Automatically adjustable measuring instrument and related measuring method

Abstract

The invention discloses a measuring instrument capable of being automatically adjusted and a related measuring method, and the measuring instrument comprises a first parallel surface pressing plate and a second parallel surface pressing plate which are parallel to each other, a first stress pressing plate located above the first parallel surface pressing plate, a second stress pressing plate located below the second parallel surface pressing plate, and a third stress pressing plate located below the second parallel surface pressing plate, the position adjusting mechanism is vertically connected with the first stress pressing plate and the second stress pressing plate and drives the first stress pressing plate and the second stress pressing plate to move relatively; the first parallel face pressing plate is fixedly connected to the first stress pressing plate through a first pressure sensor, and the second parallel face pressing plate is fixedly connected to the second stress pressing plate through a second pressure sensor. The measuring instrument is simple in structural design, small and exquisite in appearance size and wide in working temperature range, and can realize constant-pressure thickness measurement, constant-gap force measurement and on-line measurement in a mixed working mode in the electrified and charging-discharging process of the battery core on the premise of ensuring the parallelism, the pressure precision and the thickness precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery measurement, in particular to a measurement instrument capable of automatic adjustment and a related measurement method. BACKGROUND

[0002] Soft package lithium battery is the third generation of power lithium battery developed on the basis of the original steel shell, aluminum shell and plastic shell battery. It is widely used in production and manufacturing industry, metal processing industry, chemical industry, commercial inspection and other fields due to its advantages of lighter, thinner, longer cycle life, better safety performance, higher energy density, stable discharge platform, excellent power performance, environmental protection and no pollution.

[0003] In recent years, the lithium ion battery industry has developed rapidly. The actual use of the battery is bound in the module. The thickness change caused by the expansion force during the charging and discharging process will directly affect the electrical performance, safety and reliability of the battery, the module and the battery pack. In scientific research and production and manufacturing, the off-line detection of the in-situ thickness and expansion force of the battery puts forward the technical requirements of on-line monitoring. Higher requirements are put forward for the parallelism, pressure accuracy and thickness accuracy involved in the current traditional scheme. In the product development process, the functions of constant pressure thickness measurement, constant gap force measurement and their mixed mode are required. SUMMARY

[0004] The present application aims to at least solve the technical problems existing in the prior art. To this end, the present application proposes a measurement instrument capable of automatic adjustment, comprising: a first parallel surface pressure plate and a second parallel surface pressure plate parallel to each other, a first force receiving pressure plate located above the first parallel surface pressure plate, a second force receiving pressure plate located below the second parallel surface pressure plate, and a position adjusting mechanism vertically connecting the first force receiving pressure plate and the second force receiving pressure plate and driving the first force receiving pressure plate and the second force receiving pressure plate to move relative to each other; The first parallel surface pressure plate is connected and fixed to the first force receiving pressure plate by a first pressure sensor, and the second parallel surface pressure plate is connected and fixed to the second force receiving pressure plate by a second pressure sensor. The number of the position adjusting mechanism is three or more than three, and is not installed on a straight line. A plurality of displacement detection mechanisms 7 are installed on the first parallel surface pressure plate and the second parallel surface pressure plate respectively, for detecting the displacement and gap of the first parallel surface pressure plate and the second parallel surface pressure plate. The measurement instrument further comprises a controller and an upper computer management system. The controller is electrically connected with the motor of the position adjusting mechanism, the pressure sensor and the displacement detection mechanism. The controller is in communication connection with the upper computer management system.

[0005] Optionally, the first parallel face pressing plate and the second parallel face pressing plate are identical in shape and size, and the first force receiving pressing plate and the second force receiving pressing plate are identical in shape and size.

[0006] Optionally, the displacement detection mechanism comprises a displacement sensor, a displacement scale and a displacement reading head, the displacement scale is fixed on the first parallel face pressing plate, the displacement reading head is fixed on the second parallel face pressing plate, and the displacement sensor is connected with the controller.

[0007] Optionally, the number of the position adjusting mechanisms is three sets, the first parallel face pressing plate and the second parallel face pressing plate are triangular, and the three sets of position adjusting mechanisms are respectively vertically connected to three vertices of the first parallel face pressing plate and the second parallel face pressing plate.

[0008] Optionally, the position adjusting mechanism is a lead screw assembly, and the lead screw assembly comprises a lead screw support structure, a motor, a lead screw, a nut, a first elastic connecting piece and a second elastic connecting piece. The fixed end of the nut is connected and fixed to the second force receiving pressing plate through the second elastic connecting piece.

[0009] Optionally, the first parallel face pressing plate and the second parallel face pressing plate are made of marble.

[0010] Optionally, the controller integrates a motor driving module and operation control algorithm, a pressure and displacement acquisition module, a constant pressure thickness measurement algorithm, a constant gap force measurement algorithm, an elastic gap algorithm, an automatic leveling algorithm, an offline mode and data storage function, and a 485 communication protocol. The upper computer management system realizes measurement control function through human-computer interaction and network communication with the controller.

