Battery connecting wire harness internal resistance detection system based on equalization module

Abstract

The utility model discloses a battery connecting wire harness internal resistance detection system based on equalization modules, which is provided with at least a plurality of equalization modules and an AFE analog front end, and is connected with a battery pack through a plurality of connecting wire harnesses, the end point of each single battery is connected with the equalization module through a connecting wire harness, each equalization module manages two adjacent single batteries, and the equalization modules are connected in a pairwise staggered manner; the AFE analog front end is connected with each single battery and is used for acquiring a voltage value of each single battery; the equalization module is used for outputting a preset constant current; the system also comprises a control module which is used for controlling the working states of the AFE analog front end and the equalization modules, controlling each equalization module to sequentially generate preset constant current, and simultaneously controlling the AFE analog front end to obtain the voltage values before and after the equalization modules work so as to obtain the internal resistance values of the corresponding connecting wire harnesses.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery charging and discharging control, in particular to a battery connection harness internal resistance detection system based on a balancing module. Background Art

[0002] With the development of the new energy industry, battery systems have been more widely used in the fields of automobiles and energy storage. In order to increase the battery capacity, the number of batteries connected in series and parallel continues to increase, and the number of battery sampling harnesses used is also increasing. Different manufacturers have different production harness processing techniques and different battery harness installation methods, which will have a significant impact on the entire system. The most obvious is the harness impedance. If the battery connection harness impedance is large, it will cause abnormal battery voltage sampling. When a large current flows through the harness, a voltage drop will be generated in the harness group. At the same time, the harness will heat up, and there is a risk of fire and short circuit, which seriously endangers personal and property safety. To deal with this risk, there needs to be a method to monitor the harness status in real time. When the battery harness is abnormal, relevant information can be reported in time to reduce safety risks. At the same time, the BMS system can also achieve long-term tracking and recording of the harness status.

[0003] At present, the method of harness internal resistance detection in the battery industry is to make a harness internal resistance detection development board, prepare a constant current source, provide a fixed constant current source to each harness in turn, and use a multimeter to measure the voltage drop at both ends of the harness. Figure 1 , which shows the principle of measuring the internal resistance of the wiring harness in the prior art, wherein the constant current source is connected to both ends of A / B. It is necessary to provide a fixed constant current source to the measured wiring harness externally, turn on the constant current source, and then use a multimeter to measure the voltage value at both ends of the wiring harness, and calculate the internal resistance based on the relationship between voltage and current. When the internal resistance of the wiring harness is very small, a relatively appropriate power resistor needs to be connected in series with the wiring harness to increase the voltage sampling value and reduce the error, see Figure 2 shown.

[0004] Therefore, in view of the defects of the prior art, it is necessary to propose a technical solution to solve the technical problems existing in the prior art. Utility Model Content

[0005] In view of this, it is indeed necessary to provide a battery connection harness internal resistance detection system based on a balancing module, which generates a constant current source through the balancing module and samples the voltage values ​​of each branch balancing module when it is working and not working through the AFE analog front end, so as to detect the internal resistance of different battery connection harnesses.

[0006] In order to solve the technical problems existing in the prior art, the technical solution of the present invention is as follows:

[0007] A battery connection harness internal resistance detection system based on a balancing module, the system is provided with at least a plurality of balancing modules and an AFE analog front end, and is connected to a battery pack through a plurality of connection harnesses, wherein the battery pack is composed of a plurality of single cells connected in series, and the end point of each single cell is connected to a balancing module through a connection harness, and each balancing module manages two adjacent single cells, and each balancing module is staggeredly connected to each other;

[0008] The AFE analog front end is connected to each single cell to obtain the voltage value of each single cell;

[0009] A balancing module for outputting a preset constant current;

[0010] The system also includes a control module for controlling the working status of the AFE analog front end and the equalization module, wherein each equalization module is controlled to generate a preset constant current in turn and the AFE analog front end is controlled to obtain the voltage value before and after the equalization module works and thereby obtain the internal resistance value of the corresponding connecting harness.

[0011] As a further improvement, the balancing module is provided with a VP terminal, a VM terminal and a VG terminal, which are respectively connected to three ports of two adjacent single cells.

[0012] As a further improvement, the balancing module adopts a buck circuit.

[0013] As a further improvement scheme, the control module is connected with the AFE analog front end and the equalization module through an isolation device.

[0014] As a further improvement solution, the isolation device uses an optocoupler or a transformer.

[0015] Compared with the prior art, the technical solution of the utility model can identify the internal resistance of different battery connection harnesses, and can quickly screen out the unreliable or disconnected contact of the battery connection harness, and the change in internal resistance after the harness has been running for a long time and aged; at the same time, the test method is simple, the response is fast, the efficiency is high, and the accuracy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The figure is a schematic diagram of the principle of detecting the internal resistance of the wiring harness in the prior art.

[0017] Figure 2 This is another schematic diagram of the principle of detecting the internal resistance of a wiring harness in the prior art.

[0018] Figure 3 The utility model is a schematic diagram of the principle of the battery connection harness internal resistance detection system based on the equalization module.

[0019] Figure 4This is a schematic diagram of the connection between a single balancing module and adjacent single cells of the utility model.

[0020] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0021] The technical solution provided by the utility model will be further described below in conjunction with the accompanying drawings.

