Cylindrical battery

Abstract

The cylindrical battery comprises a shell and a roll core, the roll core is located in the shell, and the roll core is provided with a roll core hole; the cylindrical battery further comprises a pressure relief structure and a current collecting plate, the pressure relief structure and the current collecting plate are arranged at the two ends of the shell in the axial direction respectively, the current collecting plate is electrically connected with a tab led out of the roll core, the current collecting plate comprises a protruding part, the protruding part is used for being electrically connected with a pole assembly of the cylindrical battery and provided with a cavity, and the cavity is communicated with the roll core hole. The distance between the surface, facing the roll core, of the protruding part and the end face, facing the current collecting disc, of the negative plate of the roll core is h, the unit is mm, the radial size of the roll core hole is D, and the unit is mm; wherein h / D is equal to 0.2 to 1.8. According to the cylindrical battery, through the reasonable design of the exhaust channel, gas accumulated on the side where the current collecting disc is located during thermal runaway can be smoothly exhausted to the side where the pressure relief structure is located, and the integrity of the posture of the cylindrical battery can be guaranteed.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cylindrical battery. Background Technology

[0002] Currently, when cylindrical batteries experience thermal runaway, the failure to vent gas in a timely manner can lead to the accumulation of flammable gas inside the battery, causing a deflagration that damages the battery's integrity, hinders the thermal management of the entire battery pack, and affects the overall safety of the battery pack.

[0003] With the explosion-proof valve structure of cylindrical batteries becoming increasingly consistent, how to rationally design the internal venting channels of cylindrical batteries to ensure the integrity of the cylindrical battery's posture in the event of thermal runaway has become a technical problem that needs to be solved by those skilled in the art. Utility Model Content

[0004] The purpose of this application is to provide a cylindrical battery in which, through the reasonable design of the exhaust channel, the gas accumulated on the side of the current collector during thermal runaway can be smoothly discharged to the side of the pressure relief structure, which helps to ensure the integrity of the cylindrical battery's posture.

[0005] To solve the above-mentioned technical problems, this application provides a cylindrical battery, which includes a casing and a core, the core being located inside the casing and having a core hole; the cylindrical battery also includes a pressure relief structure and a current collector, the pressure relief structure and the current collector being respectively disposed at two ends of the casing in the axial direction, the current collector being electrically connected to a tab led out from the core, the current collector including a protrusion for electrically connecting to the terminal assembly of the cylindrical battery, the protrusion having a cavity communicating with the core hole, the distance between the surface of the protrusion facing the core and the end face of the negative electrode sheet of the core facing the current collector being h, in mm; the radial dimension of the core hole is D, in mm; wherein, h / D = 0.2~1.8.

[0006] Using the aforementioned cylindrical battery, a protrusion with a cavity is provided in the current collector, which is connected to the core hole. This forms an exhaust channel between the current collector and the core. When thermal runaway occurs in the cylindrical battery, the gas accumulated at the first end inside the casing can be smoothly discharged through the cavity to the core hole and then through the core hole to the end where the pressure relief structure is located. This prevents gas from accumulating at the end of the core facing away from the pressure relief structure, thus avoiding the phenomenon of incomplete battery posture caused by the accumulated gas impacting the relevant structures at the first end of the cylindrical battery. At the same time, limiting the h / D ratio to the range of 0.2 to 1.8 can prevent gas from being unable to be discharged smoothly from the cavity to the core hole, and can also avoid the problem of interference between the tab and the core hole caused by the core hole area being too large. This avoids the problem of the tab blocking the core hole and affecting the exhaust. Attached Figure Description

[0007] Figure 1 This is a structural diagram of a cylindrical battery in one embodiment provided in this application;

[0008] Figure 2 for Figure 1 The diagram shows the structure of the cylindrical battery from another perspective.

[0009] Figure 3 A cross-sectional view of a cylindrical battery in one embodiment provided in this application;

[0010] Figure 4 for Figure 3 A magnified view of a portion of the J1 area;

[0011] Figure 5 for Figure 4 A magnified view of the J2 section;

[0012] Figure 6 This is a schematic diagram of the structure of the core before bending in a specific embodiment;

[0013] Figure 7 This is a schematic diagram of the structure of the core after the tabs are bent and stacked in a specific embodiment.