[0011] The second aspect of the application provides a constant pressure thickness measurement method, which is applied to the measuring instrument of the first aspect, and the method comprises the following steps: Placing a first object to be measured on the second parallel face pressing plate; Controlling the position adjusting mechanism to drive the first force receiving pressing plate and the second force receiving pressing plate to move up and down by using the controller until the gap values between the first parallel face pressing plate and the second parallel face pressing plate collected by each displacement sensor are equal; Setting a target pressure value in the upper computer management system and clicking a thickness measurement button, and controlling the position adjusting mechanism to move up and down by using the controller until the first pressure value of the first force receiving pressing plate collected by the first pressure sensor and the second pressure value of the second force receiving pressing plate collected by the second pressure sensor both reach the target pressure value; The gap value between the first parallel face presser and the second parallel face presser detected by each displacement sensor is acquired, and the thickness value of the first object to be measured under constant pressure is determined according to the gap value.

[0012] The third aspect of the present application provides a constant gap force measurement method, which is applied to the measuring instrument of the first aspect, and the method comprises: The second object to be measured is placed on the second parallel face presser; The first force receiving presser and the second force receiving presser are moved up and down by the position adjusting mechanism controlled by the controller until the gap values between the first parallel face presser and the second parallel face presser collected by each displacement sensor are equal; The target gap value is set in the upper computer management system and the force measurement button is clicked, and the position adjusting mechanism is moved up and down by the controller until the gap between the first parallel face presser and the second parallel face presser collected by each displacement sensor reaches the target gap value; The electric core of the second object to be measured is controlled to start charging and discharging; The first pressure value of the first force receiving presser detected by the first pressure sensor and the second pressure value of the second force receiving presser detected by the second pressure sensor are acquired during the charging and discharging process of the electric core; The pressure value of the electric core of the second object to be measured under constant gap is determined according to the first pressure value and the second pressure value.

[0013] The fourth aspect of the present application provides a 0 pressure weighing method, which is applied to the measuring instrument of the first aspect, and the method comprises: The third object to be measured is placed on the second parallel face presser; The first force receiving presser and the second force receiving presser are moved up and down by the position adjusting mechanism controlled by the controller until the gap values between the first parallel face presser and the second parallel face presser collected by each displacement sensor are equal; The first force receiving presser is set as the pressure value in the upper computer management system and the force measurement button is clicked, and the position adjusting mechanism is moved up and down by the controller until the third pressure value of the first force receiving presser collected by the first pressure sensor is 0; The fourth pressure value of the second force receiving presser collected by the second pressure sensor is acquired, and the fourth pressure value is taken as the weight of the third object to be measured.

[0014] The above-mentioned scheme has the following beneficial effects: The automatic-adjustable measuring instrument provided by the embodiment of the present application comprises: a first parallel surface pressing plate and a second parallel surface pressing plate which are parallel to each other, a first force receiving pressing plate located above the first parallel surface pressing plate, a second force receiving pressing plate located below the second parallel surface pressing plate, and a position adjusting mechanism vertically connecting the first force receiving pressing plate and the second force receiving pressing plate and driving the first force receiving pressing plate and the second force receiving pressing plate to move relatively; the first parallel surface pressing plate is connected and fixed to the first force receiving pressing plate through a first pressure sensor, and the second parallel surface pressing plate is connected and fixed to the second force receiving pressing plate through a second pressure sensor; the number of the position adjusting mechanisms is three or more than three, and the position adjusting mechanisms are not installed in a straight line; a plurality of displacement detection mechanisms are installed on the first parallel surface pressing plate and the second parallel surface pressing plate respectively, and are used for detecting the displacement and the gap of the first parallel surface pressing plate and the second parallel surface pressing plate; the measuring instrument further comprises a controller and an upper computer management system, the controller is electrically connected with motors of the position adjusting mechanisms, the pressure sensors and the displacement detection mechanisms, and the controller is in communication connection with the upper computer management system. The measuring instrument has simple structure design, small size, wide working temperature range, and can realize the online measurement in the constant pressure thickness measurement, the constant gap force measurement and the mixed working mode under the premise of ensuring the parallelism, the pressure accuracy and the thickness accuracy. The measuring instrument provides support for the cell material development, the structure design, the process optimization and the related mechanism research, and provides reliable structure parameters for the module and the battery pack design. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a three-dimensional view of an automatic-adjustable measuring instrument provided by the embodiment of the present application; Figure 2 FIG. 2 is a front view of the automatic-adjustable measuring instrument provided by the embodiment of the present application; Figure 3 FIG. 3 is a top view of a triangular parallel surface pressing plate provided by the embodiment of the present application; Figure 4 FIG. 4 is a step flow chart of a constant pressure thickness measurement method provided by the embodiment of the present application; Figure 5 FIG. 5 is a step flow chart of a constant gap force measurement method provided by the embodiment of the present application; Figure 6 FIG. 6 is a step flow chart of a constant gap force measurement method provided by the embodiment of the present application. DETAILED DESCRIPTION

[0016] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0017] Hereinafter, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise stated, the meaning of "a plurality of" is two or more. In addition, the use of "based on" or "according to" means openness and inclusiveness, because the process, step, calculation or other action "based on" or "according to" one or more stated conditions or values can be based on additional conditions or values beyond the stated values in practice.

[0018] Figure 1 A three-dimensional view of an automatically adjustable measuring instrument is provided for the embodiments of the present application.

[0019] Figure 2 A front view of an automatically adjustable measuring instrument is provided for the embodiments of the present application.

