grounded, and the other path and the negative electrode of the battery cluster are respectively connected with a voltage detection module, a sampling operational amplifier circuit, a digital processing module and a fault alarm module in sequence; and a switch is arranged between one resistor on the positive side of the battery cluster and the equivalent insulation resistance, and between one resistor on the negative side of the battery cluster and the equivalent insulation resistance.
The battery cluster consists of a plurality of batteries which are connected in series to form a battery string, and the plurality of batteries are connected in series and in parallel to form the battery cluster; the insulation resistance of each battery to the case is RsnpnAnd finally, adding the equivalent insulation resistance Ri to the insulation resistance of all the batteries.
The resistors are a resistor R1, a resistor R2, a resistor R3 and a resistor R4; the two resistors on the positive side of the battery cluster are a resistor R1 and a resistor R3, and the two resistors on the negative side of the battery cluster are a resistor R2 and a resistor R4; the resistance values of R3 and R4 are far smaller than the resistance values of R1 and R2; the switches are respectively arranged on the side surfaces of the resistor R3 and the resistor R4.
The resistor R3 and the resistor R4 are switched by the switch S1 and the switch S2.
Fig. 1 is an equivalent schematic diagram of a battery box unit and its insulation monitoring circuit, assuming that the insulation resistance of each battery to the casing is Rs × b, and the final equivalent insulation resistance value Ri is the insulation sum of all batteries. In the circuit design, the resistance values of R3 and R4 are much smaller than the resistance values of R1 and R2. Wherein R1, R3 are switched through S1, R2, R4 are switched through S2, S1, S2 are the switch.
A first switching mode:
s1 and S2 are both in an open state, and after the processor starts the insulation resistance detection function, S1 is first closed and S2 is opened, as shown in fig. 2, the sampled value of Earth voltage to the negative pole of the battery is UE1, the sampled value of positive pole voltage to the negative pole of the battery is UBAT +, and then the following equations can be listed according to the node current:
and a second switching mode:
then, S1 is opened and S2 is closed, as shown in fig. 3, when the voltage sample value of Earth to the negative electrode of the battery is UE2, the following equations can be listed according to the node current:
calculating equivalent impedance:
wherein the equivalent insulation resistance of the whole battery pack is:
Rs1p1+Rs1p2+......+Rs1pn+Rs1p1+Rs1p2+......+Rs2pn+Rs2p1+Rs2p2+......+Rsnpn＝Ri(formula three)
Solving the equations with the first, second and third equations can obtain a fourth equation as follows:
software flow:
fig. 4 shows a software flowchart of insulation monitoring, the starting states of S1 and S2 are all disconnected, after insulation monitoring is started, S1 is closed first, S2 is kept in the disconnected state, the state keeping time is T1, in this period of time, the processor samples UE1 and the voltage sampling value UBAT + of the positive electrode and the negative electrode of the battery, then S1 is disconnected, S2 is closed, and T1 is also kept for the same time, at this time, the processor samples UE2, then S1 is disconnected, S2 is called by a formula, a final equivalent resistance is calculated, when the calculated resistance value is greater than the set protection threshold value, the detection is passed, the insulation impedance is determined to be normal, when the calculated resistance value is less than the set protection threshold value, the detection is not passed, the insulation impedance is determined to be abnormal, and a system error report is reported.
Claims (5)
1. An insulation monitoring circuit of a lithium battery pack is characterized by comprising a battery cluster, a voltage detection module, a sampling operational amplifier circuit, a digital processing module, a fault alarm module, a switch, equivalent insulation impedance and a plurality of resistors; the positive electrode and the negative electrode of the battery cluster are respectively connected with two resistors; the battery cluster is connected with equivalent insulation resistance, the equivalent insulation resistance is divided into two paths, one path is grounded, and the other path and the negative electrode of the battery cluster are respectively connected with a voltage detection module, a sampling operational amplifier circuit, a digital processing module and a fault alarm module in sequence; and a switch is arranged between one resistor on the positive side of the battery cluster and the equivalent insulation resistance, and between one resistor on the negative side of the battery cluster and the equivalent insulation resistance.
2. The insulation monitoring circuit of a lithium battery pack as claimed in claim 1, wherein the battery cluster is composed of a plurality of batteries, the plurality of batteries are connected in series to form a battery string, and the plurality of battery strings are connected in parallel to form the battery cluster; the insulation resistance of each battery to the case is RsnpnAnd finally, adding the equivalent insulation resistance Ri to the insulation resistance of all the batteries.
3. The insulation monitoring circuit of a lithium battery pack as claimed in claim 2, wherein the plurality of resistors are a resistor R1, a resistor R2, a resistor R3 and a resistor R4; the two resistors on the positive side of the battery cluster are a resistor R1 and a resistor R3, and the two resistors on the negative side of the battery cluster are a resistor R2 and a resistor R4; the resistance values of R3 and R4 are far smaller than the resistance values of R1 and R2; the switches are respectively arranged on the side surfaces of the resistor R3 and the resistor R4.
