Cylindrical battery and battery pack

Abstract

The utility model discloses a cylindrical battery and a battery pack. The cylindrical battery comprises a shell, a roll core, a first cover plate and a first current collector, the roll core comprises a main body part and a plurality of first tab bundles, the plurality of first tab bundles are arranged at the same end of the main body part, each first tab bundle comprises a plurality of tabs, and the first tab bundles are distributed in the circumferential direction of the main body part at intervals; the first current collecting piece comprises a flow guide part and a plurality of first welding parts, the first welding parts are arranged on the peripheral side of the flow guide part at intervals, each first welding part is correspondingly and electrically connected with one first tab bundle, the first cover plate is provided with a filling through hole, and the flow guide part and the filling through hole are oppositely arranged; an infiltration space is defined by the shell, the main body part, the first cover plate and the two adjacent first tab bundles; the flow guide part is used for guiding the electrolyte to flow towards the infiltration space. And the flow direction of the electrolyte is changed by arranging the flow guide part, so that the electrolyte flows towards the infiltration space, full contact between the electrolyte and the end part of the main body part is ensured, and the infiltration efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a cylindrical battery and a battery pack. Background Art

[0002] With the development of battery technology, cylindrical batteries are widely used. After the cylindrical battery is assembled, the electrolyte will be injected through the injection hole on the cover plate, and the electrolyte will penetrate into the diaphragm of the core through the gaps at both ends of the core. In actual operation, the end of the core is in close contact with the cover plate, and the electrolyte is difficult to penetrate, and the electrolyte cannot evenly cover the end of the core, resulting in uneven wetting of the core and low wetting efficiency, affecting the performance and service life of the entire battery cell.

[0003] Therefore, it is necessary to improve the existing technology. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art and provides a cylindrical battery and a battery pack.

[0005] According to one aspect of the present application, the present application provides a cylindrical battery having an axial direction and a radial direction perpendicular to each other, the cylindrical battery comprising a shell, a winding core, a first cover plate and a first current collector; the winding core is accommodated in the shell, the winding core comprises a main body and a plurality of first pole tab bundles, the plurality of first pole tab bundles are arranged at the same end of the main body in the axial direction, each of the first pole tab bundles comprises a plurality of pole tabs arranged along the radial direction, and each of the first pole tab bundles is spaced apart along the circumferential direction of the main body; the first cover plate is provided on the end of the shell close to the first pole tab bundle; the first current collector comprises a guide portion and a plurality of first welding portions, each of the first welding portions is spaced apart on the circumferential side of the guide portion, each of the first welding portions is electrically connected to a corresponding first pole tab bundle, the first cover plate has a filling through hole, the guide portion is arranged opposite to the filling through hole; the shell, the main body, the first cover plate and two adjacent first pole tab bundles enclose a wetting space; the guide portion is used to guide the electrolyte injected from the filling through hole to flow toward the wetting space.

[0006] Furthermore, the guide portion, the first cover plate, and ends of two adjacent first welding portions close to the guide portion together form a connecting channel, and the connecting channel connects the filling through hole and the infiltration space.

[0007] Optionally, the guide portion and the first cover plate are spaced apart from each other in the axial direction.

[0008] Furthermore, the guide portion has a first surface and a second surface which are opposite to each other in the axial direction, and a side wall connected between the outer edges of the first surface and the second surface, and the filling hole has a hole wall; in the radial direction, the side wall is spaced apart from the hole wall, and the side wall is at least partially arranged opposite to the hole wall.

[0009] Furthermore, the side wall includes a first sub-wall and a second sub-wall, the second sub-wall is connected to the side of the first sub-wall away from the first cover plate, the first sub-wall is arranged opposite to the hole wall, and the circumference of the second sub-wall gradually increases in the direction approaching the main body to guide the electrolyte injected from the filling through hole to flow toward the infiltration space.

[0010] Furthermore, the guide portion has a guide protrusion facing the first cover plate; in the axial direction, the size of the guide protrusion gradually increases from the outer edge of the guide portion to the center of the guide portion.

[0011] Furthermore, a first mounting groove is formed on a side of the first cover plate facing the main body, and the first welding portion is embedded in the first mounting groove to fix the relative position of the first welding portion and the first cover plate in the circumferential direction.

[0012] Furthermore, the number of the first tab bundles is N, satisfying: 3≤N≤24.