[0020] As shown in Figure 1 , Figure 2 , the measuring instrument comprises: a first parallel surface pressing plate 1 and a second parallel surface pressing plate 2 which are parallel to each other, a first force pressing plate 3 located above the first parallel surface pressing plate 1, a second force pressing plate 4 located below the second parallel surface pressing plate 2, and a position adjusting mechanism 5 vertically connecting the first force pressing plate 3 and the second force pressing plate 4 and driving the first force pressing plate 3 and the second force pressing plate 4 to move relatively; The first parallel surface pressing plate 1 is connected and fixed to the first force pressing plate 3 by a first pressure sensor 8, and the second parallel surface pressing plate 2 is connected and fixed to the second force pressing plate 4 by a second pressure sensor 9; The number of the position adjusting mechanism 5 is three or more than three, and is not installed in a straight line; A plurality of displacement detection mechanisms 7 are installed on the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2 respectively, for detecting the displacement and gap of the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2; The measuring instrument further comprises a controller 6 and an upper computer management system, the controller 6 is electrically connected with the motor of the position adjusting mechanism 5, the pressure sensor and the displacement monitoring mechanism, and the controller 6 is in communication connection with the upper computer management system.

[0021] In the embodiment of the present application, the first parallel face pressing plate 1 and the second parallel face pressing plate 2 constitute a parallel face plate pressure measuring thickness mechanism, and the parallelism control of the first parallel face pressing plate 1 and the second parallel face pressing plate 2 is realized by controlling the gap of at least three points not on a straight line.

[0022] The measured object is placed between the first force pressing plate 3 and the second force pressing plate 4, the position adjusting mechanism 5 can control the up and down movement of the first force pressing plate 3 and the second force pressing plate 4, and the displacement detection mechanism 7 is used to detect the size of the gap between the first force pressing plate 3 and the second force pressing plate 4, so that the gap reaches the target gap value, thereby realizing constant gap force measurement.

[0023] The displacement detection mechanism 7 can detect the change of the distance between the first parallel face pressing plate 1 and the second parallel face pressing plate 2 in the vertical direction, and also can determine the parallelism of the first parallel face pressing plate 1 and the second parallel face pressing plate 2 through multi-point detection data.

[0024] The displacement detection mechanism 7 is installed at the end of the first force pressing plate 3 and the second force pressing plate 4, can be close to the installation position of the position adjusting mechanism 5, and the number can be the same as that of the position adjusting mechanism 5, so as to accurately detect the change of displacement after position adjustment.

[0025] The first parallel face pressing plate 1 is connected and fixed to the first force pressing plate 3 through the first pressure sensor 8, and the second parallel face pressing plate 2 is connected and fixed to the second force pressing plate 4 through the second pressure sensor 9, so that the first pressure sensor 8 can detect the pressure received by the first force pressing plate 3, and the second pressure sensor 9 can detect the pressure received by the second force pressing plate 4.

[0026] The measured object is placed between the first force pressing plate 3 and the second force pressing plate 4, the position adjusting mechanism 5 controls the up and down movement of the first force pressing plate 3 and the second force pressing plate 4, so that the pressure readings of the two reach the target pressure value, thereby realizing constant pressure thickness measurement.

[0027] The upper computer management system can give the controller 6 a constant pressure thickness measurement instruction or a constant gap force measurement instruction, the controller 6 is connected with the pressure sensor, the displacement detection mechanism 7 and the motor of the position adjusting mechanism 5, the controller 6 controls the motor of the position adjusting mechanism 5 to work according to the measurement instruction, and realizes the up and down movement of the position adjusting mechanism 5.

[0028] The controller 6 receives the pressure reading of the pressure sensor, the displacement reading of the displacement detection mechanism 7, determines whether the constant pressure or constant gap is achieved according to the pressure reading and the displacement reading, and obtains the reading of the corresponding sensor to obtain the measurement value when it is determined that the constant pressure or constant gap is achieved.

[0029] The number of the position adjusting mechanisms 5 is three sets or more, and they are not installed in a straight line. According to the principle of three-point defining a plane, when the number of the position adjusting mechanisms is three sets or more, the three sets of position adjusting mechanisms move up and down at the same time, so that the displacement amount of each position of the first parallel face pressing plate 1 and the second parallel face pressing plate 2 is the same, thereby ensuring that the first parallel face pressing plate 1 and the second parallel face pressing plate 2 are always in a parallel state.

[0030] As an optional embodiment, the first parallel face pressing plate 1 and the second parallel face pressing plate 2 are the same in shape and size, and the first force pressing plate 3 and the second force pressing plate 4 are the same in shape and size.

[0031] The first parallel face pressing plate 1 and the second parallel face pressing plate 2 are the same in shape and size, and the first force pressing plate 3 and the second force pressing plate 4 are the same in shape and size, which can ensure that the force and displacement are the same under the same conditions, thereby reducing the system error.

[0032] As an optional embodiment, the displacement detection mechanism 7 includes a displacement ruler and a displacement reading head, the displacement ruler is fixed on the first parallel face pressing plate, and the displacement reading head is fixed on the second parallel face pressing plate.

