Cylindrical battery expansion test device and cylindrical battery expansion test method

Abstract

The invention provides a cylindrical battery expansion test device and a cylindrical battery expansion test method, the expansion test device comprises a hard outer frame, a through hole is formed in the middle part of the hard outer frame, and the cross section area of the through hole is larger than that of the cylindrical battery so as to surround the cylindrical battery; and a compressible pad attached to the inner circumferential surface of the through-hole over the entire circumferential range; when the cylindrical battery is located in the through hole, the compressible pad makes contact with the outer circumferential face of the cylindrical battery in the whole circumferential range and is compressed along with deformation of the cylindrical battery, and the expansion testing device detects the compression amount of the compressible pad. And the expansion testing device calculates the expansion force of the cylindrical battery according to the compression amount of the compressible pad. With the adoption of the application, the expansion force and deformation test of the cylindrical battery can be well realized with a simple structure.

Description

TECHNICAL FIELD

[0001] The present application relates to an expansion testing device for cylindrical batteries and an expansion testing method for cylindrical batteries. BACKGROUND

[0002] Due to the radial uneven expansion of the internal winding core of a cylindrical battery, the cylindrical battery gradually becomes an ellipse during the expansion process, and thus it is difficult to measure the expansion force and deformation of the cylindrical battery, but the expansion has a huge impact on the capacity attenuation and service life of the battery.

[0003] Although there are some expansion force testing devices and methods at present, there are the following problems: most of the measuring devices are complex and need to be matched with tooling fixtures, sensors and motion mechanisms for analysis. In patent document 1, a cylindrical battery expansion force and displacement measuring device is provided, the clamping device for clamping the battery is driven by a driving control device, and two sensors are also needed to cooperate, and the overall structure is complex. In patent document 2, an expansion force testing tool for cylindrical battery cells is provided, which needs to be provided with multiple pressing plates around the circumference of the battery, and also provides a motion mechanism for rotating the cylindrical battery cell, and the overall structure is also relatively complex.

[0004] In addition, in patent documents 1 and 2, the expansion force and deformation law of the cylindrical battery during the entire test period are not considered.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent document 1: CN113358253A

[0008] Patent document 2: CN222144355U SUMMARY

[0009] In view of the above, the present application provides an expansion testing device for cylindrical batteries and an expansion testing method for cylindrical batteries, which can well realize the testing of the expansion force and deformation of the cylindrical battery with a simple structure.

[0010] One of the technical solutions of the present application provides an expansion testing device for cylindrical batteries, characterized in that the expansion testing device comprises: a hard outer frame, a through hole is formed in the middle part of the hard outer frame, the cross-sectional area of the through hole is larger than the cross-sectional area of the cylindrical battery so as to be able to surround the cylindrical battery; and a compressible pad, which is installed on the inner circumferential surface of the through hole in the entire circumferential range; when the cylindrical battery is located in the through hole, the compressible pad is in contact with the outer circumferential surface of the cylindrical battery in the entire circumferential range, and is compressed along with the deformation of the cylindrical battery, the expansion testing device detects the compression amount of the compressible pad, and the expansion testing device calculates the expansion force of the cylindrical battery according to the compression amount of the compressible pad.

[0011] Preferably, the hard outer frame is formed by butt joint of two single-sided outer frames independent of each other, both of the single-sided outer frames have a notch, the through hole is formed by butt joint of the two single-sided outer frames together, the compressible pad is installed on the inner circumferential surface of the notch of both of the single-sided outer frames, and the expansion testing device further has a clamping member for fastening the two single-sided outer frames together.

[0012] Preferably, the notch is in a semicircular shape when viewed from above, and the compressible pad is in a semicircular ring shape when viewed from above.

[0013] Preferably, the hard outer frame is formed by a whole outer frame formed integrally.

[0014] Preferably, the height of the hard outer frame and the height of the compressible pad are both less than the height of the cylindrical battery to be used.

[0015] Preferably, the thickness of the compressible pad is set to 1mm-5mm, and / or the height of the hard outer frame and the height of the compressible pad are both 1 / 5-1 / 2 of the height of the cylindrical battery to be used; and / or the compressible pad is compressible foam.

[0016] Preferably, the expansion testing device takes a photo of at least the compressible pad by using an industrial camera with a resolution of at least 0.005mm, and the expansion testing device obtains the compression amount of the compressible pad based on the photo taken by the industrial camera through image processing.

