Battery cell and battery pack

Abstract

The application relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a cover plate assembly and a pole group. The cover plate assembly comprises a pole post and a cover plate body; the pole post comprises a pole post bottom plate and at least two pole post columns arranged on the pole post bottom plate, and the pole post columns and the pole post bottom plate are integrally connected; the cover plate body is provided with a number of first pole post mounting holes corresponding to the pole post columns, the pole post bottom plate is arranged on a first surface of the cover plate body, and the pole post columns are arranged in the first pole post mounting holes; the pole group is provided with a tab, a plurality of layers of foil materials of the tab are connected into one body through ultrasonic welding, the tab is connected with the pole post bottom plate through laser welding, and the laser welding is located in the ultrasonic welding; along an X direction, the distance from the laser welding to the side edge of the pole post bottom plate is L1, the length of the laser welding increases by Delta L, and L1 and Delta L satisfy a preset condition. The application can increase the welding area between the tab and the pole post bottom plate, improve the overcurrent capacity, and meet the fast charging and high current demand.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to battery cells and battery packs. Background Technology

[0002] In recent years, with the rapid development of new energy vehicles and energy storage technologies, lithium-ion batteries have become the mainstream choice for power batteries due to their high energy density, long cycle life, and environmental friendliness. To shorten charging time, fast charging technology has become a key research focus in the industry, which places higher demands on the battery's overcurrent capacity, heat dissipation performance, and structural reliability.

[0003] In battery cell structure design, traditional riveted cover plates typically use a single terminal block or two independent terminals to achieve current transmission. However, with the increase in fast charging current, the cross-sectional area of ​​a single terminal block is limited, resulting in limited overcurrent capacity. While the bipolar design can shunt current, the discrete terminals weaken the structural strength and further reduce the overcurrent capacity due to uneven current distribution. Moreover, the solder area between the terminal block base plate and the tab of the bipolar design is limited, making it difficult to meet the requirements of high-power fast charging.

[0004] Therefore, how to improve the current carrying capacity of the electrode while ensuring structural strength has become a key issue that current lithium-ion battery fast charging technology urgently needs to solve. Summary of the Invention

[0005] In view of this, the present invention provides a battery cell and battery pack to solve the problem of poor current carrying capacity of the terminals.

[0006] In a first aspect, the present invention provides a battery cell, including a cover plate assembly and an electrode assembly. The cover plate assembly includes a terminal post and a cover plate body; the terminal post includes a terminal post base plate and at least two terminal post bodies disposed on the terminal post base plate, the terminal post bodies and the terminal post base plate being integrally connected; the cover plate body has a first surface and a second surface disposed opposite to each other, the cover plate body is provided with a number of first terminal post mounting holes corresponding to the number of terminal post bodies, the first terminal post mounting holes penetrating the first surface and the second surface of the cover plate body, the terminal post base plate being disposed on the first surface of the cover plate body, and the terminal post bodies being disposed in the first terminal post mounting holes; the electrode assembly is provided with tabs, the tabs including multiple layers of foil, the multiple layers of foil being integrally connected by ultrasonic welding, the tabs being connected to the terminal post base plate by laser welding, the laser welding being located within the range of the ultrasonic welding;

[0007] Along the X direction, the distance from the laser-printed electrode to the side edge of the base plate is L1, in mm.

[0008] The length increase of the laser solder mark is ΔL, in mm.

[0009] The width of the laser solder mark is W, in mm.

[0010] The increased flow area of ​​laser soldering is S, in mm. 2 ,

[0011] The current carrying capacity per unit cross-sectional area of ​​laser soldering is J, with units of A / mm². 2 ,

[0012] The current carrying capacity of laser soldering is I, measured in amperes (A).

[0013] satisfy:

[0014] S = ΔL × W,

[0015] I = J × S,

[0016] 2mm≤L1≤6.5mm,

[0017] ΔL≥4mm.

[0018] Beneficial effects: The battery cell provided by the present invention integrates two or more traditionally separate terminals into one unit. That is, two or more terminal bodies are set on a terminal base plate, and the terminal base plate and the terminal bodies are integrally connected. The terminal base plate can provide a larger area for welding with the tabs, thereby significantly increasing the soldering area, improving the current carrying capacity, and meeting the high current requirements of fast charging.