[0013] Furthermore, the winding core also includes a plurality of second pole lug bundles, which are arranged at the end of the main body away from the first pole lug bundles, each of the second pole lug bundles includes a plurality of pole lugs arranged along the radial direction, and each of the second pole lug bundles is distributed at intervals along the circumference of the main body.

[0014] Furthermore, the cylindrical battery also includes a second cover plate and a second current collector, the second cover plate is arranged on the end of the shell close to the second pole lug bundle, the second current collector includes a connecting portion and a plurality of second welding portions, each of the second welding portions is arranged at intervals on the circumference of the connecting portion, and each of the second welding portions is connected to a corresponding second pole lug bundle.

[0015] Furthermore, a second mounting groove is formed on one side of the second cover plate facing the main body, and the second welding portion is embedded in the second mounting groove to fix the relative position of the second welding portion and the second cover plate in the circumferential direction.

[0016] Further, a size of the second welding portion in the axial direction is smaller than a size of the second mounting groove in the axial direction.

[0017] Furthermore, in the axial direction, the main body has a third surface and a fourth surface opposite to each other; the ratio of the orthographic projection area of ​​the first tab bundle on the plane where the third surface is located to the area of ​​the third surface is η, satisfying: 10%≤η≤90%.

[0018] According to another aspect of the present application, a battery pack is provided, comprising any of the cylindrical batteries described above.

[0019] The beneficial effect of the present application is as follows: the present application changes the flow direction of the electrolyte filled from the filling through hole by setting the guide part, so that the electrolyte flows toward the infiltration space, ensuring that the electrolyte is in full contact with the end of the main body, thereby improving the infiltration efficiency. At the same time, the setting of the guide part can divert the electrolyte to multiple infiltration spaces, ensuring the uniformity of the infiltration and improving the infiltration effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0021] Figure 1 is a cross-sectional view of a cylindrical battery provided in one embodiment of the present application.

[0022] Figure 2 yes Figure 1 An enlarged view of an embodiment at A in the middle.

[0023] Figure 3 yes Figure 1 An enlarged view of another embodiment at A in the middle.

[0024] Figure 4 It is a schematic diagram of the internal structure of a cylindrical battery provided in one embodiment of the present application.

[0025] Figure 5 It is a structural schematic diagram of the first cover plate and the first current collecting member in one embodiment of the present application.

[0026] Figure 6 yes Figure 5 Schematic diagram from another perspective.

[0027] Figure 7 yes Figure 6 An enlarged view of an embodiment at B in the figure.

[0028] Figure 8 Schematic diagram of a winding core provided in one embodiment of the present application.

[0029] Fig. 9 It is a structural schematic diagram of the second cover plate and the second current collecting member in one embodiment of the present application.

[0030] Fig.10 It is a cross-sectional view of a cylindrical battery provided in another embodiment of the present application.

[0031] Fig.11 yes Fig.10 An enlarged view of an embodiment at C in the middle.

[0032] Fig.12 It is a structural schematic diagram of the first cover plate and the first current collecting member in another embodiment of the present application.

[0033] Fig.13 yes Fig.12 An enlarged view of an embodiment at D in the middle.

[0034] Fig.14 yes Fig.12 Schematic diagram from another perspective.

[0035] In the figure:

[0036] 10. Shell;

[0037] 20, winding core; 21, main body; 211, center hole; 212, third surface; 213, fourth surface; 22, first pole lug bundle; 23, second pole lug bundle;

[0038] 30. Infiltrate space;

[0039] 40. first cover plate; 41. filling through hole; 411. hole wall; 42. first mounting groove;

[0040] 50, first current collecting member; 51, first welding portion; 52, flow guiding portion; 521, first surface; 522, second surface; 523, side wall; 5231, first sub-wall; 5232, second sub-wall; 524, flow guiding protrusion;

[0041] 60. Connecting channel;

[0042] 70. second cover plate; 71. second mounting groove;