[0017] Another aspect of the present application provides a swelling test method for a cylindrical battery, characterized by using the swelling test device for a cylindrical battery according to any one of the above aspects to test the cylindrical battery, the swelling test method comprising: a fixing step in which the hard outer frame is fixed to the cylindrical battery with the compressible pad in contact with the outer circumferential surface of the cylindrical battery over the entire circumferential range; a cycle step in which the cylindrical battery is subjected to charge and discharge cycles; a compression amount detection step in which the compression amount of the compressible pad is detected; and a swelling force test step in which the swelling force of the cylindrical battery is calculated based on the compression amount.

[0018] Preferably, in the fixing step, the hard outer frame and the compressible pad are fixed to the middle portion of the cylindrical battery in the up-down direction.

[0019] Preferably, in the cycle step, the compression amount detection step is performed once or the compression amount detection step and the swelling force test step are performed once every predetermined number of cycles.

[0020] With the present application, the swelling force and deformation of a cylindrical battery can be well tested with a simple structure. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a top view schematic diagram of a swelling test device according to an embodiment of the present application before clamping a cylindrical battery.

[0022] Figure 2 is a top view schematic diagram of a swelling test device according to an embodiment of the present application after clamping a cylindrical battery.

[0023] Figure 3 is a front view cross-sectional view of a swelling test device according to an embodiment of the present application after clamping a cylindrical battery.

[0024] Figure 4 is a schematic diagram of a compressible foam compression curve.

[0025] Figure 5 is a top view schematic diagram of a swelling test device according to another example of the present application before clamping a cylindrical battery.

[0026] Figure 6 is a top view schematic diagram of a swelling test device according to another example of the present application after clamping a cylindrical battery.

[0027] REFERENCE NUMERALS

[0028] 1, single-sided outer frame (hard outer frame); 2, compressible foam; 3, cylindrical battery; 4, bolt hole; 5, notch (through hole); 10, overall outer frame (hard outer frame); 50, through hole DETAILED DESCRIPTION

[0029] The following describes the structure of the present application based on the drawings, but the following description is not intended to limit the present application, and each constituent element in the technical solution can be changed, replaced, combined, deleted, etc. without departing from the spirit of the present application.

[0030] <Expansion test device>

[0031] In Figure 1 , a top view schematic diagram of one example of an expansion test device for a cylindrical battery according to the present application is shown. As Figure 1 indicated, the expansion test device holds the battery by a clamp. In one example, the clamp is, for example, in a structure in which the compressible foam 2 is fixed to the inner side of the single-sided outer frame 1. Specifically, the clamp includes two single-sided outer frames 1 as hard outer frames, the single-sided outer frames 1 have a shape with a notch 5 (or recessed portion) when viewed from the top, and the compressible foam 2 is fixed to the inner peripheral surface of the notch 5 of the two single-sided outer frames 1.

[0032] As Figure 1 and Figure 2 indicated, by butting the two single-sided outer frames 1, a hard outer frame that surrounds the cylindrical battery 3 can be formed. When butting, the butting is performed in such a manner that the notches 5 of the respective single-sided outer frames 1 collectively form one through hole, that is, the two notches 5 form the through hole that surrounds the cylindrical battery 3.

[0033] As Figure 2 indicated, when the cylindrical battery 3 is surrounded by the clamp, the two identical single-sided outer frames 1 collectively constitute the outer hard outer frame, and the through hole formed by the two notches 5 is formed in the middle portion of the hard outer frame. The compressible foam 2 as the inner flexible member is fixedly formed to the inner peripheral surface of the two notches 5. Thus, the clamp as a whole forms a nested structure device of the inner flexibility and the outer rigidity, and the fixing manner of the compressible foam 2 with respect to the single-sided outer frame 1 can be adhesion or the like. The material of the single-sided outer frame 1 can be metal or other hard material. It is preferable that the notch 5 has a semicircular shape when viewed from the top, and the compressible foam 2 fixed to the inner peripheral surface of the notch 5 has a semicircular ring shape when viewed from the top.