[0019] Furthermore, the integrated connection between the electrode post and the base plate reduces contact resistance and improves conductivity. Simultaneously, the design of multiple electrode posts allows for higher current carrying capacity within a limited space. The integrated connection between the electrode post and the base plate avoids the weakening of the electrode structure caused by the separate design of traditional bipolar posts, thus improving the structural strength of the electrode post.

[0020] Finally, this embodiment of the invention also limits the side distance L1 of the laser-printed electrode base plate along the X direction to be not less than 2mm. Otherwise, it will be difficult to press the electrode tab in place and the welding yield between the electrode tab and the electrode base plate will be low.

[0021] This invention, by designing two or more poles in related technologies into an integral structure, can increase the length of laser soldering, so that ΔL is at least 4mm.

[0022] In one optional embodiment, the side distance from the laser weldment to the ultrasonic weldment along the X direction is L2 (mm), the side distance from the laser weldment to the electrode base plate along the Y direction is L3 (mm), and the side distance from the laser weldment to the ultrasonic weldment along the Y direction is L4 (mm), satisfying:

[0023] 1.5mm≤L2≤5mm

[0024] 2mm≤L3≤4.5mm,

[0025] 1.5mm≤L4≤4mm.

[0026] In one alternative implementation, the ultrasonic weld mark is a continuous line along the X direction; or, the ultrasonic weld mark is multiple lines along the X direction, and adjacent ultrasonic weld marks have overlapping areas.

[0027] In one alternative implementation, the laser weld mark is a continuous line along the X direction; or, the laser weld mark is multiple lines along the X direction, and adjacent laser weld marks have overlapping areas.

[0028] In one optional embodiment, the cross-sectional shape of the pole post along the XY plane is circular; or, the cross-sectional shape of the pole post along the XY plane is racetrack-shaped, including two oppositely arranged straight edge segments and an arc segment connecting the two straight edge segments, the straight edge segments being arranged along the X direction.

[0029] In one alternative implementation, the electrode post is made of pure copper or pure aluminum.

[0030] In one optional embodiment, the pole base plate includes a base plate body and a base plate column segment protruding from the base plate body. The pole column body and the base plate column segment are integrally connected. The pole base plate is made of copper, and the pole column body is made of aluminum.

[0031] In one optional embodiment, the cover plate assembly further includes a riveting block, a first insulating member, and a second insulating member. The riveting block has a number of second pole mounting holes corresponding to the pole body; the riveting block is disposed on the second surface of the cover plate body; the first insulating member has a number of third pole mounting holes corresponding to the pole body; the first insulating member is disposed between the riveting block and the second surface of the cover plate body, insulatingly connecting the riveting block and the cover plate body; the second insulating member has a number of fourth pole mounting holes corresponding to the pole body; the second insulating member is disposed between the first surface of the cover plate body and the pole base plate, insulatingly connecting the cover plate body and the pole base plate; the pole body passes sequentially through the fourth pole mounting hole, the first pole mounting hole, the third pole mounting hole, and the second pole mounting hole, and is riveted or welded to the riveting block.

[0032] In one alternative embodiment, the device further includes a housing. The housing has a receiving cavity and at least one open end communicating with the receiving cavity; an electrode assembly is disposed within the receiving cavity, and the electrode assembly has a positive electrode tab and a negative electrode tab leading out; a cover plate assembly is disposed at the open end of the housing and encapsulates the electrode assembly within the housing; the electrode post includes a positive electrode post and a negative electrode post, the positive electrode post being welded to the positive electrode tab and the negative electrode post being welded to the negative electrode tab.

[0033] Secondly, the present invention also provides a battery pack comprising multiple battery cells from more than one technical solution, wherein the battery cells are electrically connected to each other.

[0034] Beneficial effects: Since the battery pack includes the cells, it has all the technical benefits of the cells, which will not be elaborated here. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of two independent poles in the related technology;

[0037] Figure 2 This is a schematic diagram of the structure of the electrode post in a battery cell according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the electrode structure in another battery cell according to an embodiment of the present invention;

[0039] Figure 4 This is a cross-sectional view of a terminal post in a battery cell according to an embodiment of the present invention;

[0040] Figure 5 This is a cross-sectional view of the terminal post in another battery cell according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram showing the dimensions of the welding of two independent terminals and tabs to a battery cell in a related technology.

