A ball impact test device for battery pack strength detection

Abstract

The present invention relates to the field of battery detection technology, and in particular to a ball hitting test device for battery pack strength detection, comprising a test module, a data acquisition module and a data analysis module, wherein the data acquisition module comprises an electrical signal acquisition unit and a physical acquisition unit; the data analysis module is used to respectively obtain first data acquired by the physical acquisition unit and second data acquired by the electrical signal acquisition unit, respectively implement a first analysis scheme and a second analysis scheme on the first data and the second data and obtain a first analysis result and a second analysis result, and obtain a comprehensive strength evaluation value A of the battery pack through a comprehensive evaluation processing formula for the first analysis result and the second analysis result. The present invention obtains the comprehensive strength evaluation value A by calculation and analyzes it, and the larger the comprehensive strength evaluation value A is, the higher the comprehensive strength of the battery pack is, and the detection method is efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of battery detection, and in particular to a ball striking test device for detecting the strength of a battery pack. Background Art

[0002] A battery pack refers to a battery group consisting of multiple battery cells and a battery management system. It is often used to refer specifically to the power supply battery pack of an electric vehicle. The battery management system, also known as the electronic control management system, plays a very important role in the safety management of the battery pack. In order to comprehensively evaluate the safety of the battery pack after an impact, the battery pack needs to be spot-checked for strength when it is developed and shipped out of the factory. This includes a variety of strength tests. The ball impact test is a type of strength test. By allowing the battery pack to fall freely against the ball head below, the degree of deformation of the battery pack after the impact can be observed, and the strength of the battery pack can be judged by observing whether the battery pack smokes or catches fire. However, the existing test results obtained by observation are quite accidental, and it is impossible to combine physical strength with the strength of the electronic control system for a comprehensive evaluation. The test is not convincing and the test effect is poor. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the background technology and to propose a ball striking test device for detecting the strength of a battery pack.

[0004] In order to achieve the above-mentioned object, the present invention adopts the following technical scheme: a ball hitting test device for detecting the strength of a battery pack, comprising a test module, a data acquisition module and a data analysis module, wherein the test module performs a ball hitting test on the battery pack according to the ball hitting test number and records the test height corresponding to the ball hitting test number, and the test module comprises an impact unit, a limit unit and a hoisting unit;

[0005] The limiting unit is used to limit the movement trajectory of the battery pack, and the lifting unit is used to lift the battery pack to a specified height;

[0006] The data acquisition module includes an electrical signal acquisition unit and a physical acquisition unit;

[0007] The impact unit includes a fixed platform, a billiard ball arranged on the upper surface of the fixed platform and having a semicircular structure, and the limiting unit includes a plurality of limiting sliding rods arranged on the upper surface of the fixed platform, a sleeve slidably arranged on the limiting sliding rod, and a connecting rope installed on the outer surface of the sleeve, and the connecting rope is fixedly connected to the upper surface of the battery pack;

[0008] The electrical signal acquisition unit includes a current monitor and a detection load connected to the battery pack;

[0009] The physical acquisition unit includes a vibration sensor arranged in the fixed platform and a plurality of pressure detection components arranged on the upper surface of the fixed platform, and the detection components include a detection seat, a pressure sensor arranged on the upper surface of the detection seat, and a spring telescopic rod connected to the pressure sensor;

[0010] The data analysis module is used to respectively acquire the first data collected by the physical acquisition unit and the second data collected by the electrical signal acquisition unit, implement the first analysis scheme S1 and the second analysis scheme S2 on the first data and the second data respectively and obtain the first analysis result and the second analysis result, obtain the comprehensive strength evaluation value A of the battery pack through the comprehensive evaluation processing formula according to the first analysis result and the second analysis result, and evaluate the comprehensive strength of the battery pack according to the comprehensive strength evaluation value A.

[0011] In the above-mentioned ball striking test device for battery pack strength detection, the steps of the first analysis scheme S1 include:

[0012] Number the four pressure sensors and mark them as n, where n=1, 2, 3, and 4; obtain the pressure value Fn collected by the pressure sensor; F is the pressure value; obtain the maximum value in the pressure value Fn and set it as the maximum pressure value F0;

[0013] The pressure mean F1 is obtained by performing mean calculation on the pressure values ​​Fn;

[0014] Count the number of pressure sensors whose pressure values ​​Fn are not 0 and obtain the total number of valid pressure sensors h;

[0015] The formula for estimating the shape variable is: ;

[0016] The deformation D corresponding to the test number is obtained; k2 is the proportional coefficient of the pressure mean F1.

