A device for performing CT testing on a battery

Abstract

The present invention relates to the field of battery technology, and in particular to a device for performing CT testing on a battery. The device comprises an upper cover, an upper pressure head, a sleeve, a lower pressure head and a lower cover, wherein the upper pressure head and the lower pressure head are inserted at both ends of the sleeve, an upper cover is arranged on the outer side of the upper pressure head, and a lower cover is arranged on the outer side of the lower pressure head. The upper cover and the lower cover are respectively threadedly connected to the two ends of the sleeve, and the sleeve is used to install the battery. The present invention is a device capable of performing CT observation on a battery parallel to the direction of the diaphragm, and at the same time, it can record the pressure changes inside the battery during this process, so as to better study the dendrite growth of the lithium battery and provide basic data for solving the growth of lithium dendrites.

Description

Technical Field

[0001] The invention relates to the technical field of batteries, and in particular to a device for performing CT testing on batteries. Technical Background

[0002] During the charging and discharging process, lithium batteries will grow dendrites, which will pierce the diaphragm and cause the battery to fail. In more serious cases, it will cause a local short circuit, causing the battery to heat up or even catch fire and explode. At the same time, the battery's internal morphology will change during the charging and discharging process and the growth of lithium dendrites. From a macroscopic perspective, the battery will expand or shrink.

[0003] The development of modern testing technology, especially the development of CT technology, makes it possible to observe the morphological changes inside the battery in situ. However, for cylindrical batteries, the thicker metal shell can obviously absorb the X-rays during the CT test, resulting in unclear CT imaging and low signal-to-noise ratio. For soft-pack batteries, whether the geometric plane of the soft-pack battery (i.e., the diaphragm plane) is parallel to the CT imaging sensor or perpendicular to it (as shown in Figure 11, a schematic diagram of the geometric position relationship between the geometric plane of the soft-pack battery and the CT imaging sensor), the layers of metal current collectors will also greatly absorb the X-rays during the CT test, resulting in a decrease in image resolution and poor imaging quality. When the number of layers of the soft-pack battery is reduced, the pressure on the middle layer is greatly different from that of the real battery due to the reduction in the number of layers. Due to the material, it is not possible to reflect the pressure and morphological changes inside the battery with a high degree of restoration. When the finished soft-pack battery is tested for CT in industry, an ultra-high power plane source CT test device is used, and the main body of the device is extremely large and the power consumption is very high. This device is not suitable for use in schools and research institutes for basic research. At present, as the main battlefield of basic research, the batteries studied by schools and research institutes are mainly buckle batteries and thin-layer soft-pack batteries. The stainless steel shell of buckle batteries can also greatly absorb the X-rays of experimental CT test devices, while thin-layer soft-pack batteries are far from real commercial soft-pack batteries due to their fewer layers. Therefore, how to remove the metal shell of the battery or pressurize the battery in situ without blocking the passage of X-rays has become the key to solving this problem.

[0004] Furthermore, there is currently no effective experimental fixture for CT testing of batteries. When a thin-layer soft-pack battery is placed in a CT testing device, the growth of lithium battery dendrites can only be well reflected during the CT image reconstruction process when its geometric plane is perpendicular to the CT imaging sensor. But the actual situation is that due to the large area of ​​the battery, it is difficult to ensure that its geometric plane is always perpendicular to the CT imaging sensor during the rotation of the test. Although the software can eliminate the error caused by the axis offset during rotation, for lithium dendrites with a growth scale of only microns and submicrons, a large part of the dendrite information is mistakenly erased during the software reconstruction and correction process. When dendrites pierce lithium batteries, they mainly grow perpendicular to the diaphragm. Therefore, if the observation can be parallel to the geometric plane of the battery (i.e., the diaphragm plane), the growth and development process of the entire lithium dendrite can be obtained very clearly.