[0033] The displacement ruler is generally a grating ruler or a magnetic grating ruler, which is a precision linear encoder ruler and is fixed on the first parallel face pressing plate by bolts or adhesion. The displacement reading head is an optical or magnetic induction sensor, which reads the scale signal of the ruler in real time and is installed on the second parallel face pressing plate. The displacement reading head maintains a certain gap with the displacement ruler to avoid mechanical contact and friction.

[0034] As an optional embodiment, the number of the position adjusting mechanisms 5 is three sets, the first parallel face pressing plate 1 and the second parallel face pressing plate 2 are both triangular, and the three sets of position adjusting mechanisms 5 are respectively vertically connected to the three vertices of the first parallel face pressing plate 1 and the second parallel face pressing plate 2.

[0035] Any three non-collinear points can accurately define a plane, when the number of the position adjusting mechanisms is three sets, the three sets of position adjusting mechanisms move up and down at the same time, so that the displacement amount of each position of the first parallel face pressing plate 1 and the second parallel face pressing plate 2 is the same, thereby ensuring that the first parallel face pressing plate 1 and the second parallel face pressing plate 2 are always in a parallel state.

[0036] Figure 3A top view of a triangular parallel face presser plate according to an embodiment of the present application.

[0037] As shown in Figure 3 the first parallel face presser plate 1 and the second parallel face presser plate 2 are both triangular, and three position adjustment mechanisms 5 are installed at the three vertices of the triangular presser plate, ensuring that the adjustment force is evenly distributed at 120°, avoiding unbalanced torque.

[0038] When the number of position adjustment mechanisms 5 is four or more, the position adjustment mechanisms 5 can also be distributed at the vertices of the face presser plate to ensure balanced force.

[0039] As an optional embodiment, the position adjustment mechanism 5 is a lead screw assembly, which includes a lead screw support structure, a motor, a lead screw 51, a nut 52, a first elastic connecting piece 53, and a second elastic connecting piece 54. The lead screw support structure is connected and fixed to the first force presser plate 3 through the first elastic connecting piece 53, and the fixed end of the nut 52 is connected and fixed to the second force presser plate 4 through the second elastic connecting piece 54.

[0040] In the embodiment of the present application, the lead screw support structure is a mechanical frame for fixing and supporting the lead screw, which usually contains a bearing seat or a support seat to ensure stable rotation of the lead screw. The motor is a power source for driving the rotation of the lead screw, which is usually directly connected to the lead screw through a shaft coupling. The lead screw 51 is a precision screw with a spiral groove, which transmits motion to the nut 52 when rotating. The nut 52 is a nut that meshes with the lead screw, which converts the rotational motion of the lead screw 52 into linear motion.

[0041] The first elastic connecting piece 53 connects the lead screw support structure and the first force presser plate 3, allowing the support structure to produce a small elastic deformation when subjected to force, which acts as a buffer or compensates for assembly errors. The second elastic connecting piece 54 connects the fixed end of the nut and the second force presser plate 4, making the linear motion of the nut flexible when transmitted to the presser plate, avoiding rigid impact or over-constraint.

[0042] In this way, the motor drives the lead screw 51 to rotate, while the nut 52 moves along the axial direction of the lead screw, pushing the first force presser plate 3 to move through the first elastic connecting piece 53, and pushing the second force presser plate 4 to move through the second elastic connecting piece 54, thereby achieving position adjustment.

[0043] As an optional embodiment, the first parallel face presser plate 1 and the second parallel face presser plate 2 are both made of marble.

[0044] The marble has a very low thermal expansion coefficient, and the aging deformation is almost zero, so that the parallelism of the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2 can be ensured, and the marble has excellent vibration damping characteristics, so that the vibration caused by the position adjusting mechanism 5 can be absorbed, and the risk of equipment resonance is reduced.

[0045] As an optional embodiment, the controller 6 integrates a motor driving module and operation control algorithm, a pressure and displacement acquisition module, a constant pressure thickness measurement algorithm, a constant gap force measurement algorithm, an elastic gap algorithm, an automatic leveling algorithm, an offline mode and data storage function, and a 485 communication protocol. The upper computer management system realizes the measurement control function through human-computer interaction and network communication with the controller 6.

[0046] In the embodiment of the application, the motor and operation control algorithm of the controller 6 are mainly used to drive the motor to move the position adjusting module up and down according to the instructions sent by the upper computer management system, and to control the movement of the position adjusting module. The pressure and displacement acquisition module is mainly used to acquire the pressure value of the pressure sensor and the displacement value of the displacement detection module. The constant pressure thickness measurement algorithm and the constant gap force measurement algorithm are used to control the position adjusting module to move up and down to realize constant pressure or constant gap, so as to measure the thickness or force of the object to be measured.

[0047] The constant gap mode includes two modes of rigid gap and elastic gap. The rigid gap is based on the principle and method adopted in the application, and realizes high-precision detection of the product to be measured, without system measurement error caused by structural deformation.

[0048] The elastic gap is based on the system error caused by the deformation of the traditional device mechanism. Based on the principle and method adopted in the application, only the rigid gap is used. In order to simulate the elastic gap, an elastic coefficient factor is introduced through a software algorithm, and the factor is revised according to the test sample of the reference product, so as to realize the consistency with the measurement system of the reference product, and realize the elastic gap algorithm.

[0049] The automatic leveling algorithm mainly refers to the simultaneous upward and downward movement of three or more sets of position adjusting mechanisms, so that the displacement amounts of the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2 at each position are the same, so as to ensure that the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2 are always in parallel state.

