A jelly-roll and lithium sub-battery

Abstract

The application belongs to the technical field of batteries, and discloses a current collecting cylinder and a lithium sub-battery. The current collecting cylinder comprises a cylinder body and a limiting structure. The cylinder body is inserted into a positive electrode member and cooperates with the side wall of a shell to provide lateral support and constraint for the positive electrode member. The limiting structure comprises an abutting portion and an elastic portion connected to the abutting portion. In the radial direction of the cylinder body, the limiting structure is configured to be spaced apart from the side wall of the shell of the lithium sub-battery, thereby ensuring the insulation between the limiting structure and the shell. The abutting portion is fixedly connected to the cylinder body and abuts against the end face of the positive electrode member of the lithium sub-battery. The elastic portion is configured to abut against the top cover of the lithium sub-battery after the positive electrode member expands. Therefore, the positive electrode member can be provided with longitudinal support and constraint, the positive electrode member can expand more uniformly, the non-uniformity of expansion can be reduced, and the consistency of discharge performance can be improved. When the lithium sub-battery applies the current collecting cylinder, the positive electrode member can expand uniformly, the non-uniformity of expansion can be reduced, and the consistency of discharge performance can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a current collector and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are disposable lithium batteries that use metallic lithium as the negative electrode and thionyl chloride as the positive electrode active material and electrolyte solvent. Their unique chemical system gives them high energy density, ultra-long storage life and excellent high and low temperature performance. They are widely used in disposable power supply scenarios with low power consumption, long-term maintenance-free operation and high reliability requirements.

[0003] In related technologies, lithium-ion batteries include a casing, a negative electrode, a positive electrode, and a current collector. The casing includes a housing, a top cover, and a terminal post mounted on the top cover. The negative electrode is annular and located inside the housing. The positive electrode is columnar and located inside the annular structure of the negative electrode. A separator for short-circuit protection is provided between the positive and negative electrodes. The current collector is inserted into the central hole of the positive electrode and is used for electrical connection with the terminal post on the top cover.

[0004] During the discharge process of lithium-ion batteries, the positive electrode will expand and deform due to product deposition. If the positive electrode is excessively deformed, the internal pressure of the battery will rise sharply, causing the casing to bulge, rupture, or even explode. It will also squeeze the separator, causing short circuits between the positive and negative electrodes and thermal runaway. It will also hinder ion migration, leading to a sharp increase in internal resistance, a sharp drop in discharge voltage, and a significant reduction in capacity, ultimately causing the battery to fail and fail to meet the needs of low-power devices, or even cause safety accidents.

[0005] This section provides background information related to this application, which is not necessarily prior art. Utility Model Content

[0006] The purpose of this application is to solve or at least alleviate some or all of the aforementioned problems. Therefore, the purpose of this application is to provide a current collector, a lithium-ion battery, and a lithium-ion battery assembly process that, during discharge, enables the positive electrode to expand uniformly, reduces expansion unevenness, and improves the consistency of discharge performance.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] In a first aspect, this application provides a manifold, the manifold comprising:

[0009] A cylindrical body configured to insert the positive electrode of the lithium-ion battery;

[0010] The limiting structure includes an abutting part and an elastic part connected to the abutting part. The abutting part is fixedly connected to the cylindrical body and abuts against the end face of the positive electrode of the lithium-ion battery. The elastic part is configured to abut against the top cover of the lithium-ion battery after the positive electrode expands.

[0011] In the radial direction of the cylindrical body, the limiting structure is configured to be spaced apart from the sidewall of the lithium-ion battery housing.

[0012] As an optional embodiment of the collector, the abutting portion includes an annular bottom wall and an outer annular side wall connected to the outer edge of the annular bottom wall. The annular bottom wall is configured to abut against the end face of the positive electrode, and the outer annular side wall is connected to the elastic portion.

[0013] As an optional feature of the collector, the annular bottom wall is provided with dispersion slots.

[0014] As an alternative to the current collector, the cylinder body has a connecting portion that extends out of the annular bottom wall and is fixedly connected to the annular bottom wall, and its end face is lower than the outer ring side wall. The connecting portion is configured to be electrically connected to the terminal post of the lithium-ion battery.

[0015] As an alternative to the current collector, the diameter of the end of the connection portion away from the positive electrode is smaller than the diameter of the other end.

[0016] As an optional embodiment of the manifold, when the elastic part is a material elastic part, the abutting part and the cylinder body are integrally formed metal structures, and the elastic part is installed on the abutting part; or

[0017] When the elastic part is a structural elastic part, the manifold is a one-piece metal structure.

[0018] As an optional embodiment of the manifold, the elastic part is a rubber component, and the free end of the outer ring sidewall is fitted with a rubber component, which has a support protrusion protruding towards the top cover.

[0019] As an alternative to the manifold, the cross-sectional area of ​​the supporting protrusion gradually increases from its top to its bottom.

[0020] As an optional feature of the manifold, the minimum distance between the elastic part and the top cover is 0 to 1.4 mm; and / or

[0021] The minimum distance between the outer ring sidewall and the sidewall of the housing is 2mm to 3mm.

[0022] As an optional embodiment of the collector, the cylinder body is divided into at least two opening regions along its axial direction, and each opening region is provided with multiple holes. The total number of holes per unit area in each opening region gradually decreases along the axial direction of the cylinder body from the end closer to the pole post to the end farther away from the pole post.

[0023] As an optional embodiment of the current collector, there are two opening areas. The opening area adjacent to the lithium-ion battery and close to its terminal post is designated as the first opening area, and the other opening area is designated as the second opening area. The hole in the first opening area is designated as the first hole, and the hole in the second opening area is designated as the second hole.

[0024] As an optional embodiment of the manifold, the ratio between the area of ​​the first opening region and the area of ​​the second opening region ranges from 0.3 to 1; and / or

[0025] The area of ​​a single first hole is not greater than the area of ​​a single second hole.

[0026] Secondly, this application provides a lithium-ion battery, comprising:

[0027] The housing includes a bottom wall and side walls, with a first end of the side wall surrounding the periphery of the bottom wall and a second end forming an opening in the housing;

[0028] A top cover assembly includes a top cover and an electrode post mounted on the top cover, wherein a sealing cap is provided at the opening;

[0029] A positive electrode is disposed inside the housing, and the positive electrode has a central hole;

[0030] As described above, the collector body is inserted into the central hole; the first end of the limiting structure of the collector abuts against the end face of the positive electrode, and its second end can abut against the top cover after the positive electrode expands; the limiting structure is spaced apart from the side wall.

