CN112666476B

CN112666476B - Method, device and equipment for detecting connection state of battery connecting piece

Info

Publication number: CN112666476B
Application number: CN202011448621.8A
Authority: CN
Inventors: 沈强; 柳志民
Original assignee: Beijing CHJ Automotive Information Technology Co Ltd
Current assignee: Beijing CHJ Automotive Information Technology Co Ltd
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2024-02-23
Anticipated expiration: 2040-12-09
Also published as: CN112666476A

Abstract

The disclosure relates to a method, a device and equipment for detecting a connection state of a battery connector. The method for detecting the connection state of the battery connector comprises the following steps: acquiring the voltage before discharging each single battery in the battery module and the voltage after discharging; obtaining a discharge pressure difference of each single battery based on the difference between the voltage before discharge and the voltage after discharge; determining a differential pressure dispersion of the discharge differential pressure of each single battery based on the discharge differential pressure of each single battery; and determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion degree of the discharging differential pressure of each single battery and a first differential pressure dispersion degree threshold value calibrated in advance, wherein the connection state comprises abnormal connection or normal connection. The technical scheme of the disclosure realizes the detection of the connection state of the battery connector.

Description

Method, device and equipment for detecting connection state of battery connecting piece

Technical Field

The disclosure relates to the technical field of battery system detection, and in particular relates to a method, a device and equipment for detecting a connection state of a battery connecting piece.

Background

With the rapid development of the electric automobile industry, the holding capacity of the electric automobile is higher and higher, and the safety accidents caused by abnormal heating of the battery due to the connection failure of the single battery in the battery system are increased rapidly.

Therefore, how to test the connection reliability of the battery system is a technical problem to be solved.

Disclosure of Invention

In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a method, an apparatus, and a device for detecting a connection state of a battery connector.

In a first aspect, the present disclosure provides a method for detecting a connection state of a battery connector, which is applied to a battery module, the battery module includes a plurality of unit batteries, and each of the unit batteries is connected in series through the battery connector, the method includes:

acquiring the voltage before discharging and the voltage after discharging of each single battery, wherein the voltage before discharging and the voltage after discharging are the voltages between battery connectors at two ends of the single battery;

obtaining a discharge pressure difference of each single battery based on the difference between the voltage before discharge and the voltage after discharge;

determining a differential pressure dispersion of the discharge differential pressure of each single battery based on the discharge differential pressure of each single battery;

and determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion degree of the discharging differential pressure of each single battery and a first differential pressure dispersion degree threshold value calibrated in advance, wherein the connection state comprises abnormal connection or normal connection.

Further, the differential pressure dispersion is a difference between a discharge differential pressure of one of the unit cells and a mean value of the discharge differential pressures of the unit cells.

Further, obtaining the voltage before discharging and the voltage after discharging of each single battery includes:

before the battery module discharges, measuring the voltage of the voltage sampling points on the battery connectors at the two ends of each single battery to obtain the voltage before the discharge of each single battery;

and when the discharging of the battery module reaches the preset time, measuring the voltage of the voltage sampling points on the battery connecting pieces at the two ends of each single battery to obtain the voltage of each single battery after the discharging.

Further, before determining the connection state of the battery connector in the battery module based on the differential pressure dispersion of the discharge differential pressure of each of the unit batteries and the first differential pressure dispersion threshold value calibrated in advance, the method further includes:

acquiring the discharge current of the battery module and the environmental temperature of the battery module;

based on the differential dispersion of the discharge differential pressure of each single battery and a first differential dispersion threshold value calibrated in advance, determining the connection state of the battery connecting piece in the battery module comprises the following steps:

And determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion degree of the discharging differential pressure of each single battery and a first differential pressure dispersion degree threshold value which is calibrated in advance and meets the conditions of the ambient temperature and the discharging current.

Further, pre-calibrating the first differential pressure dispersion threshold value includes:

respectively acquiring voltages before and after each single battery in a preset battery module under a preset environment temperature and a preset discharge current, wherein the preset environment temperature comprises a plurality of different environment temperatures, and the preset discharge current comprises a plurality of different discharge currents;

obtaining the discharge pressure difference of each single battery in the preset battery module based on the difference between the voltages before and after the discharge of each single battery in the preset battery module;

and determining the differential pressure dispersion of the discharge differential pressure of the target single battery in the preset battery module based on the discharge differential pressure of each single battery in the preset battery module, and determining the differential pressure dispersion of the discharge differential pressure of the target single battery as the first differential pressure dispersion threshold, wherein the battery connecting piece connected with the target single battery is abnormal in connection.

Further, determining the connection state of the battery connector in the battery module based on the differential dispersion of the discharge differential pressure of each single battery and a pre-calibrated first differential dispersion threshold value includes:

if the differential pressure dispersion of the discharge differential pressure of any single battery is larger than or equal to the first differential pressure dispersion threshold value, judging that the connection of the battery connecting piece in the battery module is abnormal;

and if the differential pressure dispersion of the discharge differential pressure of any single battery is smaller than the first differential pressure dispersion threshold value, judging that the connection of the battery connecting piece in the battery module is normal.