[0042] Figure 7 This is a schematic diagram of the dimensions of the electrode post and electrode tab welding in a battery cell according to an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the solder mark structure in another battery cell according to an embodiment of the present invention;

[0044] Figure 9 This is a schematic diagram of the structure of a cover plate assembly for a battery cell according to an embodiment of the present invention;

[0045] Figure 10 for Figure 9 Top view of the cover plate assembly shown;

[0046] Figure 11 For along Figure 10 Sectional view at point AA;

[0047] Figure 12 For along Figure 10 Sectional view at point BB;

[0048] Figure 13 for Figure 9 An exploded view of the cover plate assembly shown;

[0049] Figure 14 This is a cross-sectional view of a cover plate assembly for a battery cell according to another embodiment of the present invention;

[0050] Figure 15 This is a schematic diagram illustrating the dimensional requirements for welding two independent terminals and tabs to a battery cell in a related technology.

[0051] Figure 16 This is a schematic diagram illustrating the dimensional requirements for welding the electrode post and electrode tab in a battery cell according to an embodiment of the present invention.

[0052] Figure 1 , Figure 6 and Figure 15 Explanation of reference numerals in the attached figures:

[0053] 1', pole post; 101', pole post base plate; 102', pole post body; 3', pole group; 301', pole tab; 4', ultrasonic welding mark; 5', laser welding mark.

[0054] Other annotations in the accompanying drawings:

[0055] 1. Pole post; 101. Pole post base plate; 1011. Base plate body; 1012. Base plate column segment; 102. Pole post column body; 1021. Assembly column segment; 1022. Riveting column segment; 2. Cover plate body; 201. First pole post mounting hole; 3. Pole group; 301. Pole lug; 4. Ultrasonic welding mark; 5. Laser welding mark; 6. Riveting block; 601. Second pole post mounting hole; 7. First insulating component; 701. Third pole post mounting hole; 8. Second insulating component; 801. Fourth pole post mounting hole; 9. Sealing ring; 10. Copper nozzle. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] The following is combined with Figures 1 to 16 The following describes embodiments of the present invention.

[0058] According to an embodiment of the present invention, in a first aspect, a battery cell is provided, including a cover plate assembly and an electrode assembly 3. The cover plate assembly includes a terminal post 1 and a cover plate body 2; the terminal post 1 includes a terminal post base plate 101 and at least two terminal post bodies 102 disposed on the terminal post base plate 101, the terminal post bodies 102 and the terminal post base plate 101 being integrally connected; the cover plate body 2 has a first surface and a second surface disposed opposite to each other, the cover plate body 2 is provided with a number of first terminal post mounting holes 201 corresponding to the number of terminal post bodies 102, the first terminal post mounting holes 201 penetrating the first surface and the second surface of the cover plate body 2, the terminal post base plate 101 being disposed on the first surface of the cover plate body 2, and the terminal post bodies 102 being disposed in the first terminal post mounting holes 201; the electrode assembly 3 is provided with tabs 301, the tabs 301 including multiple layers of foil, the multiple layers of foil being connected integrally by ultrasonic welding 4, the tabs 301 being connected to the terminal post base plate 101 by laser welding 5, the laser welding 5 being located within the range of the ultrasonic welding 4;

[0059] Along the X direction, the side distance from the laser-printed electrode 5 to the base plate 101 is L1, in mm.

[0060] The length increase of laser-etched mark 5 is ΔL, in mm.

[0061] The width of laser weld mark 5 is W, in mm.

[0062] The increased flow area of ​​laser soldering 5 is S, in mm. 2 ,

[0063] The current carrying capacity per unit cross-sectional area of ​​laser solder mark 5 is J, with units of A / mm. 2 ,

[0064] The current carrying capacity of laser soldering 5 increases by I, in amperes (A).

[0065] satisfy:

[0066] S = ΔL × W,

[0067] I = J × S,

[0068] 2mm≤L1≤6.5mm,

[0069] ΔL≥4mm.

[0070] Specifically, in Figure 11 and Figure 12 In the view shown, the first surface of the cover plate body 2 is its lower surface, and the second surface of the cover plate body 2 is its upper surface. In the cell structure, the first surface of the cover plate body 2 is the surface close to the electrode group 3, and the second surface of the cover plate body 2 is the surface away from the electrode group 3.