[0017] In the above-mentioned ball hitting test device for battery pack strength detection, data analysis is performed on the deformation variable D. If the deformation variable D is not greater than the specified upper limit of the deformation variable, the deformation variable D is marked as a valid deformation variable D1; if the deformation variable D is not greater than the specified upper limit of the deformation variable, the deformation variable D is marked as an invalid deformation variable D2; the specified upper limit of the deformation variable is obtained based on historical test big data;

[0018] Obtain a number of effective deformation variables D1, search and obtain the maximum effective deformation variable D1max among the effective deformation variables D1, obtain the test number corresponding to the maximum effective deformation variable D1max and mark it as the effective test number, obtain the test height corresponding to the effective number and mark it as the maximum test height Hmax;

[0019] By first evaluating the formula: ;

[0020] The physical strength evaluation value A1 of the battery pack strength is calculated; G is the weight of the battery pack.

[0021] In the above-mentioned ball striking test device for battery pack strength detection, the steps of the second analysis scheme include:

[0022] Determine whether the first monitoring current and the second monitoring current are both within the zero value range (0, Ib) in the first time period and the second time period, respectively. If the first monitoring current and the second monitoring current are both within the zero value range (0, Ib) in the first time period and the second time period, respectively, determine that the battery management system is effective and generate a zero-level safety assessment value addition tag; Ib is a zero-value current error; the zero-level safety assessment value addition tag is the highest level of the safety tag; the start time point of the first time period is when the vibration sensor detects the vibration amplitude; the first time period includes a filtering period;

[0023] During the first time period, if the first monitoring current is not 0, the current change amplitude of the first monitoring current during the first time period is obtained; if the current change amplitude is not greater than the standard current change amplitude Ia, a first-level safety assessment value increase label is generated; if the current change amplitude is greater than the standard current change amplitude Ia, a safety assessment value reduction label is generated; the standard current change amplitude Ia is obtained based on the current monitor detection before the ball hit test.

[0024] In the above-mentioned ball strike test device for detecting the strength of a battery pack, a plurality of first monitoring currents detected between the starting time point after the end of the filtering period and the end time point of the first period are compared with the first monitoring current judgment interval (Is-Ia, Is+Ia), the first monitoring current belonging to the first monitoring current judgment interval (Is-Ia, Is+Ia) is marked as a normal first monitoring current, the occurrence times of a plurality of normal first monitoring currents are statistically analyzed to obtain the corresponding normal monitoring time, a plurality of normal monitoring currents are summed to obtain the total normal monitoring time, a difference calculation is performed between the monitoring time corresponding to the first period and the total normal monitoring time to obtain the monitoring current recovery time, and data analysis is performed on the monitoring current recovery time;

[0025] If the recovery time of the monitoring current is not longer than the standard recovery time, a secondary safety assessment value increase tag is generated; if the recovery time of the monitoring current is longer than the standard recovery time, a same safety assessment value decrease tag is generated;

[0026] A first time period label result is generated according to the label data of the first time period.

[0027] In the above-mentioned ball strike test device for battery pack strength detection, the tag results of the first time period are traversed, and if the traversal results do not contain a tag with a reduced safety assessment value, a monitoring end instruction is generated; if the traversal results contain a tag with a reduced safety assessment value, an abnormality judgment instruction is generated;

[0028] Acquire a number of first monitoring currents in a first time period and a number of second monitoring currents in a second time period according to the monitoring end instruction, and calculate the average of the first monitoring current and the second monitoring current to obtain an average monitoring current Ia;

[0029] According to the abnormal judgment instruction, it is judged whether the second monitoring current has abnormal characteristics within the second time period; if there are no abnormal characteristics, a third-level safety assessment value increase label is generated; if there are abnormal characteristics, the same safety assessment value reduction label is generated.