[0005] In order to solve the above problems, it is necessary to provide a device that can perform CT observation on the battery parallel to the direction of the diaphragm. At the same time, the battery can be pressurized during the test, or the pressure changes inside the battery during this process can be recorded to better study the dendrite growth of lithium batteries and provide basic data for solving the growth of lithium dendrites. Summary of the invention

[0006] In order to solve the above problems, the purpose of the present invention is to provide a device for CT testing of batteries. The device can perform CT observation of the battery parallel to the diaphragm direction, and at the same time, can record the pressure changes inside the battery during this process, so as to better study the dendrite growth of lithium batteries and provide basic data for solving the growth of lithium dendrites.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A device for performing CT testing on a battery comprises an upper cover, an upper pressure head, a sleeve, a lower pressure head and a lower cover, wherein the upper pressure head and the lower pressure head are inserted at both ends of the sleeve, an upper cover is arranged on the outer side of the upper pressure head, and a lower cover is arranged on the outer side of the lower pressure head, the upper cover and the lower cover are respectively threadedly connected to the two ends of the sleeve, and the sleeve is used to install the battery.

[0009] A pressure sensor is arranged between the upper pressure head and the upper cover.

[0010] An upper cover thread is arranged on the inner wall of the upper cover, and an upper cover pressurizing surface in contact with the pressure sensor is arranged on the inner bottom of the upper cover; and an upper cover wire lead-out hole is arranged on the side wall of the upper cover.

[0011] The sleeve is of a structure that is thin in the middle and thick at both ends, and a sleeve through hole is provided along the axis.

[0012] The sleeve is made of insulating material.

[0013] The upper pressure head and the lower pressure head are T-shaped structures, and both include a pressure head column and a pressure head pressure surface arranged at the end of the pressure head column, and the pressure head column is inserted into the sleeve.

[0014] The upper cover, the upper pressure head, the lower pressure head and the lower cover are all made of metal materials.

[0015] The upper pressure head and the lower pressure head are made of metal material with a Rockwell hardness greater than 35.

[0016] The upper cover and the lower cover are made of stainless steel.

[0017] The upper cover and the lower cover are respectively connected to the positive and negative electrodes of a battery tester for testing.

[0018] The advantages and beneficial effects of the present invention are:

[0019] The present invention is a device capable of performing CT observation on a battery in parallel to the diaphragm direction, and at the same time, can record the pressure changes inside the battery during this process, so as to better study the dendrite growth of the lithium battery and provide basic data for solving the growth of lithium dendrites. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a device for performing CT testing on a battery according to the present invention;

[0021] Figure 2 is an exploded view of a device for performing CT testing on a battery according to the present invention;

[0022] Figure 3 It is a structural schematic diagram of the upper cover in the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the pressure sensor in the present invention;

[0024] Figure 5 It is a schematic structural diagram of the upper pressure head in the present invention;

[0025] Figure 6 It is a structural schematic diagram of the sleeve in the present invention;

[0026] Figure 7 It is a structural schematic diagram of the pressing head of the present invention;

[0027] Figure 8 It is a schematic diagram of the structure of the lower cover in the present invention;

[0028] Fig. 9 It is a schematic diagram of the testing process of the present invention;

[0029] Fig.10 It is a schematic diagram of the assembly of the present invention;

[0030] Figure 11 is a schematic diagram of the geometric position relationship between the soft-pack battery geometric plane and the CT imaging sensor: (a) is a schematic diagram in which the soft-pack battery geometric plane and the CT imaging sensor are perpendicular to each other; (b) is a schematic diagram in which the soft-pack battery geometric plane and the CT imaging sensor are parallel to each other.

[0031] In the figure: 1 is an upper cover, 101 is a wire lead-out hole of the upper cover, 102 is an upper cover thread, 103 is a pressurized surface of the upper cover, 2 is a pressure sensor, 201 is an upper end surface of the pressure sensor, 202 is a lower end surface of the pressure sensor, 203 is a signal line of the pressure sensor, 3 is an upper pressure head, 301 is an upper pressure head column, 302 is a pressure surface of the upper pressure head, 4 is a sleeve, 401 is a sleeve through hole, 402 is an upper thread of the sleeve, 403 is a lower thread of the sleeve, 5 is a lower pressure head, 501 is a lower pressure head column, 502 is a pressure surface of the lower pressure head, 6 is a lower cover, 601 is a lower cover thread, and 602 is a pressurized surface of the lower cover. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1-2 As shown, the present invention provides a device for performing CT testing on a battery, comprising an upper cover 1, an upper pressure head 3, a sleeve 4, a lower pressure head 5 and a lower cover 6, wherein the upper pressure head 3 and the lower pressure head 5 are inserted at both ends of the sleeve 4, the upper cover 1 is arranged on the outer side of the upper pressure head 3, the lower cover 6 is arranged on the outer side of the lower pressure head 5, the upper cover 1 and the lower cover 6 are respectively threadedly connected to the two ends of the sleeve 4, and the sleeve 4 is used to install the battery.