[0050] The application is a measurement method for monitoring the thickness and pressure of the battery cell during the charging and discharging process, i.e. an online measurement method. In addition, the constant pressure thickness measurement method of the application is also applicable to offline measurement, i.e. measuring the thickness when the battery cell is not charging and discharging.

[0051] The data storage function of the application refers to the storage of thickness measurement data and force measurement data.

[0052] The controller 6 and the upper computer management system use the 485 communication protocol for communication.

[0053] The automatically adjustable measuring instrument provided by the present application can automatically level, automatically adjust pressure, automatically adjust gap, automatically collect pressure and gap, has simple structure design, small size and wide working temperature range, and can realize online measurement in the constant pressure thickness measurement, constant gap force measurement and mixed working mode during the charging and discharging process of the battery cell under the premise of ensuring the parallelism, pressure accuracy and thickness accuracy. The detection objects can include electrode sheet materials, battery cells, soft packages and square shell battery cells, etc., which can provide support for the development of battery cell materials, the design of battery cell structures, the optimization of battery cell processes and the related mechanism research, and can provide reliable structural parameters for the design of modules and battery packs.

[0054] In summary, the automatically adjustable measuring instrument provided by the present application comprises: a first parallel surface pressure plate 1 and a second parallel surface pressure plate 2 which are parallel to each other, a first force receiving pressure plate 3 located above the first parallel surface pressure plate 1, a second force receiving pressure plate 4 located below the second parallel surface pressure plate 2, and a position adjusting mechanism 5 vertically connecting the first force receiving pressure plate 3 and the second force receiving pressure plate 4 and driving the first force receiving pressure plate 3 and the second force receiving pressure plate 4 to move relatively; the first parallel surface pressure plate 1 is connected and fixed to the first force receiving pressure plate 3 through a first pressure sensor 8, and the second parallel surface pressure plate 2 is connected and fixed to the second force receiving pressure plate 4 through a second pressure sensor 9; the number of the position adjusting mechanism 5 is three or more than three, and the position adjusting mechanism 5 is not installed in a straight line; a plurality of displacement detection mechanisms 7 are installed on the first parallel surface pressure plate 1 and the second parallel surface pressure plate 2 respectively, for detecting the displacement and gap of the first parallel surface pressure plate 1 and the second parallel surface pressure plate 2; the measuring instrument further comprises a controller 6 and an upper computer management system, the controller 6 is electrically connected with the motors of the position adjusting mechanism 5, the pressure sensors and the displacement detection mechanisms 7, and the controller 6 is in communication connection with the upper computer management system. The measuring instrument has simple structure design, small size and wide working temperature range, and can realize online measurement in the constant pressure thickness measurement, constant gap force measurement and mixed working mode during the charging and discharging process of the battery cell under the premise of ensuring the parallelism, pressure accuracy and thickness accuracy. The measuring instrument can provide support for the development of battery cell materials, the design of battery cell structures, the optimization of battery cell processes and the related mechanism research, and can provide reliable structural parameters for the design of modules and battery packs.

[0055] Figure 4 is a step flow chart of a constant pressure thickness measurement method provided by the present application. As shown in Figure 4 , the method comprises the following steps: Step 101, placing a first to-be-detected object on the second parallel surface pressure plate 2.

[0056] The first to-be-detected object can be any object that requires pressure for thickness measurement, such as a battery cell, a module and a battery pack, a rubber sheet, a rubber pad, etc.

[0057] The first object to be measured is placed on the surface of the second parallel surface presser plate 2, which is a fixed reference plane for supporting the object to be measured. The first parallel surface presser plate 1 is located above and will be pressed down by the position adjusting mechanism 5 to jointly clamp the object to be measured with the second parallel surface presser plate 2 Step 102, use the controller 6 to control the position adjusting mechanism 5 to drive the first force presser plate 3 and the second force presser plate 4 to move up and down until the gap values between the first parallel surface presser plate 1 and the second parallel surface presser plate 2 collected by each displacement sensor are equal.

[0058] The position adjusting mechanism 5 drives the first force presser plate 3 and the second force presser plate 4 to move and adjust their relative positions, thereby indirectly adjusting the gap between the first parallel surface presser plate 1 connected to the first force presser plate 3 and the second parallel surface presser plate 2 connected to the second force presser plate 4.

[0059] The displacement sensors monitor the gap between the first and second parallel surface presser plates 2 in real time, and the controller 6 adjusts through feedback to ensure that the gap values detected by all displacement sensors are consistent, indicating that the first parallel surface presser plate 1 and the second parallel surface presser plate 2 have reached a parallel state.

[0060] Step 103, set the target pressure value in the upper computer management system and click the thickness measurement button. Use the controller 6 to control the position adjusting mechanism 5 to move up and down until the first pressure value of the first force presser plate 3 collected by the first pressure sensor 8 and the second pressure value of the second force presser plate 4 collected by the second pressure sensor 9 both reach the target pressure value.

[0061] The operator inputs the target pressure value in the upper computer management system and starts the thickness measurement process.

[0062] The controller 6 controls the position adjusting mechanism 5 to apply pressure, causing the first force presser plate 3 and the second force presser plate 4 to apply force to the object to be measured simultaneously. The pressure sensors monitor the applied pressure in real time, and when the pressure values of the two presser plates both reach the target value, the controller 6 controls the position adjusting mechanism 5 to stop moving.