[0031] As an optional solution for the lithium-ion battery, the inner surface of the top cover is covered with a first insulating sheet, and the minimum distance between the limiting structure and the first insulating sheet is 0 to 1.2 mm.

[0032] As an optional embodiment of the lithium-ion battery, the inner surface of the bottom wall has several inwardly protruding positioning protrusions, and the cylindrical body has several positioning grooves that mate with the positioning protrusions one by one.

[0033] As an optional solution for the lithium-ion battery, a second insulating sheet is provided between the cylindrical body and the bottom wall, and a portion of the second insulating sheet is sandwiched between the positioning protrusion and the positioning groove.

[0034] As an optional solution for the lithium-ion battery, an explosion-proof groove is provided on the bottom wall opposite to the cylindrical body, and the second insulating sheet has a through hole corresponding to the explosion-proof groove.

[0035] As an optional solution for the lithium-ion battery, the explosion-proof groove includes a central groove and an emission groove. A plurality of the emission grooves are arranged around the periphery of the central groove and communicate with the central groove. The ratio between the area of ​​the circumscribed circle corresponding to the central groove, the area of ​​the through hole, and the end face area of ​​the second end of the cylindrical body is 1:0.8:1.5.

[0036] As an optional embodiment of the lithium-ion battery, the thickness of the bottom wall in the explosion-proof groove is Tx, and the value of Tx has at least a continuously varying range and / or a discontinuous range.

[0037] As an optional embodiment of the lithium-ion battery, the thickness of the bottom wall is T1, and the minimum value of Tx is T4, wherein 0.15T1≤T4≤0.50T1.

[0038] The beneficial effects of this application are as follows:

[0039] The current collector provided in this application includes a cylinder body and a limiting structure. The cylinder body is inserted into the positive electrode component and, in conjunction with the side wall of the housing, provides lateral support and constraint for the positive electrode component. The limiting structure includes an abutment portion and an elastic portion connected to the abutment portion. In the radial direction of the cylinder body, the limiting structure is configured to be spaced apart from the side wall of the lithium-ion battery housing to ensure insulation between the limiting structure and the housing. The abutment portion is fixedly connected to the cylinder body and abuts against the end face of the positive electrode component of the lithium-ion battery. The elastic portion is configured to abut against the top cover of the lithium-ion battery after the positive electrode component expands. This provides longitudinal support and constraint for the positive electrode component, making its expansion more uniform, reducing expansion non-uniformity, and improving the consistency of discharge performance. By using the aforementioned current collector, the positive electrode component of this lithium-ion battery can expand uniformly during discharge, reducing expansion non-uniformity and improving the consistency of discharge performance.

[0040] The lithium-thionyl chloride battery provided in this application, by using the aforementioned current collector, causes the positive electrode to expand and deform during discharge due to the deposition of discharge products and the increase in temperature. Since the body of the current collector is inserted into the central hole of the positive electrode, and its limiting structure abuts against the upper end face of the positive electrode, it can provide stable support and constraint forces for the positive electrode in the lateral and longitudinal directions, making the expansion of the positive electrode more uniform and improving the uniformity of the positive electrode. This results in a stable voltage plateau at the end of the battery reaction process, and the voltage fluctuation range can be controlled within ±50mV. Attached Figure Description

[0041] Figure 1 This is a cross-sectional schematic diagram of the lithium-ion battery provided in the embodiments of this application.

[0042] Figure 2 This is a schematic diagram of the manifold structure provided in the embodiments of this application.

[0043] Figure 3This is a schematic diagram of the housing provided in the embodiment of this application, viewed from its opening.

[0044] Figure 4 This is a partial cross-sectional schematic diagram of the lithium-ion battery provided in the embodiments of this application.

[0045] Figure 5 This is a schematic diagram of the structure of the shell provided in the embodiment of this application.

[0046] Figure 6 This is a schematic diagram of the structure of the first insulating sheet provided in the embodiments of this application.

[0047] Figure 7 This is a partial cross-sectional schematic diagram of the housing provided in an embodiment of this application.

[0048] Figure 8 This is a schematic diagram of the manifold structure of the first example provided in the embodiments of this application.

[0049] Figure 9 A schematic diagram of the structure of the manifold provided in the second example of this application embodiment.

[0050] Figure 10 A schematic diagram of the structure of the manifold provided in the third example of the embodiments of this application.

[0051] Figure 11 A schematic diagram of the structure of the manifold provided in the fourth example of this application embodiment.

[0052] Figure 12 A schematic diagram of the structure of the manifold provided in the fifth example of this application embodiment.

[0053] Figure 13 This is a partial cross-sectional schematic diagram of the manifold provided in the embodiments of this application.

[0054] Figure 14 This is an exploded view of the lithium-ion battery provided in the embodiments of this application.

[0055] Figure 15 This is a comparison chart of a room temperature discharge curve provided in the embodiments of this application and a pair of proportions.

[0056] In the picture:

[0057] 1. Shell; 11. Bottom wall; 111. Explosion-proof groove; 1111. Central groove; 1112. Emission groove; 112. Positioning protrusion; 113. Boss; 114. Recess; 12. Side wall; 2. Top cover assembly; 21. Top cover; 22. Electrode post; 3. Negative electrode; 4. Positive electrode; 5. Collector tube; 51. Tube body; 5100. Positioning groove; 510. Opening area; 5101. Hole; 511. First opening area; 5111 512. First hole; 513. Second opening area; 514. Second hole; 515. Connecting part; 52. Limiting structure; 5201. Abutting part; 5202. Elastic part; 52021. Supporting protrusion; 521. Annular bottom wall; 5211. Dispersion groove; 522. Outer ring side wall; 6. Electrode; 81. Side diaphragm; 82. Bottom diaphragm; 83. First insulating sheet; 84. Middle diaphragm; 85. First insulating sheet; 851. Through hole. Detailed Implementation

[0058] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0059] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0060] In the description of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0061] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0062] This application provides a lithium-ion battery that, during discharge, enables the positive electrode to expand uniformly, reducing expansion unevenness and improving the consistency of discharge performance. It also features high energy density, ultra-long storage life, and excellent high and low temperature performance, making it widely applicable to low-power, long-term maintenance-free, and high-reliability single-use power supply scenarios such as smart meters, IoT sensors, industrial automation instruments, implantable medical devices, smoke detectors, and automotive tire pressure monitoring systems.

[0063] For ease of understanding and description of the technical solution of this application, such as Figure 1 As shown, Figure 1 The vertical direction in the text is defined as the longitudinal direction of the lithium-ion battery; Figure 1 The horizontal direction in the figure is defined as the lateral direction of the lithium-ion battery. In the following application, the terms "upper," "lower," "inner," and "outer," etc., are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application.