4. The insulation monitoring circuit of a lithium battery pack as claimed in claim 3, wherein the resistor R3 and the resistor R4 are switched by the switch S1 and the switch S2.
5. A monitoring method of an insulation monitoring circuit of a lithium battery pack, which is based on any one of claims 1 to 4, and comprises the following steps:
step 1, after the processor starts the self-checking function, firstly closing S1 and opening S2 to obtain that Earth has a voltage sampling value of UE1 for the negative pole of the battery, and a voltage sampling value of the positive pole of the battery is UBAT +, and an equation formula one can be listed according to the node current:
step 2, opening S1, closing S2, obtaining that the voltage sampling value of Earth to the battery cathode is UE2, and listing an equation formula two according to the node current:
step 3, listing the equivalent insulation resistance of the whole battery box body to obtain a formula III:
Rs1p1+Rs1p2+......+Rs1pn+Rs1p1+Rs1p2+......+Rs2pn+Rs2p1+Rs2p2+......+Rsnpn＝Ri(formula three);
step 4, solving the equations with the first, second and third formulas to obtain an equivalent insulation resistance value formula IV as follows:
step 5, comparing the result of the formula IV with a protection threshold value set in a program so as to judge whether the battery box body has insulation fault;
step 6: after the processor processes the monitoring signals, if insulation monitoring faults exist, the processor transmits the insulation monitoring fault signals to the host computer so as to remind relevant workers to check.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010612859.3A CN111751744A (en) | 2020-06-30 | 2020-06-30 | Insulation monitoring circuit and monitoring method for lithium battery pack |
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| CN202010612859.3A CN111751744A (en) | 2020-06-30 | 2020-06-30 | Insulation monitoring circuit and monitoring method for lithium battery pack |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004117226A (en) * | 2002-09-27 | 2004-04-15 | Furukawa Battery Co Ltd:The | Internal impedance measuring method for battery |
| CN103033729A (en) * | 2012-11-26 | 2013-04-10 | 浙江高泰昊能科技有限公司 | Insulation detection circuit and detection method used for battery box |
| CN205609645U (en) * | 2016-03-26 | 2016-09-28 | 深圳市沃特玛电池有限公司 | Battery energy storage system |
| KR20170057004A (en) * | 2015-11-16 | 2017-05-24 | 주식회사 엘지화학 | System and apparatus for measuring of insulation resistance |
| CN110568372A (en) * | 2019-09-27 | 2019-12-13 | 安徽鸿创新能源动力有限公司 | Detection circuit and method for total voltage and insulation resistance of battery pack |
| CN110707386A (en) * | 2019-11-20 | 2020-01-17 | 桑顿新能源科技有限公司 | Battery pack, detection method and detection device for electric leakage position point of battery pack and vehicle |
| CN110716150A (en) * | 2019-10-15 | 2020-01-21 | 阳光电源股份有限公司 | Energy storage system and insulation detection method thereof |
-
2020
- 2020-06-30 CN CN202010612859.3A patent/CN111751744A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004117226A (en) * | 2002-09-27 | 2004-04-15 | Furukawa Battery Co Ltd:The | Internal impedance measuring method for battery |
| CN103033729A (en) * | 2012-11-26 | 2013-04-10 | 浙江高泰昊能科技有限公司 | Insulation detection circuit and detection method used for battery box |
| KR20170057004A (en) * | 2015-11-16 | 2017-05-24 | 주식회사 엘지화학 | System and apparatus for measuring of insulation resistance |
| EP3258280A1 (en) * | 2015-11-16 | 2017-12-20 | LG Chem, Ltd. | Insulation resistance measuring system and device |
| CN205609645U (en) * | 2016-03-26 | 2016-09-28 | 深圳市沃特玛电池有限公司 | Battery energy storage system |
| CN110568372A (en) * | 2019-09-27 | 2019-12-13 | 安徽鸿创新能源动力有限公司 | Detection circuit and method for total voltage and insulation resistance of battery pack |
| CN110716150A (en) * | 2019-10-15 | 2020-01-21 | 阳光电源股份有限公司 | Energy storage system and insulation detection method thereof |
| CN110707386A (en) * | 2019-11-20 | 2020-01-17 | 桑顿新能源科技有限公司 | Battery pack, detection method and detection device for electric leakage position point of battery pack and vehicle |
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Effective date of registration: 20221219 Address after: Room 501, Zone B, Financial Investment Integrated Circuit Industrial Park, No. 5, Guanshan Road, Xinwu District, Wuxi City, Jiangsu Province, 214029 Applicant after: Jiangsu Ping'an New Energy Technology Co.,Ltd. Address before: Room 2963, 14C, No. 309, Tanggu Road, Hongkou District, Shanghai, 200080 Applicant before: Shanghai Pingan New Energy Technology Co.,Ltd. |
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Application publication date: 20201009 |
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