[0043] 80. Second current collecting member; 81. Second welding portion; 82. Connecting portion. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0045] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] In order to solve the technical problems of poor electrolyte infiltration effect and low infiltration rate in the prior art, an embodiment of the present application provides a cylindrical battery, having an axial direction and a radial direction perpendicular to each other, wherein the cylindrical battery comprises a shell, a winding core, a first cover plate and a first current collecting member; the winding core is accommodated in the shell, the winding core comprises a main body and a plurality of first pole lug bundles, the plurality of first pole lug bundles are arranged at the same end of the main body in the axial direction, each of the first pole lug bundles comprises a plurality of pole lugs arranged along the radial direction, and each of the first pole lug bundles is spaced apart along the circumference of the main body; the first cover plate The plate cover is arranged at the end of the shell body close to the first pole lug bundle; the first current collector includes a guide part and a plurality of first welding parts, each of the first welding parts is arranged at intervals around the guide part, each of the first welding parts is electrically connected to a corresponding first pole lug bundle, the first cover plate has a filling through hole, and the guide part is arranged opposite to the filling through hole; the shell body, the main body, the first cover plate and the two adjacent first pole lug bundles enclose a wetting space; the guide part is used to guide the electrolyte injected from the filling through hole to flow toward the wetting space. The following is a detailed description.

[0047] See also Figure 1 , Figure 2 and Figure 4 In one embodiment, the cylindrical battery has mutually perpendicular axes (such as Figures 1 to 3 , Figure 8 , Fig.10 and Fig.11 direction Y, the same below) and radial direction (as shown in Figures 1 to 3 as well as Figures 10-11As shown in the direction X, the same below), the cylindrical battery includes a shell 10, a winding core 20, a first cover plate 40 and a first current collector 50, the winding core 20 is accommodated in the shell 10, the winding core 20 includes a main body 21 and a plurality of first pole tab bundles 22, in the present embodiment, three first pole tab bundles 22 are provided, and are arranged at the same end of the main body 21 in the axial direction, each first pole tab bundle 22 includes a plurality of pole tabs arranged in a radial direction, and the three first pole tab bundles 22 are distributed at intervals along the circumferential direction of the main body 21; the first cover plate 40 is provided on the end of the shell 10 close to the first pole tab bundle 22, the first current collector 50 includes a guide portion 52 and a plurality of first welding portions 51, the number of the first welding portions 51 is equal to the number of the first pole tab bundles 22 (that is, three), and the three first welding portions 51 are provided. The connecting portion 51 is arranged at intervals on the circumferential side of the above-mentioned guide portion 52, and each of the above-mentioned first welding portion 51 is electrically connected to a corresponding one of the above-mentioned first pole lug bundles 22. At the same time, the above-mentioned first cover plate 40 has a filling through hole 41, and the above-mentioned guide portion 52 is arranged opposite to the filling through hole 41. The infiltration space 30 is surrounded by the above-mentioned shell 10, the main body 21, the first cover plate 40 and the two adjacent first pole lug bundles 22. The above-mentioned guide portion 52 is arranged opposite to the above-mentioned filling through hole 41 to ensure that the electrolyte injected from the filling through hole 41 flows to the guide portion 52 first. Under the guiding effect of the above-mentioned guide portion 52, the electrolyte can be guided to flow toward the above-mentioned infiltration space 30. The electrolyte injected into the filling through hole 41 preferentially flows to the above-mentioned infiltration space 30 under the action of the guide portion 52, that is, the electrolyte preferentially flows to the upper end of the main body 21 ( Figure 4 The end of the main body 21 is wetted in the area between the first tab bundle 22 to reduce the amount of electrolyte entering the central hole 211, thereby reducing the impact on the wetting uniformity and wetting efficiency. At the same time, the first current collector 50 and the first tab bundle 22 are arranged to separate the upper end of the main body 21 to be wetted into a plurality of smaller wetting intervals (such as Figure 8 As shown), such an arrangement can improve the uniformity of the electrolyte infiltration into the winding core 20.

[0048] It should be noted that the above-mentioned guide portion 52, the first cover plate 40, and the ends of the two adjacent first welding portions 51 close to the above-mentioned guide portion 52 are combined to form a connecting channel 60, which connects the above-mentioned filling through hole 41 and the above-mentioned wetting space 30. The electrolyte injected into the above-mentioned filling through hole 41 flows into the above-mentioned wetting space 30 through the above-mentioned connecting channel 60 after passing through the above-mentioned guide portion 52. In some embodiments, the above-mentioned connecting channel 60 can be formed in other ways to ensure that the electrolyte can flow to the above-mentioned wetting space 30, but it is not limited to this and will not be repeated here; the number of the above-mentioned first pole lug bundles 22 in other embodiments can be set to other numbers, but it is not limited to this, and it is determined according to the design requirements of the cylindrical battery; the above-mentioned first welding portion 51 and the above-mentioned first pole lug bundle 22 can be welded by penetration welding.