[0014] Explanation of reference numerals in the attached figures:

[0015] Cylindrical battery 10, first end 101, second end 102;

[0016] Outer shell 11, outer shell 111, outer shell periphery 1111, outer shell bottom 1112, cover 112;

[0017] Core 12, core hole 121, end face 122, tab 123, tab piece 1231;

[0018] Pressure relief structure 13;

[0019] Collector plate 14, protrusion 141, flat plate 1411, peripheral wall 1412, arc transition 14121, through hole 1413, plate 142;

[0020] 15 pole post, 151 groove, 1511 arc-shaped wall section;

[0021] Chamber 1S, gap 2S, spatial region 3S. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Please refer to Figures 1 to 4 , Figure 1This is a structural diagram of a cylindrical battery in one embodiment provided in this application. Figure 2 for Figure 1 The diagram shows the structure of the cylindrical battery from another perspective. Figure 3 This is a cross-sectional view of a cylindrical battery in one embodiment provided in this application. Figure 4 for Figure 3 A magnified view of part J1. This is to clearly illustrate the improvements of this application. Figure 3 Only the casing 11, core 12, pressure relief structure 13, current collector 14, and terminal 15 of the cylindrical battery 10 are shown, while other structures (such as the connection and sealing structure between the terminal 15 and the casing 11) are omitted.

[0024] This embodiment provides a cylindrical battery 10, which includes a housing 11 and a core 12. The core 12 is located inside the housing 11 and has a core hole 121, which is a through hole that penetrates both ends of the core 12.

[0025] The cylindrical battery 10 also includes a pressure relief structure 13 and a current collector 14, which is electrically connected to a tab 123 extending from the core 12. The current collector 14 includes a protrusion 141 for electrical connection to the terminal assembly of the cylindrical battery 10. The protrusion 141 has a chamber 1S that communicates with the core hole 121. The distance between the surface of the protrusion 141 facing the core 12 and the end face 122 of the negative electrode sheet of the core 12 facing the current collector 14 is h. The radial dimension of the core hole 121 is D, where h / D = 0.2~1.8. The units for both the distance h and the radial dimension D are mm.

[0026] The cylindrical battery 10 has a first end 101 and a second end 102 that are axially opposite each other. In the illustrated example, the current collector 14 is located at the first end 101 and the pressure relief structure 13 is located at the second end 102.

[0027] In some embodiments, the pressure relief structure 13 may be an annular groove structure provided on the bottom 1112 of the housing 111. (See reference...) Figure 2 and Figure 3 The pressure relief structure 13 is an annular groove formed by the indentation of the outer surface of the bottom of the shell 1112 towards the first end 101 of the cylindrical battery 10.

[0028] When the cylindrical battery 10 experiences thermal runaway, once the internal pressure of the battery reaches a certain value, the pressure relief structure 13 can burst open, and the gas accumulated inside the battery can be discharged from the bursting position of the pressure relief structure 13 along the core hole 121, so as to ensure the safe use performance of the cylindrical battery 10.

[0029] The cylindrical battery 10 using the above-described embodiment has a protrusion 141 with a chamber 1S in the current collector 14. The chamber 1S communicates with the winding core hole 121, thus forming an exhaust channel between the current collector 14 and the winding core 12. When thermal runaway occurs, the gas accumulated in the first end 101 of the casing 11 can be smoothly discharged through the chamber 1S to the winding core hole 121, and then discharged through the winding core hole 121 to the end where the pressure relief structure 13 is located, preventing gas from accumulating at the end of the winding core 12 facing away from the pressure relief structure 13, thereby avoiding... To prevent the cylindrical battery 10 from being damaged by accumulated gas impacting the related structures (such as the terminal post 15) at the first end 101, thus avoiding incomplete battery posture; at the same time, limiting the h / D ratio to the range of 0.2 to 1.8 can, on the one hand, prevent gas from being unable to smoothly exit from the chamber 1S to the winding hole 121, and on the other hand, avoid the problem of interference between the tab 123 and the winding hole 121 caused by the excessive area of ​​the winding hole 121, thus avoiding the problem of the tab 123 blocking the winding hole 121 and affecting the exhaust.

[0030] In some application examples, the distance h between the surface of the protrusion 141 facing the core 12 and the end face 122 of the negative electrode sheet of the core 12 facing the current collector 14 is 1.5mm to 8.6mm.

[0031] Specifically, the aforementioned distance h can be 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm or 8.6mm.

[0032] In some application examples, the radial dimension D of the core hole 121 is 3.5mm to 8mm.

