Liquid injection structure of sodium ion bipolar battery

Abstract

The application belongs to the technical field of sodium ion batteries, and particularly relates to a liquid injection structure of a sodium ion bipolar battery, which comprises a bipolar electrode sheet group formed by stacking a plurality of bipolar electrode sheets, and the outer circle of the adhering surface of two adjacent bipolar electrode sheets is a sealant area coated with sealant, and the range surrounded by the sealant area is coated with active material. The adjacent bipolar electrode sheets are fused and fixed through the sealant area, an unfused area is reserved in the local section of the sealant area, and a liquid injection sleeve is inserted into the unfused area, one end of the liquid injection sleeve inserted into the bipolar electrode sheet group is an insertion end, and the end reserved outside the bipolar electrode sheet group is a connecting end, wherein the insertion end is provided with a communication port, and the connecting end is used for connecting an external device; the outer wall of the liquid injection sleeve is adhesively sealed with the sealant area. The liquid injection structure expands the caliber of the liquid injection port by arranging the liquid injection sleeve between the bipolar electrode sheets, so that the liquid injection port is convenient to connect with a liquid injection device, thereby overcoming the defect that the bipolar battery is thin and difficult to inject liquid.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sodium ion batteries, and particularly relates to a liquid injection structure of a sodium ion bipolar battery. BACKGROUND

[0002] The sodium ion bipolar battery group has the characteristics of thin battery thickness and large area, and the positive and negative electrode spacing of the battery group is very narrow, and there is no liquid injection space, so the liquid injection process of the structure is very difficult, and the battery group injection step cannot be completed by using the traditional liquid injection equipment and process. SUMMARY

[0003] The purpose of the application is to provide a liquid injection structure for conveniently injecting liquid into a bipolar battery. For a bipolar battery with thin thickness and large area, the liquid injection structure can achieve the purposes of convenient liquid injection and rapid liquid injection, thereby solving the problem of difficult liquid injection.

[0004] To achieve the above purpose, the application provides the following technical scheme: a liquid injection structure of a sodium ion bipolar battery, comprising a bipolar electrode sheet group formed by stacking a plurality of bipolar electrode sheets, and the outer circle of the bonding surface of the adjacent two bipolar electrode sheets is a sealing glue area coated with sealing glue, and the range surrounded by the sealing glue area is coated with active material. The adjacent bipolar electrode sheets are fixed by fusion through the adjacent sealing glue area, and an unfused area is reserved in the local section of the sealing glue area; a liquid injection sleeve is inserted into the unfused area, one end of the liquid injection sleeve inserted into the bipolar electrode sheet group is an insertion end, and the end reserved outside the bipolar electrode sheet group is a connection end, wherein the insertion end has a communication port and extends between the adjacent active materials, and the connection end is used for connecting an external device; the outer wall of the liquid injection sleeve is adhesively sealed with the sealing glue area.

[0005] In the above technical scheme, when the bipolar electrode sheet group is fixed by heat fusion, an unfused area is reserved at the edge, and a liquid injection sleeve is inserted into the unfused area. The liquid injection sleeve is used to enlarge the liquid injection caliber between the adjacent bipolar electrode sheets. By connecting the connection end of the liquid injection machine to the liquid injection sleeve, the purpose of rapid liquid injection can be achieved, thereby overcoming the defect that the bipolar battery is not easy to inject liquid due to its thin thickness. After the liquid injection is completed, the sleeve and the sealing film can be fused together by heat sealing to achieve the sealing of the battery, so the sleeve does not need to be taken out. This can avoid the liquid entering between the unheated sealing films during the process of taking out the sleeve, thereby ensuring the sealing performance.

[0006] Preferably, the connection end of the liquid injection sleeve has a sleeve ring for connecting the liquid injection pipe of the liquid injection equipment. The sleeve ring is used to increase the structural strength of the connection end and realize the stable connection and sealing of the connection end and the liquid injection pipe by fixing the sleeve ring.

[0007] Preferably, the liquid injection sleeve further comprises a clamping piece arranged on the liquid injection sleeve and extending to both sides along the width direction, and the clamping piece is integrated with the sealant at the unfused area. The clamping piece is a transition contact structure between the liquid injection sleeve and the unfused area, which can eliminate the gap formed on both sides of the liquid injection sleeve due to the thickness of the liquid injection sleeve. By reasonably setting the shape of the clamping piece, the thickness of the clamping piece gradually decreases from the middle to the ends, which can further ensure that the clamping piece and the unfused area do not have a gap, thereby achieving complete sealing between the liquid injection sleeve and the unfused area.