[0049] See also Figure 5 , Figure 6 and Figure 7 In one embodiment, the guide portion 52 and the first cover plate 40 are spaced apart in the axial direction. After the electrolyte injected through the filling through hole 41 hits the guide portion 52, the flow direction of the electrolyte changes from the axial direction to the radial direction. By distributing the guide portion 52 and the first cover plate 40 at intervals in the axial direction, the connecting channel 60 is located below the first cover plate 40, that is, the electrolyte after changing its flow direction can directly flow toward the wetting space 30 through the connecting channel 60, thereby improving the wetting efficiency.

[0050] It should be noted that in some embodiments, when the guide portion 52 is able to cover the central hole 211 (i.e. Figure 4 In the top view perspective, the guide portion 52 can completely cover the center hole 211), and the electrolyte flows toward the wetting space 30 under the action of the guide portion 52. Through the above-mentioned arrangement, it can be ensured that all the electrolyte first enters the upper end of the main body 21 and then flows radially toward the shell 10 (no part of the electrolyte will flow into the center hole 211), and then flows toward the center hole 211 after hitting the shell 10. In this process, it can be ensured that the upper end of the main body 21 is completely infiltrated by the electrolyte, ensuring the uniformity of the infiltration and improving the infiltration efficiency. Of course, in some other embodiments, the guide portion 52 and the center hole 211 can also be arranged in other forms, which will not be repeated here.

[0051] Further, see Figure 3 In one embodiment, the guide portion 52 has a guide protrusion 524 facing the first cover plate 40. In the axial direction, the size of the guide protrusion 524 gradually increases from the outer edge of the guide portion 52 to the center of the guide portion 52, that is, the middle is high and the surroundings are low ( Figure 3Such a configuration can reduce the impact of the electrolyte on the guide portion 52 through the guide protrusion 524, thereby improving the safety of the guide portion 52, and at the same time can effectively divert the electrolyte, so that the electrolyte flows into the infiltration space 30 more smoothly.

[0052] It should be noted that the gradual increase in the size of the guide protrusion 524 may be linear (with a consistent increase), that is, the side wall of the guide protrusion 524 is arranged in a straight line in the cross-sectional view; or Figure 3 In the perspective, the increase from the bottom to the middle of the guide protrusion 524 gradually decreases, and the increase from the middle to the top gradually increases, that is, the side wall of the guide protrusion 524 is a curved setting with a concave center of the guide protrusion 524 in the cross-sectional view (such as Figure 3 ); it can also be Figure 3 In the perspective, the increase range from the bottom to the middle of the guide protrusion 524 gradually increases, and the increase range from the middle to the top gradually decreases, that is, the side wall of the guide protrusion 524 is arranged in a curve away from the center of the guide protrusion 524 in the cross-sectional view; or the above three increase situations are combined and arranged, which will not be repeated here; in some embodiments, the middle part of the above guide protrusion 524 ( Figure 3 The axial dimension of the guide protrusion 524 remains unchanged, that is, the middle part of the side wall of the guide protrusion 524 is arranged in a straight line extending radially in the cross-sectional view, but the guide protrusion 524 as a whole is still arranged to be high in the middle and low around, which can effectively divert the electrolyte, and the electrolyte flows into the infiltration space 30 more smoothly, but is not limited to this.

[0053] See also Fig.10 and Fig.11 In one embodiment, the guide portion 52 has a first surface 521 and a second surface 522 that are arranged opposite to each other in the axial direction, and a side wall 523 connected between the outer edges of the first surface 521 and the second surface 522. The filling through hole 41 has a hole wall 411, and the side wall 523 is at least partially arranged opposite to the hole wall 411. In this embodiment, the side wall 523 is partially arranged opposite to the hole wall 411, and part of the side wall 523 is located below the hole wall 411 (such as Fig.11 As shown), the guide portion 52 is arranged partially inside the filling through hole 41 (as shown in FIG. Figures 12-14 As shown), it can effectively reduce the axial space occupied by the cylindrical battery, which is beneficial to the improvement of the energy density of the cylindrical battery.

[0054] It should be noted that, in some embodiments, the guide portion 52 may completely fall into the filling through hole 41, that is, the side walls 523 are all arranged opposite to the hole wall 411, which can further improve the energy density, and will not be elaborated here.