[0034] The two single-sided outer frames 1 are independent of each other, whereby the cylindrical battery 3 can be easily surrounded by butting the two single-sided outer frames 1 from both sides of the cylindrical battery 3. The size of the notch 5 formed in the single-sided outer frame 1 can be appropriately set according to the thickness of the compressible foam 2 and the size of the cylindrical battery 3. The cross-sectional area of the through hole formed by the notch 5 is larger than the cross-sectional area of the cylindrical battery 3 so as to be able to surround the cylindrical battery 3, for example, the notch 5 is formed such that, after the compressible foam 2 is fixed to the inner circumferential surface of the notch 5 and the two single-sided outer frames 1 are butted, the remaining size of the notch 5 is able to surround the cylindrical battery 3 and the two single-sided outer frames 1 can be smoothly butted. Here, for the through hole formed by the notch 5, the compressible foam 2 is fixed to the inner circumferential surface of the through hole in the entire circumferential range, whereby the compressible foam 2 can be in contact with the outer circumferential surface of the cylindrical battery 3 in the entire circumferential range when the cylindrical battery 3 is located in the through hole.

[0035] The contact state of the compressible foam 2 with the outer circumferential surface of the cylindrical battery 3 only needs to satisfy that the compressible foam 2 can be compressed along with the deformation of the cylindrical battery 3. For example, the compressible foam 2 can be in contact with the cylindrical battery 3 in a state of not being compressed at all, or can be in contact with the cylindrical battery 3 in a state of being compressed to a certain degree but still being further compressed along with the deformation of the cylindrical battery 3. It is preferable that the compressible foam 2 is in contact with the outer circumferential surface of the cylindrical battery 3 in a state of initial compression amount of 0 (i.e., a state of not being compressed).

[0036] The shape of the notch 5 of the single-sided outer frame 1 and the shape of the compressible foam 2 can also be appropriately changed under the condition of satisfying the above requirements, for example, the notches 5 of the two single-sided outer frames 1 are butted to form an elliptical through hole, and the outer shape of the compressible foam 2 can also be formed in an elliptical shape to match the notch 5. Of course, the shapes of the notch 5 and the compressible foam 2 can also be other arbitrary shapes, as long as the compressible foam 2 can be compressed along with the deformation of the cylindrical battery 3.

[0037] In Figure 3 , a cross-sectional view of the expansion test device clamping the cylindrical battery is shown from the front view. As shown in Figure 3 , the single-sided outer frame 1 clamps the cylindrical battery 3 at the middle part in the up-down direction of the cylindrical battery 3. Specifically, after the two single-sided outer frames 1 are butted to form a hard outer frame to surround the cylindrical battery 3, the two single-sided outer frames 1 are fastened together using a clamping member, so that the compressible foam 2 is in contact with the outer circumferential surface of the cylindrical battery 3 in the entire circumferential range. The clamping member is, for example, a bolt and a bolt hole 4 as shown in Figure 3 , but is not limited thereto, and can be other structures capable of achieving the clamping function, for example, a structure in which a protrusion is formed on one side of the two single-sided outer frames 1 (for example, the upper side of the single-sided outer frame 1) and a recess is formed on the other side (for example, the lower side of the single-sided outer frame 1) to be matched with the protrusion. Figure 1The left side of the two single-sided outer frames 1 can be provided with a hole, and the two single-sided outer frames 1 can be rotatably connected by inserting a pin into the holes of the two single-sided outer frames 1, and the other side of the two single-sided outer frames 1 (for example, the right side of the two single-sided outer frames 1) can be connected by a hole-pin structure or a latch structure. Figure 1

[0038] In addition, as shown in FIG. 1, the upper edge of the single-sided outer frame 1 (hard outer frame) is flush with the upper edge of the compressible foam 2, and the lower edge of the single-sided outer frame 1 (hard outer frame) is flush with the lower edge of the compressible foam 2. At this time, the height of the hard outer frame and the compressible foam 2 is the same, but the upper edge and the lower edge of the compressible foam 2 can be adjusted appropriately without affecting the compression of the compressible foam 2 with the deformation of the cylindrical battery 3. Preferably, the height of the hard outer frame and the compressible foam 2 is the same, and the height of both is set to 1 / 5 to 1 / 2 of the height (or length) of the cylindrical battery 3 to be used, for example, 1 / 5 to 1 / 4. Figure 3 That is, as shown in FIG. 1, it is preferable that H / 5≤h≤H / 4. In addition, the thickness t of the compressible foam 2 (the thickness of the compressible foam 2 in the radial direction of the cylindrical battery 3) is, for example, 1 to 5 mm, and preferably, the thickness t is 1 to 3 mm.