[0030] In the above-mentioned ball striking test device for battery pack strength detection, the method for distinguishing abnormal characteristics is specifically as follows:

[0031] Construct a two-dimensional coordinate system for the real-time change of the second monitoring current in the second time period, use the timestamp and the second monitoring current as the horizontal and vertical coordinates of the two-dimensional coordinate system respectively, and generate a second monitoring current judgment interval (Is-Ib, Is+Ib) according to the current change amplitude; Ib is the abnormal second monitoring current change value; Ib can be set to 1.5 times the current change amplitude;

[0032] The number of second monitoring currents less than the minimum value of the second monitoring current judgment interval (Is-Ib, Is+Ib) and the number of second monitoring currents greater than the maximum value of the second monitoring current judgment interval (Is-Ib, Is+Ib) are counted respectively to obtain the total number i of the upper second monitoring currents and the total number j of the lower second monitoring currents.

[0033] In the above-mentioned ball strike test device for battery pack strength detection, data analysis is performed on the upper second monitoring current total i and the lower second monitoring current total j. If the upper second monitoring current total i and the lower second monitoring current total j are both greater than the abnormal judgment value, a first abnormal label is generated; if the upper second monitoring current total i and the lower second monitoring current total j are both not greater than the abnormal judgment value, a first normal label is generated;

[0034] And, classify and mark all second monitoring currents monitored and obtained in the second time period, mark the second monitoring current that exceeds the second monitoring current judgment interval as the target second monitoring current, count the time when the target second monitoring current appears to obtain the abnormal time period, calculate the ratio of the abnormal time period to the monitoring time corresponding to the second time period to obtain the current abnormal occupancy rate, and perform data analysis on the current abnormal occupancy rate; if the current abnormal occupancy rate is greater than the abnormal judgment occupancy rate, generate a second abnormal label; if the current abnormal occupancy rate is not greater than the abnormal judgment occupancy rate, generate a second normal label;

[0035] A second time period label result is generated according to the label data in the second time period.

[0036] In the above-mentioned ball striking test device for detecting strength of a battery pack, the label result of the second time period is traversed, and if there is no abnormal label in the traversal result, it is determined that the second monitoring current has abnormal characteristics in the second time period; if there is a safety abnormal label in the traversal result, it is determined that the monitoring current has no abnormal characteristics in the second time period;

[0037] Acquire a number of first monitoring currents in the first time period and a number of second monitoring currents in the second time period, and calculate the average of the first monitoring currents and the second monitoring currents to obtain an average monitoring current Ia;

[0038] According to the safety evaluation value, the tag is increased to generate a first evaluation parameter Up, and according to the safety evaluation value, the tag is decreased to generate a second evaluation parameter Down;

[0039] By the second evaluation formula: ;

[0040] The strength assessment value A2 of the electric control system is calculated; where c0, c1, c2 and c3 represent the number of times the zero-level safety assessment value increase label, the first-level safety assessment value increase label, the second-level safety assessment value increase label and the third-level safety assessment value increase label appear respectively; d is the number of times the safety assessment value decrease label appears.

[0041] In the above-mentioned ball striking test device for battery pack strength detection, the physical strength evaluation value A1 and the electronic control system strength evaluation value A2 are processed by a comprehensive evaluation formula: ;

[0042] The comprehensive strength evaluation value A is calculated.

[0043] Compared with the prior art, the advantages of the present invention are:

[0044] 1. The pressure generated by the deformation of the battery pack during the collision is obtained through the pressure sensor, and the deformation variable D is obtained by calculating the pressure value. The effective deformation variable D1 and the invalid deformation variable D2 are obtained by performing data analysis on the deformation variable D, which can effectively determine the deformation degree of the battery pack after the impact.

[0045] 2. The physical strength evaluation value A1 of the battery pack is calculated by the first evaluation formula, so as to intuitively reflect the impact resistance of the battery pack.

[0046] 3. Perform data analysis on the first monitoring current in the first time period and the second monitoring current in the second time period through the second analysis scheme to obtain corresponding analysis results. Generate different levels of safety assessment values ​​according to different analysis results, increase the label of one level and reduce the label of several safety assessment values. Calculate the electric control system strength assessment value A2 according to the second assessment formula to facilitate the detection and reflection of the electric control system strength of the battery pack.

[0047] 4. The comprehensive strength evaluation value A of the battery pack is calculated through the comprehensive evaluation processing formula. The maximum comprehensive strength evaluation value A of the battery pack can be found in the test. The method is efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the planar structure of the present invention.

[0049] Figure 2 It is a schematic diagram of the planar structure of the detection load of the present invention.

[0050] Figure 3 It is a structural schematic diagram of the testing device of the present invention.