[0033] Specifically, the radial dimension D of the core hole 121 can be 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm or 8mm.

[0034] In some application examples, the h / D ratio can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 or 1.8.

[0035] In some embodiments, the outer casing 11 includes a housing 111 and a cover 112. The housing 111 is generally cylindrical and includes a periphery 1111 and a bottom 1112. The top of the housing 111 is open to facilitate the assembly of the core 12 of the cylindrical battery 10 and related accessories (e.g., an insulating film covering the core). The cover 112 is connected to the housing 111 and is used to seal the top opening of the housing 111. The housing 111 and the cover 112 are separate structures.

[0036] In other embodiments, the housing 11 may also be a one-piece structure.

[0037] The cylindrical battery 10 also includes terminals 15, and a current collector 14 is electrically connected to the terminals 15. The current collector 14 is used to achieve the electrical connection between the terminals 15 and the tabs 123.

[0038] In practice, the current collector 14 and the electrode tab 123 can be electrically connected by welding, and the current collector 14 and the electrode post 15 can also be electrically connected by welding. Welding has high reliability and is easy to operate.

[0039] In some embodiments, the end face 122 of the negative electrode sheet of the aforementioned core 12 facing the current collector 14 is simply referred to as the end face 122 of the core 12. A spatial region 3S is formed between the end face 122 of the core 12 and the outer casing 11, and the chamber 1S of the protrusion 141 communicates with the spatial region 3S. The spatial region 3S is located between the shell wall of the outer casing 11 at the end where the current collector 14 is located and the core 12. In this way, when the cylindrical battery 10 experiences thermal runaway, the gas located in the spatial region 3S can flow smoothly to the side where the pressure relief structure 13 is located through the chamber 1S and the core 121, and be discharged through the bursting part of the pressure relief structure 13, so as to ensure the safety of the cylindrical battery 10 and reduce the probability of deflagration caused by the inability of gas to be discharged in time.

[0040] As shown in the example in the figure, the space region 3S is located between the end face 122 of the core 12 and the cover 112.

[0041] The end of the protrusion 141 of the collector plate 14 facing the core 12 is an open end. There is a gap between the end face of the collector plate 14 facing the core 12 and the core 12. The chamber 1S of the protrusion 141 can communicate with the space region 3S through this gap.

[0042] In some embodiments, the protrusion 141 has an axial dimension of 1mm to 6mm in the cylindrical battery 10. This arrangement increases the overall exhaust space and prevents hot gases from pushing open the side where the protrusion 141 is located, thus avoiding serious safety accidents.

[0043] Specifically, the axial dimension of the protrusion 141 on the cylindrical battery 10 can be 1mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm or 6mm.

[0044] In some embodiments, the inner diameter of the chamber 1S of the protrusion 141 can be larger than the aperture D of the core hole 121. In this way, when thermal runaway occurs, it is convenient to introduce the gas in the space region 3S into the chamber 1S and discharge it through the core hole 121.

[0045] In some embodiments, the protrusion 141 of the current collector 14 includes a flat plate portion 1411 and a peripheral wall portion 1412 located on the outer periphery of the flat plate portion 1411. The flat plate portion 1411 and the peripheral wall portion 1412 enclose a cavity 1S, and the peripheral wall portion 1412 is provided with at least one through hole 1413. In this way, when the cylindrical battery 10 experiences thermal runaway, the gas accumulated in the space region 3S can flow into the cavity 1S through the through hole 1413 and be discharged through the core hole 121. This can accelerate the discharge of the gas accumulated in the space region 3S, reduce the probability of the cylindrical battery 10 exploding due to excessive gas accumulation inside, and help ensure the integrity of the cylindrical battery 10's attitude during thermal runaway.

[0046] In some embodiments, the peripheral wall portion 1412 of the protrusion 141 may be provided with a plurality of through holes 1413, which may be evenly distributed along the circumference of the peripheral wall portion 1412. In this way, the gas in the space region 3S can be discharged more quickly through the chamber 1S to the core hole 121, while avoiding deflagration caused by excessive gas accumulation in some areas.

[0047] The area of ​​the through hole 1413 can be set reasonably. The area of ​​the through hole 1413 should not be too large, so as to avoid the gas impacting the manifold 14 and affecting the structure of the chamber 1S. The area of ​​the through hole 1413 should not be too small, so as to avoid affecting the smoothness of exhaust.