[0039] Figure 3 After the hard outer frame and the compressible foam 2 are clamped to the cylindrical battery 3 as shown in FIG. 1, the cylindrical battery 3 is subjected to charge and discharge cycles. With the charge and discharge of the cylindrical battery 3, the internal winding core of the cylindrical battery 3 expands unevenly in the radial direction, and the cylindrical battery 3 gradually becomes an elliptical cylinder. By making the compressible foam 2 contact the outer circumferential surface of the cylindrical battery 3 over the entire circumferential range, when the cylindrical battery 3 expands and deforms, the compressible foam 2 at the corresponding position is compressed. Therefore, the deformation position and the deformation amount of the cylindrical battery 3 can be reliably detected by the compressed position and the compression amount of the compressible foam 2. In addition, by providing the clamp (hard outer frame and compressible foam 2) at the middle position in the height direction of the cylindrical battery 3, the deformation position and the deformation amount of the cylindrical battery 3 can be further reliably detected.

[0040] After the hard outer frame and the compressible foam 2 are clamped to the cylindrical battery 3 as shown in FIG. 1, the cylindrical battery 3 is subjected to charge and discharge cycles. With the charge and discharge of the cylindrical battery 3, the internal winding core of the cylindrical battery 3 expands unevenly in the radial direction, and the cylindrical battery 3 gradually becomes an elliptical cylinder. By making the compressible foam 2 contact the outer circumferential surface of the cylindrical battery 3 over the entire circumferential range, when the cylindrical battery 3 expands and deforms, the compressible foam 2 at the corresponding position is compressed. Therefore, the deformation position and the deformation amount of the cylindrical battery 3 can be reliably detected by the compressed position and the compression amount of the compressible foam 2. In addition, by providing the clamp (hard outer frame and compressible foam 2) at the middle position in the height direction of the cylindrical battery 3, the deformation position and the deformation amount of the cylindrical battery 3 can be further reliably detected. Figure 2 Figure 3

[0041] The expansion test device can detect the compression amount of the compressible foam 2. Specifically, the expansion test device uses a high-precision industrial camera to take a picture of the cylindrical battery 3 from above or below. The resolution of the industrial camera is at least 0.005 mm, so that the compressed position and the compression amount of the compressible foam 2 can be reliably obtained.

[0042] ​​​​It is understood that in one example, in the case of taking a picture of the cylindrical battery 3 and the expansion test device thereon from below, the support area of the cylindrical battery 3 can be reduced on the lower side, or the expansion test device can be lifted up.

[0043] The expansion test device can calculate the expansion force of the cylindrical battery 3 according to the compression amount of the compressible foam 2. Specifically, the expansion test device has an image processing component that obtains the compression position and compression amount of the compressible foam 2 at each position around the cylindrical battery 3 based on the picture taken by the industrial camera. The compression amount of the compressible foam 2 is the expansion deformation of the cylindrical battery 3, and in Figure 4 The compression curve of the compressible foam 2 is shown in FIG. 6, and the expansion force of the cylindrical battery 3 can be deduced from the compression mechanical property curve of the compressible foam 2.

[0044] Preferably, a picture is taken once every certain number of charge and discharge cycles, for example, 20 times. The change in the compression amount of the compressible foam 2 at each position around the cylindrical battery 3 during the battery cycle can be recorded by combining image processing technology, thereby achieving simultaneous measurement of the expansion force and deformation law of the cylindrical battery 3 during the full cycle.

[0045] <Expansion test method>

[0046] Hereinafter, the expansion test method for testing the cylindrical battery 3 using the above expansion test device will be briefly described.

[0047] The expansion test method includes a fixing step, a cycle step, a compression amount detection step, and an expansion force test step.

[0048] In the fixing step, the two single-sided outer frames 1 are respectively abutted against the cylindrical battery 3 from one side and the other side of the cylindrical battery 3, so that the two single-sided outer frames 1 are butted together to form a through hole with the two notches 5 and the cylindrical battery 3 located in the through hole, and the two single-sided outer frames 1 are fixed to the cylindrical battery 3 in a manner that the compressible foam 2 contacts the outer circumferential surface of the cylindrical battery 3 in the entire circumferential range.

[0049] In the cycle step, the cylindrical battery 3 is subjected to charge and discharge cycles, and the cylindrical battery 3 undergoes uneven expansion during the process, resulting in deformation of the cylindrical battery 3 in a manner that the cross section becomes elliptical.

[0050] In the compression amount detection step, a high-precision industrial camera is used to take a picture of at least the compressible foam 2, and the compression position and compression amount of the compressible foam 2 are obtained based on the picture taken by the industrial camera through image processing. In addition, other detection devices can also be used as long as the compression position and compression amount of the compressible foam 2 can be obtained.