[0071] exist Figure 6 and Figure 7In the middle, the X direction is the length direction of the cover plate body 2 or the pole base plate 101, and the Y direction is the width direction of the cover plate body 2 or the pole base plate 101.

[0072] In some related technologies, to improve current carrying capacity, separate independent terminals 1' are used. Taking two as an example, refer to... Figure 1 A cell cover assembly includes two independent terminals 1', each terminal 1' comprising a terminal base plate 101' and a terminal body 102'. After assembly, the terminal base plates 101' of both terminals 1' are welded to the tabs 301' of the electrode group 3', with ultrasonic welding marks 4' and laser welding marks 5' as specified. Figure 6 As shown.

[0073] Specifically, the tab 301' of the electrode assembly 3' is composed of multiple layers of foil stacked together, which are then ultrasonically welded together. The two pole posts 1' are designated as the first pole post and the second pole post, respectively. Figure 6 In the X-direction, the length of the base plate 101' of the first pole post is A (mm), the length of the base plate 101' of the second pole post is B (mm), and the maximum side distance between the two base plates 101' is E (mm). The first pole post and the tab 301' are connected by a first laser solder joint, and the second pole post and the tab 301' are connected by a second laser solder joint. The distance from the right end of the first laser solder joint to the right end of the base plate 101' of the first pole post is L1, and the distance from the left end of the second laser solder joint to the left end of the base plate 101' of the second pole post is L1, where L1 ≥ 2mm. The distance between the first and second laser solder joints is D (mm).

[0074] In the battery cell provided by this invention, the terminal post 1 adopts an integrated structure, which also includes a terminal post base plate 101 and a terminal post body 102. However, only one terminal post base plate 101 is provided, and two or more terminal post bodies 102 are arranged at intervals on the same terminal post base plate 101. Again, taking two as an example, refer to... Figures 2 to 5 After assembly, the base plate 101 of pole post 1 and the tab 301 of pole group 3 are welded together, and the weld marks are as follows: Figure 7 or Figure 8 As shown.

[0075] Specifically, in this invention, an integrated pole post 1 is used, and there are two size design schemes.

[0076] Option 1, refer to Figure 7 Along the X direction, with Figure 6Compared to the scheme shown, the total dimensions occupied by the base plate 101 of the pole post 1 remain unchanged. That is, in this scheme, the length of the base plate 101 of the pole post 1 is L, where L = E > A + B. This does not change the structure of the original cover plate body 2 and other components, such as the position of the mounting holes of the pole post 1. In this scheme, it is only necessary to ensure that the distance L1 between the two sides of the laser-welded stamp 5 and the two sides of the base plate 101 is ≥ 2mm. The remaining length can be used to arrange the laser-welded stamp 5, and... Figure 6 Compared with related technologies, in this solution, the length of the laser welding mark 5 increases by ΔL, ΔL=D, and D≥4mm.

[0077] Option 2, refer to Figure 8 Along the X direction, with Figure 6 Compared to the scheme shown, the length of the pole base plate 101 remains unchanged. That is, in this scheme, the length of the pole base plate 101 of the pole 1 is L, where L = A + B. In this scheme, it is only necessary to ensure that the distance L1 between the two sides of the laser welding mark 5 and the two sides of the pole base plate 101 is ≥ 2mm. The remaining length can be used to arrange the laser welding mark 5, and... Figure 6 Compared with related technologies, in this solution, the length of the laser welding mark 5 increases by ΔL, where ΔL ≥ 4mm.

[0078] Option 2 not only increases the area of ​​the laser welding mark 5 and improves the current carrying capacity, but also saves at least 4mm in length of the tab 301, thus achieving weight reduction and cost reduction, provided that the current carrying capacity of the tab 301 itself is sufficient.

[0079] The present invention can increase the length of the laser welding mark 5, with L1≥2mm and ΔL≥4mm, which will be described in detail below.