[0048] In application, the ratio of the sum of the areas of the through holes 1413 provided in the peripheral wall portion 1412 to the surface area of ​​the peripheral wall portion 1412 is 0.01 to 0.6.

[0049] Specifically, the ratio of the sum of the areas of each through hole 1413 to the surface area of ​​the peripheral wall portion 1412 can be 0.01, 0.02, 0.05, 0.07, 0.1, 0.13, 0.16, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, or 0.6.

[0050] In actual setup, the area of ​​the through hole 1413 can be set by combining the number and arrangement of the through holes 1413 and the venting requirements of the cylindrical battery 10, and can be determined through simulation or experiment.

[0051] Please refer to this as well. Figure 5 , Figure 5 for Figure 4 A magnified view of the J2 section.

[0052] In some embodiments, the pole piece 15 has a recessed portion 151, and at least a portion of the protrusion 141 of the collector plate 14 is embedded in the recessed portion 151. In this way, the positions of the collector plate 14 and the pole piece 15 can be defined, which facilitates the assembly of the collector plate 14 and the pole piece 15.

[0053] For example, the flat plate portion 1411 of the collector plate 14 can be attached to and welded to the bottom wall of the groove portion 151 to ensure the electrical connection effect between the collector plate 14 and the pole post 15.

[0054] A gap 2S exists between the groove sidewall of the groove portion 151 and the peripheral wall portion 1412 of the protrusion portion 141, and the through hole 1413 of the peripheral wall portion 1412 can communicate with the gap 2S. With this arrangement, during exhaust, the gas located in the space region 3S can enter the chamber 1S through the gap 2S and the through hole 1413, and then be discharged to the core hole 121. This avoids the gas from being obstructed from flowing to the chamber 1S through the through hole 1413 due to the cooperation between the protrusion portion 141 and the groove portion 151, and ensures that the gas located in the space region 3S can be smoothly discharged through the chamber 1S and the core hole 121.

[0055] The size of the 2S gap can be set according to the actual exhaust needs; no specific value is specified here.

[0056] In a specific implementation, the groove sidewall of the groove portion 151 includes an arc-shaped wall section 1511, and the peripheral wall portion 1412 of the protrusion portion 141 has an arc-shaped transition portion 14121 at the end away from the flat plate portion 1411. The aforementioned gap 2S is located between the arc-shaped wall section 1511 and the arc-shaped transition portion 14121. Thus, the airflow channel between the spatial region 3S and the through hole 1413 has an arc-shaped transition channel structure between the groove portion 151 and the protrusion portion 141. When gas flows from the spatial region 3S to the gap 2S, there is no significant bend, and the gas can flow relatively smoothly from the spatial region 3S to the through hole 1413. In other words, the coordinated arrangement of the arc-shaped wall section 1511 and the arc-shaped transition portion 14121 reduces the flow resistance of gas flowing to the through hole 1413, facilitating rapid gas discharge in the event of thermal runaway.

[0057] Please refer to this as well. Figure 6 and Figure 7 , Figure 6 This is a schematic diagram of the core electrode tab before it is bent in a specific embodiment. Figure 7 This is a schematic diagram of the structure of the core after the tabs are bent and stacked in a specific embodiment.

[0058] The tabs 123 of the cylindrical battery 10 are led out from the end face of the core 12. Specifically, the core 12 includes multiple electrode winding layers, and at least some of the electrode winding layers have tabs leading out. The tabs 123 include multiple layers of tabs 1231, which are stacked after being bent at the end of the core 12.

[0059] In applications, the thickness of the single-layer tab 1231 is 4μm to 20μm, for example, it can be 4μm, 5μm, 7μm, 8μm, 10μm, 12μm, 16μm, 18μm or 20μm. The thickness of the tab 1231 affects the overall thickness of the tab 123, and also affects the distance h between the surface of the protrusion 141 facing the core 12 and the end face 122 of the core 12. By setting the thickness of the tab 1231, h can be reasonably controlled, which is conducive to the smooth discharge of gas in the event of thermal runaway.

[0060] In applications, the maximum thickness t of the tab 123 formed by bending and stacking multiple tabs 1231 is (marked on) Figure 7 The thickness of the tab 123 can be 0.2mm to 2mm. For example, the maximum thickness of the tab 123 can be 0.2mm, 0.3mm, 0.4mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm or 2mm.