Further, after determining that the connection of the battery connectors in the battery module is normal, the method further includes:

if the differential pressure dispersion degree of the discharging differential pressure of any single battery is larger than or equal to a second differential pressure dispersion degree threshold value calibrated in advance, judging that the connection state of the battery connecting piece in the battery module has a trend of deterioration from normal connection to abnormal connection.

Further, the method further comprises:

and if the connection state of the battery connecting piece in the battery module has a trend of deterioration from normal connection to abnormal connection, sending out an early warning signal.

and if the differential pressure dispersion of the discharge differential pressure of the target single battery in each single battery is larger than or equal to the first differential pressure dispersion threshold value, judging that the connection of the battery connecting piece connected with the target single battery is abnormal.

Further, the method further comprises:

and if the connection of the battery connecting piece in the battery module is abnormal, sending out an alarm signal.

In a second aspect, the present disclosure provides a battery connector connection state detection device applied to a battery module, where the battery module includes a plurality of unit batteries, and each of the unit batteries is connected in series through the battery connector, the device includes:

the discharging parameter obtaining module is used for obtaining the voltage before discharging and the voltage after discharging of each single battery, wherein the voltage before discharging and the voltage after discharging are both voltages between battery connectors at two ends of the single battery;

the discharging pressure difference acquisition module is used for acquiring the discharging pressure difference of each single battery based on the difference between the voltage before discharging and the voltage after discharging;

The differential pressure dispersion determining module is used for determining differential pressure dispersion of the discharge differential pressure of each single battery based on the discharge differential pressure of each single battery;

the connection state detection module is used for determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion degree of the discharge differential pressure of each single battery and a first differential pressure dispersion degree threshold value calibrated in advance, wherein the connection state comprises abnormal connection or normal connection.

Further, the discharge parameter obtaining module is further configured to: acquiring the discharge current of the battery module and the environmental temperature of the battery module;

the connection state detection module is specifically used for: and determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion degree of the discharging differential pressure of each single battery and a first differential pressure dispersion degree threshold value which is calibrated in advance and meets the conditions of the ambient temperature and the discharging current.

Further, the connection state detection module includes:

a first judging unit, configured to judge that the connection of the battery connectors in the battery module is abnormal if the differential dispersion of the discharge differential pressure of any one of the single batteries is greater than or equal to the first differential dispersion threshold;

And the second judging unit is used for judging that the connection of the battery connecting pieces in the battery module is normal if the differential pressure dispersion of the discharge differential pressure of any single battery is smaller than the first differential pressure dispersion threshold value.

In a third aspect, the present disclosure provides a battery connector connection state detection apparatus including:

a processor;

a memory for storing the processor-executable instructions;

the processor is configured to read the executable instruction from the memory, and execute the executable instruction to implement the method for detecting a connection state of a battery connector provided by any embodiment of the present disclosure.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:

according to the technical scheme, the voltage of each single battery before and after discharging in the battery module is obtained, so that the discharging pressure difference of each single battery is obtained, the pressure difference dispersion degree of the discharging pressure difference of each single battery is determined through the discharging pressure difference of each single battery, and then the connection state of the battery connecting piece in the battery module is determined through comparing the pressure difference dispersion degree of the discharging pressure difference of each single battery with the first pressure difference dispersion threshold value. Therefore, according to the technical scheme, through the analysis of the differential pressure dispersion of the discharge differential pressure of each single battery, the change of the connection resistance of the battery connector can be reflected more objectively, and the detection of the connection state of the battery connector is realized.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments of the present disclosure or the solutions in the prior art, the drawings that are required for the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a flowchart of a method for detecting a connection state of a battery connector according to an embodiment of the present disclosure;

fig. 2 is a schematic structural view of a battery module according to an embodiment of the present disclosure;

fig. 3 is a block diagram of a battery connector connection state detection device according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a battery connector connection state detection apparatus according to an embodiment of the present disclosure.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, a further description of aspects of the present disclosure will be provided below. It should be noted that, without conflict, the embodiments of the present disclosure and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced otherwise than as described herein; it will be apparent that the embodiments in the specification are only some, but not all, embodiments of the disclosure.

As described in the background art, the prior art has a problem of inaccurate connection reliability test of a battery system. The inventor finds that the single batteries are connected by a battery connecting piece, and the battery connecting piece and the single batteries are usually fixed by bolt locking or welding, so that the formed connecting resistance comprises the resistance of the battery connecting piece and the contact resistance of the battery connecting piece and the single batteries, wherein the size of the contact resistance has great correlation with the fastening degree of connection. After the vehicle runs for a long time or the battery system is vibrated, the battery connector can be aged and loosened, so that the contact resistance is gradually increased, the battery system is locally overheated in the charging and discharging process, and the safety of the battery is affected. Therefore, the main cause of abnormal heat generation of the battery is an increase in contact resistance of the battery connector and the unit battery.

According to the technical scheme, the connection state of the battery connector is detected, and the connection state of the battery connector is determined based on a first prespecified differential pressure dispersion threshold value.