[0080] In related technologies, the split-type pole solution, taking two poles as an example, refers to... Figure 15When welding the electrode base plate to the electrode tab, a welding fixture is required to clamp and fix the electrode base plate and the electrode tab. Taking a copper clamping nozzle 10 as an example, the wall thickness t of the copper clamping nozzle 10 is usually 1mm to 2mm. The copper clamping nozzle 10 needs to occupy the dimension of the electrode base plate along the X direction, that is, the wall thickness t of the copper clamping nozzle 10. In order to increase the welding area and improve the current carrying capacity, the thinner the wall thickness of the copper clamping nozzle 10, the better, that is, 1mm is preferred. During laser welding, the arc initiation point is close to the copper pressure nozzle 10, which can easily burn the copper pressure nozzle 10 and affect its service life. Therefore, a safety distance 'a' (in mm) needs to be reserved between the arc initiation point and the copper pressure nozzle 10, where 'a' ≥ 1 mm. Thus, the edge of the laser weld mark must be L1 from the single-side edge of the pole base plate, and L1 must be at least 2 mm. Each pole must have a distance of L1 at both ends. Therefore, for a split-type bipolar pole design, at least 4 × L1 blank length needs to be reserved. This invention designs two or more pole base plates as an integrated structure. Taking at least two pole bodies 102 as an example, only a blank length of L1 needs to be reserved at each end of the pole base plate. Figure 16 As shown, a blank length of 2×L1 is reserved. Correspondingly, the length of the laser soldering is increased by ΔL≥2×L1, that is, ΔL≥4mm.

[0081] When the width of the laser solder mark 5 is W, the increased flow area S of the laser solder mark 5 is ΔL×W.

[0082] The current carrying capacity per unit cross-sectional area of ​​laser solder mark 5 is J, with units of A / mm. 2 That is, a current of J amperes can pass through each square millimeter.

[0083] The current carrying capacity of the laser solder joint is I, measured in amperes (A), which is the maximum current that the laser solder joint can safely carry. I = J × S = J × ΔL × W.

[0084] Therefore, the battery cell provided by the present invention integrates two or more traditionally separate terminals 1 into one unit. That is, two or more terminal pillars 102 are provided on a terminal base plate 101, and the terminal base plate 101 and the pillars are integrally connected. The terminal base plate 101 can provide a larger area for welding with the tab 301, thereby significantly increasing the solder area, improving the current carrying capacity after the tab and terminal are welded, and meeting the high current requirements of fast charging.

[0085] Furthermore, the integral connection between the electrode post 102 and the electrode base plate 101 reduces contact resistance and improves conductivity. Simultaneously, the design of multiple electrode posts 102 allows for higher current carrying capacity within a limited space. The integral connection between the electrode post 102 and the electrode base plate 101 avoids the weakening of the electrode post 1's structural strength caused by the traditional separate bipolar electrode design, thus improving the structural strength of the electrode post 1.

[0086] Finally, this embodiment of the invention also limits the side distance L1 from the laser-welded stamp 5 to the electrode base plate 101 along the X direction to be no less than 2mm. Otherwise, it will be difficult to press the tab 301 in place, and the welding yield between the tab 301 and the electrode base plate 101 will be low. L1 should not exceed 6.5mm at most; otherwise, it will have a significant impact on the area of ​​the laser-welded stamp 5, affecting the current carrying capacity.

[0087] By designing two or more pole posts 1 in related technologies into an integral structure, the present invention can increase the length of the laser solder mark 5, so that ΔL is at least 4mm.

[0088] In some embodiments, along the X direction, the side distance from the laser weld mark 5 to the ultrasonic weld mark 4 is L2 (mm); along the Y direction, the side distance from the laser weld mark 5 to the electrode base plate 101 is L3 (mm); and along the Y direction, the side distance from the laser weld mark 5 to the ultrasonic weld mark 4 is L4 (mm), satisfying the following:

[0089] 1.5mm≤L2≤5mm

[0090] 2mm≤L3≤4.5mm,

[0091] 1.5mm≤L4≤4mm.

[0092] Specifically, refer to Figure 7 Along the X direction, the side distance L2 between laser weld marks 5 and ultrasonic weld marks 4, and along the Y direction, the side distance L4 between laser weld marks 5 and ultrasonic weld marks 4, must both be greater than or equal to 1.5mm. Otherwise, laser welding will be difficult, and the weld may easily hit the copper nozzle 10 during the welding process. It should be noted that along the X direction, there are two side distances L2, which can be equal or unequal, but both must meet the requirement of at least 1.5mm. Similarly, along the X direction, there are two side distances L4, which can be equal or unequal, but both must meet the requirement of at least 1.5mm.