[0008] Preferably, the communication port on the insertion end of the liquid injection sleeve is a series of through holes arranged on the two layers of pipe walls of the insertion end, and the injected liquid seeps into the battery interior through the through holes. During the liquid injection process, the liquid enters the liquid injection sleeve and seeps out from the through holes of the insertion end, and uniformly fills the interior of the bipolar electrode group.

[0009] Preferably, the through holes are arranged in a staggered manner, and any two through holes on the two layers of pipe walls of the insertion end of the liquid injection sleeve are completely staggered when the insertion end is in a flat state. Due to the extrusion of adjacent bipolar electrodes and the narrow gap between the bipolar electrodes, the insertion end naturally adheres to the two pipe walls, and the two pipe walls generate a space for liquid flow during liquid injection. The staggered arrangement of the through holes is beneficial to the close adhesion of the two pipe walls during the liquid injection interval or after the completion of liquid injection, thereby preventing liquid overflow from the liquid injection sleeve.

[0010] Preferably, the liquid injection sleeve is made of flexible PET material. After the liquid injection is completed, the connection end is cut off, and the unfused area is heat-sealed and fused to achieve sealing of the unfused area, or part of the connection end is cut off, and the remaining connection end is heat-sealed and fused, or after the bipolar electrode group is packaged with the sealing film, the liquid injection sleeve and the sealing film are heat-sealed and fused together. Regardless of the heat-sealing treatment method, the liquid injection sleeve and the sealing film can be fused together through heat-sealing to achieve sealing of the battery, which can avoid liquid entering the unfused area or between the sealing films that are not heated during the removal of the liquid injection sleeve, thereby ensuring the sealing performance of the liquid injection structure after liquid injection.

[0011] Preferably, the pipe wall of the liquid injection sleeve is flat and adheres in a natural state, and the thickness of the liquid injection sleeve in the flat state is 10-50 microns. Within this range, the thickness of the liquid injection sleeve is adapted to the gap between adjacent bipolar electrodes, so that the liquid injection sleeve can fill the reserved gap of the unfused area without significantly increasing the thickness at this position, thereby ensuring that the final battery appearance is not affected by the liquid injection structure.

[0012] Preferably, for the multi-layer stacked or folded bipolar battery, at least two liquid injection sleeves for liquid injection are arranged in the same layer, and the liquid injection sleeves are uniformly distributed along the length direction of the bipolar battery in the same layer, several liquid injection sleeves are simultaneously filled with liquid during liquid injection, and the liquid in each liquid injection sleeve only needs to permeate in the adjacent area to make the liquid permeate throughout the length, thereby further accelerating the liquid injection process and improving the production efficiency.

[0013] Preferably, an unfused area is arranged on the side opposite to the liquid injection sleeve, a vacuum extraction sleeve is inserted into the unfused area, and the outer wall of the vacuum extraction sleeve is sealingly connected with the corresponding unfused area. The outer end of the vacuum extraction sleeve is connected with a vacuum extraction device, and the inner end is communicated with the gap inside the bipolar electrode group. The bipolar electrode group is vacuumed before liquid injection, which can improve the liquid injection efficiency and make the liquid completely filled, thereby improving the battery performance.

[0014] Preferably, the vacuum extraction sleeve has a connecting end, an insertion end, a clamping piece and a sleeve ring. Compared with the liquid injection sleeve, the difference lies in the structure of the insertion end. Specifically, the through holes on the two side walls of the insertion end of the vacuum extraction sleeve are opposite to each other, and the tube wall has a point-shaped protruding structure protruding towards the inside of the vacuum extraction sleeve or a strip-shaped protruding structure extending along the length direction of the vacuum extraction sleeve, and the point-shaped protruding structure or the strip-shaped protruding structure is arranged between the through holes. The through holes arranged opposite to each other on the tube wall can prevent the tube wall from being attracted due to negative pressure, thereby blocking the through holes. At the same time, the point-shaped protruding structure or the strip-shaped protruding structure arranged along the length direction of the vacuum extraction sleeve can limit the caliber of the insertion end of the vacuum extraction sleeve, so that the insertion end has a stable airflow channel during vacuum extraction, and the internal air pressure of the bipolar electrode group is stably changed.

