CN220960397U

CN220960397U - Device for measuring expansion stress of cylindrical battery

Info

Publication number: CN220960397U
Application number: CN202322656985.0U
Authority: CN
Inventors: 华安; 陆东振; 廖少杰; 刘新新; 肖斌; 黄小鹏; 安伟峰; 林�建
Original assignee: Shenzhen Bak Power Battery Co Ltd
Current assignee: Shenzhen Bak Power Battery Co Ltd
Priority date: 2023-09-28
Filing date: 2023-09-28
Publication date: 2024-05-14
Anticipated expiration: 2033-09-28

Abstract

The application provides a device for measuring the expansion stress of a cylindrical battery, which comprises a clamp, an adjusting piece and a pressure sensor, wherein the clamp is used for clamping the cylindrical battery; the inside of the clamp is provided with a containing cavity which is used for containing the packaged battery cell; the pressure sensor is arranged in the accommodating cavity and is used for detecting the expansion stress of the battery cell body in the packaged battery cell; one end of the adjusting piece is arranged outside the accommodating cavity, and under the action of external force, the adjusting piece pushes the pressure sensor so that the pressure sensor can be pressed on the packaging battery cell, and the adjusting piece can provide initial pressure for the pressure sensor. The pressure sensor in the device for measuring the expansion stress of the cylindrical battery can not be in direct contact with electrolyte, so that the stability of the pressure sensor in the test is enhanced; and the regulating part provides certain initial pressure for the pressure sensor, so that the accuracy of the measured data of the expansion stress of the cylindrical battery is improved.

Description

Device for measuring expansion stress of cylindrical battery

Technical Field

The application relates to the technical field of battery performance testing, in particular to a device for measuring expansion stress of a cylindrical battery.

Background

Lithium ion batteries are widely used in the fields of electronic consumption, electric automobiles, energy storage and the like due to high energy density, safety, good cycle stability and excellent rate capability. Lithium ion batteries are also called rocking chair batteries, and rely on lithium ions to move back and forth between the anode and the cathode to finish energy storage and release.

In the process of storing and releasing energy of the battery, complicated mechanical pressure changes occur in the battery, and the mechanical pressure can truly reflect the internal state of the battery, such as reversible and irreversible expansion of crystal lattices and compression degree of pole pieces and diaphragms, so that the electrochemical process of the battery is affected, the capacity of the battery is finally attenuated, the circulation performance is finally reduced, and even short circuit is caused between the pole pieces, so that the safety performance of the battery is greatly reduced.

Recently, optical fiber sensors, thin film pressure sensors, and thin film strain sensors have been widely used in monitoring the internal pressure of batteries because of their small size, in-situ monitoring, sensitivity to reaction, and the like. However, the flexible film pressure sensor product which is mature in the market at present cannot stably and accurately run due to poor electrolyte corrosion resistance, so that the expansion stress of the cylindrical battery is difficult to monitor, and therefore, a device for measuring the expansion stress of the cylindrical battery needs to be developed, so that the problem that the pressure sensor is unstable and even fails in the testing process is solved.

Disclosure of utility model

The application provides a device for measuring the expansion stress of a cylindrical battery, which can solve the problem that a flexible film pressure sensor is not corrosion-resistant in electrolyte and fails in the testing process of the expansion stress of the cylindrical battery.

In order to solve the technical problems, the application provides a device for measuring the expansion stress of a cylindrical battery, which comprises a clamp, an adjusting piece and a pressure sensor; the inside of the clamp is provided with a containing cavity which is used for containing the packaged battery cell; the pressure sensor is arranged in the accommodating cavity and is used for detecting the expansion stress of the battery cell body in the packaged battery cell; one end of the adjusting piece is arranged outside the accommodating cavity, and under the action of external force, the adjusting piece pushes the pressure sensor so that the pressure sensor can be pressed on the packaging battery cell, and the adjusting piece can provide initial pressure for the pressure sensor.

In one embodiment, a portion of the adjustment member is disposed within the receiving chamber and is fixedly coupled to the pressure sensor.