[0055] Please continue reading Fig.11In one embodiment, the side wall 523 includes a first sub-wall 5231 and a second sub-wall 5232, and the second sub-wall 5232 is connected to a side of the first sub-wall 5231 away from the first cover plate 40, that is, the second sub-wall 5232 is arranged below the first cover plate 40 ( Fig.11 The first sub-wall 5231 is arranged opposite to the hole wall 411, and the perimeter of the second sub-wall 5232 gradually increases in the direction close to the main body 21, that is, the second sub-wall 5232 is arranged obliquely, and the electrolyte enters the connecting channel 60 after passing through the guide portion 52. After exiting the connecting channel 60, the electrolyte can be inclined to flow toward the infiltration space 30 through the arrangement of the second sub-wall 5232, so as to ensure that the electrolyte enters the top of the main body 21 ( Fig.10 Perspective, the same below) can flow radially toward the shell 10, and then flow back to the center hole 211 after impacting the shell 10, which can ensure that the top of the main body 21 is completely infiltrated with the electrolyte, thereby improving the wetting effect and reducing the axial space occupation, which is beneficial to the improvement of the energy density of the cylindrical battery.

[0056] It should be noted that the increase in the circumference of the second sub-wall 5232 is similar to the increase in the axial dimension of the guide protrusion 524, which will not be described in detail here.

[0057] Please continue reading Figure 6 In one embodiment, a first mounting groove 42 is formed on one side of the first cover plate 40 facing the main body portion 21, and the first welding portion 51 is embedded in the first mounting groove 42. Such a configuration can fix the relative position of the first welding portion 51 and the first cover plate 40 in the circumferential direction, thereby improving the stability of the cylindrical battery during assembly; at the same time, the above configuration can reduce the axial space occupied inside the cylindrical battery, which is beneficial to the improvement of energy density.

[0058] It should be noted that the axial size of the above-mentioned first mounting groove 42 can be greater than or equal to or smaller than the axial size of the above-mentioned first welding part 51. When the axial size of the first welding part 51 is smaller than the axial size of the above-mentioned first mounting groove 42, the first welding part 51 will completely fall into the above-mentioned first mounting groove 42. At this time, part of the first pole lug bundle 22 will be embedded in the above-mentioned first mounting groove 42. Such a setting can further reduce the occupation of the axial space inside the cylindrical battery, and can effectively improve the energy density of the cylindrical battery. In the actual assembly process, the above-mentioned first pole lug bundle 22 should first be welded to the above-mentioned first welding part 51, and then the above-mentioned first welding part 51 should be embedded in the above-mentioned first mounting groove 42. Such operation can avoid installation interference and effectively avoid the formation of cold welding between the above-mentioned first pole lug bundle 22 and the above-mentioned first welding part 51, which affects the quality and safety of the cylindrical battery.

[0059] Please continue reading Figure 8 and Fig.10 In one embodiment, the winding core 20 further includes a plurality of second pole tab bundles 23. In this embodiment, three second pole tab bundles 23 are provided, and the three second pole tab bundles 23 are arranged at the end of the main body 21 away from the first pole tab bundle 22, that is, the second pole tab bundle 23 and the first pole tab bundle 22 are respectively arranged at both ends of the main body 21, each of the second pole tab bundles 23 includes a plurality of pole tabs arranged in the radial direction, and the three second pole tab bundles 23 are distributed at intervals along the circumferential direction of the main body 21; in this embodiment, the cylindrical battery further includes a second cover plate 70 and a second current collector 80, the second cover plate 70 is covered at the end of the shell 10 close to the second pole tab bundle 23, the second current collector 80 includes a connecting portion 82 and a plurality of second welding portions 81, the plurality of second welding portions 81 are arranged at intervals on the circumferential side of the connecting portion 82, in this embodiment, the number of the second welding portions 81 is equal to the number of the second pole tab bundles 23, and each of the second welding portions 81 is connected to a corresponding second pole tab bundle 23.