[0063] Step 104, obtain the gap values between the first parallel surface presser plate 1 and the second parallel surface presser plate 2 detected by each displacement sensor, and determine the thickness value of the first object to be measured under constant pressure based on the gap values.

[0064] Under constant pressure, the displacement sensors measure the final gap value between the two presser plates, and the average of the readings of multiple displacement sensors is used as the thickness value of the first object to be measured under constant pressure.

[0065] Figure 5is a step flow chart of a constant gap force measurement method provided by an embodiment of the present application.

[0066] The method is applied to a measuring instrument in Figure 1 , as shown in Figure 5 , the method comprises the following steps: Step 201, placing a second to-be-measured object on the second parallel surface pressure plate 2.

[0067] The second to-be-measured object can be a battery cell, a module, a battery pack, or other objects that need to be measured in the charging and discharging process.

[0068] The second to-be-measured object is placed on the surface of the second parallel surface pressure plate 2, which is a fixed reference plane for supporting the second to-be-measured object. The first parallel surface pressure plate 1 is located above and will be pressed down by the position adjusting mechanism 5 later to jointly clamp the to-be-measured object with the second parallel surface pressure plate 2 Step 202, using the controller 6 to control the position adjusting mechanism 5 to drive the first force pressure plate 3 and the second force pressure plate 4 to move up and down until the gap values between the first parallel surface pressure plate 1 and the second parallel surface pressure plate 2 collected by each displacement sensor are equal.

[0069] The position adjusting mechanism 5 drives the first force pressure plate 3 and the second force pressure plate 4 to move and adjust the relative position between them, so as to indirectly adjust the gap between the first parallel surface pressure plate 1 connected with the first force pressure plate 3 and the second parallel surface pressure plate 2 connected with the second force pressure plate 4.

[0070] The displacement sensor monitors the gap between the first and second parallel surface pressure plates 2 in real time, and the controller 6 adjusts through feedback to ensure that the gap values detected by all displacement sensors are consistent, indicating that the first parallel surface pressure plate 1 and the second parallel surface pressure plate 2 have reached a parallel state.

[0071] Step 203, setting a target gap value in the upper computer management system and clicking the force measurement button, and using the controller 6 to control the position adjusting mechanism 5 to move up and down until the gap between the first parallel surface pressure plate 1 and the second parallel surface pressure plate 2 collected by each displacement sensor reaches the target gap value.

[0072] The target gap value is a pre-set fixed gap, for example, the target gap value = battery cell nominal thickness + buffer layer thickness. The target gap value needs to consider the safe deformation range of the battery cell to avoid excessive extrusion.

[0073] The controller 6 drives the position adjusting mechanism 5 to make the gap between the first parallel surface pressure plate 1 and the second parallel surface pressure plate 2 reach the target gap value.

[0074] This step switches to the constant gap mode, and the subsequent pressure change is caused by the volume expansion or volume shrinkage in the charging and discharging process of the battery cell.

[0075] Step 204, control the second object to be measured to start the charging and discharging of the battery cell.

[0076] The controller 6 controls the constant current / constant voltage charging and discharging of the battery cell through the external host computer management system, The internal chemical reaction of the battery cell during charging and discharging will cause volume change, such as the expansion of the negative electrode of the lithium ion battery.

[0077] The charging and discharging time, capacity and other data can be recorded synchronously, and the pressure value is analyzed in association.

[0078] Step 205, during the charging and discharging of the battery cell, the first pressure value of the first force receiving plate 3 detected by the first pressure sensor 8 is obtained, and the second pressure value of the second force receiving plate 4 detected by the second pressure sensor 9 is obtained.

[0079] The pressure value fluctuates with the change of the volume of the battery cell during the charging and discharging process, such as the rise of the pressure caused by the expansion during charging. The first pressure sensor 8 detects the pressure applied by the upper pressure plate (the first force receiving plate 3) to the battery cell, and the second pressure sensor 9 detects the reaction force of the lower pressure plate (the second force receiving plate 4).

[0080] The pressure sensor needs to sample the pressure data at high frequency to capture the instantaneous change.

[0081] Step 206, determining the pressure value of the second object to be measured under constant gap according to the first pressure value and the second pressure value.

[0082] The average of the two pressure values is taken, and after checking the difference, the abnormal value is eliminated, a pressure-time curve is generated, and the pressure change in each stage of charging and discharging is analyzed.

[0083] The pressure change under constant gap directly reflects the mechanical properties of the battery cell, and the purpose of the constant pressure force test is to evaluate the volume stability of the battery cell and detect the safety of the battery, which can also be used to compare the pressure curves of different battery cells (such as different electrolytes and electrode materials).

[0084] Figure 6 It is a step flow chart of a constant gap force measurement method provided by an embodiment of the present application.

[0085] The method is applied to Figure 1 The measuring instrument, as shown in Figure 6 The method comprises the following steps: Step 301, placing a third object to be measured on the second parallel surface pressure plate 2.

[0086] The third object to be measured can be any object that needs to be weighed.

[0087] Step 302, use the controller 6 to control the position adjusting mechanism 5 to drive the first force plate 3 and the second force plate 4 to move up and down until the gap between the first parallel plate 1 and the second parallel plate 2 collected by each displacement sensor is equal.