[0051] Figure 4 It is a flow chart of the data analysis module of the present invention.

[0052] In the figure: 1. test module; 101. fixed table; 102. billiard ball; 103. limit slide bar; 104. bushing; 105. connecting rope; 106. lifting piece; 107. current monitor; 108. detection load; 109. detection seat; 110. spring telescopic rod; 2. data acquisition module; 3. data analysis module. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0054] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0055] Example 1: Reference Figure 1 and Figure 2 , a ball hitting test device for battery pack strength detection, comprising a test module 1, a data acquisition module 2 and a data analysis module 3;

[0056] The test module 1 includes an impact unit, a limiting unit and a lifting unit; the limiting unit is used to limit the movement trajectory of the battery pack, and the lifting unit is used to lift the battery pack to a specified height;

[0057] The data acquisition module 2 includes an electrical signal acquisition unit and a physical acquisition unit; the electrical signal acquisition unit is used to detect the electrical signal change of the battery pack; the physical acquisition unit is used to detect the deformation degree of the battery pack;

[0058] The impact unit includes a fixed platform 101, a billiard ball 102 arranged on the upper surface of the fixed platform 101 and having a semicircular structure, the limiting unit includes a plurality of limiting slide bars 103 arranged on the upper surface of the fixed platform 101, a sleeve 104 slidably arranged on the limiting slide bar 103 and a connecting rope 105 installed on the outer surface of the sleeve 104, the connecting rope 105 is fixedly connected to the upper surface of the battery pack, and the hoisting unit includes a crane and a lifting member 106 arranged on the crane cable; the lifting member 106 can be a prior art device such as a mechanical claw or a hook lock, and the specific details are not elaborated in detail;

[0059] The electrical signal acquisition unit includes a current monitor 107 and a detection load 108 connected to the battery pack; the physical acquisition unit includes a vibration sensor arranged in the fixed platform 101 and a plurality of pressure detection components arranged on the upper surface of the fixed platform 101, the detection components include a detection seat 109, a pressure sensor arranged on the upper surface of the detection seat 109 and a spring telescopic rod 110 connected to the pressure sensor; four pressure detection components are provided, and the four pressure detection components are respectively arranged at the four corners of the fixed platform 101; the detection load 108 is powered by the battery pack according to the rated current Is, and the first monitoring current in the first time period after the battery pack is impacted and the second monitoring current in the second time period are obtained through the current monitor 107;

[0060] The test module 1 performs a ball hitting test on the battery pack according to the ball hitting test number, and records the test height corresponding to the ball hitting test number.

[0061] Example 2: Reference Figure 3 and Figure 4 , the data analysis module 3 is used to respectively obtain the first data collected by the physical acquisition unit and the second data collected by the electrical signal acquisition unit, respectively implement the first analysis scheme S1 and the second analysis scheme S2 on the first data and the second data and obtain the first analysis result and the second analysis result, obtain the comprehensive strength evaluation value A of the battery pack according to the first analysis result and the second analysis result through the comprehensive evaluation processing formula, and evaluate the comprehensive strength of the battery pack according to the comprehensive strength evaluation value A;

[0062] The steps of the first analysis scheme S1 include:

[0063] S100, number four pressure sensors and mark them as n, where n=1, 2, 3, 4; obtain pressure values ​​Fn collected by the pressure sensors; F is the magnitude of the pressure value; obtain the maximum value of the pressure value Fn and set it as the maximum pressure value F0;

[0064] The pressure mean F1 is obtained by performing mean calculation on the pressure values ​​Fn;

[0065] Count the number of pressure sensors whose pressure values ​​Fn are not 0 and obtain the total number of valid pressure sensors h;

[0066] The formula for estimating the shape variable is: ;

[0067] The deformation D corresponding to the test number is obtained; k2 is the proportionality coefficient of the pressure mean F1;

[0068] S101, performing data analysis on the deformation variable D. If the deformation variable D is not greater than the upper limit of the specified deformation variable, the deformation variable D is marked as a valid deformation variable D1; if the deformation variable D is not greater than the upper limit of the specified deformation variable, the deformation variable D is marked as an invalid deformation variable D2; the upper limit of the specified deformation variable is obtained according to historical test big data;