[0015] In summary, the present application enlarges the caliber of the liquid injection port by arranging the liquid injection sleeve between the bipolar electrodes, which is convenient for connecting with the liquid injection equipment, thereby overcoming the defect that the bipolar battery is not easy to be injected due to its thin thickness. The structure of the insertion end of the liquid injection sleeve is arranged, so that the liquid uniformly diffuses through the through holes of the inner end of the sleeve after entering the sleeve, and uniformly enters the inside of the battery group. Through the selection of the material and the design of the structure of the liquid injection sleeve, the sleeve and the sealing film can be fused together by heat sealing after the liquid injection is completed, thereby realizing the sealing of the battery, and the sleeve does not need to be taken out. This can avoid the liquid entering the unheated sealing film during the process of taking out the sleeve, thereby ensuring the sealing performance. In addition, the vacuum extraction sleeve is additionally arranged, which can extract the battery before liquid injection, thereby improving the liquid injection efficiency and making the liquid completely filled, thereby improving the battery performance. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0017] Figure 1 A schematic diagram of the planar structure of the bipolar battery liquid injection structure embodiment provided by the present application;

[0018] Figure 2 A schematic diagram of the planar structure of the bipolar battery liquid injection structure embodiment provided by the present application; Figure 1 A schematic diagram of the overall structure of the liquid injection sleeve;

[0019] Figure 3 A schematic diagram of the planar structure of the bipolar battery liquid injection structure embodiment provided by the present application; Figure 2 A schematic diagram of the structure of the insertion end of the liquid injection sleeve;

[0020] Figure 4 A schematic diagram of the planar structure of the bipolar battery liquid injection structure embodiment provided by the present application; Figure 1 A schematic diagram of the overall structure of the vacuum extraction sleeve;

[0021] Figure 5 A schematic diagram of the planar structure of the bipolar battery liquid injection structure embodiment provided by the present application; Figure 4 A schematic diagram of the structure of the insertion end of the vacuum extraction sleeve.

[0022] In the drawings, the bipolar sheet group 1, the sealing glue area 2, the non-fusion area 3, the liquid injection sleeve 4, the connection end 5, the insertion end 6, the sleeve ring 9, the through hole 6, the clamping piece 7, the vacuum extraction sleeve 8, the sleeve ring 9, and the through hole 10. DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in detail below with reference to the drawings and examples, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented.

[0024] Figures 1-5 For an embodiment of the present application, a sodium-ion bipolar battery liquid injection structure includes a bipolar sheet group 1 formed by stacking a plurality of rectangular sodium-ion bipolar sheets. The edges of the front and back surfaces of the current collector of the sodium-ion bipolar sheet are rectangular sealing glue areas 2. The rectangular surface surrounded by the sealing glue areas 2 is coated with positive active material and negative active material. For the stacked bipolar sheet group 1, the positive active material and the negative active material are attached between adjacent sodium-ion bipolar sheets, and the sealing glue areas 2 are opposite each other, with a 10-50 micron thick gap reserved between adjacent sodium-ion bipolar sheet pieces. For the bipolar sheet group 1, adjacent sodium-ion bipolar sheets are fixed by fusion through adjacent sealing glue areas 2 to achieve the fixation of each bipolar sheet. In the present application, two suitable positions are found on the left and right sides of the bipolar sheet group 1 before heat sealing, and non-fusion areas 3 are formed at the two positions, respectively. That is, the sealing glue areas 2 at these positions do not fuse, such as Figure 1As shown, two unfused areas 3 are distributed at the left and right positions of the bipolar electrode sheet group 1. And in the unfused area 3 at the right, a liquid injection sleeve 4 is inserted, the end of which inserted into the bipolar electrode sheet group 1 is an insertion end 6, and the end reserved outside the bipolar electrode sheet group 1 is a connection end 5; in the unfused area 3 at the left, a vacuum extraction sleeve 8 with similar structure to the liquid injection sleeve 4 is inserted, also including a connection end 5 and an insertion end 6. Based on the distance between the bipolar electrode sheet pieces, the thickness of the liquid injection sleeve 4 and the vacuum extraction sleeve 8 in the flat state (two tube walls adhering) is selected to be 10-50 microns. According to the gap between the adjacent bipolar electrode sheets, the thickness of the liquid injection sleeve 4 is selected to be adaptive, so that the liquid injection sleeve 4 can fill the reserved gap of the unfused area 3, and will not significantly increase the thickness at this place, so as to make the final battery appearance not affected by the liquid injection structure.