In one embodiment, the clamp is of a cylindrical structure, and the side wall of the clamp is provided with an assembly hole which penetrates through the side wall of the clamp; the adjusting piece is assembled on the side wall of the clamp through the assembly hole, and can reciprocate along the axial direction of the assembly hole under the action of external force.

In one embodiment, the mounting hole is a threaded hole, and the adjusting member is threadedly coupled to the threaded hole.

In one embodiment, the pressure sensor is an arcuate sheet structure and includes one or more of a resistive sensor, a flexible thin film capacitive sensor, and a strain gauge sensor.

In an embodiment, the device for measuring the expansion stress of the cylindrical battery further comprises a packaging battery cell, the packaging battery cell comprises a battery cell body, a first electrode lug, a second electrode lug and a packaging piece, a vacuum packaging space is arranged in the packaging piece, the battery cell body is arranged in the packaging space, one end of the first electrode lug is connected with the battery cell body, the other end of the first electrode lug is arranged outside the packaging piece, one end of the second electrode lug is connected with the battery cell body, and the other end of the second electrode lug is arranged outside the packaging piece.

In one embodiment, the device for measuring the expansion stress of the cylindrical battery further comprises a cell support, wherein the cell support is arranged at two ends of the cell body, and a perforation is arranged on the cell support and used for enabling the first tab or the second tab to pass through.

In one embodiment, the device for measuring the expansion stress of the cylindrical battery further comprises a tab protection gasket, wherein the tab protection gasket is arranged in the packaging piece and wraps the first tab and the second tab in the packaging piece.

In one embodiment, the package is an aluminum plastic film, and the package battery core is provided with a first package line, a second package line and a third package line, and the first package line, the second package line and the third package line can package the battery core body in the package space; the first packaging line is parallel to the axis direction of the battery cell body and is spaced from the battery cell body; the second packaging line and the third packaging line are parallel to the radial direction of the battery cell body, and are respectively arranged on two opposite sides of the battery cell body and are spaced from the battery cell body, and the second packaging line and the third packaging line are intersected with the first packaging line; the extending direction of the first tab is intersected with the first packaging line, and the extending direction of the second tab is intersected with the second packaging line.

In one embodiment, the shortest distance between the first packaging line and the cell body is 4mm-10mm, and the shortest distance between the second packaging line or the third packaging line and the cell body is 5mm-20mm.

The application provides a device for measuring the expansion stress of a cylindrical battery, which comprises a clamp, an adjusting piece and a pressure sensor, wherein the clamp is used for clamping the cylindrical battery; the inside of the clamp is provided with a containing cavity which is used for containing the packaged battery cell; the pressure sensor is arranged in the accommodating cavity and is used for detecting the expansion stress of the battery cell body in the packaged battery cell; one end of the adjusting piece is arranged outside the accommodating cavity, and under the action of external force, the adjusting piece pushes the pressure sensor so that the pressure sensor can be pressed on the packaging battery cell, and the adjusting piece can provide initial pressure for the pressure sensor. Because the pressure sensor is arranged on the packaging battery core, the pressure sensor can not directly contact the battery core body, but contact the packaging piece outside the battery core body, so that the pressure sensor can not directly contact the electrolyte, the pressure sensor is prevented from being corroded by the electrolyte, and the stability of the pressure sensor in the testing process is enhanced. The pressure sensor can be pushed by the regulating piece, so that the pressure sensor is tightly pressed to the packaging battery core, the pressure sensor is always in good contact with the packaging battery core, and certain initial pressure is provided for the pressure sensor by the regulating piece, so that the actual expansion stress of the battery is obtained by subtracting the initial pressure value from the display value of the sensor, and the accuracy of the measured data of the expansion stress of the cylindrical battery is improved.

Drawings

FIG. 1 is a schematic view of an apparatus for measuring expansion stress of a cylindrical battery according to an embodiment of the present application;

FIG. 2 is a schematic view of an apparatus for measuring expansion stress of a cylindrical battery according to another embodiment of the present application;

fig. 3 is a schematic structural diagram of a packaged battery cell according to an embodiment of the present application;

Fig. 4 is a schematic flow chart of measuring the expansion stress of a cylindrical battery according to an embodiment of the application.