[0069] S102, obtaining a number of valid deformation amounts D1 of a battery pack of the same model, searching for and obtaining a maximum valid deformation amount D1max among the valid deformation amounts D1, obtaining a test number corresponding to the maximum valid deformation amount D1max and marking it as a valid test number, obtaining a test height corresponding to the valid number and marking it as a maximum test height Hmax;

[0070] By first evaluating the formula: ;

[0071] The physical strength evaluation value A1 of the battery pack strength is calculated; G is the weight of the battery pack;

[0072] The steps of the second analysis scheme S2 include:

[0073] S200, judging whether the first monitoring current and the second monitoring current belong to the zero value range (0, Ib) in the first time period and the second time period respectively; if the first monitoring current and the second monitoring current belong to the zero value range (0, Ib) in the first time period and the second time period respectively, judging that the battery management system is effective and generating a zero-level safety assessment value addition label; Ib is a zero-value current error; the zero-level safety assessment value addition label is the highest level of the safety label; the starting time point of the first time period is when the vibration sensor detects the vibration amplitude; the first time period includes a filtering period; the first time period can be set to 15s; the second time period is a continuous period after the end of the first time period, and the second time period can be set to 30s;

[0074] In the first time period, if the first monitoring current is not 0, the current change amplitude of the first monitoring current in the first time period is obtained, and if the current change amplitude is not greater than the standard current change amplitude Ia, a first-level safety assessment value increase label is generated; if the current change amplitude is greater than the standard current change amplitude Ia, a safety assessment value reduction label is generated; the standard current change amplitude Ia is obtained according to the detection of the current monitor 107 before the ball hitting test;

[0075] The method for obtaining the current change amplitude is specifically as follows:

[0076] The current change amplitude within the filtering period when the vibration sensor starts to detect the amplitude is filtered, and the difference and absolute value of the several first monitoring currents detected between the subsequent time point and the end time point of the first period are calculated with the rated current to obtain the monitoring current change values ​​corresponding to the several first monitoring currents, and the maximum value of the several calculated first monitoring current change values ​​is marked as the current change amplitude; the filtering period can be set to 1.5s, in order to remove the influence of the instability of the battery pack under the impact state caused by the impact on the first monitoring current;

[0077] S201. Compare a number of first monitoring currents detected between the starting time point after the end of the filtering period and the end time point of the first period with the first monitoring current judgment interval (Is-Ia, Is+Ia), mark the first monitoring current belonging to the first monitoring current judgment interval (Is-Ia, Is+Ia) as a normal first monitoring current, count the appearance times of a number of normal first monitoring currents to obtain the corresponding normal monitoring time, sum up a number of normal monitoring currents to obtain a total normal monitoring duration, perform a difference calculation between the monitoring duration corresponding to the first period and the total normal monitoring duration to obtain a monitoring current recovery duration, and perform data analysis on the monitoring current recovery duration;

[0078] If the recovery time of the monitored current is not longer than the standard recovery time, a secondary safety assessment value increase tag is generated; if the recovery time of the monitored current is longer than the standard recovery time, a same safety assessment value decrease tag is generated;

[0079] Generate a first period label result according to the label data of the first period;

[0080] S202, traversing the tag results of the first period, if the traversal results do not contain a tag with a reduced safety assessment value, generating a monitoring end instruction; if the traversal results contain a tag with a reduced safety assessment value, generating an abnormality judgment instruction;

[0081] Execute step S206 according to the monitoring end instruction; determine whether the second monitoring current has abnormal characteristics in the second time period according to the abnormal judgment instruction; if there is no abnormal characteristic, generate a third-level safety assessment value increase tag; if there is an abnormal characteristic, generate the same safety assessment value reduction tag;

[0082] The specific method for distinguishing abnormal features is as follows:

[0083] S203, construct a two-dimensional coordinate system for the real-time change of the second monitoring current in the second time period, use the timestamp and the second monitoring current as the horizontal and vertical coordinates of the two-dimensional coordinate system respectively, and generate a second monitoring current judgment interval (Is-Ib, Is+Ib) according to the current change amplitude in step S200; Ib is the abnormal second monitoring current change value; Ib can be set to 1.5 times the current change amplitude;

[0084] The number of second monitoring currents less than the minimum value of the second monitoring current judgment interval (Is-Ib, Is+Ib) and the number of second monitoring currents greater than the maximum value of the second monitoring current judgment interval (Is-Ib, Is+Ib) are counted respectively to obtain the total number i of the upper second monitoring currents and the total number j of the lower second monitoring currents;