[0064] Continue as Figures 1 to 2 As shown, the lithium-ion battery includes a casing 1, a top cover assembly 2, a positive electrode 4, a negative electrode 3, and a current collector 5. The casing 1 includes a bottom wall 11 and side walls 12. The first end of the side wall 12 surrounds the periphery of the bottom wall 11, and its second end forms an opening in the casing 1. The top cover assembly 2 includes a top cover 21 and an electrode post 22 mounted on the top cover 21. The top cover 21 is sealed at the opening. The positive electrode 4 is disposed within the casing 1 and has a bottom diaphragm 82 between it and the bottom wall 11. The positive electrode 4 has a central hole penetrating its longitudinal direction. The electrode 3 is disposed inside the housing 1 and surrounds the positive electrode 4, with a side diaphragm 81 between them. The current collector 5 includes a cylinder body 51 and a limiting structure 52. The axial direction of the cylinder body 51 is the longitudinal direction of the lithium-ion battery. The cylinder body 51 is inserted into the central hole of the positive electrode 4. The lower end of the limiting structure 52 abuts against the end face of the positive electrode 4, and the upper end of the limiting structure 52 abuts against the top cover 21 after the positive electrode 4 expands. The peripheral sidewall of the limiting structure 52 is spaced apart from the sidewall of the housing to avoid electrical connection between them. In some embodiments, the positive electrode 4 can be a carbon pack, which can be a porous cylindrical structure formed by mixing and pressing carbon powder, binder, etc., while the negative electrode 3 can be a lithium foil, lithium sheet, or lithium strip, without limitation.

[0065] It is understandable that the cylinder body 51 is inserted into the center hole of the positive electrode 4, and together with the side wall 12 of the shell 1, it provides lateral support and constraint for the positive electrode 4. The lower end of the limiting structure 52 abuts against the end face of the positive electrode 4, and its upper end abuts against the top cover 21 after the positive electrode 4 expands, thereby providing longitudinal support and constraint for the positive electrode 4, making the expansion of the positive electrode 4 more uniform, reducing expansion non-uniformity, and improving the consistency of discharge performance.

[0066] In some embodiments, the cylindrical body 51 is positioned and engaged with the bottom wall 11. For example, the lower end of the cylindrical body 51 is provided with a positioning groove 5100, and the inner surface of the bottom wall 11 is provided with a positioning protrusion 112. The cylindrical body 51 and the bottom wall 11 are positioned and engaged by mechanical pressing. Since the cylindrical body 51 of the current collector 5 is inserted into the center hole of the positive electrode 4 and positioned and engaged with the bottom wall 11, and its limiting structure 52 abuts against the upper end face of the positive electrode 4, the current collector 5 will not rotate relative to the positive electrode 4 under the action of the expansion of the positive electrode 4. This not only reduces the friction between the current collector 5 and the positive electrode 4, but also provides stable support and constraint forces for the lateral and longitudinal directions of the positive electrode 4, making the expansion of the positive electrode 4 more uniform and improving the uniformity of the positive electrode 4. This makes the voltage plateau stable at the end of the battery reaction process, and the voltage fluctuation range can be controlled within ±50mV.

[0067] Specifically, in the lateral direction of the positive electrode 4, since the cylindrical body 51 is inserted into the central hole of the positive electrode 4, it provides support to the positive electrode 4 from the center to the outside. Combined with the constraint effect of the side wall 12 of the shell 1 on the positive electrode 4 from the outside to the center, the positive electrode 4 can expand uniformly in the lateral direction and reduce the amount of expansion deformation in the lateral direction to a certain extent. In the longitudinal direction of the positive electrode 4, since the limiting structure 52 is fixedly connected to the cylindrical body 51 and abuts against the upper end face of the positive electrode 4, the limiting structure 52 can abut against the top cover after the positive electrode 4 expands. This allows the limiting structure 52 itself and under the action of the top cover 21 to generate a vertical constraint force on the positive electrode 4 from top to bottom, which enables the positive electrode 4 to expand uniformly in the longitudinal direction and reduces the amount of expansion deformation in the longitudinal direction to a certain extent. This makes the positive electrode 4 expand uniformly as a whole, reduces expansion non-uniformity, and improves the consistency of discharge performance.

[0068] In other words, the cylinder body 51 of the current collector 5 is inserted into the center hole of the positive electrode 4, and the limiting structure 52 abuts against the upper end face of the positive electrode 4. With the combined action of the current collector 5, the housing 1, and the top cover 21, the current collector 5 provides a "skeleton" for the positive electrode 4. On the one hand, it can fix the positive electrode 4 in a designated position inside the housing 1 to prevent displacement during assembly; on the other hand, it can counteract the expansion stress generated by product deposition in the positive electrode 4 during discharge, reducing the risk of breakage or excessive deformation of the positive electrode 4, and indirectly ensuring the contact stability between the electrode and the diaphragm and the negative electrode. In addition, the surface of the cylinder body 51 is in close contact with the positive electrode 4, which can quickly collect electrons generated at various points of the positive electrode 4, and then conduct the electrons to the electrode post 22 through the tab 6, and finally connect to the external circuit to supply power to the load.

[0069] In some embodiments, the limiting structure 52 includes an abutment portion 5201 and an elastic portion 5202 connected to the abutment portion 5201. The abutment portion 5201 abuts against the end face of the positive electrode 4, and the elastic portion 5202 is configured to abut against the top cover 2 of the lithium-ion battery after the positive electrode 4 expands.

[0070] When the elastic part 5202 is a material elastic part, the abutment part 5201 and the cylinder body 51 are integrally formed metal structures. The elastic part 5202 is detachably installed on the abutment part 5201. The materials of the abutment part 5201 and the cylinder body 51 include, but are not limited to, conductive metals such as stainless steel and nickel. If stainless steel is used, one of ferritic stainless steel, austenitic stainless steel, austenitic-ferritic duplex stainless steel, martensitic stainless steel, and precipitation-hardening stainless steel can be selected. Furthermore, it is not limited to using a single metal material; a stainless steel coating or other metal coating can also be applied to its surface. When the elastic part 5202 is a structural elastic part, the current collector 5 is an integrally formed metal structure, which reduces the number of parts in the current collector 5, facilitates the assembly of the current collector 5, and improves the assembly efficiency of the lithium-ion battery. The materials of the current collector 5 include, but are not limited to, conductive metals such as stainless steel and nickel. If stainless steel is used, one of ferritic stainless steel, austenitic stainless steel, austenitic-ferritic duplex stainless steel, martensitic stainless steel, and precipitation-hardening stainless steel can be selected. In addition, it is not limited to choosing a single metal material; stainless steel or other metal coatings can also be applied to its surface.