[0051] In this expansion force testing step, the expansion force of the cylindrical battery 3 is inversely deduced from the compression amount by the compression mechanical property curve of the compressible foam 2.

[0052] As shown above, it is preferable that, in the fixing step, the jig (the hard outer frame, the compressible foam 2) is fixed to the middle part of the cylindrical battery 3 in the up-down direction. In the cycle step, the compression amount detection step is performed once every predetermined number of cycles (for example, 20 cycles), and thus the change process of the compression amount of the compressible foam 2 around the cylindrical battery 3 during the battery cycle is recorded. After the completion of the entire cycle, all the measured compression amounts are inversely deduced, the expansion forces at different periods during the battery cycle are obtained, and the deformation law is summarized.

[0053] Alternatively, in the cycle step, the compression amount detection step and the expansion force testing step (or referred to as the expansion force calculation step) are performed once every predetermined number of cycles (for example, 20 cycles). Thus, the expansion force of the cylindrical battery 3 is obtained in real time as the cycle proceeds, and after the completion of the entire cycle, the deformation law is summarized.

[0054] <Modification>

[0055] The above describes the structure in which two single-sided outer frames 1 are butted against each other to form a hard outer frame with a through hole. However, as shown in Figs. 6 and 7, the hard outer frame can also be formed by an integral outer frame 10. In this case, a through hole 50 is also formed in the middle part of the integral outer frame 10, and the compressible foam 2 is fixed to the inner circumferential surface of the through hole 50 in the entire circumferential range. It is preferable that the through hole 50 is circular in plan view, and the compressible foam 2 is circular ring-shaped in plan view. Figure 5 Figure 6 By nesting the integral outer frame 10 in the cylindrical battery 3, the expansion force of the cylindrical battery 3 can also be inversely deduced by the compression of the compressible foam 2. The modification is only different from the above description in that the hard outer frame is integrally formed. The requirements for the compressible foam 2 and the like are the same as those described above.

[0056] By nesting the integral outer frame 10 in the cylindrical battery 3, the expansion force of the cylindrical battery 3 can also be inversely deduced by the compression of the compressible foam 2. The modification is only different from the above description in that the hard outer frame is integrally formed. The requirements for the compressible foam 2 and the like are the same as those described above.

[0057] <Effects>

[0058] By the structure of the present application, the expansion testing device for the cylindrical battery can be simplified. A jig with a complex structure is not needed. By only using the inner-soft-outer-hard structure composed of the hard outer frame and the compressible foam, the outer circumferential surface of the cylindrical battery can be simply clamped, and the expansion force of the cylindrical battery can be cleverly embodied by the compressible foam. The expansion force of the cylindrical battery is inversely deduced from the detected compression amount of the compressible foam and the compression mechanical property of the compressible foam. Thus, the test for the expansion force of the cylindrical battery can be reliably realized with a simple structure.​

[0059] In addition, the compressible foam is detected for compression amount every predetermined number of expansion cycles. The change in compression amount of the compressible foam around the cylindrical battery during the battery cycle can be recorded. In addition to the compression amount of the compressible foam, the expansion force and deformation of the cylindrical battery during the full cycle can be measured by recording the compression position of the compressible foam.

[0060] If the hard outer frame is formed by butting two single-sided outer frames, the two single-sided outer frames can be used to butt from both sides of the cylindrical battery to easily nest the jig (hard outer frame, compressible foam 2) in the cylindrical battery.

[0061] In summary, the expansion testing device of the present application can well achieve the test of the expansion force and deformation of the cylindrical battery with a simple structure. The expansion testing method of the present application can take advantage of the simple structure to easily and well achieve the test of the expansion force and deformation of the cylindrical battery.

[0062] Of course, the present application is not limited to the above description, and those skilled in the art can make various modifications and changes under the teaching of the present application without departing from the scope of the present application.

[0063] For example, in one example, other compressible deformable materials such as sponge, felt can be used instead of the compressible foam. The compressible deformable material can also use or include cotton, synthetic fiber, etc. Here, the compressible deformable material including the foam is referred to as a compressible pad.