Detailed Description

The application will be described in further detail below with reference to the drawings by means of specific embodiments. Wherein like elements in different embodiments are numbered alike in association. In the following embodiments, numerous specific details are set forth in order to provide a better understanding of the present application. However, one skilled in the art will readily recognize that some of the features may be omitted, or replaced by other elements, materials, or methods in different situations. In some instances, related operations of the present application have not been shown or described in the specification in order to avoid obscuring the core portions of the present application, and may be unnecessary to persons skilled in the art from a detailed description of the related operations, which may be presented in the description and general knowledge of one skilled in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments, and the operational steps involved in the embodiments may be sequentially exchanged or adjusted in a manner apparent to those skilled in the art. Accordingly, the description and drawings are merely for clarity of describing certain embodiments and are not necessarily intended to imply a required composition and/or order.

The numbering of the components itself, e.g. "first", "second", etc., is used herein merely to distinguish between the described objects and does not have any sequential or technical meaning. The term "coupled" as used herein includes both direct and indirect coupling (coupling), unless otherwise indicated.

Fig. 1 to 3 show a schematic structural view of an apparatus for measuring expansion stress of a cylindrical battery according to an embodiment of the present application, and fig. 2 shows a schematic structural view of another apparatus for measuring expansion stress of a cylindrical battery according to an embodiment of the present application. Fig. 3 is a schematic structural diagram of a packaged battery cell according to an embodiment of the present application. The application provides a device for measuring the expansion stress of a cylindrical battery, such as a cylindrical lithium ion battery, and the device can be applied to the expansion stress test of other types of cylindrical batteries.

The device for measuring the expansion stress of the cylindrical battery comprises an adjusting piece 1, a clamp 3 and a pressure sensor 4; the inside of anchor clamps 3 is equipped with holds chamber 31, holds chamber 31 and is used for holding encapsulation electric core 2. The packaged battery cell 2 in the present application at least includes a battery cell body 250, a first tab 260, a second tab 270, and a package 210, where the package 210 is configured to package the battery cell body 250, the first tab 260, and the second tab 270.

The pressure sensor 4 is disposed inside the accommodating cavity 31, and the pressure sensor 4 is used for detecting expansion stress of the cell body 250 in the package cell 2. One end of the adjusting member 1 is disposed outside the accommodating chamber 31, and the adjusting member 1 pushes the pressure sensor 4 under the action of external force so that the pressure sensor 4 can be pressed against the package cell 2, and the adjusting member 1 can provide an initial pressure to the pressure sensor 4.

Specifically, the pressure sensor 4 is in direct contact with the outer surface of the package 210, and the pressure sensor 4 is indirectly pressed against the cell body 250 through the package 210, that is, when the pressure sensor 4 is pressed against the packaged cell 2, the pressure sensor 4 is sandwiched between the regulator 1 and the package 210, and the package 210 in contact with the pressure sensor 4 is sandwiched between the pressure sensor 4 and the cell body 250.

Because the pressure sensor 4 is disposed on the package electric core 2, i.e. disposed outside the package 210, the pressure sensor 4 does not directly contact the electric core body 250, but contacts the package 210 outside the electric core body 250, so that the pressure sensor 4 does not contact the electrolyte in the package 210, thereby preventing the pressure sensor 4 from being corroded by the electrolyte in the testing process, and enhancing the stability of the pressure sensor 4 in the testing process.

Moreover, as the pressure sensor 4 can be pushed by the adjusting piece 1, the pressure sensor 4 can be pressed onto the packaging battery core 2, so that the pressure sensor 4 is always in good contact with the packaging battery core 2, and inaccurate measurement results caused by disconnection between the pressure sensor 4 and the packaging battery core 2 are prevented. The adjusting element 1 can provide a certain initial pressure for the pressure sensor 4, the display value of the sensor minus the initial pressure value is the true expansion stress of the battery, and the pressure sensor 4 has the initial pressure value to prove good contact between the pressure sensor 4 and the packaging battery cell 2 (the pressure sensor 4 is tightly pressed on the packaging battery cell 2), so that the accuracy of the measured data of the expansion stress of the cylindrical battery is improved.