Specifically, fig. 1 is a flowchart of a method for detecting a connection state of a battery connector according to an embodiment of the disclosure. The method can be executed by a battery connector connection state detection device, the device can be realized in a software and/or hardware mode, and the method can be applied to battery connector connection state detection equipment, and the battery connector connection state detection equipment can comprise a remote server, such as a cloud server. Specifically, the method for detecting the connection state of the battery connecting piece is applied to a battery module (such as a battery module of an automobile), and the battery module comprises a plurality of single batteries which are connected in series through the battery connecting piece. As shown in fig. 1, the method comprises the steps of:

and S110, acquiring the voltage before discharging each single battery and the voltage after discharging.

The voltage before discharging and the voltage after discharging are voltages between the battery connectors at two ends of the single battery.

In some embodiments, referring to fig. 2, the battery module includes a plurality of unit cells 11 connected in series, any two adjacent unit cells 11 are electrically connected through a battery connector 12, and a voltage sampling terminal is disposed on any one of the battery connectors 12 to form a voltage sampling point 13. Since each unit cell 11 includes a first electrode (e.g., a positive electrode) and a second electrode (e.g., a negative electrode), two battery connectors 12, i.e., a first battery connector and a second battery connector, are connected to each unit cell 11, and one battery connector 12 is shared between two adjacent unit cells 11. In some embodiments, the second battery connector of the previous cell is used as the first battery connector of the next cell, for example, the structure shown in fig. 2 is used as an exemplary structure, including the cell 1, the cell 2, the cell 3 and the cell 4 connected in sequence, and the battery connector 12 connected between the cell 2 and the cell 3 is the second battery connector of the cell 2 and is also the first battery connector of the cell 3.

It should be noted that the voltage sampling point 13 may be located at any position on the battery connector 12, and specifically may be set according to the position of the voltage sampling point when the first differential pressure dispersion threshold is calibrated. In some embodiments, the voltage sampling point 13 may be located in the middle of the battery connector 12, or may be located at a position where the battery connector 12 contacts the unit battery 11.

In the embodiment of the disclosure, voltage at each voltage sampling point 13 can be collected by using voltage collection devices such as a battery management system and a voltmeter, and then the collected voltage at each voltage sampling point 13 is sent to a battery connector connection state detection device, and the voltage at each voltage sampling point 13 is analyzed and processed by the battery connector connection state detection device, so that the voltage before discharging and the voltage after discharging of each single battery in the battery module are obtained.

In some embodiments, obtaining the voltage before discharge and the voltage after discharge of each cell may include: before the battery module discharges, measuring the voltage of the voltage sampling points on the battery connectors at the two ends of each single battery to obtain the voltage before the discharge of each single battery; and when the battery module discharges for a preset time, measuring the voltage of the voltage sampling points on the battery connectors at the two ends of each single battery to obtain the voltage of each single battery after discharging. Specifically, the voltage before the discharge and the voltage after the discharge of the No. 2 single cell are obtained as an example. The positive pole of the No. 2 single battery is connected with the first battery connecting piece, the negative pole is connected with the second battery connecting piece, the first voltage sampling point is positioned on the first battery connecting piece, and the second voltage sampling point is positioned on the second battery connecting piece. Before the battery module discharges, the voltage of the first voltage sampling point and the voltage of the second voltage sampling point are obtained through a battery management system, and the voltage before the discharge of the No. 2 single battery is obtained according to the difference between the voltage of the first voltage sampling point and the voltage of the second voltage sampling point; when the battery module is discharged and the preset time is elapsed, the voltage of the first voltage sampling point and the voltage of the second voltage sampling point are obtained through the battery management system, and the voltage of the No. 2 single battery is obtained according to the difference between the voltage of the first voltage sampling point and the voltage of the second voltage sampling point.

In some embodiments, it is considered that the discharge current changes with the lapse of the discharge time during the actual discharge process of the battery module, thereby affecting the measurement of the voltage after the discharge of the unit battery. Therefore, the preset time is set to be in the range of 1 second to 5 seconds to prevent the discharge current from being changed. In a preferred embodiment, the preset time is 1 second, so that under the condition of ensuring that the discharge current is constant, the voltage after the single battery is discharged can be ensured to be changed relative to the voltage before the single battery is discharged, the subsequent calculation can be performed, and the detection efficiency can be improved.

And S120, obtaining the discharge pressure difference of each single battery based on the difference between the voltage before discharge and the voltage after discharge.

In the discharging process of the single battery, the discharging voltage of the single battery can be gradually reduced, and then a certain pressure difference exists between the obtained voltage before discharging and the obtained voltage after discharging, namely the discharging pressure difference is a positive value.

S130, determining the differential pressure dispersion of the discharge differential pressure of each single battery based on the discharge differential pressure of each single battery.

The differential pressure dispersion of the single battery discharging differential pressure is used for representing the degree of deviation of the single battery discharging differential pressure from the average value of the single battery discharging differential pressures. The larger the differential dispersion of the discharging differential pressure of a certain single battery is, the larger the discharging differential pressure of the single battery is compared with the discharging differential pressure of other single batteries, and further the larger the connection resistance (mainly contact resistance) of the battery connecting piece connected with the single battery is changed (the connection resistance is increased). Therefore, the magnitude of the differential pressure dispersion can reflect the increasing degree of the connection resistance of the battery connector, and the larger change of the connection resistance of the battery connector can reflect the problem of incomplete connection of the battery connector. Accordingly, the present disclosure may determine the connection state of the battery connector based on the differential pressure dispersion.