[0071] It should be noted that when the elastic part 5202 is a material elastic part, the elastic part 5202 can be a rubber part, such as a silicone part; when the elastic part 5202 is a structural elastic part, the elastic part 5202 can be a spring or a spring sheet. In this case, an insulating structure must be provided between the elastic part 5202 and the top cover 21 to ensure that the elastic part 5202 and the top cover 21 are insulated from each other.

[0072] In some embodiments, a bottom diaphragm 82 is provided between the positive electrode 4 and the bottom wall 11. The bottom diaphragm 82 is used to prevent the positive electrode 4 from short-circuiting with the negative electrode 3 through the bottom wall 11 of the housing 1. A first insulating sheet 83 is provided on the inner surface of the top cover 21. The first insulating sheet 83 can be used to ensure the insulating fit between the limiting structure 52 and the top cover 21. An intermediate diaphragm 84 is provided between the limiting structure 52 and the upper end face of the positive electrode 4. This is used to ensure the insulating fit between the limiting structure 52 and the positive electrode 4, and to ensure that the released electrons can only be conducted through the cylinder body 51 to the limiting structure 52, and then to the electrode post 22.

[0073] Since the cylinder body 51 and the bottom wall 11 are positioned and fitted together, a second insulating sheet 85 is provided between the cylinder body 51 and the bottom wall 11 to improve contact safety. The second insulating sheet 85 ensures the insulation of the contact area between the cylinder body 51 and the bottom wall 11. The second insulating sheet 85 can be made of a highly polymerizable material, such as polytetrafluoroethylene (PTFE) or polyvinyl chloride (PVC). This material has a dielectric strength ≥50kV / mm (measured value), wide temperature range thermal stability (-200℃~260℃ operating conditions), and resistance to electrolyte corrosion (volume change rate <0.5% after immersion for 500h).

[0074] In theory, the diameter of the second insulating sheet 85 can be larger than the diameter of the cylindrical body 51. However, in order to avoid the second insulating sheet 85 shifting during assembly and causing the cylindrical body 51 to directly contact the bottom wall 11, the ratio between the diameter of the second insulating sheet 85 and the diameter of the cylindrical body 51 can be 1.5 to 2.5. This ensures that even if the second insulating sheet 85 moves during assembly, the insulating fit between the cylindrical body 51 and the bottom wall 11 can still be guaranteed.

[0075] In some embodiments, the side diaphragm, bottom diaphragm, and middle diaphragm may be made of glass fiber. The first insulating sheet 83 and the second insulating sheet 85 may be made of polytetrafluoroethylene (PTFE) microporous membrane, polypropylene (PP) microporous membrane, or polyethylene (PE) microporous membrane. These materials have resistance to electrolyte (SOCl2) corrosion, high ion permeability, excellent mechanical strength, and good high temperature resistance to achieve positive and negative electrode isolation and lithium ion conduction.

[0076] like Figures 2 to 4 As shown, the inner surface of the bottom wall 11 has several inwardly protruding positioning protrusions 112, and the cylindrical body 51 has several positioning grooves 5100 that mate with the positioning protrusions 112 one by one. A portion of the second insulating sheet 85 is sandwiched between the positioning protrusions 112 and the positioning grooves 5100. For example, the inner surface of the bottom wall 11 has four positioning protrusions 112 arranged circumferentially, and the lower end of the cylindrical body 51 has four positioning grooves 5100. The positioning grooves 5100 are correspondingly arranged with the positioning protrusions 112 to ensure that the cylindrical body 51 will not rotate or shift when the positive electrode 4 expands and deforms, ensuring stable contact between it and the positive electrode 4, reducing the friction between them, ensuring the overall integrity of the positive electrode 4, and ensuring that the current collector 5 can provide stable support and constraint forces for the positive electrode 4 in the lateral and longitudinal directions. In other embodiments, the number of positioning protrusions 112 and positioning grooves 5100 is not limited to four, but can also be two, three, five, etc., which is not limited here.

[0077] like Figures 5 to 6 and combined Figure 1As shown, an explosion-proof groove 111 is provided on the bottom wall 11 opposite to the cylindrical body 51, and a through hole 851 corresponding to the explosion-proof groove 111 is provided on the second insulating sheet 85. The hollow area of ​​the cylindrical body 51 forms a pressure relief channel, which can serve as a pressure release path inside the battery and has a certain guiding effect on the gas. When the battery discharges, the generated gas can enter the hollow area of ​​the cylindrical body 51 and then flow through the through hole 851 of the second insulating sheet 85 to the explosion-proof groove 111 on the bottom wall 11. When the pressure reaches the threshold of the explosion-proof groove 111, the explosion-proof groove 111 ruptures, allowing the gas to be discharged outside the shell 1.

[0078] The explosion-proof groove 111 includes a central groove 1111 and launching grooves 1112. Several launching grooves 1112 are arranged around the central groove 1111 and communicate with the central groove 1111. The ratio between the area of ​​the circumscribed circle corresponding to the central groove 1111, the area of ​​the through hole 851, and the end face area of ​​the second end of the cylinder body 51 is 1:0.8:1.5. This ratio can ensure the smooth flow of the pressure relief channel and avoid short circuits caused by direct contact between the collecting cylinder 5 and the bottom wall 11.

[0079] See Figure 7 As shown, the thickness of the bottom wall 11 in the explosion-proof groove 111 is Tx, and the value of Tx has at least one continuously varying range and / or one discontinuously varying range. That is, the thickness of the bottom wall 11 at the central groove 1111 and the emission groove 1112 is Tx, and the value of Tx has at least one continuously varying range and / or one discontinuously varying range. When the internal pressure of the battery rises rapidly, the bottom wall 11 preferentially ruptures at the region corresponding to the minimum value of Tx to form a pressure relief port. Then, the part connected to this region is sequentially expanded under the impact of the gas, so that the opening area of ​​the pressure relief port gradually increases, further improving the gas discharge efficiency, preventing the explosion-proof shell 1 from exploding under the action of high-pressure gas, and improving the safety of the battery.

[0080] It should be noted that, in this application, "continuous change in thickness Tx" refers to a smooth, gradual transition of thickness without interruption during the change process, with minimal thickness differences between adjacent positions and no sudden jumps or interruptions, such as a linear or nonlinear change in thickness. "Discontinuous change in thickness Tx" refers to a sudden and significant jump in thickness at a certain position, with obvious thickness differences between adjacent regions and a clear "boundary," such as a step-like change in thickness.