[0060] It should be noted that, in this configuration, the electrolyte at the top of the main body 21 (the electrolyte has completely covered the top of the main body 21 and then flows to the central hole 211) flows from the central hole 211 to the bottom of the main body 21 ( Fig.10 From the perspective of the embodiment of the present invention, by providing the second pole lug bundle 23 and the second welding portion 81, there is a space for accommodating the electrolyte between the main body 21 and the second cover plate 70, and the electrolyte flowing out from the central hole 211 flows to the part of the main body 21 between the adjacent second pole lug bundles 23, and infiltrates the main body 21 from bottom to top, so that the electrolyte can infiltrate both ends of the main body 21 at the same time, thereby improving the infiltration efficiency.

[0061] See also Fig. 9 In one embodiment, a second mounting groove 71 is formed on one side of the second cover plate 70 facing the main body portion 21, and the second welding portion 81 is embedded in the second mounting groove 71. Such a configuration can fix the relative position of the second welding portion 81 and the second cover plate 70 in the circumferential direction, thereby improving the stability of the cylindrical battery during assembly. At the same time, the above configuration can reduce the axial space occupied inside the cylindrical battery, which is beneficial to the improvement of energy density.

[0062] It should be noted that the axial size of the second mounting groove 71 may be greater than, equal to, or smaller than the axial size of the second welding portion 81. When the axial size of the second welding portion 81 is smaller than the axial size of the second mounting groove 71 (e.g. Fig. 9As shown), the second welding part 81 will completely fall into the second mounting groove 71, and part of the second pole ear bundle 23 will be embedded in the second mounting groove 71. Such a setting can further reduce the occupation of the axial space inside the cylindrical battery, and can effectively improve the energy density of the cylindrical battery. In the actual assembly process, the second pole ear bundle 23 should be welded with the second welding part 81 first, and then the second welding part 81 is embedded in the second mounting groove 71. Such an operation can avoid installation interference and effectively avoid the formation of a virtual weld between the second pole ear bundle 23 and the second welding part 81, which affects the quality and safety of the cylindrical battery. It should also be noted that in actual use, the second welding part 81 can be electrically connected to the second cover plate 70, or the connecting part 82 can be electrically connected to the pole (the pole is set at the center of the second cover plate 70, not marked in the figure), which is set according to the actual use requirements for the polarity of the cylindrical battery (the positive and negative poles are located on the same side of the cylindrical battery, or the positive and negative poles are located on both sides of the cylindrical battery), and no specific limitation is made here.

[0063] In one embodiment, the number of the first tab bundles 22 is N, satisfying: 3≤N≤24; for example, 3, 6, 12, 24, etc. In this way, by setting the number of the first tab bundles 22, both the ohmic internal resistance and the manufacturing cost can be taken into consideration.

[0064] It should be noted that the above-mentioned ohmic internal resistance is inversely proportional to the conduction path of the current. The more the number of first tab bundles 22 is, the shorter the maximum conduction path (the maximum conduction path is half the arc length of the outermost circle) is, but the number of welding times increases, which increases the manufacturing cost, so both need to be taken into account.

[0065] In one embodiment, in the axial direction, the main body 21 has a third surface 212 and a fourth surface 213 (eg, Figure 8 As shown), the ratio of the orthographic projection area of ​​the first pole lug bundle 22 on the plane where the third surface 212 is located to the area of ​​the third surface 212 is η, which satisfies: 10%≤η≤90%, for example, 10%, 30%, 90%, etc.; in this way, by setting the η value, it is beneficial to improve the wetting effect.

[0066] It should be noted that the above embodiment takes a cylindrical battery of 46950 (diameter D=46㎜, height 95㎜) as an example. The above embodiment reflects the wetting efficiency and wetting effect of the electrolyte through the value of DCR (mΩ) of the cylindrical battery. The smaller the value of DCR of the battery cell, the smoother the electrolyte can enter the wetting space 30 to improve the wetting efficiency and the wetting effect. At the same time, in order to more intuitively reflect the wetting effect, the above embodiment intuitively reflects the quality of the wetting effect through the weight (g) of the free electrolyte. The lower the weight of the free electrolyte, the better the wetting effect; the energy density of the cylindrical battery is reflected by the value of the volume energy density (Wh / L), and the larger the value of the volume energy density, the better. Among them, the DCR of the cylindrical battery is the DC internal resistance of the cylindrical battery. The test method is as follows: charge the cylindrical battery to 100% SOC at a rate of 0.5C (1C is the current for a full charge in one hour), then discharge it to 50% SOC at 0.5C, and then discharge it at 3C for 10s. Record the data of 3C discharge for 10s. DCR = (voltage before discharge - voltage after discharge) / discharge current; The weight test method of free electrolyte is as follows: 50g of electrolyte is added to the cylindrical battery and heated at 45°C. Let it stand for two hours in a safe environment, then disassemble the cylindrical battery and weigh the free electrolyte to obtain the weight of the free electrolyte; the measurement method of the AC internal resistance (i.e., ohmic internal resistance) is as follows: use a 1KHz sinusoidal current (generally mA level) to test the voltage drop caused, thereby calculating the AC internal resistance; the test method of volume energy density is as follows: charge and discharge the cylindrical battery at 1C, record the energy of the cylindrical battery, and test the volume of the cylindrical battery by the drainage method, volume energy density = cylindrical battery energy / volume.