In some embodiments, the differential pressure dispersion is the difference between the differential discharge pressure of one cell and the average of the differential discharge pressures of the cells. The differential pressure dispersion of the discharge differential pressure of any single battery in the battery module can be calculated according to the following formula:

α _i ＝ΔV _i -(ΔV ₁ +ΔV ₂ +L+ΔV _i +L+ΔV _n )/n；

wherein alpha is _i Differential pressure dispersion, deltaV, of discharge differential pressure of ith single battery in battery module _i The discharge pressure difference is the i-th single battery in the battery module, and n is the number of single batteries in the battery module.

And S140, determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion of the discharge differential pressure of each single battery and a first differential pressure dispersion threshold value calibrated in advance.

Wherein, the connection state comprises abnormal connection or normal connection. The abnormal connection refers to that the connection between the battery connecting piece and the single battery is not completely broken (such as unwelding or bolt falling off) and can comprise virtual connection when the battery connecting piece is welded with the single battery or loosening when the battery connecting piece is connected with the single battery through bolts; the normal connection means that the contact resistance meets the design requirement of safe operation of the battery.

Before detecting the connection state of the battery connector, performing discharge test on the battery module with abnormal connection of the battery connector, and calibrating a first differential pressure dispersion threshold value, wherein the first differential pressure dispersion threshold value is the differential pressure dispersion corresponding to the single battery connected with the abnormal connection of the battery connector during discharge test. And then, when the connection state of the battery connector is detected, the pressure difference dispersion of the discharging pressure differences of the single batteries obtained at present is respectively compared with a first pressure difference dispersion threshold value, and the connection state of the battery connector in the battery module is determined according to the comparison result.

The first differential pressure dispersion threshold value is the differential pressure dispersion corresponding to the single battery connected with the battery connecting piece with abnormal connection. Therefore, in actual detection, when the differential pressure dispersion corresponding to the single battery reaches the first differential pressure dispersion threshold value, abnormal connection of the battery connecting piece can be determined. Based on this, in an embodiment of the present disclosure, if the differential dispersion of the discharge differential pressure of any one of the unit batteries is greater than or equal to the first differential dispersion threshold, it is determined that the connection of the battery connectors in the battery module is abnormal; if the differential dispersion of the discharge differential pressure of any single battery is smaller than the first differential dispersion threshold, the connection of the battery connecting piece in the battery module is judged to be normal. In other words, if the differential dispersion of the discharge differential pressure of only one single battery in the battery module is greater than or equal to the first differential dispersion threshold, the connection of the battery connector in the battery module is abnormal; if the differential pressure dispersion of the discharge differential pressure of all the single batteries in the battery module is smaller than the first differential pressure dispersion threshold, the battery connectors in the battery module are connected normally. Therefore, the technical scheme can accurately judge the connection state of the battery connecting piece in the battery module.

In some embodiments, the battery connector connection state detection method provided by the present disclosure may further include:

When the connection of the battery connecting piece in the battery module is abnormal, an alarm signal is automatically sent, a driver can be timely reminded, the thermal runaway of the battery system caused by the continuous deterioration of the connection state of the battery connecting piece is prevented, and the occurrence probability of the safety accident of the battery system is effectively reduced. In this embodiment, the audible alarm may be used for audible alarm, the light alarm may be used for light alarm, and the audible and visual alarm may be used for audible and visual alarm. Wherein, audible alarm, light alarm or audible and visual alarm can set up in the well accuse district of vehicle. In some embodiments, if the battery connector in the battery module is connected normally, a safety signal is sent to prompt the driver to drive with confidence. The safety signal may be indicated by an LED lamp disposed in the central control area, for example, the LED lamp emits green light, and the LED lamp may be turned off after being continuously turned on for a certain time (for example, 5 seconds).

In one embodiment of the disclosure, the cloud server sends an alarm signal when determining that the connection of the battery connector in the battery module is abnormal; when the cloud server judges that the connection of the battery connectors in the battery module is normal, the connection state normal information of the battery connectors in the battery module is recorded.

In addition, the material of the battery connector is usually copper or aluminum, and the higher the ambient temperature is, the larger the resistance of the battery connector is, and secondly, the difference of discharge current also affects the detection of the connection resistance. Therefore, when the influence of the ambient temperature and the discharge current on the self resistance of the battery connector is not considered, the connection reliability test of the battery module is inaccurate.

Based on the above technical problem, in some embodiments, before determining the connection state of the battery connector in the battery module based on the differential pressure dispersion of the discharge differential pressure of each unit cell and the first differential pressure dispersion threshold value calibrated in advance, the method further includes: and obtaining the discharge current of the battery module and the environmental temperature of the battery module.

The temperature sensor can be used for collecting the ambient temperature of the single battery, and the ammeter is used for collecting the discharge current of the battery system. And sending the collected ambient temperature and discharge current to battery connector connection state detection equipment, so as to obtain the voltage before discharge and the voltage after discharge of each single battery in the battery module under the ambient temperature and discharge current.