In addition, since the existing steel shell of the cylindrical battery cell is inconvenient to set the adjusting piece 1 (inconvenient to punch), the clamp 3 is adopted in the application, so that the charging and discharging of the battery cell body 250 in the steel shell can be simulated, and the adjusting piece 1 can be conveniently set on the clamp 3.

In one embodiment, as shown in fig. 1 and 2, a part of the regulator 1 is disposed inside the housing chamber 31 and is fixedly connected to the pressure sensor 4. Specifically, the first end of the adjusting member 1 is disposed inside the accommodating chamber 31, and the first end of the adjusting member 1 is connected with the pressure sensor 4, and the second end of the adjusting member 1 is disposed outside the clamp 3 through the sidewall of the clamp 3. The structure of the regulating member 1 located outside the clamp 3 is convenient to receive an external force, which may be from an operator or a driving mechanism, to drive the movement of the pressure sensor 4.

More specifically, the jig 3 is a cylindrical structure. The side wall of the clamp 3 is provided with an assembly hole, and the assembly hole penetrates through the side wall of the clamp 3. The adjusting member 1 is fitted to the side wall of the jig 3 through the fitting hole, and the adjusting member 1 can reciprocate in the axial direction of the fitting hole under the action of external force. Specifically, the assembly hole may be a threaded hole, and the adjusting member 1 is screwed with the threaded hole. That is, the adjusting member 1 can be spirally reciprocated in the axial direction of the fitting hole by the external force, and the adjusting member 1 can be fixed at the present position when the external force is lost.

In one embodiment, the pressure sensor 4 is in an arc-shaped sheet structure, and one surface of the depression of the pressure sensor 4 faces the packaging battery core 2, so that the surface of the pressure sensor 4 facing the packaging battery core 2 can be completely attached to the packaging battery core 2, that is, the pressure sensor 4 is in surface contact with the packaging battery core 2 in the testing process, and the shape of the pressure sensor 4 is matched with the shape of the cylindrical battery core 2, so that the testing accuracy of the pressure sensor 4 is improved.

The pressure sensor 4 may include one or more of a resistive sensor, a flexible thin film capacitive sensor, and a strain gauge sensor, among others.

In one embodiment, as shown in fig. 3, the means for measuring the expansion stress of the cylindrical battery further comprises an encapsulated cell 2. The packaged battery cell 2 includes a battery cell body 250, a first tab 260, a second tab 270, and a package 210. The inside of the package 210 is provided with a vacuum package space, the battery cell body 250 is disposed in the package space, one end of the first tab 260 is connected with the battery cell body 250, the other end of the first tab 206 is disposed outside the package 210, one end of the second tab 270 is connected with the battery cell body 250, and the other end of the second tab 270 is disposed outside the package 210. Packaging the cell body 250 in the package 210 may prevent the pressure sensor 4 from directly contacting the electrolyte on the cell body 250.

Specifically, one way of packaging the battery cells 2 is as follows: the package 210 is an aluminum plastic film, and the package battery core 2 has a first package line 220, a second package line 230 and a third package line 240, and the first package line 220, the second package line 230 and the third package line 240 can package the battery core body 250 in the package space. For example, in fig. 3, after the packaged battery cell 2 is placed on the aluminum plastic film, the aluminum plastic film is folded to form a closed bottom side and an open top side and two open side sides, a first packaging line 220 is used to package the top side, and a second packaging line 230 and a third packaging line 240 are used to package the two side sides, thereby completely sealing the battery cell body 250 in the package 210.

Further, the first packaging line 220 is parallel to the axial direction of the cell body 250, and the first packaging line 220 is spaced apart from the cell body 250, and the shortest spacing distance between the first packaging line 220 and the cell body 250 may be 4mm-10mm.