[0034] Furthermore, a pressure sensor 2 is provided between the upper pressure head 3 and the upper cover 1 , and the upper pressure head 3 and the lower pressure head 5 at both ends of the battery are pressed by the upper cover 1 and the lower cover 6 , the pressure sensor 2 is attached to the upper pressure head 3 , and the pressure value is transmitted through the pressure sensor 2 .

[0035] like Figure 3 As shown, an upper cover thread 102 is provided on the inner wall of the upper cover 1 , and an upper cover pressurizing surface 103 in contact with the pressure sensor 2 is provided at the inner bottom of the upper cover 1 ; an upper cover wire lead-out hole 104 is provided on the side wall of the upper cover 1 .

[0036] like Figure 4 As shown, the pressure sensor 2 includes a pressure sensor upper end surface 201 , a pressure sensor lower end surface 202 and a pressure sensor signal line 203 , and the pressure sensor signal line 203 is led out from the upper cover wire lead-out hole 104 .

[0037] In order to prevent the upper pressure head 3 and the lower pressure head 5 from shaking and ensure that the pressure planes are parallel, the upper pressure head 3 and the lower pressure head 5 adopt a T-shaped structure, both of which include a pressure head column and a pressure head pressure surface arranged at the end of the pressure head column, and the pressure head column is inserted in the sleeve.

[0038] Specifically: Figure 5 As shown, the upper pressure head 3 includes an upper pressure head column 301 and an upper pressure head pressure surface 302 connected to the end of the upper pressure head column 301; Figure 7 As shown, the pressing head 5 includes a pressing head column 501 and a pressing head pressure surface 502 connected to the end of the pressing head column 501 .

[0039] like Figure 8 As shown, a lower cover thread 601 is provided on the inner wall of the lower cover 6 , and a lower cover pressurizing surface 602 is provided on the inner bottom of the lower cover 6 .

[0040] like Figure 6 As shown, in the embodiment of the present invention, in order to reduce the obstruction of CT rays and improve the clarity of the observed part, the sleeve 4 is a structure that is thin in the middle and thick at both ends, that is, the sleeve 4 is a "dumbbell" structure. A sleeve through hole 401 is provided along the axis of the sleeve 4, and the battery is installed in the sleeve through hole 401; the thick parts at both ends of the sleeve 4 are provided with sleeve upper threads 402 and sleeve lower threads 403, and the sleeve upper threads 402 and sleeve lower threads 403 are connected to the upper cover 1 and the lower cover 6 respectively.

[0041] Furthermore, the sleeve 4 is made of insulating material. In the embodiment of the present invention, the sleeve 4 is made of PEEK, PTFE or ABS material with low X-ray absorption.

[0042] In the embodiment of the present invention, in order to ensure close contact between the layers inside the battery, the upper cover 1 and the lower cover 6 are "cap" structures with internal threads, which can be fixed to the sleeve 4; the upper cover 1 is deep, leaving space for installing the pressure sensor 2. There is an upper cover wire lead-out hole at the bottom of the side wall of the upper cover 1, which is convenient for leading out the signal line of the pressure sensor 2.

[0043] The upper cover 1, the upper pressure head 3, the lower pressure head 5 and the lower cover 6 are all made of metal materials; preferably, the upper pressure head 3 and the lower pressure head 5 are made of metal materials with a Rockwell hardness greater than 35, and the upper cover 1 and the lower cover 6 can be made of ordinary stainless steel. The upper cover 1 and the lower cover 6 are connected to the positive and negative electrodes of the battery tester for testing.