[0025] As shown in Figure 2 and Figure 4 , the liquid injection sleeve 4 and the vacuum extraction sleeve 8 have the following common points: the outer end of the connection end 5 of both is provided with a sleeve ring 9, which can increase the structural strength of the connection end 5, wherein the sleeve ring 9 on the liquid injection sleeve 4 is used to connect the liquid injection pipe of the liquid injection equipment, and the sleeve ring 9 on the vacuum extraction sleeve 8 is used to connect the vacuum extraction device, and the sleeve ring 9 is fixed by means of other components (such as a strap or a hoop), so as to realize the stable connection and sealing of the connection end 5 with the liquid injection pipe and the vacuum extraction device. In addition to the same structure of the connection end 5, the liquid injection sleeve 4 and the vacuum extraction sleeve 8 also have the same clamping piece 7, which extends to both sides along the width direction of the liquid injection sleeve 4, and the clamping piece 7 is integrally bonded with the sealant at the unfused area 3, that is, the clamping piece 7 is the transition contact structure between the liquid injection sleeve 4 and the unfused area 3, which can eliminate the gap formed on both sides of the liquid injection sleeve 4 due to the thickness of the liquid injection sleeve 4, and by reasonably setting the shape of the clamping piece 7, the thickness gradually decreases from the middle to the two ends, which can further ensure that the clamping piece 7 and the unfused area 3 will not have a gap, so as to realize the complete sealing between the liquid injection sleeve 4 and the unfused area 3.

[0026] In addition, the insertion end of the liquid injection sleeve 4 and the vacuum extraction sleeve 8 extends to between the bipolar electrode sheets, so that the insertion end overlaps to form a flat structure, as shown in Figure 2 and Figure 4 , a through hole 10 is arranged on the upper tube wall and the lower tube wall of the insertion end of the liquid injection sleeve 4 and the vacuum extraction sleeve 8. For the liquid injection sleeve 4, as shown in Figure 3As shown, the through holes 10 on the upper and lower tube walls are staggered, and any two through holes on the two layers of tube walls of the insertion end 6 of the liquid injection sleeve 4 are completely staggered when the insertion end 6 is in a flat state. During the liquid injection process, liquid enters the liquid injection sleeve 4 and seeps out from the through holes of the insertion end, and uniformly fills the interior of the bipolar electrode group 1. Moreover, under the extrusion of adjacent bipolar electrodes, and with the narrow gap between the bipolar electrodes, the insertion end 6 naturally adheres to the two tube walls, and the two tube walls generate a space for liquid flow during the liquid injection process. The staggered through holes are conducive to the close adhesion of the two tube walls during the liquid injection interval or after the liquid injection is completed, thereby preventing liquid from overflowing from the liquid injection sleeve 4.

[0027] For the vacuum extraction sleeve 8, the outer end of the vacuum extraction sleeve 8 is connected to a vacuum extraction device, and the insertion end communicates with the gap inside the bipolar electrode group 1. The bipolar electrode group 1 is vacuumed before liquid injection, which can improve the liquid injection efficiency and make the liquid completely filled, thereby improving the battery performance. Figure 5 As described above, the through holes 10 on the two side walls of the insertion end 6 of the vacuum extraction sleeve 8 are opposite, and the tube walls have strip-shaped protruding structures protruding towards the interior of the vacuum extraction sleeve 8 and extending along the length direction of the vacuum extraction sleeve 8, and the strip-shaped protruding structures are arranged between the through holes 10. During the vacuum extraction process, the opposite through holes 10 on the tube walls can prevent the tube walls from being attracted due to negative pressure, thereby blocking the through holes 10. At the same time, the strip-shaped protruding structures arranged along the length direction of the vacuum extraction sleeve 8 can limit the caliber of the insertion end 6 of the vacuum extraction sleeve 8, so that the insertion end 6 has a stable airflow channel during the vacuum extraction, thereby ensuring the stable change of the air pressure inside the bipolar electrode group 1.

[0028] In this embodiment, when the bipolar electrode group 1 is fixed by heat melting, an unfused area 3 is reserved at the edge, and the liquid injection sleeve 4 is inserted into the unfused area 3. The liquid injection sleeve 4 is used to expand the liquid injection caliber between adjacent bipolar electrodes. By connecting the connection end 5 of the liquid injection sleeve 4 to the liquid injection machine, the purpose of rapid liquid injection can be achieved, thereby overcoming the defect that the bipolar battery is not easy to inject liquid due to its thin thickness. The liquid injection sleeve 4 is made of flexible PET material. After the liquid injection is completed, the connection end 5 is cut off, and the unfused area 3 is heat sealed and fused. At this time, the two layers of tube walls are fused and fused with the sealing glue of the unfused area 3, thereby realizing the sealing of the unfused area 3. Alternatively, part of the connection end 5 is cut off, and the remaining part of the connection end 5 is heat sealed and fused. The liquid injection sleeve 4 can also be heat sealed and fused together with the sealing film after the bipolar electrode group 1 is sleeved with the sealing film. Regardless of the heat sealing treatment method, the liquid injection sleeve 4 can be removed without liquid entering the unfused area 3 or the sealing film that is not heated during the removal of the sleeve.