The second and third packaging lines 230 and 240 are parallel to the radial direction of the cell body 250, and the second and third packaging lines 230 and 240 are disposed at opposite sides of the cell body 250, respectively, and are spaced apart from the cell body 250, and the shortest spacing distance between the second or third packaging line and the cell body is 5mm-20mm. The second and third packaging lines 230, 240 each intersect the first packaging line 220.

The extending direction of the first tab 260 intersects the first packaging line 220, i.e. the first packaging line 220 is further used for packaging a part of the first tab 260 close to the cell body 250, and the extending direction of the second tab 270 intersects the second packaging line 230, i.e. the second packaging line 230 is further used for packaging a part of the second tab 270 close to the cell body 250. During packaging, the first packaging line 220 and the second packaging line 230 are preferably packaged, and before the third packaging line 240 is packaged, liquid is injected from the opening where the third packaging line 240 is located, and air is pumped for multiple times, so that the inside of the packaging part 210 is in a vacuum state, the battery cell body 250 is in a compact state, the battery cell body 250 is ensured to be capable of being charged and discharged normally, and support is provided for detection of the next pressure sensor 4.

Wherein, the times of vacuumizing for a plurality of times can be 1-3 times, and the time for maintaining the vacuumizing each time is 2-4 s. The packaging process temperature at which the first and second packaging lines 220 and 230 are performed may be 280±5 degrees celsius, and the process temperature at which the third packaging line 240 is performed may be 185±5 degrees celsius.

In other embodiments, the package 210 may be, for example, an aluminum case, and the packaging method may be other packaging methods, which are not limited to the above.

In one embodiment, the device for measuring the expansion stress of the cylindrical battery further comprises a cell support 6, the cell support 6 is disposed at two ends of the cell body 250, and a perforation is disposed on the cell support 6, and the perforation is used for passing the first tab 260 or the second tab 270. Through set up electric core support piece 6 at the both ends of electric core body 250, can support the both ends of electric core body 250, prevent the both ends deformation of electric core body 250.

In one embodiment, the device for measuring the expansion stress of the cylindrical battery further comprises a tab protection pad 7, wherein the tab protection pad 7 is disposed in the package 210, and the tab protection pad 7 wraps the first tab 260 and the second tab 270 in the package 210. The tab protection gasket 7 can prevent the tab from tearing due to larger gas expansion generated in the packaged battery cell 2, and the integrity of the packaged battery cell 2 is protected.

The application also provides a method for measuring the expansion stress of the cylindrical battery, as shown in fig. 4, which comprises the following steps:

step S110: and packaging the battery cell body 250 and the electrode lugs to form the packaged battery cell 2.

Specifically, the packaging of the cell body 250 and the tab may be: the cell body 250, the first tab 260 and the second tab 270 are packaged by using an aluminum plastic film, so as to form a semi-packaged cell, and then the semi-packaged cell is sequentially subjected to liquid injection and vacuum pumping, and then is packaged by the third packaging line 240.

Step S120: the packaged cells 2 are loaded into a fixture 3.

Wherein the encapsulated cells 2 may be loaded into the receiving cavities 31 of the fixture 3.

Step S130: a pressure sensor 4 is installed.

Specifically, the pressure sensor 4 may be mounted on the adjustment member 1 such that movement of the adjustment member 1 may drive movement of the pressure sensor 4.

Step S140: the initial pressure of the pressure sensor 4 is adjusted by adjusting the adjusting member 1.

Specifically, the adjusting member 1 may be moved along a side toward the cell body 250 to drive the pressure sensor 4 so that the pressure sensor 4 is pressed against the package cell 2. The pressing force of the pressure sensor 4 pressing on the package cell 2 is adjusted according to the position of the adjusting member 1, thereby adjusting the initial pressure of the pressure sensor 4.

Step S150: the cell body 250 is charged and discharged, and data acquired by the pressure sensor 4 is recorded.