[0067] The technical solution provided in the embodiments of the present application is evaluated in conjunction with specific embodiments below.

[0068] Provide examples 1 to 10. Examples 1 to 8 satisfy 3≤N≤24, while Examples 9 and 10 do not satisfy 3≤N≤24. Examples 1 to 8 and 9 satisfy 10%≤η≤90%, while Example 10 does not satisfy 10%≤η≤90%. Specific parameters and test results are detailed in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] It can be seen that in the above-mentioned embodiments 1 to 4, η remains unchanged, and the embedding ratio of the first current collector 50 and the second current collector 80 remains unchanged. As the number (N) of the first pole lug bundles 22 increases, the value of the AC resistance gradually decreases, which is beneficial to the improvement of the performance of the cylindrical battery. At the same time, the more the number of the first pole lug bundles 22 is, the more welding times are, and the higher the production cost of the cylindrical battery becomes. Therefore, it is necessary to take into account the setting of the AC internal resistance and the number of the first pole lug bundles 22; in the above-mentioned embodiments 2 and embodiments 5 to 6, the number of the first pole lug bundles 22 remains unchanged, and the embedding ratio of the first current collector 50 and the second current collector 80 remains unchanged. The smaller the value of η, the larger the value of the DCR of the cylindrical battery, and the smaller the corresponding amount of free electrolyte, and thus the better the infiltration efficiency of the cylindrical battery; in the above-mentioned embodiments 9 and 10, the embedding ratio of the first current collector 50 and the second current collector 80 is 0, that is, the first current collector The first current collector 50 and the second current collector 80 are not embedded in the first cover plate 40 and the second cover plate 70. Compared with embodiments 1 to 8, the energy density of the cylindrical battery in embodiments 9 and 10 is relatively small. Therefore, the embedding of the first current collector 50 and the second current collector 80 is beneficial to the improvement of the energy density. It should be noted that since the thickness of the first current collector 50 and the second current collector 80 is relatively small, the difference in energy density is relatively small. However, on the whole, the setting of embedding the first current collector 50 and the second current collector 80 in the first cover plate 40 and the second cover plate 70 is beneficial to the improvement of the energy density of the cylindrical battery. In the above embodiment 9, N=1. Although the value of η is within the value range, the AC internal resistance in embodiment 9 is too large, which is not conducive to the improvement of the performance of the cylindrical battery. In the above embodiment 10, the value of η is too large, and the weight value of the free electrolyte is large, which is not conducive to the improvement of the wetting effect of the cylindrical battery.

[0073] On the other hand, the present application also provides a battery pack, comprising any one of the aforementioned cylindrical batteries.

[0074] The cylindrical battery and battery pack provided in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A cylindrical battery, characterized in that: The cylindrical battery has an axial direction (Y) and a radial direction (X) that are perpendicular to each other, and includes: Housing (10); A winding core (20) is accommodated in the shell (10), the winding core (20) comprises a main body (21) and a plurality of first pole lug bundles (22), the plurality of first pole lug bundles (22) are arranged at the same end of the main body (21) in the axial direction (Y), each of the first pole lug bundles (22) comprises a plurality of pole lugs arranged along the radial direction (X), and each of the first pole lug bundles (22) is distributed at intervals along the circumference of the main body (21); a first cover plate (40) covering an end of the housing (10) close to the first electrode tab bundle (22); and A first current collecting member (50) comprises a flow guide portion (52) and a plurality of first welding portions (51), wherein the first welding portions (51) are arranged at intervals on the peripheral side of the flow guide portion (52), each first welding portion (51) is electrically connected to a corresponding first electrode lug bundle (22), the first cover plate (40) has a filling through hole (41), and the flow guide portion (52) is arranged opposite to the filling through hole (41); The shell (10), the main body (21), the first cover plate (40) and two adjacent first tab bundles (22) enclose a wetting space (30); the guide portion (52) is used to guide the electrolyte injected from the filling through hole (41) to flow toward the wetting space (30).