[0081] The stamping forming process of the explosion-proof groove 111 is stamping from the outer surface of the bottom wall 11 toward the direction where the inner surface of the bottom wall 11 is located. Therefore, the explosion-proof groove 111 forms a groove structure on the outer surface of the bottom wall 11, and forms an inwardly extending protruding structure on the inner surface of the bottom wall 11, and the protruding structure is the aforementioned positioning protrusion 112. The explosion-proof groove 111 formed by stamping has a longitudinal cross-section shape substantially in an "Ji" shape. The explosion-proof structure has safe, efficient and stable pressure relief, can solve the problems of swelling and explosion caused by internal pressure imbalance of the battery, reduces the risk of thermal failure, and improves the safety and stability of the battery. In addition, the structure can also enable external extrusion force and impact force to be preferentially and uniformly dispersed, preventing the casing 1 from deforming.

[0082] In some embodiments, the longitudinal cross-sectional shape of the central groove 1111 is an axisymmetric figure, the thickness of the bottom wall 11 at the axisymmetric center line of the central groove 1111 is the smallest, and the thickness of the bottom wall 11 on one side of the axisymmetric center line of the central groove 1111 has a numerical interval with continuous change and / or a numerical interval with discontinuous change; the longitudinal cross-sectional shape of the emitting groove 1112 is an axisymmetric figure, the thickness of the bottom wall 11 at the axisymmetric center line of the emitting groove 1112 is the smallest, and the thickness of the bottom wall 11 on one side of the axisymmetric center line of the emitting groove 1112 has a numerical interval with continuous change and / or a numerical interval with discontinuous change.

[0083] The thickness of the bottom wall 11 is T1, and the minimum value of Tx is T4, wherein 0.15T1≤T4≤0.50T1. T4 can take values of 0.15T1, 0.2T1, 0.25T1, 0.30T1, 0.35T1, 0.40T1, 0.45T1, 0.50T1, etc., preferably 0.20T1. Further, the outer surface of the bottom wall 11 is provided with a boss 113, the region on the inner surface of the bottom wall 11 corresponding to the boss 113 is a concave portion 114, the explosion-proof groove 111 is located within the outer contour range of the boss 113, wherein T1 is the thickness of the bottom wall 11 in the region corresponding to the boss 113 and the concave portion 114.

[0084] In actual research and development, researchers found that when a lithium-thionyl chloride battery discharges, under the condition that the electrolyte can fully infiltrate the positive electrode member 4, at the end close to the pole post 22, after electrons are generated from the positive electrode member 4, they only need to conduct through a short carbon particle gap to the current collecting cylinder 5, and then reach the pole post 22 through a short path of the current collecting cylinder 5. The whole process has small resistance, low loss, and smoother electron flow, and the positive electrode reaction in the corresponding region is also faster and more sufficient. While the electron flow path at the end far away from the pole post 22 is longer, the resistance is larger, and the efficiency is lower, which leads to relatively lagging reaction of the positive electrode member 4 in this region, and insufficient reaction is prone to occur, so that the positive electrode member 4 has a large temperature difference in the longitudinal direction, which affects the consistency of the discharge capacity of the battery.

[0085] In order to solve the above problems, as Figures 8 to 12 As shown, the cylindrical body 51 is divided into at least two opening regions 510 along its axial direction. Each opening region 510 has multiple holes 5101. The total number of holes 5101 per unit area in each opening region 510 gradually decreases along the axial direction of the cylindrical body 51 from the end closer to the electrode post 22 to the end farther away from the electrode post 22. This can provide "equidistant" electron outflow paths for each region in the longitudinal direction of the positive electrode 4, so that the current is evenly distributed in the positive electrode 4, promotes the overall synchronous reaction of the positive electrode 4, reduces the problem of local overheating or reaction imbalance, and improves the battery discharge performance and consistency.

[0086] Experimental verification shows that, for the optimized design of discharge performance, arranging the holes 5101 on the cylinder body 51 in a gradient density layout from top to bottom along the axial direction can reduce the tortuosity of the electron transport path, provide a low-impedance current path, and reduce the battery's internal resistance by 10% to 15%. Specifically, during the battery discharge process, the sparse hole layout in the lower part of the cylinder body 51 can promote the rapid wetting of the positive electrode 4 by the electrolyte in the initial stage of discharge. When the high current discharge occurs, the dense hole layout in the upper part of the cylinder body 51 can ensure the rapid electron transport in the current region, avoid concentration polarization, achieve temperature uniformity control, reduce the temperature difference, and make the temperature difference less than or equal to 5℃.

[0087] In addition, the holes 5101 on the cylinder body 51 can ensure that the electrolyte penetrates into the positive electrode 4 quickly and evenly. On the one hand, the injected electrolyte can directly enter the contact gap between the current collector 5 and the positive electrode 4 through the holes 5101 on the cylinder body 51, breaking the limitation of slow penetration from the outside of the positive electrode 4 and greatly accelerating the electrolyte wetting speed. On the other hand, the holes 5101 can construct a flow channel for the electrolyte inside the positive electrode 4, avoiding the formation of a "dry area" in the positive electrode 4 due to lack of electrolyte, ensuring that the electrolyte fills the pores of the positive electrode 4 evenly, laying the foundation for the smooth migration of electrons in the subsequent discharge reaction, and at the same time, it can also expel the air in the pores of the positive electrode 4, preventing air bubbles from hindering the electrolyte wetting and reaction.

[0088] Understandably, the number of openings can be determined based on the axial height of the manifold 5, for example, it can be two, three, four, five, etc., and there is no limitation here. In addition, a progressive punching die can be used to ensure that there is no stress concentration in the hole transition area, and the surface of the cylinder body 51 can be treated to reduce the cross-sectional impedance.

[0089] exist Figure 8 In the example shown, the cylindrical body 51 is divided into three opening regions along its axial direction. Each opening region 510 has multiple holes 5101. The total number of holes 5101 per unit area in each opening region 510 gradually decreases from top to bottom along the axial direction of the cylindrical body 51. This gradient mesh layout can make the current density distribution uniformity of the upper part of the cylindrical body 51 greater than or equal to 90%.

[0090] exist Figures 9 to 12 In the example shown, the cylindrical body 51 is divided into two opening regions 510 along its axial direction. Each opening region 510 has multiple holes 5101. The opening region 510 adjacent to the lithium-ion battery and close to its terminal post 22 is called the first opening region 511, and the other opening region 510 is called the second opening region 512. The hole 5101 in the first opening region 511 is called the first hole 5111, and the hole 5101 in the second opening region 512 is called the second hole 5121.