[0093] Continue to refer to Figure 7 Along the Y direction, the side distance L3 between the laser-welded stamp 5 and the electrode base plate 101 must be at least 2mm. This makes it difficult to press the tab 301 firmly, resulting in a low welding yield between the tab 301 and the electrode base plate 101. It should be noted that along the Y direction, there are two side distances L3. These two side distances L3 can be equal or unequal, but both must meet the requirement of being at least 2mm.

[0094] Based on the positional relationship between the ultrasonic weld mark 4 and the electrode base plate 101, two schemes are proposed:

[0095] Option 1: Along the X direction, the edge of the ultrasonic weld is flush with the two sides of the pole base plate, or the edge of the ultrasonic weld extends beyond the two sides of the pole base plate.

[0096] Option 2: The edge of the ultrasonic weld mark is located on the inner side of both sides of the electrode base plate. Figure 16 In the process, the edge of the ultrasonic weld mark extends beyond the two side edges of the electrode base plate. Figure 7 and Figure 8 In the process, the edge of the ultrasonic weld mark is located inside the two sides of the electrode base plate.

[0097] For Scheme 2, the requirement is 2mm≤L1≤5mm.

[0098] To verify the technical effects of the present invention, specific experimental cases are provided according to the two schemes described above, as detailed in Table 1 and Table 2.

[0099] Table 1

[0100]

[0101] Table 2

[0102]

[0103] Therefore, by controlling L1, L2, L3, and L4 within the above-mentioned value ranges, it is possible to improve the current carrying capacity after welding the tabs and posts while ensuring a welding yield of ≥99%.

[0104] In some embodiments, the ultrasonic weld mark 4 is a continuous line along the X direction; or, the ultrasonic weld mark 4 is multiple lines along the X direction, and adjacent ultrasonic weld marks 4 have overlapping areas.

[0105] Specifically, such as Figure 7 As shown, the ultrasonic welding stamp 4 can be set as a continuous single line; or it can be set as multiple lines, such as... Figure 8 As shown, however, to ensure the connection strength of the tab 301, when multiple ultrasonic weld marks 4 are set, there is an overlap area between adjacent ultrasonic weld marks 4. Figure 8 In the diagram, K1 refers to the overlapping area of ​​ultrasonic welding stamp 4.

[0106] In some embodiments, the laser weld mark 5 is a continuous line along the X direction; or, the laser weld mark 5 is multiple lines along the X direction, and adjacent laser weld marks 5 have overlapping areas.

[0107] Specifically, such as Figure 7 As shown, the laser welding mark 5 can be set to a continuous line; or it can be set to multiple lines, such as... Figure 8 As shown, however, to ensure the connection strength between the tab 301 and the base plate 101, when multiple laser weld lines 5 are provided, there is an overlap area between adjacent laser weld lines 5. Figure 8 In the diagram, K2 refers to the overlapping area of ​​laser soldering mark 5.

[0108] In some embodiments, the cross-sectional shape of the pole post 102 along the XY plane is circular; or, the cross-sectional shape of the pole post 102 along the XY plane is racetrack-shaped, including two oppositely arranged straight edge segments and an arc segment connecting the two straight edge segments, the straight edge segments being arranged along the X direction.

[0109] The battery cell provided by this invention has a terminal 1 suitable for both circular and racetrack-shaped terminals. Specifically, the structure of the circular terminal is as follows: Figure 2 The cross-sectional shape of the pole post 102 along the XY plane is circular. The structure of the runway-shaped pole post is referenced. Figure 3 The cross-sectional shape of the pole post 102 along the XY plane is racetrack-shaped. The two opposite ends along the X direction are circular arc segments, and the two opposite ends along the Y direction are straight edge segments.

[0110] There are two connection methods between the pole post 1 and the cover plate body 2 of both shapes: riveting and welding.

[0111] For the riveting scheme, the shape of the pole post 102 of pole post 1 will change before and after riveting. Before riveting, the structure of the pole post 102 of pole post 1 is as follows: Figure 4 As shown, the pole post body 102 includes an assembly column section 1021 connected to the pole post base plate 101 and a riveting column section 1022 located on the upper part of the assembly column section 1021. During assembly, the assembly column section 1021 is used to fit into the first pole post mounting hole 201 of the cover plate, and the riveting column section 1022 is used to fit into the riveting block 6 during assembly. After riveting, the structure of the riveting column section 1022 undergoes expansion deformation, resulting in the following... Figure 5 The pole post 1 is shown. The structure of the cover plate assembly for the riveting scheme is as follows: Figures 9 to 13 As shown.