[0088] The controller 6 drives the position adjusting mechanism 5 to adjust the position of the first force plate 3 and the second force plate 4. Real-time feedback is provided by the multi-point displacement sensor to ensure that the two plates are completely parallel.

[0089] Step 303, set the first force plate to 0 pressure value in the upper computer management system and click the force button. Use the controller 6 to control the position adjusting mechanism 5 to move up and down until the third pressure value of the first force plate 3 collected by the first pressure sensor 8 is 0.

[0090] The upper computer sends instructions to require the first pressure sensor 8 of the first force plate 3 (upper plate) to read 0.

[0091] The controller 6 controls the position adjusting mechanism 5 to slowly move the upper plate down until it just contacts the surface of the object but does not apply pressure, i.e. the sensor detects contact but the pressure value is 0.

[0092] In technical implementation, the pressure sensor needs to have high sensitivity to ensure accurate determination of zero pressure state.

[0093] This step takes the contact point between the upper plate and the object as the measurement reference surface to exclude the influence of the weight of the mechanical structure.

[0094] Step 304, obtain the fourth pressure value of the second force plate 4 collected by the second pressure sensor 9, and take the fourth pressure value as the weight of the third object to be measured.

[0095] The upper plate only contacts the object but does not apply pressure, so the third pressure value = 0. At this time, the weight of the object is completely supported by the second parallel plate 2 (lower plate). The pressure value detected by the second pressure sensor 9 is the actual weight of the object.

[0096] If the unit of the pressure sensor is force (N), it can be converted to mass unit by G=mg. In addition, the system needs to automatically deduct the weight of the second plate.

[0097] The automatically adjustable measuring instrument of the application is connected with one or more pressure sensors through the parallel upper pressing plate to realize pressure detection; is connected with one or more pressure sensors through the parallel lower pressing plate to realize weighing or pressure detection; the displacement measuring mechanism is fixed with the parallel upper pressing plate and the parallel lower pressing plate respectively to realize gap detection near the fixed positions of the two parallel panels; three or more displacement measuring mechanisms are fixed to the parallel upper pressing plate and the parallel lower pressing plate respectively through reasonable layout to realize gap detection of multiple points near the fixed positions of the two parallel panels; the pressure executing mechanism is fixed with the force applying pressing plate and the force bearing pressing plate respectively, adjusts the gap between the parallel panels through the motor driven pressure executing mechanism to realize stepless pressure regulation; the controller 6 is connected with the motor, the pressure sensor, the displacement sensor, the A / D and the I / O external device respectively, realizes power-on self-test, weighing, pressure, displacement, A / D and I / O signal acquisition and storage through the controller 6 program; realizes three working modes of constant pressure thickness measurement, constant gap force measurement and elastic gap force measurement through the main control program. The scheme adopts the pressure adjustable mode to measure the battery cell, does not need the traditional gram weight to be placed manually to reach the required pressure, can realize self-checking and calibration of the pressure and the thickness, solves the problem that the battery cell is bound in the module during actual use, the thickness change during the charging and discharging process causes the expansion force to directly affect the electrical performance, safety and reliability of the battery cell, the module and the battery pack and other performances.

[0098] In summary, in the embodiment of the application, the automatic-adjustable measuring instrument comprises: a first parallel surface pressing plate 1 and a second parallel surface pressing plate 2 which are parallel to each other, a first force receiving pressing plate 3 located above the first parallel surface pressing plate 1, a second force receiving pressing plate 4 located below the second parallel surface pressing plate 2, and a position adjusting mechanism 5 vertically connecting the first force receiving pressing plate 3 and the second force receiving pressing plate 4 and driving the first force receiving pressing plate 3 and the second force receiving pressing plate 4 to move relatively; the first parallel surface pressing plate 1 is connected and fixed to the first force receiving pressing plate 3 through a first pressure sensor 8, and the second parallel surface pressing plate 2 is connected and fixed to the second force receiving pressing plate 4 through a second pressure sensor 9; the number of the position adjusting mechanism 5 is three sets or more than three sets, and the position adjusting mechanism 5 is not installed in a straight line; a plurality of displacement detection mechanisms 7 are installed on the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2 respectively, for detecting the displacement and gap of the first parallel surface pressing plate 1 and the second parallel surface pressing plate 2; the measuring instrument further comprises a controller 6 and an upper computer management system, the controller 6 is electrically connected with the motor of the position adjusting mechanism 5, the pressure sensor and the displacement detection mechanism 7, and the controller 6 is in communication connection with the upper computer management system. The measuring instrument has simple structure design, small size, wide working temperature range, and can realize constant pressure thickness measurement, constant gap force measurement and 0 pressure weighing during the process of cell charging and discharging under the premise of ensuring parallelism, pressure accuracy and thickness accuracy. It provides support for cell material development, structure design, process optimization and related mechanism research, and provides reliable structure parameters for module and battery pack design.

[0099] The technical features of the above embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered as the scope of the description.