[0091] In some embodiments, the ratio between the area of ​​the first opening region 511 and the area of ​​the second opening region 512 ranges from 0.3 to 1. In other embodiments, the ratio between the area of ​​the first opening region 511 and the area of ​​the second opening region 512 ranges from 0.5 to 0.9. For example, Figure 9 In the example shown, the ratio between the area of ​​the first opening region 511 and the area of ​​the second opening region 512 is approximately 1. Figures 10 to 12 In the example shown, the ratio between the area of ​​the first opening region 511 and the area of ​​the second opening region 512 is approximately 0.5. In other cases, the ratio can also be 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, etc. This ratio design can enhance the structural strength of the cylinder body 51 while strengthening the current collection point, improving the uniformity of the discharge reaction, and thus improving the consistency of the battery's discharge capacity.

[0092] In some embodiments, the apertures of the holes 5101 in each opening region can be the same or different. During design, the main considerations are the relationship between the number of holes per unit area, the structural strength of the cylinder body 51 itself, and the influence of the opening ratio on the resistance of the cylinder body 51. For example, Figures 9 to 10 In the example shown, the first hole 5111 and the second hole 5121 have the same diameter. Figures 11 to 12 In the example shown, the diameters of the first hole 5111 and the second hole 5121 are different.

[0093] In some embodiments, preferably, the area of ​​a single first hole 5111 is not greater than the area of ​​a single second hole 5121. For example, Figures 8 to 10 In the example shown, the area of ​​a single first hole 5111 is equal to the area of ​​a single second hole 5121. Figures 11 to 12In the example shown, the area of ​​a single first hole 5111 is smaller than the area of ​​a single second hole 5121. When the area of ​​a single first hole 5111 is smaller than the area of ​​a single second hole 5121, the opening ratio within the first opening region 511 is less than the opening ratio within the second opening region 512, where the opening ratio = (area of ​​a single hole × total number of openings per unit area) ÷ unit area × 100%.

[0094] In some embodiments, the arrangement of the first holes 5111 in the first opening region 511 may be the same as or different from the arrangement of the second holes 5121 in the second opening region 512.

[0095] for example, Figures 8 to 11 In the example shown, the arrangement of the first holes 5111 in the first opening area 511 is as follows: all the first holes 5111 on the circumference at the same axial height of the cylinder body 51 form a group of first holes. Multiple groups of first holes are spaced apart along the axial direction of the cylinder body 51, and the first holes 5111 in adjacent groups of first holes correspond one-to-one. The arrangement of the second holes 5121 in the second opening area 512 is as follows: all the second holes 5121 on the circumference at the same axial height of the cylinder body 51 form a group of second holes. Multiple groups of second holes are spaced apart along the axial direction of the cylinder body 51, and the second holes 5121 in adjacent groups of second holes correspond one-to-one.

[0096] Figure 12 In the example shown, all the first holes 5111 on the circumference at the same axial height of the cylinder body 51 form a group of first holes. Multiple groups of first holes are spaced apart along the axial direction of the cylinder body 51, and the first holes 5111 in adjacent groups of first holes are staggered. All the second holes 5121 on the circumference at the same axial height of the cylinder body 51 form a group of second holes. Multiple groups of second holes are spaced apart along the axial direction of the cylinder body 51, and the second holes 5121 in adjacent groups of second holes are staggered.

[0097] In some embodiments, the diameter of the cylindrical body 51 ranges from 9.5mm to 11mm, such as 9.5mm, 10mm, 10.5mm, 11mm, etc.; the height of the cylindrical body 51 in its axial direction ranges from 32mm to 40mm, such as 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, etc.; the diameter of the first hole 5111 ranges from 1mm to 2.5mm, such as 1mm, 1.5mm, etc. The diameter of the second hole 5121 ranges from 1mm to 2.5mm, for example, 1mm, 1.5mm, 2.0mm, 2.5mm, 3mm, etc.; the minimum distance between adjacent first holes 5111 is 1mm to 3mm, for example, 1mm, 1.5mm, 2.0mm, 2.5mm, etc.; the minimum distance between adjacent second holes 5121 is 4mm to 6mm, for example, 4mm, 4.5mm, 5.0mm, 5.5mm, 6mm, etc.

[0098] like Figure 13 As shown, the limiting structure 52 includes an annular bottom wall 521 and an outer annular side wall 522. The annular bottom wall 521 is approximately parallel to and abuts against the end face of the positive electrode 4. A middle spacer 84 is provided between the annular bottom wall 521 and the end face of the positive electrode 4. The outer annular side wall 522 is connected to the outer periphery of the annular bottom wall 521 and extends away from the positive electrode 4. The free end of the outer annular side wall 522 is spaced apart from the top cover 21. On the one hand, the annular bottom wall 521 is approximately parallel to the end face of the positive electrode 4, which can better abut against the upper end face of the positive electrode 4 and flatten the upper end face of the positive electrode 4. On the other hand, the outer annular side wall 522 extends away from the positive electrode 4, and the outer annular side wall 522 can abut against the inner surface of the top cover 21 to achieve longitudinal constraint and limiting of the positive electrode 4.

[0099] To facilitate rapid wetting of the positive electrode 4 by the electrolyte, a dispersion groove 5211 is provided on the annular bottom wall 521 (see...). Figure 2 When the electrolyte is injected, as it flows into the annular bottom wall 521, it can flow to the positive electrode 4 through the dispersion slots 5211, improving the efficiency of electrolyte wetting of the positive electrode 4. Furthermore, the dispersion slots 5211 can reduce the duty cycle of the annular bottom wall 521, increasing the electrolyte capacity per unit space and improving battery performance. Understandably, while ensuring the structural strength of the annular bottom wall 521, the more dispersion slots 5211, the better.

[0100] When the elastic part 5202 is a rubber component, the free end of the outer ring sidewall 522 is fitted with a rubber component, which has a support protrusion 52021 protruding towards the top cover 21. This design ensures, on the one hand, that the contact between the outer ring sidewall 522 and the top cover 21 is an insulated contact, and on the other hand, the support protrusion 52021 of the rubber component can deform under force. When the positive electrode 4 expands longitudinally and the rubber component on the limiting structure 52 abuts against the inner surface of the top cover 21, the elastic deformation of the rubber component can generate a certain longitudinal limiting force on the positive electrode 4 and provide a certain space margin for the expansion of the positive electrode 4, avoiding stress accumulation inside the positive electrode 4 and ensuring that the positive electrode 4 can discharge normally.

[0101] In some embodiments, the cross-sectional area of ​​the support protrusion 52021 gradually increases from its top to its bottom, which enables the pressure provided per unit compression to gradually increase.