In one embodiment, the cell body 250 is model 18650, the positive electrode material is a ternary NCM system, the negative electrode is graphite, the rated capacity is 2.5Ah, the charge-discharge multiplying power is 0.1C and 0.2C, and the charge cut-off voltage is 4.2V.

Step S160: and outputting an experiment result.

Wherein the true value of the cell expansion stress is the value displayed by the pressure sensor 4 minus the initial pressure value.

The foregoing description of the utility model has been presented for purposes of illustration and description, and is not intended to be limiting. Several simple deductions, modifications or substitutions may also be made by a person skilled in the art to which the utility model pertains, based on the idea of the utility model.

Claims

1. A device for measuring the expansion stress of a cylindrical battery, comprising a clamp, an adjusting piece and a pressure sensor; the inside of the clamp is provided with a containing cavity which is used for containing the packaged battery cell; the pressure sensor is arranged in the accommodating cavity and is used for detecting the expansion stress of the battery cell body in the packaged battery cell; one end of the adjusting piece is arranged outside the accommodating cavity, the adjusting piece pushes the pressure sensor under the action of external force, so that the pressure sensor can be tightly pressed on the packaging battery cell, and the adjusting piece can provide initial pressure for the pressure sensor.

2. The apparatus for measuring the expansion stress of a cylindrical battery according to claim 1, wherein a portion of the regulating member is disposed inside the accommodating chamber and fixedly connected to the pressure sensor.

3. The apparatus for measuring the expansion stress of a cylindrical battery according to claim 2, wherein the jig is of a cylindrical structure, and a fitting hole is provided in a side wall of the jig, the fitting hole penetrating through the side wall of the jig; the adjusting piece is assembled on the side wall of the clamp through the assembly hole, and can reciprocate along the axial direction of the assembly hole under the action of external force.

4. A device for measuring the expansion stress of a cylindrical battery according to claim 3, wherein the fitting hole is a threaded hole, and the regulating member is screwed with the threaded hole.

5. The apparatus for measuring the expansion stress of a cylindrical battery according to any one of claims 1 to 4, wherein the pressure sensor is an arcuate sheet-like structure, and the pressure sensor includes one or more of a resistive sensor, a flexible thin film capacitive sensor, and a strain gauge sensor.

6. The device for measuring expansion stress of a cylindrical battery according to any one of claims 1 to 4, further comprising the package battery cell, wherein the package battery cell comprises a battery cell body, a first tab, a second tab and a package, wherein a vacuum package space is provided in the package, the battery cell body is disposed in the package space, one end of the first tab is connected with the battery cell body, the other end of the first tab is disposed outside the package, one end of the second tab is connected with the battery cell body, and the other end of the second tab is disposed outside the package.

7. The device for measuring the expansion stress of a cylindrical battery according to claim 6, further comprising a cell support member, wherein the cell support member is provided at both ends of the cell body, and wherein a perforation is provided on the cell support member, the perforation being for passing the first tab or the second tab.

8. The device for measuring the expansion stress of a cylindrical battery of claim 6, further comprising a tab protection spacer disposed within the package, the tab protection spacer wrapping the first tab and the second tab within the package.

9. The device for measuring the expansion stress of the cylindrical battery according to claim 6, wherein the packaging piece is an aluminum plastic film, and the packaging battery cell is provided with a first packaging line, a second packaging line and a third packaging line, and the first packaging line, the second packaging line and the third packaging line can package the battery cell body in the packaging space; the first packaging line is parallel to the axis direction of the battery cell body and is spaced from the battery cell body; the second packaging line and the third packaging line are parallel to the radial direction of the battery cell body, and are respectively arranged on two opposite sides of the battery cell body and are spaced from the battery cell body, and the second packaging line and the third packaging line are intersected with the first packaging line; the extending direction of the first tab is intersected with the first packaging line, and the extending direction of the second tab is intersected with the second packaging line.

10. The apparatus for measuring the expansion stress of a cylindrical battery according to claim 9, wherein the shortest distance between the first packaging line and the cell body is 4mm to 10mm, and the shortest distance between the second packaging line or the third packaging line and the cell body is 5mm to 20mm.