[0100] The above embodiments only express several implementation manners of the application, and the description is specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the application, and these are within the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. An automatically adjustable measuring instrument, characterized in that, include: The first parallel surface pressure plate and the second parallel surface pressure plate are parallel to each other, the first force-bearing pressure plate is located above the first parallel surface pressure plate, the second force-bearing pressure plate is located below the second parallel surface pressure plate, and the position adjustment mechanism is vertically connected to the first force-bearing pressure plate and the second force-bearing pressure plate and drives the first force-bearing pressure plate and the second force-bearing pressure plate to move relative to each other. The first parallel surface pressure plate is connected and fixed to the first force-bearing pressure plate through a first pressure sensor, and the second parallel surface pressure plate is connected and fixed to the second force-bearing pressure plate through a second pressure sensor; The number of the position adjustment mechanisms is three or more, and they are not installed in a straight line; Multiple displacement detection mechanisms 7 are respectively installed on the first parallel surface pressure plate and the second parallel surface pressure plate to detect the displacement and gap of the first parallel surface pressure plate and the second parallel surface pressure plate; The measuring instrument also includes a controller and a host computer management system. The controller is electrically connected to the motor of the position adjustment mechanism, the pressure sensor, and the displacement detection mechanism, and is communicatively connected to the host computer management system.

2. The measuring instrument according to claim 1, characterized in that, The first parallel surface pressure plate and the second parallel surface pressure plate have the same shape and size, and the first force-bearing pressure plate and the second force-bearing pressure plate have the same shape and size.

3. The measuring instrument according to claim 1, characterized in that, The displacement detection mechanism includes a displacement sensor, a displacement ruler, and a displacement reading head. The displacement ruler is fixed on the first parallel surface pressure plate, the displacement reading head is fixed on the second parallel surface pressure plate, and the displacement sensor is connected to the controller.

4. The measuring instrument according to claim 1, characterized in that, The number of the position adjustment mechanism is three sets. The first parallel surface pressure plate and the second parallel surface pressure plate are both triangular. The three sets of position adjustment mechanisms are vertically connected to the three vertices of the first parallel surface pressure plate and the second parallel surface pressure plate, respectively.

5. The measuring instrument according to claim 1, characterized in that, The position adjustment mechanism is a lead screw assembly, which includes a lead screw support structure, a motor, a lead screw, a lead screw nut, a first elastic connector, and a second elastic connector. The lead screw support structure is connected and fixed to the first pressure plate via a first elastic connector, and the fixed end of the lead screw nut is connected and fixed to the second pressure plate via a second elastic connector.

6. The measuring instrument according to claim 1, characterized in that, Both the first parallel surface pressure plate and the second parallel surface pressure plate are made of marble.

7. The measuring instrument according to claim 1, characterized in that, The controller integrates a motor drive module and motion control algorithm, pressure and displacement acquisition module, constant pressure thickness measurement algorithm, constant gap force measurement algorithm, elastic gap algorithm, automatic leveling algorithm, offline mode and data storage function, and 485 communication protocol; The host computer management system realizes measurement and control functions through human-computer interaction and network communication with the controller.

8. A constant pressure thickness measurement method, characterized in that, The method is applied to the measuring instrument according to any one of claims 1-7, and the method includes: The first object to be tested is placed on the second parallel surface pressure plate; The controller controls the position adjustment mechanism to move the first and second pressure plates up and down until the gap values ​​between the first and second parallel pressure plates collected by each displacement sensor are equal. In the host computer management system, set the target pressure value and click the thickness measurement button. The controller controls the position adjustment mechanism to move up and down until the first pressure value of the first pressure plate collected by the first pressure sensor and the second pressure value of the second pressure plate collected by the second pressure sensor both reach the target pressure value. The gap values ​​between the first parallel surface pressure plate and the second parallel surface pressure plate detected by each of the displacement sensors are obtained, and the thickness value of the first test object under constant pressure is determined based on the gap values.

9. A constant gap force measurement method, characterized in that, The method is applied to the measuring instrument according to any one of claims 1-7, and the method includes: Place the second object to be tested on the second parallel surface pressure plate; The controller controls the position adjustment mechanism to move the first and second pressure plates up and down until the gap values ​​between the first and second parallel pressure plates collected by each displacement sensor are equal. In the host computer management system, set the target gap value and click the force measurement button. The controller controls the position adjustment mechanism to move up and down until the gap between the first parallel surface pressure plate and the second parallel surface pressure plate collected by each displacement sensor reaches the target gap value. The battery cell of the second test object is controlled to begin charging and discharging. During the charging and discharging process of the battery cell, the first pressure value of the first pressure plate detected by the first pressure sensor and the second pressure value of the second pressure plate detected by the second pressure sensor are obtained. The pressure value of the battery cell of the second test object under constant gap is determined based on the first pressure value and the second pressure value.

10. A zero-pressure weighing method, characterized in that, The method is applied to the measuring instrument according to any one of claims 1-7, and the method includes: The third test object is placed on the second parallel surface pressure plate; The controller controls the position adjustment mechanism to move the first and second pressure plates up and down until the gap values ​​between the first and second parallel pressure plates collected by each displacement sensor are equal. In the host computer management system, the first force panel is set to the pressure value and the force measurement button is clicked. The position adjustment mechanism is controlled to move up and down by the controller until the third pressure value of the first force plate collected by the first pressure sensor is 0. The fourth pressure value of the second pressure plate collected by the second pressure sensor is obtained, and the fourth pressure value is used as the weight of the third object to be measured.

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