[0029] Based on the above injection structure with the above characteristics, for the multi-layer stacked or folded bipolar battery, two or more injection sleeves 4 for liquid injection can be arranged in the same layer, and the injection sleeves 4 are uniformly distributed along the length direction of the bipolar battery (bipolar electrode sheet group) in the same layer. During liquid injection, several injection sleeves 4 are simultaneously injected, and the liquid in each injection sleeve 4 only needs to penetrate in the adjacent area, so that the liquid can be fully penetrated, thereby further accelerating the liquid injection process and improving the production efficiency.

[0030] As used in the specification and claims, certain terminology is used to designate certain components. One of skill in the art will understand that different names can be used by hardware manufacturers to refer to the same component. The specification and claims do not differentiate between names used to refer to the same component, but rather the functionality of the component as understood by one of skill in the art. As used throughout the specification and claims, "comprising" is to be read as "comprising, without limitation." "Approximately" means within an acceptable error range for the corresponding function, as would be understood by one of skill in the art.

[0031] It should be noted that the terms "comprising," "including," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the recited element.

[0032] The above description illustrates and describes several preferred embodiments of the present application, but as previously mentioned, it is to be understood that the present application is not limited to the above-described forms, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the inventive concept described herein, by the above teachings or related art or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application should be within the protection scope of the appended claims of the present application.

Claims

1. A sodium-ion bipolar battery electrolyte filling structure, comprising a bipolar electrode group formed by stacking a plurality of bipolar electrodes, wherein the outer ring of the mating surface of two adjacent bipolar electrodes is a sealant area coated with sealant, and an active material is coated within the area enclosed by the sealant area, characterized in that: Adjacent bipolar electrodes are fused together and fixed by adjacent sealant areas, with a partially unfused section reserved in the sealant area. An injection sleeve is inserted into this unfused section. One end of the injection sleeve is inserted into the bipolar electrode assembly as the insertion end, and the other end, remaining outside the assembly, is the connection end. The insertion end has a connecting port extending between adjacent active materials, while the connection end is used to connect to external equipment. The outer wall of the injection sleeve is bonded and sealed to the sealant area. The connection end of the injection sleeve has a collar for connecting to the injection equipment. The injection sleeve also includes clips extending to both sides along its width. The clips gradually decrease in thickness from the middle to both ends, and the clips are bonded to the sealant in the unfused area to ensure a seal between the sleeve and the sealing film. The communication port on the insertion end of the injection sleeve is a series of through holes set on the two layers of tube walls at the insertion end. The injected liquid seeps into the battery through the through holes. The through holes are staggered. When the insertion end of the injection sleeve is in a flat state, any two through holes on the two layers of tube walls at the insertion end are completely staggered.

2. The electrolyte filling structure for a sodium-ion bipolar battery as described in claim 1, characterized in that: The injection sleeve is made of flexible PET material. After the injection is completed, the connecting end is cut off, and the unfused area is heat-sealed to achieve a seal for the unfused area; or part of the connecting end is cut off, and the remaining part of the connecting end is heat-sealed.

3. The electrolyte filling structure for a sodium-ion bipolar battery as described in claim 1, characterized in that: In its natural state, the wall of the injection cannula is flat and fitted, and the thickness of the cannula is 10-50 micrometers when it is flat.

4. The electrolyte filling structure of a sodium-ion bipolar battery as described in any one of claims 1-3, characterized in that: For multi-layer stacked or folded bipolar batteries, at least two liquid injection sleeves for liquid injection are provided in the same layer, and these liquid injection sleeves are evenly distributed along the length direction of the bipolar battery in the same layer.

5. The electrolyte filling structure of a sodium-ion bipolar battery as described in any one of claims 1-3, characterized in that: An unfused zone is provided on the side opposite to the injection sleeve. A vacuum sleeve is inserted into the unfused zone, and the outer wall of the vacuum sleeve is sealed to the corresponding unfused zone.

6. The electrolyte filling structure for a sodium-ion bipolar battery as described in claim 5, characterized in that: The vacuum sleeve has a connecting end, an insertion end, a clamp, and a collar, wherein the collar is used to connect the vacuum device. Compared with the liquid injection sleeve, the difference lies in the structure of the insertion end. Specifically, the through holes on the two side walls of the insertion end of the vacuum sleeve are aligned, and the sleeve wall has a dot-shaped protrusion structure protruding towards the inside of the vacuum sleeve or a strip-shaped protrusion structure extending along the length of the vacuum sleeve, and the dot-shaped protrusion structure or the strip-shaped protrusion structure is arranged between the through holes.

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