[0061] In applications, the lead-out length L of the single-layer tab 1231 is 2mm~12mm. The lead-out length L of the single-layer tab 1231 affects the overall thickness of the tab 123 and the connection stability between the tab 123 and the collector plate 14. This affects the distance h between the surface of the protrusion 141 facing the core 12 and the end face 122 of the core 12. h can be reasonably controlled by setting the lead-out length L of the tab 1231 to facilitate the smooth discharge of gas during thermal runaway.

[0062] Figure 6 Three monolayer tabs 1231 with different lead-out lengths are illustrated in the example.

[0063] Specifically, the lead-out length L of the single-layer tab 1231 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm or 12mm.

[0064] The core 12 of the cylindrical battery 10 includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. At the end of the core 12 facing the current collector 14, i.e., at the first end 101 of the cylindrical battery 10, the separator of the core 12 extends beyond the negative electrode by 0.5~2mm. This arrangement ensures that the separator provides insulation protection between the positive and negative electrodes while preventing the separator from extending too far beyond the negative electrode, which could affect the emission of gas in the space region 3S.

[0065] Specifically, the diaphragm of the core 12 can extend beyond the negative electrode sheet by 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2mm.

[0066] In some embodiments, a portion of the current collector 14 can be electrically connected to the positive electrode tab led out from the positive electrode sheet of the core 12, and another portion can be electrically connected to the electrode post, in which case the electrode post serves as the positive output terminal.

[0067] In some embodiments, a portion of the collector plate 14 can be electrically connected to the negative electrode tab led out from the negative electrode sheet of the core 12, and another portion can be electrically connected to the electrode post, in which case the electrode post serves as the negative output terminal.

[0068] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A cylindrical battery, characterized in that, The cylindrical battery includes a casing and a core, the core being located inside the casing and having a core hole. The cylindrical battery also includes a pressure relief structure and a current collector, the pressure relief structure and the current collector being located at opposite ends of the casing in the axial direction. The current collector is electrically connected to a tab extending from the core. The current collector includes a protrusion for electrical connection to the terminal assembly of the cylindrical battery. The protrusion has a chamber communicating with the core hole. The distance between the surface of the protrusion facing the core and the end face of the negative electrode sheet of the core facing the current collector is h (in mm). The radial dimension of the core hole is D (in mm); where h / D = 0.2~1.

8.

2. The cylindrical battery according to claim 1, characterized in that, The protrusion has an axial dimension of 1mm to 6mm in the cylindrical battery.

3. The cylindrical battery according to claim 1, characterized in that, The tabs comprise multiple layers of tab sheets distributed radially, and the maximum thickness of the tabs in the axial direction of the cylindrical battery is 0.2 mm to 2 mm.

4. The cylindrical battery according to claim 1, characterized in that, The electrode tabs include multiple layers of electrode tabs distributed radially, and the core includes multiple electrode winding layers, with at least a portion of the electrode winding layers having electrode tabs extending out, the extension length of the electrode tabs being 2mm to 12mm.

5. The cylindrical battery according to claim 1, characterized in that, At the end of the winding core facing the current collector, the diaphragm of the winding core extends beyond the negative electrode sheet by 0.5~2mm.

6. The cylindrical battery according to any one of claims 1-5, characterized in that, The protrusion includes a flat plate portion and a peripheral wall portion located on the outer periphery of the flat plate portion. The flat plate portion and the peripheral wall portion enclose the cavity, and the peripheral wall portion is provided with at least one through hole.

7. The cylindrical battery according to claim 6, characterized in that, The peripheral wall portion is provided with a plurality of through holes, which are evenly distributed along the circumference of the peripheral wall portion.

8. The cylindrical battery according to claim 6, characterized in that, The ratio of the sum of the areas of all the through holes to the surface area of ​​the peripheral wall is 0.01 to 0.

6.

9. The cylindrical battery according to claim 6, characterized in that, The cylindrical battery includes a terminal post, the current collector is electrically connected to the terminal post, the terminal post has a groove, at least a portion of the protrusion is embedded in the groove, there is a gap between the groove sidewall and the peripheral wall, and the through hole communicates with the gap.

10. The cylindrical battery according to claim 9, characterized in that, The groove sidewall includes an arc-shaped wall section, and the peripheral wall portion has an arc-shaped transition portion at the end away from the flat plate portion. The gap is located between the arc-shaped transition portion and the arc-shaped wall section.

11. The cylindrical battery according to any one of claims 1-5, characterized in that, A spatial region is formed between the end face of the core facing the collector and the outer shell, and the chamber communicates with the spatial region.

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