Correspondingly, based on the differential pressure dispersion of the discharge differential pressure of each single battery and a first differential pressure dispersion threshold value calibrated in advance, the connection state of the battery connecting piece in the battery module is determined, and the method comprises the following steps: and determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion of the discharge differential pressure of each single battery and a first differential pressure dispersion threshold value which is calibrated in advance and meets the conditions of the ambient temperature and the discharge current. Similarly, before detecting the connection state of the battery connector, the battery module with abnormal connection of the battery connector can be subjected to discharge test under the conditions of different environment temperatures and different discharge currents, and a plurality of first differential pressure dispersion thresholds under the conditions of different environment temperatures and different discharge currents are marked, wherein the first differential pressure dispersion thresholds are differential pressure dispersion corresponding to single batteries connected with the battery connector with abnormal connection during the discharge test. And then, when the connection state of the battery connector is detected, a first differential pressure dispersion threshold meeting the conditions of the ambient temperature and the discharge current is selected from a plurality of first differential pressure dispersion thresholds calibrated in advance according to the ambient temperature and the discharge current which are obtained at present (during actual detection), so that the differential pressure dispersion of the discharge differential pressure of each single battery is respectively compared with the first differential pressure dispersion threshold, and the connection state of the battery connector in the battery module is determined according to the comparison result.

In the technical scheme, as the differential pressure dispersion of the discharge differential pressure of each single battery is the same as the environmental temperature and the discharge current condition of the differential pressure dispersion threshold calibrated in advance, the influence of the environmental temperature and the discharge current on the discharge differential pressure of each single battery is eliminated, the obtained differential pressure dispersion of the discharge differential pressure of each single battery is more accurate, and the accuracy of detecting the connection state of the battery connecting piece is improved.

In the above technical solution, in order to ensure implementation of the technical solution of the present disclosure and ensure accuracy of the detection result, the first differential pressure dispersion threshold value needs to be calibrated in advance. In some embodiments, pre-calibrating the first differential pressure dispersion threshold value may include the steps of:

a. and respectively acquiring the voltages before and after discharging each single battery in the preset battery module under the preset environment temperature and the preset discharging current.

The preset environment temperature comprises a plurality of different environment temperatures, and the preset discharge current comprises a plurality of different discharge currents.

Specifically, an ambient temperature can be determined first, at which the discharge current is adjusted by the discharge device, and the voltage before and the voltage after the discharge of each single battery in the preset battery module are measured sequentially under a plurality of different discharge currents. And then changing the ambient temperature, and measuring the voltage before discharging and the voltage after discharging of each single battery in the preset battery module under a plurality of different discharging currents in sequence. Repeating the above operation until all the measurement of the voltage at the preset ambient temperature is completed.

b. And obtaining the discharge pressure difference of each single battery in the preset battery module based on the voltage difference between the single batteries in the preset battery module before and after discharging.

c. And determining the differential pressure dispersion of the discharge differential pressure of the target single battery in the preset battery module based on the discharge differential pressure of each single battery in the preset battery module, and determining the differential pressure dispersion of the discharge differential pressure of the target single battery as a first differential pressure dispersion threshold.

Wherein, the battery connecting piece that the target monomer battery connects abnormally.

The calibration process of the first differential pressure dispersion threshold in this embodiment is the same as the differential pressure dispersion calculation process of the single battery discharge differential pressure in the above embodiment, and will not be described here again.

According to the method for detecting the connection state of the battery connecting piece, the voltage of each single battery in the battery module before and after discharging is obtained, the discharging pressure difference of each single battery is obtained, the pressure difference dispersion degree of the discharging pressure difference of each single battery is determined according to the discharging pressure difference of each single battery, the first pressure difference dispersion degree threshold value meeting the conditions of the environment temperature and the discharging current is determined based on the environment temperature and the discharging current, and finally the connection state of the battery connecting piece in the battery module is determined by comparing the pressure difference dispersion degree of the discharging pressure difference of each single battery with the first pressure difference dispersion degree threshold value. Therefore, the technical scheme disclosed by the invention considers the influence of temperature and discharge current on the connection resistance of the battery connector, and can reflect the change of the connection resistance of the battery connector more accurately, thereby improving the accuracy of the connection state detection of the battery connector.

Based on the above technical solution, in some embodiments, determining the connection state of the battery connection member in the battery module based on the differential dispersion of the discharge differential pressure of each unit battery and the first differential dispersion threshold value calibrated in advance under the conditions of satisfying the ambient temperature and the discharge current may include:

The target single battery is any single battery in all single batteries. If the differential pressure dispersion of the discharge differential pressure of the target single battery is larger than or equal to the first differential pressure dispersion threshold value, the connection of the battery connecting piece connected with the target single battery is abnormal. Therefore, compared with the embodiment, the embodiment can further determine which single battery is particularly positioned on the battery connecting piece with abnormal connection, and is convenient for maintenance personnel to further detect and maintain.

In some embodiments, after determining that the connection of the battery connector in the battery module is normal, the method may further include:

if the differential pressure dispersion of the discharge differential pressure of any single battery is larger than or equal to a second differential pressure dispersion threshold value calibrated in advance, judging that the connection state of the battery connecting piece in the battery module has a trend of deterioration from normal connection to abnormal connection.