[0022] In the prior art, as the battery capacity and the number of batteries connected in series and parallel continue to increase, the consistency of the overall single-cell voltage of the system seriously affects the battery capacity. Therefore, it is necessary to add a balancing module to the system. When the voltage of a battery is too low, the energy of the connected power supply is transferred to the battery. Conversely, the energy of the battery voltage that is too high is transferred to the power supply, so as to fully realize the real-time balancing during charging and discharging, and give full play to the potential of each battery. It is ensured that each battery can be fully charged during charging, and each battery can be discharged to the lowest limit during discharging. Each battery can also maintain the same voltage during the charging and discharging process, so that the capacity of each battery in the battery pack can be fully utilized. Thereby, the life of the entire battery group is also effectively extended. Usually, each balancing module manages two adjacent battery groups, and the balancing modules are staggered and connected in pairs. The balancing module can generate a constant current, which is equivalent to a constant current source.

[0023] join Figure 3 , shown is a schematic diagram of the principle of a battery connection harness internal resistance detection system based on a balancing module provided by the utility model, the system is provided with at least a plurality of balancing modules and an AFE analog front end, and is connected to a battery pack through a plurality of connecting harnesses, wherein the battery pack is connected in series with a plurality of single cells, and the end point of each single cell is connected to a balancing module through a connecting harness, each balancing module manages two adjacent single cells, and each balancing module is staggeredly connected in pairs;

[0024] The AFE analog front end is connected to each single cell to obtain the voltage value of each single cell;

[0025] A balancing module for outputting a preset constant current;

[0026] The system also includes a control module for controlling the working status of the AFE analog front end and the equalization module, wherein each equalization module is controlled to generate a preset constant current in turn and the AFE analog front end is controlled to obtain the voltage value before and after the equalization module works and thereby obtain the internal resistance value of the corresponding connecting harness.

[0027] As a further improvement scheme, the control module is connected to the AFE analog front end and the equalization module through an isolation device, and the isolation device adopts an optical coupler or a transformer.

[0028] In the above technical solution, the AFE analog front end and the equalization module can be implemented using existing technologies. Figure 4 , which is a schematic diagram of the principle of a balancing module in a preferred embodiment, wherein the balancing module is provided with a VP terminal, a VM terminal and a VG terminal, which are respectively connected to three ports of two adjacent single cells, and the balancing module adopts a buck circuit.

[0029] The following combination Figure 3 and Figure 4 The specific implementation method of the utility model illustrates the working principle of the utility model. The balancing modules U1, U2, U3,,, Un-1 can generate a set current I0i, I1i, I2i,,, Ini, and the high-precision AFE analog front end can sample the single cell voltage of each battery in real time. After the system is powered on, the control module controls the analog front end to sample the voltage value of each single cell V1i, V2i, V3i,,, Vni through the isolation device OA1, and then controls the balancing module U1 to generate a fixed current Ii through the isolation device OP1. At this time, there will be corresponding currents I0i, I1i, I2i on the corresponding three lines and the corresponding relationship is I0i=I1i=I2i. At the same time, the control module controls the AFE analog front end to sample the single cell voltage values ​​corresponding to U1 and U2 as V1o, V2o, V3o, and record the data. Then, the isolating device OP2 controls the equalizing module U2 to generate a constant current source Io. At this time, the corresponding three lines I1k, I2k, and I3k have a corresponding relationship of I1k=I2k=I3k. At the same time, the control module controls the AFE analog front end to sample the monomer voltage values ​​corresponding to U2 and U3 as V2k, V3k, and V4k, and records the data, and so on. In the initial state, the current value that can be generated by each equalizing module is configured, and the corresponding current value is implanted into the control module, and the corresponding actual position is recorded.

[0030] Assuming that the internal resistance of each wire is R0, R1, R2,,, Rn-1, Rn, the measured value of each line is calculated: R0 = (V1i-V1-V3+V3i+V2-V2i) / I0i, R1 = (V3-V3i-V2+V2i) / I2i, R2 = (V3-V3i) / I2i, R3 = (V3-V3k) / I3k-(V3-V3i) / I2i,,,,, Rn = (Vn-Vnz) / Inz-(Vn-Vn z-1) / In-1y and so on. The control module obtains the internal resistance value of each connecting line.

[0031] The above embodiments are only used to help understand the method and core idea of ​​the utility model. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made to the utility model without departing from the principle of the utility model, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

[0032] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery connection harness internal resistance detection system based on a balancing module, characterized in that: The system is provided with at least a plurality of balancing modules and an AFE analog front end, which are connected to the battery pack through a plurality of connecting wire harnesses, wherein the battery pack is composed of a plurality of single cells connected in series, and the end point of each single cell is connected to the balancing module through the connecting wire harness, and each balancing module manages two adjacent single cells, and each balancing module is staggeredly connected to each other; The AFE analog front end is connected to each single cell to obtain the voltage value of each single cell; A balancing module for outputting a preset constant current; The system also includes a control module for controlling the working status of the AFE analog front end and the equalization module, wherein each equalization module is controlled to generate a preset constant current in turn and the AFE analog front end is controlled to obtain the voltage value before and after the equalization module works and thereby obtain the internal resistance value of the corresponding connecting harness.

2. The battery connection harness internal resistance detection system based on the equalization module according to claim 1 is characterized in that: The balancing module is provided with a VP terminal, a VM terminal and a VG terminal, which are respectively connected to three ports of two adjacent single cells.

3. The battery connection harness internal resistance detection system based on the equalization module according to claim 1 or 2, characterized in that: The balancing module adopts a buck circuit.

4. The battery connection harness internal resistance detection system based on the equalization module according to claim 3 is characterized in that: The control module is connected with the AFE analog front end and the equalization module through an isolation device.

5. The battery connection harness internal resistance detection system based on the equalization module according to claim 4 is characterized in that: The isolation device uses an optocoupler or a transformer.

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