[0064] In one example, the axial end surface (end surface in the height direction) of the single-sided outer frame 1 or the overall outer frame 10 can be provided with a circumferential and / or radial (radial direction of the notch 5 or the cylindrical battery 3) scale (dimensional line), so that it is easier to calculate (image processing) or more accurate to calculate (image processing) when the compression amount or gap size of the compressible foam is calculated by taking a picture. It can be understood that the gap size also reflects the compression amount of the compressible pad (compressible foam).

[0065] In one example, the expansion testing device can include a support that supports the single-sided outer frame 1 or the overall outer frame 10 and / or the cylindrical battery, so that the relative position of the single-sided outer frame 1 or the overall outer frame 10 and the cylindrical battery in the height direction can be maintained, avoiding sliding or large friction between the single-sided outer frame 1 or the overall outer frame 10 and the cylindrical battery in the height direction.

[0066] It is to be understood that, in the present application, the compressible pad between the cylindrical battery and the inner circumferential surface of the hard outer frame is not limited to being fixed to the inner circumferential surface of the hard outer frame by, for example, adhesion, but can also be, for example, adhered to the outer circumferential surface of the cylindrical battery or simply sandwiched between the outer circumferential surface of the cylindrical battery and the inner circumferential surface of the hard outer frame. The compressible pad can be disposable or repeatedly reusable.

Claims

1. An expansion testing device for a cylindrical battery, characterized by comprising: The expansion testing device includes: a hard outer frame having a through-hole (50) formed in a middle portion thereof, the through-hole having a cross-sectional area larger than that of the cylindrical battery (3) to be able to surround the cylindrical battery; a compressible pad installed to an inner circumferential surface of the through-hole over an entire circumferential range; when the cylindrical battery (3) is located in the through-hole (50), the compressible pad is in contact with an outer circumferential surface of the cylindrical battery (3) over the entire circumferential range and is compressed as the cylindrical battery is deformed, the expansion testing device detects a compression amount of the compressible pad, the expansion testing device calculates an expansion force of the cylindrical battery according to the compression amount of the compressible pad. 2.The expansion testing device of the cylindrical battery according to claim 1, wherein the hard outer frame is formed by butting two single-sided outer frames (1) independently from each other, both of the single-sided outer frames have notches (5) that, by being butted together, collectively form the through-hole, the compressible pad is installed to an inner circumferential surface of the notches (5) of both of the single-sided outer frames (1), the expansion testing device further has a clamping member (4) that fastens both of the single-sided outer frames together. 3.The expansion testing device of the cylindrical battery according to claim 2, wherein the notches (5) have a semicircular shape in plan view, and the compressible pad has a semicircular ring shape in plan view. 4.The expansion testing device of the cylindrical battery according to claim 1, wherein the hard outer frame is formed by a unitary outer frame (10) formed integrally. 5.The expansion testing device of the cylindrical battery according to claim 1, wherein both of a height of the hard outer frame and a height of the compressible pad are smaller than a height of the cylindrical battery (3) to be used. 6.The expansion testing device of the cylindrical battery according to claim 1, wherein a thickness of the compressible pad is set to 1 mm to 5 mm, and / or both of a height of the hard outer frame and a height of the compressible pad are 1 / 5 to 1 / 2 of a height of the cylindrical battery (3) to be used; and / or the compressible pad is a compressible foam (2). 7.The expansion testing device of the cylindrical battery according to claim 1, wherein the expansion testing device photographs at least the compressible pad using an industrial camera having a resolution of at least 0.005 mm, the expansion testing device obtains the compression amount of the compressible pad based on a photograph taken by the industrial camera through image processing. 8.A method of testing expansion of a cylindrical battery, wherein the cylindrical battery is tested using the expansion testing device of the cylindrical battery according to any one of claims 1 to 7, the method of testing expansion includes: a fixing step in which the hard outer frame is fixed to the cylindrical battery such that the compressible pad is in contact with an outer circumferential surface of the cylindrical battery over an entire circumferential range; a cycle step in which the cylindrical battery is subjected to charge and discharge cycles. a compression amount detection step in which a compression amount of the compressible pad is detected; an expansion force test step in which an expansion force of the cylindrical battery is calculated based on the compression amount.

9. The cylindrical battery expansion test method according to claim 8, wherein in the fixing step, the hard outer frame and the compressible pad are fixed to a middle portion in an up-down direction of the cylindrical battery.

10. The cylindrical battery expansion test method according to claim 8 or 9, wherein the compression amount detection step is performed once every predetermined number of cycles in the repeating step, or the compression amount detection step and the expansion force test step are performed once every predetermined number of cycles in the repeating step.

Images