Wherein the second differential pressure dispersion threshold is less than the first differential pressure dispersion threshold. In an embodiment of the present disclosure, pre-calibrating the second differential pressure dispersion threshold value may include the steps of:

C. And determining the differential pressure dispersion of the discharge differential pressure of the target single battery in the preset battery module based on the discharge differential pressure of each single battery in the preset battery module, and determining the differential pressure dispersion of the discharge differential pressure of the target single battery as a second differential pressure dispersion threshold.

Wherein, the battery connecting piece that the target monomer battery connects normally.

When the connection state of the battery connector is detected, under the condition that the battery connector in the battery module is determined to be normally connected, namely, the differential pressure dispersion of the discharging differential pressure of any single battery is smaller than the first differential pressure dispersion threshold, the differential pressure dispersion of the discharging differential pressure of any single battery is further compared with the second differential pressure dispersion threshold, and when the differential pressure dispersion of the discharging differential pressure of any single battery is larger than or equal to the second differential pressure dispersion threshold, the connection state of the battery connector in the battery module can be determined to have a trend of normal connection to abnormal connection degradation, and then an early warning signal can be sent out to inform a user to overhaul the battery connector in advance, so that the battery connector is effectively prevented from continuously degrading to be abnormal connection.

Corresponding to the method for detecting the connection state of the battery connector provided by the embodiment of the disclosure, the embodiment of the disclosure also provides a device for detecting the connection state of the battery connector. Fig. 3 is a block diagram of a battery connector connection state detection device according to an embodiment of the present disclosure, where the device is applied to a battery module, and the battery module includes a plurality of unit batteries, and each of the unit batteries is connected in series through the battery connector. As shown in fig. 3, the battery connector connection state detecting apparatus includes:

the discharging parameter obtaining module 21 is configured to obtain a voltage before discharging and a voltage after discharging of each unit battery, where the voltage before discharging and the voltage after discharging are voltages between battery connectors at two ends of the unit battery;

a discharging voltage difference obtaining module 22, configured to obtain a discharging voltage difference of each unit cell based on a voltage before discharging and a voltage after discharging;

a differential pressure dispersion determining module 23, configured to determine a differential pressure dispersion of the discharge differential pressure of each unit cell based on the discharge differential pressure of each unit cell;

the connection state detection module 24 is configured to determine a connection state of the battery connection member in the battery module based on a differential dispersion of a discharge differential pressure of each unit battery and a first differential dispersion threshold value calibrated in advance, where the connection state includes abnormal connection or normal connection.

In this embodiment, the battery module (battery module) includes a plurality of series-connected unit batteries, and two arbitrary adjacent unit batteries are connected through the battery connecting piece electricity, are provided with voltage sampling terminal on arbitrary battery connecting piece, form voltage sampling point. Because each single battery comprises a first electrode (such as a positive electrode) and a second electrode (such as a negative electrode), two battery connectors, namely a first battery connector and a second battery connector, are connected to each single battery, and one battery connector is shared between two adjacent single batteries. In some embodiments, the second battery connector of the previous cell serves as the first battery connector of the subsequent cell.

It should be noted that the voltage sampling point may be located at any position on the battery connector, and specifically may be set according to the position of the voltage sampling point when the first differential pressure dispersion threshold is calibrated. In some embodiments, the voltage sampling point may be located in the middle of the battery connector or may be located at a position where the battery connector contacts the unit battery.

In some embodiments, voltage at each voltage sampling point can be collected by using a voltage collection device such as a battery management system and a voltmeter, so as to obtain the voltage before discharging and the voltage after discharging of each single battery in the battery module.

In addition, the differential dispersion of the single cell discharge differential pressure is used for representing the degree of deviation of the single cell discharge differential pressure from the average value of the single cell discharge differential pressure. The larger the differential dispersion of the discharging differential pressure of a certain single battery is, the larger the discharging differential pressure of the single battery is compared with the discharging differential pressure of other single batteries, and further the larger the connection resistance (mainly contact resistance) of the battery connecting piece connected with the single battery is changed (the connection resistance is increased). Therefore, the magnitude of the differential pressure dispersion can reflect the increasing degree of the connection resistance of the battery connector, and the larger change of the connection resistance of the battery connector can reflect the problem of incomplete connection of the battery connector. Accordingly, the present disclosure may determine the connection state of the battery connector based on the differential pressure dispersion.

In the above technical solution, the connection state includes abnormal connection or normal connection. The abnormal connection refers to that the connection between the battery connecting piece and the single battery is not completely broken (such as unwelding or bolt falling off) and can comprise virtual connection when the battery connecting piece is welded with the single battery or loosening when the battery connecting piece is connected with the single battery through bolts; the normal connection means that the contact resistance meets the design requirement of safe operation of the battery.

Before detecting the connection state of the battery connector, a discharge test can be performed on the battery system with abnormal connection of the battery connector, and a plurality of first differential pressure dispersion thresholds with different environment temperatures and different discharge currents are marked, wherein the first differential pressure dispersion thresholds are differential pressure dispersion corresponding to single batteries connected with the abnormal connection battery connector during the discharge test. And then, when the connection state of the battery connector is detected, comparing the pressure difference dispersion of the currently obtained discharging pressure differences of the single batteries with a first pressure difference dispersion threshold value respectively, and determining the connection state of the battery connector in the battery module according to the comparison result.