[0112] Regarding the welding scheme, the pole post body 102 structure of pole post 1 is as follows: Figure 4 As shown, the structure of the welded cover plate assembly is as follows: Figure 14 As shown.

[0113] In some embodiments, the pole post 1 is made of pure copper or pure aluminum.

[0114] In this invention, the electrode post 1 adopts an integrated structure, applicable to both positive and negative electrodes. When the electrode post 1 is made of pure copper, it is the negative electrode post, used for welding to the negative electrode tab. When the electrode post 1 is made of pure aluminum, it is the positive electrode post, used for welding to the positive electrode tab.

[0115] In some embodiments, the pole base plate 101 includes a base plate body 1011 and a base plate column segment 1012 protruding from the base plate body 1011. The pole column 102 is integrally connected to the base plate column segment 1012. The pole base plate 101 is made of copper and the pole column 102 is made of aluminum.

[0116] In some embodiments, the negative electrode post is a copper-aluminum composite electrode post. (Refer to...) Figure 4 or Figure 5 The pole base plate 101 (base plate body 1011 and base plate column section 1012) is made of copper, and the pole column 102 is made of aluminum. For this composite material pole 1, an integral molding structure can be achieved using existing processing techniques, such as machining or cold heading.

[0117] In some embodiments, the cover plate assembly further includes a riveting block 6, a first insulating member 7, and a second insulating member 8. The riveting block 6 is provided with a number of second pole mounting holes 601 corresponding to the pole post 102; the riveting block 6 is disposed on the second surface of the cover plate body 2; the first insulating member 7 is provided with a number of third pole mounting holes 701 corresponding to the pole post 102; the first insulating member 7 is disposed between the riveting block 6 and the second surface of the cover plate body 2, insulatingly connecting the riveting block 6 and the cover plate body 2; the second insulating member 8 is provided with a number of fourth pole mounting holes 801 corresponding to the pole post 102; the second insulating member 8 is disposed between the first surface of the cover plate body 2 and the pole post base plate 101, insulatingly connecting the cover plate body 2 and the pole post base plate 101; the pole post 102 passes sequentially through the fourth pole mounting hole 801, the first pole mounting hole 201, the third pole mounting hole 701, and the second pole mounting hole 601, and is riveted or welded to the riveting block 6.

[0118] The rivet block 6 can be used to fix the terminal post 1, providing mechanical support for the terminal post 1. At the same time, since there is a conductive connection between the rivet block 6 and the terminal post 1, the rivet block 6 can serve as a conductive structure. For square batteries, the rivet block 6 can serve as an intermediate connector between the terminal post 1 and the module busbar.

[0119] In the cell cover assembly, the rivet block 6 and the cover body 2 are usually made of metal. Setting a first insulating element 7 between the rivet block 6 and the cover body 2 can prevent the two from contacting directly, enhance electrical insulation safety, and prevent short circuit risk.

[0120] Similarly, the base plate 101 is also made of conductive material. A second insulating element 8 is provided between the base plate 101 and the cover plate body 2, which can block the conductive path between the pole 1 and the cover plate body 2 and eliminate the risk of short circuit caused by electrolyte leakage or metal shavings residue.

[0121] In some embodiments, both the first insulating member 7 and the second insulating member 8 are plastic parts.

[0122] In some embodiments, a sealing ring 9 is also included. The sealing ring 9 is sleeved on the pole post body 102 of the pole post 1. At least a portion of the sealing ring 9 is located between the inner wall of the first pole post mounting hole 201 and the pole post body 102, and at least another portion of the sealing ring 9 is located between the pole post base plate 101 and the cover plate body 2. The sealing ring 9 seals the pole post 1 and the cover plate body 2 together.

[0123] In this embodiment, the sealing ring 9 has at least two sealing sections, including an axial sealing section and a radial sealing section. At least a portion of the sealing ring 9 is located between the inner wall of the first electrode mounting hole 201 and the electrode body 102. This section is the axial sealing section. The sealing ring 9 is compressed between the inner wall of the first electrode mounting hole 201 and the electrode body 102 to achieve axial sealing, fill the microscopic gaps caused by metal processing tolerances, and prevent electrolyte leakage along the side wall of the electrode 1. At least another portion of the sealing ring 9 is located between the electrode base plate 101 and the cover plate body 2. This section is the radial sealing section. The sealing ring 9 extends between the electrode base plate 101 and the cover plate body 2 to form an end face compression seal, achieving radial sealing and preventing electrolyte vapor from entering from the top.