[0085] S204, performing data analysis on the total number i of the upper second monitoring current and the total number j of the lower second monitoring current. If both the total number i of the upper second monitoring current and the total number j of the lower second monitoring current are greater than the abnormal judgment value, a first abnormal label is generated; if both the total number i of the upper second monitoring current and the total number j of the lower second monitoring current are not greater than the abnormal judgment value, a first normal label is generated; wherein, the abnormal judgment value can be 10, specifically, it can be adjusted according to the effective deformation amount D1, when the effective deformation amount D1 obtained in this ball hitting test increases compared with the effective deformation amount D1 obtained in the previous ball hitting test, the abnormal judgment value of this ball hitting test can be adjusted to 20;

[0086] And, classify and mark all the second monitoring currents monitored and obtained in the second time period, mark the second monitoring current that exceeds the second monitoring current judgment interval as the target second monitoring current, count the time when the target second monitoring current appears to obtain the abnormal time period, calculate the ratio of the abnormal time period to the monitoring time corresponding to the second time period to obtain the current abnormal occupancy rate, and perform data analysis on the current abnormal occupancy rate; if the current abnormal occupancy rate is greater than the abnormal judgment occupancy rate, generate a second abnormal label; if the current abnormal occupancy rate is not greater than the abnormal judgment occupancy rate, generate a second normal label; wherein the abnormal occupancy rate can be set to 60%, specifically, it can be adjusted according to the effective deformation amount D1, when the effective deformation amount D1 obtained in this ball hitting test increases compared with the effective deformation amount D1 obtained in the previous ball hitting test, the abnormal occupancy rate of this ball hitting test can be adjusted to 80%;

[0087] Generate a second time period label result according to the label data in the second time period;

[0088] S205, traversing the label results of the second time period, if the traversal results do not contain abnormal labels, determining that the second monitoring current has abnormal characteristics in the second time period; if the traversal results contain safety abnormal labels, determining that the monitoring current does not have abnormal characteristics in the second time period;

[0089] S206, obtaining a number of first monitoring currents in a first time period and a number of second monitoring currents in a second time period, and performing average calculation on the first monitoring currents and the second monitoring currents to obtain an average monitoring current Ia;

[0090] According to the safety evaluation value, the tag is increased to generate a first evaluation parameter Up, and according to the safety evaluation value, the tag is decreased to generate a second evaluation parameter Down;

[0091] By the second evaluation formula: ;

[0092] The electric control system strength assessment value A2 is calculated; wherein c0, c1, c2 and c3 represent the number of times that the zero-level safety assessment value increase label, the first-level safety assessment value increase label, the second-level safety assessment value increase label and the third-level safety assessment value increase label appear respectively; d is the number of times that the safety assessment value decrease label appears; it should be noted that if the battery pack produces smoke, fire and other phenomena observable to the naked eye, the electric control system strength assessment value A2 is determined to be invalid, and the relevant data in the last ball hitting test are selected, and the relevant data include D1max, c0, c1, c2, c3, d and Ia; otherwise, the electric control system strength assessment value A2 is determined to be valid;

[0093] S207, through comprehensive evaluation processing formula: ;

[0094] The comprehensive strength evaluation value A is calculated; the comprehensive strength evaluation value A is used to indicate the comprehensive strength of the battery pack under the ball impact test. The larger the comprehensive strength evaluation value A is, the higher the comprehensive strength of the battery pack is.

[0095] It is further explained that the above-mentioned fixed connection should be understood in a broad sense unless otherwise clearly specified and limited. For example, it can be welding, gluing, or one-piece molding, etc., which are conventional means well known to those skilled in the art.