Based on above-mentioned technical scheme, in order to guarantee the implementation of this disclosed technical scheme and ensure the accuracy of testing result, battery connector connection state detection device still includes first pressure differential dispersion threshold calibration module, and first pressure differential dispersion threshold calibration module includes:

the target voltage acquisition unit is used for respectively acquiring the voltages before and after the discharge of each single battery in the preset battery module under the preset environment temperature and the preset discharge current, wherein the preset environment temperature comprises a plurality of different environment temperatures, and the preset discharge current comprises a plurality of different discharge currents;

The target discharging pressure difference acquisition unit is used for obtaining the discharging pressure difference of each single battery based on the difference between the voltages before and after the discharging of each single battery in the preset battery module;

the first differential pressure dispersion threshold value determining unit is used for determining differential pressure dispersion of the discharge differential pressure of the target single battery in the preset battery module based on the discharge differential pressure of each single battery in the preset battery module, and determining the differential pressure dispersion of the discharge differential pressure of the target single battery as the first differential pressure dispersion threshold value, wherein the battery connecting piece connected with the target single battery is abnormal in connection.

α _i ＝ΔV _i -(ΔV ₁ +ΔV ₂ +L+ΔV _i +L+ΔV _n )/n；

In some embodiments, the discharge parameter acquisition module includes:

the first voltage acquisition unit is used for measuring the voltage of the voltage sampling points on the battery connectors at the two ends of each single battery before the battery module discharges to obtain the voltage before the discharge of each single battery;

And the second voltage acquisition unit is used for measuring the voltage of the voltage sampling points on the battery connectors at the two ends of each single battery when the battery module discharges for a preset time to obtain the voltage of each single battery after discharge.

In some embodiments, it is contemplated that the discharge current may change over time during actual discharge of the battery system, thereby affecting the measurement of the second voltage. Therefore, the preset time is set to be in the range of 1 second to 5 seconds to prevent the discharge current from being changed. In a preferred embodiment, the preset time is 1 second, so that under the condition of ensuring that the discharge current is constant, the second voltage can be ensured to be changed relative to the first voltage for subsequent calculation, and the detection efficiency can be improved.

In some embodiments, the discharge parameter acquisition module is further to: acquiring the discharge current of the battery module and the environmental temperature of the battery module;

the connection state detection module is specifically used for: and determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion of the discharge differential pressure of each single battery and a first differential pressure dispersion threshold value which is calibrated in advance and meets the conditions of the ambient temperature and the discharge current.

The first differential pressure dispersion threshold value is the differential pressure dispersion corresponding to the single battery connected with the battery connecting piece with abnormal connection. Therefore, in actual detection, when the differential pressure dispersion corresponding to the single battery reaches the first differential pressure dispersion threshold value, abnormal connection of the battery connecting piece can be determined. In some embodiments, the connection state detection module includes:

the first judging unit is used for judging that the connection of the battery connecting piece in the battery module is abnormal if the differential pressure dispersion of the discharge differential pressure of any single battery is larger than or equal to a first differential pressure dispersion threshold value;

In some embodiments, the battery connector connection state detection device further includes:

and the alarm module is used for sending an alarm signal if the connection of the battery connecting piece in the battery module is abnormal.

In some embodiments, the connection state detection module further comprises:

and the third judging unit is used for judging that the connection state of the battery connecting piece in the battery module has a trend of deteriorating from normal connection to abnormal connection if the differential pressure dispersion of the discharge differential pressure of any single battery is larger than or equal to a second differential pressure dispersion threshold value calibrated in advance after judging that the battery connecting piece in the battery module is normally connected.

In some embodiments, the connection state detection module is specifically configured to:

The battery connector connection state detection device disclosed in the above embodiments can execute the battery connector connection state detection method disclosed in each embodiment, and has the same or corresponding beneficial effects, and in order to avoid repetition, the description is omitted here.

The embodiment of the disclosure also provides a battery connector connection state detection device, which includes: a processor; a memory for storing processor-executable instructions; and the processor is used for reading the executable instructions from the memory and executing the executable instructions to realize the battery connector connection state detection method provided by any embodiment of the disclosure.

Fig. 4 is a schematic hardware structure diagram of a battery connector connection state detection device according to an embodiment of the present disclosure. As shown in fig. 4, the battery connector connection state detection apparatus includes one or more processors 301 and a memory 302.

The processor 301 may be a Central Processing Unit (CPU) or other form of processing unit having data processing capabilities and/or instruction execution capabilities and may control the battery connector connection to other components in the status detection device to perform desired functions.

Memory 302 may include one or more computer program products that may include various forms of computer-readable storage media, such as volatile memory and/or non-volatile memory. The volatile memory may include, for example, random Access Memory (RAM) and/or cache memory (cache), and the like. The non-volatile memory may include, for example, read Only Memory (ROM), hard disk, flash memory, and the like. One or more computer program instructions may be stored on the computer readable storage medium that may be executed by the processor 301 to implement the battery connector connection status detection method of embodiments of the present disclosure described above, and/or other desired functions. Various contents such as an input signal, a signal component, a noise component, and the like may also be stored in the computer-readable storage medium.

In one example, the battery connector connection state detection apparatus may further include: an input device 303, and an output device 304, which are interconnected by a bus system and/or other forms of connection mechanisms (not shown).