[0102] In some embodiments, the minimum gap between the rubber component and the top cover 2 is 0 to 1.4 mm. When the inner surface of the top cover 21 is provided with a first insulating sheet 83, the minimum gap between the rubber component and the first insulating sheet 83 is 0 to 1.2 mm, providing a certain space allowance for the longitudinal deformation of the positive electrode component 4.

[0103] In some embodiments, the minimum distance between the outer periphery of the outer ring sidewall 522 and the sidewall 12 is 2 mm to 3 mm, and the outer ring sidewall 522 and the sidewall 12 are blocked by a side diaphragm 81, which can play an insulating protection role.

[0104] The cylindrical body 51 has a connecting portion 513, which extends out of the annular bottom wall 521 and is fixedly connected to the annular bottom wall 521. Its end face is lower than the outer annular side wall 522. The connecting portion 513 is electrically connected to the terminal post 22 of the lithium-ion battery. In some embodiments, the connecting portion 513 is electrically connected to the terminal post 22 via a tab 6.

[0105] The diameter of the end of the connecting part 513 furthest from the positive electrode 4 is smaller than the diameter of the other end. This design, which is smaller at the top and larger at the bottom, can reduce the probability of welding slag and other debris falling into the collector cylinder 5 during the subsequent assembly of the top cover 21. It can also facilitate the welding and fixing of the electrode tab 6 to the outer surface of the inner ring wall 523, providing a more convenient working surface for welding operations.

[0106] Based on the lithium-ion battery provided above, this application also provides a lithium-ion battery assembly process for assembling the aforementioned lithium-ion battery, such as... Figure 14 As shown, it includes the following steps:

[0107] Insert the bottom diaphragm 82 into the housing 1;

[0108] The negative electrode 3 is installed into the housing 1 and attached to the side wall 12 of the housing 1;

[0109] The side diaphragm 81 is inserted into the housing 1 and attached to the inner surface of the negative electrode 3;

[0110] Insert the second insulating sheet 85 into the housing 1;

[0111] The positive electrode 4 is installed into the housing 1 and attached to the inner surface of the side diaphragm 81;

[0112] The current collector 5 is installed into the housing 1. The cylinder body 51 of the current collector 5 is inserted into the center hole of the positive electrode 4 and positioned and engaged with the bottom wall 11 of the housing 1 through the second insulating sheet 85 and the bottom diaphragm 82, and the limiting structure 52 of the current collector 5 abuts against the end face of the positive electrode 4.

[0113] Connect the top cover assembly 2 to the collector cylinder 5 electrically, and seal the top cover assembly 2 at the opening of the housing 1.

[0114] In some embodiments, during the assembly of the collector cylinder 5, a mechanical pressing method is used to position and engage the positioning groove 5100 of the cylinder body 51 with the positioning protrusion 112 of the bottom wall 11, and to flatten the end face of the positive electrode 4 with the limiting structure 52, so as to ensure that the positioning groove 5100 of the cylinder body 51 and the positioning protrusion 112 of the bottom wall 11 can be positioned and engaged, and at the same time, the limiting structure 52 flattens the upper end face of the positive electrode 4, ensuring that the entire positive electrode 4 is stably installed. For example, the positioning groove 5100 of the cylinder body 51 and the positioning protrusion 112 of the bottom wall 11 are mechanically pressed and assembled with a 0.1mm thick second insulating sheet 85 as a barrier, and the positive electrode 4 is tightly fitted to the annular bottom wall 521 of the limiting structure 52 under a pressure of 3 MPa.

[0115] In some embodiments, before the manifold 5 is installed into the housing 1, one end of the tab 6 is welded to the limiting structure 52. The inner ring wall 523 of the limiting structure 52 and the tab 6 are laser welded together, which can ensure both electrical connection and connection stability.

[0116] Before assembling the top cover assembly 2, the first insulating sheet 83 is first assembled on the inner surface of the top cover 21, and then the pole post 22 of the top cover assembly 2 is electrically connected to the pole tab 6.

[0117] Furthermore, during the electrical connection between the current collector 5 and the top cover assembly 2, the other end of the tab 6 is welded to the pole post 22 of the top cover assembly 2. The tab 6 and the pole post 22 are laser welded, which ensures both electrical connection and connection stability.

[0118] like Figure 15 As shown, taking a lithium-thionyl chloride battery as an example, experiments were conducted using one embodiment and a pair of proportions to analyze the effectiveness of the technical solution of this application.

[0119] In this embodiment: the shell 1 is made of stainless steel using an integral stamping process, and the bottom wall 11 of the shell 1 is stamped to form an explosion-proof groove 111. The minimum thickness of the bottom wall 11 at the explosion-proof groove 111 is 0.15mm, and the valve opening pressure is set to 3.2MPa. The manifold 5 is made of stainless steel in one piece, and the holes 5101 on the cylinder body 51 are processed by a progressive punching die. The diameter of the first hole 5111 in the first opening area 511 is 1.5mm, and the spacing is 2mm; the diameter of the second hole 5121 in the second opening area 512 is 1.5mm, and the spacing is 6mm. The height of the limiting structure 52 in the axial direction of the cylinder body 51 is 2.7mm, and the diameter is 16mm. It is annealed at 230℃ for 2 hours to relieve stress. During the test, the cylinder body 51 of the current collector 5, together with the shell 1, provides lateral limiting support and lateral constraint for the positive electrode 4. The limiting structure 52, together with the top cover 21, provides longitudinal limiting support and longitudinal constraint for the positive electrode 4. The surface of the positive electrode 4 expands uniformly, and the measured expansion non-uniformity is reduced by 40%. The voltage plateau fluctuation at the end of the battery discharge is reduced to ±50mV. At the same time, the consistency of discharge performance is improved, and the deviation of the room temperature discharge capacity of the same batch of batteries is reduced from 5% to 1%.

[0120] Comparative Example: The main difference between this example and the embodiment is that the current collector 5 only includes the cylinder body 51 and does not include the limiting structure 52; the holes 5101 on the cylinder body 51 are evenly distributed, all holes 5101 have a diameter of 1.5 mm and a spacing of 3 mm. The cylinder body 51 and the bottom wall 11 are separated by a common insulating sheet, which has no central hole design. During the test, the battery's pressure relief path was restricted. When the valve opening pressure reached the threshold, some batteries failed to open the valve normally, and some batteries had an extended valve opening response time. Moreover, the positive electrode 4 expanded unevenly, with significant protrusions at its edges. The measured expansion unevenness deviation was 38%. Under the same discharge conditions, the room temperature discharge capacity deviation increased to 5.2%, and the voltage plateau fluctuation at the end of the battery discharge was ±330 mV.