[0096] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A ball striking test device for detecting strength of a battery pack, comprising a test module (1), a data acquisition module (2) and a data analysis module (3), characterized in that: The test module (1) performs a ball impact test on the battery pack according to the ball impact test number, and records the test height corresponding to the ball impact test number. The test module (1) comprises an impact unit, a limit unit and a hoisting unit; The limiting unit is used to limit the movement trajectory of the battery pack, and the lifting unit is used to lift the battery pack to a specified height; The data acquisition module (2) comprises an electrical signal acquisition unit and a physical acquisition unit; The impact unit comprises a fixed platform (101), a billiard ball (102) arranged on the upper surface of the fixed platform (101) and having a semicircular structure, and the limiting unit comprises a plurality of limiting sliding bars (103) arranged on the upper surface of the fixed platform (101), sleeves (104) slidably arranged on the limiting sliding bars (103), and a connecting rope (105) installed on the outer surface of the sleeve (104), and the connecting rope (105) is fixedly connected to the upper surface of the battery pack; The electrical signal acquisition unit comprises a current monitor (107) and a detection load (108) connected to the battery pack; The physical acquisition unit comprises a vibration sensor arranged in a fixed platform (101) and a plurality of pressure detection components arranged on the upper surface of the fixed platform (101), the detection components comprising a detection seat (109), a pressure sensor arranged on the upper surface of the detection seat (109), and a spring telescopic rod (110) connected to the pressure sensor; The data analysis module (3) is used to respectively acquire first data collected by the physical acquisition unit and second data collected by the electrical signal acquisition unit, respectively implement a first analysis scheme S1 and a second analysis scheme S2 on the first data and the second data to obtain a first analysis result and a second analysis result, obtain a comprehensive strength evaluation value A of the battery pack according to the first analysis result and the second analysis result through a comprehensive evaluation processing formula, and evaluate the comprehensive strength of the battery pack according to the comprehensive strength evaluation value A; The steps of the second analysis scheme S2 include: Determine whether the first monitoring current and the second monitoring current are both within the zero value range (0, Ib) in the first time period and the second time period, respectively. If the first monitoring current and the second monitoring current are both within the zero value range (0, Ib) in the first time period and the second time period, respectively, determine that the battery management system is effective and generate a zero-level safety assessment value addition tag; Ib is a zero-value current error; the zero-level safety assessment value addition tag is the highest level of the safety tag; the start time point of the first time period is when the vibration sensor detects the vibration amplitude; the first time period includes a filtering period; In the first time period, if the first monitoring current is not zero, then the current change amplitude of the first monitoring current in the first time period is obtained, and if the current change amplitude is not greater than the standard current change amplitude Ia, then a first-level safety assessment value increase tag is generated; if the current change amplitude is greater than the standard current change amplitude Ia, then a safety assessment value decrease tag is generated; the standard current change amplitude Ia is obtained based on the detection of the current monitor (107) before the ball impact test; Compare a number of first monitoring currents detected between the starting time point after the end of the filtering period and the end time point of the first period with the first monitoring current judgment interval (Is-Ia, Is+Ia), mark the first monitoring current belonging to the first monitoring current judgment interval (Is-Ia, Is+Ia) as a normal first monitoring current, count the appearance times of a number of normal first monitoring currents to obtain the corresponding normal monitoring time, sum up a number of normal monitorings to obtain a total normal monitoring duration, perform a difference calculation between the monitoring duration corresponding to the first period and the total normal monitoring duration to obtain a monitoring current recovery duration, and perform data analysis on the monitoring current recovery duration; If the recovery time of the monitoring current is not longer than the standard recovery time, a secondary safety assessment value increase tag is generated; if the recovery time of the monitoring current is longer than the standard recovery time, a same safety assessment value decrease tag is generated; Generate a first time period label result according to the label data of the first time period; Traversing the tag results of the first time period, if the traversal results do not contain a tag with a reduced safety assessment value, generating a monitoring end instruction; if the traversal results contain a tag with a reduced safety assessment value, generating an abnormality judgment instruction; Acquire a number of first monitoring currents in a first time period and a number of second monitoring currents in a second time period according to the monitoring end instruction, and calculate the average of the first monitoring current and the second monitoring current to obtain an average monitoring current Ia; According to the abnormal judgment instruction, it is judged whether the second monitoring current has abnormal characteristics within the second time period; if there are no abnormal characteristics, a third-level safety assessment value increase label is generated; if there are abnormal characteristics, the same safety assessment value reduction label is generated.

2. A ball striking test device for battery pack strength detection according to claim 1, characterized in that: The steps of the first analysis scheme S1 include: The four pressure sensors are numbered and marked as n, where n=1, 2, 3, and 4; a pressure value Fn collected by the pressure sensor is obtained; F is the magnitude of the pressure value; the maximum value of the pressure value Fn is obtained and set as the maximum pressure value F0; Performing mean calculation on the pressure values ​​Fn to obtain the pressure mean value F1; Count the number of pressure sensors whose pressure values ​​Fn are not 0 and obtain the total number of valid pressure sensors h; The formula for estimating the shape variable is: ; The deformation D corresponding to the test number is calculated; k2 is the proportionality coefficient of the pressure mean F1.