In addition, the input device 303 may also include, for example, a keyboard, a mouse, and the like.

The output device 304 may output various information to the outside, including the determined distance information, direction information, and the like. The output device 304 may include, for example, a display, speakers, a printer, and a communication network and remote output devices connected thereto, etc.

Of course, only some of the components related to the present disclosure in the battery connector connection state detection apparatus are shown in fig. 4 for simplicity, and components such as buses, input/output interfaces, and the like are omitted. In addition, the battery connector connection status detection device may include any other suitable components depending on the particular application.

It should be noted that in this document, relational terms such as "first" and "second" and the like are 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. Moreover, 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. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a specific embodiment of the disclosure to enable one skilled in the art to understand or practice the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown and described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The battery connecting piece connection state detection method is applied to a battery module, the battery module comprises a plurality of single batteries, and the single batteries are connected in series through the battery connecting piece, and is characterized in that the method comprises the following steps:

Determining a connection state of a battery connecting piece in the battery module based on the differential pressure dispersion of the discharge differential pressure of each single battery and a first differential pressure dispersion threshold value calibrated in advance, wherein the connection state comprises abnormal connection or normal connection;

after determining that the connection of the battery connectors in the battery module is normal, the method further includes:

if the differential pressure dispersion of the discharging differential pressure of any single battery is smaller than the first differential pressure dispersion threshold and is larger than or equal to a second differential pressure dispersion threshold calibrated in advance, judging that the connection state of the battery connecting piece in the battery module has a trend of abnormal connection from normal connection, wherein the first differential pressure dispersion threshold is the differential pressure dispersion corresponding to the single battery connected with the abnormal battery connecting piece in discharging test, the second differential pressure dispersion threshold is the differential pressure dispersion corresponding to the single battery connected with the normal battery connecting piece in discharging test, and the second differential pressure dispersion threshold is smaller than the first differential pressure dispersion threshold.

2. The method according to claim 1, wherein the differential pressure dispersion is a difference between a discharge differential pressure of one of the unit cells and a mean value of the discharge differential pressures of the unit cells.

3. The battery connector connection state detection method according to claim 1, wherein obtaining the voltage before discharge and the voltage after discharge of each of the unit batteries includes:

4. The battery connector connection state detection method according to claim 1, wherein before determining the connection state of the battery connector in the battery module based on the differential pressure dispersion of the discharge differential pressure of each of the unit cells and a first differential pressure dispersion threshold value calibrated in advance, the method further comprises:

5. The battery connector connection state detection method of claim 4, wherein pre-calibrating the first differential pressure dispersion threshold value comprises:

6. The battery connector connection state detection method according to claim 1, wherein determining the connection state of the battery connector in the battery module based on the differential pressure dispersion of the discharge differential pressure of each of the unit batteries and a first differential pressure dispersion threshold value calibrated in advance, comprises:

7. The battery connector connection state detection method according to claim 1, characterized in that the method further comprises:

8. The battery connector connection state detection method according to claim 1, wherein determining the connection state of the battery connector in the battery module based on the differential pressure dispersion of the discharge differential pressure of each of the unit batteries and a first differential pressure dispersion threshold value calibrated in advance, comprises:

9. The battery connector connection state detection method according to claim 1, characterized in that the method further comprises:

10. The utility model provides a battery connector connection state detection device, is applied to the battery module, the battery module includes a plurality of battery cells, each battery cell is established ties through battery connector, its characterized in that, the device includes:

The connection state detection module is used for determining the connection state of the battery connecting piece in the battery module based on the differential pressure dispersion degree of the discharge differential pressure of each single battery and a first differential pressure dispersion degree threshold value calibrated in advance, wherein the connection state comprises abnormal connection or normal connection;

the connection state detection module further comprises a third determination unit, and the third determination unit is used for determining that after the battery connectors in the battery module are normally connected, if the differential pressure dispersion of the discharge differential pressure of any single battery is smaller than a first differential pressure dispersion threshold and is larger than or equal to a second differential pressure dispersion threshold calibrated in advance, the connection state of the battery connectors in the battery module is determined to have a trend of abnormal connection degradation from the normal connection, wherein the first differential pressure dispersion threshold is the differential pressure dispersion corresponding to the single battery connected with the abnormal battery connector during discharge test, and the second differential pressure dispersion threshold is the differential pressure dispersion corresponding to the single battery connected with the normal battery connector during discharge test, and the second differential pressure dispersion threshold is smaller than the first differential pressure dispersion threshold.

11. The battery connector connection state detection apparatus according to claim 10, wherein the differential pressure dispersion is a difference between a discharge differential pressure of one of the unit batteries and a mean value of the discharge differential pressures of the unit batteries.

12. The battery connector connection state detection apparatus according to claim 10, wherein the discharge parameter acquisition module is further configured to: acquiring the discharge current of the battery module and the environmental temperature of the battery module;

13. The battery connector connection state detection device according to claim 10, wherein the connection state detection module includes:

14. A battery connector connection state detection apparatus, characterized in that the battery connector connection state detection apparatus comprises:

a processor;

a memory for storing the processor-executable instructions;

the processor is configured to read the executable instructions from the memory and execute the executable instructions to implement the battery connector connection state detection method according to any one of claims 1-9.