2. The cylindrical battery according to claim 1, characterized in that: The guide portion (52), the first cover plate (40) and the ends of two adjacent first welding portions (51) close to the guide portion (52) together form a connecting channel (60), and the connecting channel (60) connects the filling through hole (41) and the wetting space (30).

3. The cylindrical battery according to claim 2, characterized in that: The guide portion (52) and the first cover plate (40) are spaced apart from each other in the axial direction (Y).

4. The cylindrical battery according to claim 2, characterized in that: The guide portion (52) comprises a first surface (521) and a second surface (522) which are separated from each other in the axial direction (Y), and a side wall (523) connected between the outer edges of the first surface (521) and the second surface (522); the filling through hole (41) comprises a hole wall (411); in the radial direction (X), the side wall (523) and the hole wall (411) are spaced apart from each other, and the side wall (523) is at least partially arranged opposite to the hole wall (411).

5. The cylindrical battery according to claim 4, characterized in that: The side wall (523) includes a first sub-wall (5231) and a second sub-wall (5232), wherein the second sub-wall (5232) is connected to a side of the first sub-wall (5231) away from the first cover plate (40), the first sub-wall (5231) is arranged opposite to the hole wall (411), and the circumference of the second sub-wall (5232) gradually increases in a direction approaching the main body (21) so as to guide the electrolyte injected from the filling through hole (41) to flow toward the infiltration space (30).

6. The cylindrical battery according to claim 1, characterized in that: The flow guide portion (52) has a flow guide protrusion (524) facing the first cover plate (40); In the axial direction (Y), the size of the flow-guiding protrusion (524) gradually increases from the outer edge of the flow-guiding portion (52) to the center of the flow-guiding portion (52).

7. The cylindrical battery according to claim 1, characterized in that: A first mounting groove (42) is provided on one side of the first cover plate (40) facing the main body (21), and the first welding portion (51) is embedded in the first mounting groove (42) to fix the relative position of the first welding portion (51) and the first cover plate (40) in the circumferential direction.

8. The cylindrical battery according to claim 1, characterized in that: The number of the first tab bundles (22) is N, satisfying: 3≤N≤24.

9. The cylindrical battery according to any one of claims 1 to 8, characterized in that: The winding core (20) further comprises a plurality of second pole lug bundles (23), wherein the plurality of second pole lug bundles (23) are arranged at the end of the main body (21) away from the first pole lug bundle (22), each of the second pole lug bundles (23) comprises a plurality of pole lugs arranged along the radial direction (X), and each of the second pole lug bundles (23) is distributed at intervals along the circumferential direction of the main body (21).

10. The cylindrical battery according to claim 9, characterized in that: The cylindrical battery further comprises a second cover plate (70) and a second current collector (80), wherein the second cover plate (70) is arranged to cover the end of the shell (10) close to the second pole lug bundle (23), and the second current collector (80) comprises a connecting portion (82) and a plurality of second welding portions (81), wherein each of the second welding portions (81) is arranged at intervals on the circumference of the connecting portion (82), and each of the second welding portions (81) is correspondingly connected to one of the second pole lug bundles (23).

11. The cylindrical battery according to claim 10, characterized in that: A second mounting groove (71) is provided on a side of the second cover plate (70) facing the main body (21), and the second welding portion (81) is embedded in the second mounting groove (71) to fix the relative position of the second welding portion (81) and the second cover plate (70) in the circumferential direction.

12. The cylindrical battery according to claim 11, characterized in that: The dimension of the second welding portion (81) in the axial direction (Y) is smaller than the dimension of the second mounting groove (71) in the axial direction (Y).

13. The cylindrical battery according to claim 1, characterized in that: In the axial direction (Y), the main body (21) has a third surface (212) and a fourth surface (213) that are opposite to each other; The ratio of the orthographic projection area of ​​the first tab bundle (22) on the plane where the third surface (212) is located to the area of ​​the third surface (212) is η, which satisfies: 10%≤η≤90%.

14. A battery pack, characterized in that: Comprising a cylindrical battery as claimed in any one of claims 1 to 13.

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