[0044] The assembly process of the device for performing CT testing on a battery of the present invention is as follows:

[0045] The upper pressure head column 301 of the pressure head 3 and the lower pressure head column 501 of the lower pressure head 5 are installed in the sleeve through hole 401 of the sleeve 4, the lower cover pressure surface 601 of the lower cover 6 is fitted with the lower pressure head pressure surface 502 of the lower pressure head 5, and the lower cover thread 601 is tightened with the sleeve lower thread 403 of the sleeve 4; the sensor lower end surface 202 of the pressure sensor 2 is fitted with the upper pressure head pressure surface 301 of the upper pressure head 3, the upper cover pressure surface 103 of the upper cover 1 is fitted with the sensor upper end surface 201 of the pressure sensor 2, the sensor signal line 203 of the sensor 2 is led out from the upper cover wire lead-out hole 101 of the upper cover 1, and the upper cover thread 102 and the sleeve upper thread 402 are tightened.

[0046] The working principle of the present invention is:

[0047] like Fig. 9 As shown, when in use, first insert the lower pressure head 5 into the sleeve 4 and tighten the lower cover 6. Load the battery from the top of the sleeve 4. If only the solid electrolyte is tested, add the electrolyte powder. Tap the sleeve 4 to make the powder flat. Then install the upper pressure head 3, place the pressure sensor 2 on the upper pressure head 3, lead the signal line out from the side hole of the upper cover 1, and tighten the upper cover 1. By adjusting the tightness of the upper cover 1, adjust the pressure applied to the solid electrolyte, put the whole device into the CT tester, connect the positive and negative poles of the battery tester to the upper cover 1 and the lower cover 6, and perform the test. The X-rays emitted by the X-ray source are projected onto the battery in the sleeve 4, and the CT imaging sensor receives the X-ray information transmitted by the battery.

[0048] like Fig.10 As shown, the battery structure in the sleeve 4 is, from bottom to top, a negative electrode current collector, a negative electrode material, a separator, a positive electrode material and a positive electrode current collector.

[0049] During the CT test of the battery by the present invention in conjunction with the CT testing device, the morphological changes inside the battery parallel to the diaphragm direction, the growth state of lithium dendrites and the internal pressure changes of the battery can be observed in situ, so as to better study the dendrite growth of the lithium battery and provide basic data for solving the growth of lithium dendrites.

[0050] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A device for performing CT testing on a battery, characterized in that: The invention comprises an upper cover (1), an upper pressing head (3), a sleeve (4), a lower pressing head (5) and a lower cover (6), wherein the upper pressing head (3) and the lower pressing head (5) are inserted at both ends of the sleeve (4), the upper cover (1) is arranged on the outer side of the upper pressing head (3), and the lower cover (6) is arranged on the outer side of the lower pressing head (5), the upper cover (1) and the lower cover (6) are respectively threadedly connected to the two ends of the sleeve (4), and the sleeve (4) is used to install a battery; A pressure sensor (2) is provided between the upper pressure head (3) and the upper cover (1); The sleeve (4) is thin in the middle and thick at both ends, and a sleeve through hole (401) is provided along the axis; the upper pressure head (3) and the lower pressure head (5) are T-shaped structures, each comprising a pressure head column and a pressure head pressure surface arranged at the end of the pressure head column, and the pressure head column is inserted into the sleeve (4); An upper cover thread (102) is provided on the inner wall of the upper cover (1), and an upper cover pressure surface (103) in contact with the pressure sensor (2) is provided on the inner bottom of the upper cover (1); an upper cover wire lead-out hole (104) is provided on the side wall of the upper cover (1); The sleeve (4) is made of insulating material; the upper cover (1), the upper pressure head (3), the lower pressure head (5) and the lower cover (6) are all made of metal material; the upper cover (1) and the lower cover (6) are respectively connected to the positive and negative electrodes of the battery tester for testing; By adjusting the tightness of the upper cover (1), the pressure applied to the battery in the sleeve (4) is adjusted, and the pressure value is transmitted through the pressure sensor (2).

2. The device for performing CT testing on a battery according to claim 1, characterized in that: The upper pressing head (3) and the lower pressing head (5) are made of a metal material with a Rockwell hardness greater than 35.

3. The device for performing CT testing on a battery according to claim 1, characterized in that: The upper cover (1) and the lower cover (6) are made of stainless steel.

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