3. A ball striking test device for battery pack strength detection according to claim 2, characterized in that: Performing data analysis on the deformation variable D, if the deformation variable D is not greater than the upper limit of the specified deformation variable, marking the deformation variable D as a valid deformation variable D1; if the deformation variable D is not greater than the upper limit of the specified deformation variable, marking the deformation variable D as an invalid deformation variable D2; The upper limit of the specified deformation variable is obtained based on historical test big data; Obtain a number of valid deformation quantities D1, search and obtain the maximum valid deformation quantity D1max among the number of valid deformation quantities D1, obtain the test number corresponding to the maximum valid deformation quantity D1max and mark it as the valid test number, obtain the test height corresponding to the valid number and mark it as the maximum test height Hmax; By first evaluating the formula: ; The physical strength evaluation value A1 of the battery pack strength is calculated; G is the weight of the battery pack.

4. A ball striking test device for battery pack strength detection according to claim 3, characterized in that: The method for distinguishing the abnormal features is specifically as follows: Construct a two-dimensional coordinate system for the real-time change of the second monitoring current in the second time period, use the timestamp and the second monitoring current as the horizontal and vertical coordinates of the two-dimensional coordinate system respectively, and generate a second monitoring current judgment interval (Is-Ib, Is+Ib) according to the current change amplitude; Ib is the abnormal second monitoring current change value; Ib can be set to 1.5 times the current change amplitude; The number of second monitoring currents less than the minimum value of the second monitoring current judgment interval (Is-Ib, Is+Ib) and the number of second monitoring currents greater than the maximum value of the second monitoring current judgment interval (Is-Ib, Is+Ib) are counted respectively to obtain the total number i of the upper second monitoring currents and the total number j of the lower second monitoring currents.

5. A ball striking test device for battery pack strength detection according to claim 4, characterized in that: Perform data analysis on the total number i of the upper second monitoring current and the total number j of the lower second monitoring current. If the total number i of the upper second monitoring current and the total number j of the lower second monitoring current are both greater than the abnormal judgment value, a first abnormal label is generated; if the total number i of the upper second monitoring current and the total number j of the lower second monitoring current are both not greater than the abnormal judgment value, a first normal label is generated; And, classify and mark all second monitoring currents monitored and obtained in the second time period, mark the second monitoring current that exceeds the second monitoring current judgment interval as the target second monitoring current, count the time when the target second monitoring current appears to obtain the abnormal time period, calculate the ratio of the abnormal time period to the monitoring time corresponding to the second time period to obtain the current abnormal occupancy rate, and perform data analysis on the current abnormal occupancy rate; If the current abnormal occupancy rate is greater than the abnormal judgment occupancy rate, a second abnormal label is generated; If the abnormal current occupancy rate is not greater than the abnormal judgment occupancy rate, a second normal label is generated; A second time period label result is generated according to the label data in the second time period.

6. A ball striking test device for battery pack strength detection according to claim 5, characterized in that: Traversing the label results of the second time period, if there is no abnormal label in the traversal results, determining that the second monitoring current has abnormal characteristics in the second time period; If there is a safety anomaly tag in the traversal result, it is determined that the monitored current has no abnormal characteristics in the second period; Acquire a number of first monitoring currents in the first time period and a number of second monitoring currents in the second time period, and calculate the average of the first monitoring currents and the second monitoring currents to obtain an average monitoring current Ia; According to the safety evaluation value, the tag is increased to generate a first evaluation parameter Up, and according to the safety evaluation value, the tag is decreased to generate a second evaluation parameter Down; By the second evaluation formula: ; The strength assessment value A2 of the electric control system is calculated; wherein c0, c1, c2 and c3 represent the number of occurrences of the zero-level safety assessment value increase label, the first-level safety assessment value increase label, the second-level safety assessment value increase label and the third-level safety assessment value increase label respectively; d is the number of times the safety assessment value reduces the label appearance.

7. A ball striking test device for battery pack strength detection according to claim 6, characterized in that: The physical strength evaluation value A1 and the electric control system strength evaluation value A2 are processed by a comprehensive evaluation formula: ; The comprehensive strength evaluation value A is calculated.

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