[0121] Based on the above experimental analysis, the collaborative design of this application significantly improves the high-current discharge performance and temperature uniformity of the battery while ensuring safety. Those skilled in the art can make adaptive adjustments to material parameters, structural dimensions, etc., according to actual needs, without departing from the core concept of this invention.

[0122] Obviously, the above embodiments of this application are merely examples for clear illustration and are not intended to limit the implementation of this application. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A current collector for lithium-ion batteries, characterized in that, The manifold includes: The cylinder body (51) is configured to insert the positive electrode (4) of the lithium-ion battery. The limiting structure (52) includes an abutment portion (5201) and an elastic portion (5202) connected to the abutment portion (5201). The abutment portion (5201) is fixedly connected to the cylindrical body (51) and abuts against the end face of the positive electrode (4) of the lithium-ion battery. The elastic portion (5202) is configured to abut against the top cover (21) of the lithium-ion battery after the positive electrode (4) expands. In the radial direction of the cylindrical body (51), the limiting structure (52) is configured to be spaced apart from the sidewall (12) of the housing (1) of the lithium-ion battery.

2. The manifold according to claim 1, characterized in that, The abutting portion (5201) includes an annular bottom wall (521) and an outer annular side wall (522) connected to the outer edge of the annular bottom wall (521). The annular bottom wall (521) is configured to abut against the end face of the positive electrode (4). The outer annular side wall (522) is connected to the elastic portion (5202).

3. The manifold according to claim 2, characterized in that, The annular bottom wall (521) is provided with a dispersion groove (5211).

4. The manifold according to claim 2, characterized in that, The cylindrical body (51) has a connecting part (513) that extends out of the annular bottom wall (521) and is fixedly connected to the annular bottom wall (521), and its end face is lower than the outer annular side wall (522). The connecting part (513) is configured to be electrically connected to the terminal (22) of the lithium-ion battery.

5. The collector cylinder according to claim 4, characterized in that, The diameter of the end of the connecting part (513) away from the positive electrode (4) is smaller than the diameter of the other end.

6. The manifold according to any one of claims 1-5, characterized in that, When the elastic part (5202) is a material elastic part (5202), the abutting part (5201) and the cylindrical body (51) are integrally formed metal structures, and the elastic part (5202) is detachably installed on the abutting part (5201); or When the elastic part (5202) is a structural elastic part (5202), the manifold is an integrally formed metal structure.

7. The manifold according to any one of claims 2-5, characterized in that, The elastic part (5202) is a rubber component, and the free end of the outer ring sidewall (522) is fitted with a rubber component, which has a support protrusion (52021) protruding towards the top cover (21).

8. The collector cylinder according to claim 7, characterized in that, The cross-sectional area of ​​the support protrusion (52021) gradually increases from its top to its bottom.

9. The collector cylinder according to claim 7, characterized in that, The minimum distance between the rubber component and the top cover (21) is 0 to 1.4 mm; and / or The minimum distance between the outer ring sidewall (522) and the sidewall (12) of the housing (1) is 2 mm to 3 mm.

10. The manifold according to claim 7, characterized in that, The cylindrical body (51) is divided into at least two opening regions (510) along its axial direction. Each opening region (510) has multiple holes (5101). The total number of holes per unit area in each opening region (510) gradually decreases along the axial direction of the cylindrical body (51) from one end close to the electrode post (22) of the lithium-ion battery to the other end away from the electrode post (22).

11. The manifold according to claim 10, characterized in that, There are two opening regions (510). The opening region (510) adjacent to the lithium-ion battery and close to its terminal post (22) is called the first opening region (511), and the other opening region (510) is called the second opening region (512). The hole (5101) of the first opening region (511) is called the first hole (5111), and the hole (5101) of the second opening region (512) is called the second hole (5121).

12. The manifold according to claim 11, characterized in that, The ratio between the area of ​​the first opening region (511) and the area of ​​the second opening region (512) ranges from 0.3 to 1; and / or The area of ​​a single first hole (5111) is not greater than the area of ​​a single second hole (5121).

13. A lithium-ion battery, characterized in that, include: The shell (1) includes a bottom wall (11) and a side wall (12), the first end of the side wall (12) surrounds the periphery of the bottom wall (11), and the second end forms an opening of the shell (1); The top cover assembly (2) includes a top cover (21) and a pole post (22) installed on the top cover (21), wherein the top cover (21) is sealed at the opening; A positive electrode (4) is disposed inside the housing (1), and the positive electrode (4) has a central hole; According to any one of claims 1-12, the cylinder body (51) of the collector is inserted into the central hole; the first end of the limiting structure (52) of the collector abuts against the end face of the positive electrode (4), and its second end can abut against the top cover (21) after the positive electrode (4) expands; the limiting structure (52) is spaced apart from the side wall (12).

14. The lithium-ion battery according to claim 13, characterized in that, The inner surface of the top cover (21) is covered with a first insulating sheet (83), and the minimum interval between the limiting structure (52) and the first insulating sheet (83) is 0 to 1.2 mm.

15. The lithium-ion battery according to claim 13, characterized in that, The inner surface of the bottom wall (11) has several inwardly protruding positioning protrusions (112), and the cylindrical body (51) has several positioning grooves (5100) that cooperate with the positioning protrusions (112) one by one.

16. The lithium-ion battery according to claim 15, characterized in that, A second insulating sheet (85) is provided between the cylindrical body (51) and the bottom wall (11), and a portion of the second insulating sheet (85) is sandwiched between the positioning protrusion (112) and the positioning groove (5100).

17. The lithium-ion battery according to claim 16, characterized in that, The bottom wall (11) is provided with an explosion-proof groove (111) at a position opposite to the cylinder body (51), and the second insulating sheet (85) is provided with a through hole (851) corresponding to the explosion-proof groove (111).

18. The lithium-ion battery according to claim 17, characterized in that, The explosion-proof groove (111) includes a central groove (1111) and a launching groove (1112). A plurality of launching grooves (1112) are arranged around the central groove (1111) and communicate with the central groove (1111). The ratio between the area of ​​the circumscribed circle corresponding to the central groove (1111), the area of ​​the through hole (851), and the end face area of ​​the second end of the cylindrical body (51) is 1:0.8:1.

5.

19. The lithium-ion battery according to claim 18, characterized in that, The thickness of the bottom wall (11) in the explosion-proof groove (111) is Tx, and the value of Tx has at least a range of values ​​that change continuously and / or a range of values ​​that change discontinuously.

20. The lithium-ion battery according to claim 19, characterized in that, The thickness of the bottom wall (11) is T1, and the minimum value of Tx is T4, wherein 0.15T1≤T4≤0.50T1.

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