[0124] In this embodiment, the sealing ring 9 provides multi-level sealing protection, completely blocking the leakage path.

[0125] Furthermore, the sealing ring 9 is made of a material resistant to electrolyte corrosion to ensure its sealing effect and service life. Furthermore, the sealing ring 9 is made of an elastic material, such as fluororubber or silicone, to absorb dimensional deviations between the electrode post 1 and the first electrode post mounting hole 201.

[0126] In some embodiments, the device further includes a housing. The housing has a receiving cavity and at least one open end communicating with the receiving cavity; the electrode assembly 3 is disposed within the receiving cavity and has a positive electrode tab and a negative electrode tab leading out; a cover plate assembly is disposed at the open end of the housing and encapsulates the electrode assembly 3 within the housing; the electrode post 1 includes a positive electrode post and a negative electrode post, the positive electrode post being welded to the positive electrode tab and the negative electrode post being welded to the negative electrode tab 301.

[0127] The cover assembly is used to seal the openings in the cell casing, serving to seal and protect the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. Terminal 1 provides a path for current inflow and outflow, ensuring current conduction during the charging and discharging process of the cell.

[0128] According to an embodiment of the present invention, in a second aspect, a battery pack is also provided, comprising a plurality of cells as described in the above embodiments, wherein the cells are electrically connected to each other.

[0129] Since the battery pack includes the battery cells and has all the technical benefits of the battery cells, it will not be elaborated here.

[0130] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. An electric cell, characterized by, The cover plate assembly comprises a pole post and a cover plate body; the pole post comprises a pole post bottom plate and at least two pole post columns arranged on the pole post bottom plate, the pole post columns and the pole post bottom plate are integrally connected; the cover plate body has a first surface and a second surface arranged oppositely, the cover plate body is provided with a number of first pole post mounting holes corresponding to the pole post columns, the first pole post mounting holes penetrate through the first surface and the second surface of the cover plate body, the pole post bottom plate is arranged on the first surface of the cover plate body, and the pole post columns are arranged in the first pole post mounting holes; The pole group is provided with a tab, the tab comprises a plurality of layers of foils, the plurality of layers of foils are connected into one body through ultrasonic welding marks, the tab is connected with the pole post bottom plate through laser welding marks, and the laser welding marks are located in the range of the ultrasonic welding marks; Along the X direction, the side distance of the laser welding mark to the pole post bottom plate is L1, and the unit is mm, Along the X direction, the length of the laser welding mark increases by ΔL, and the unit is mm, The width of the laser welding mark is W, and the unit is mm, The increased current-carrying capacity of the laser welding mark is I, and the unit is A, The laser welding imprint increased flow area is S, unit: mm 2 , The overcurrent capacity of the laser welding print per unit cross-sectional area is J, with the unit of A / mm 2 , Satisfies: S=ΔL×W, I= J×S, 2mm≤L1≤6.5mm, ΔL≥4mm; Along the X direction, the side distance of the laser welding mark to the ultrasonic welding mark is L2, and the unit is mm, Along the Y direction, the side distance of the laser welding mark to the pole post bottom plate is L3, and the unit is mm, Along the Y direction, the side distance of the laser welding mark to the ultrasonic welding mark is L4, and the unit is mm, Satisfies: 1.5mm≤L2≤5mm, 2mm≤L3≤4.5mm, 1.5mm≤L4≤4mm; Along the X direction, the ultrasonic welding mark is a continuous one; or, along the X direction, the ultrasonic welding mark is a plurality of ones, and adjacent ultrasonic welding marks have an overlapping area; Along the X direction, the laser welding mark is a continuous one; or, along the X direction, the laser welding mark is a plurality of ones, and adjacent laser welding marks have an overlapping area. The cross-sectional shape of the pole post column along the X-Y plane is circular; 2. The electric cell of claim 1, wherein, Or, the cross-sectional shape of the pole post column along the X-Y plane is a racetrack shape, which comprises two oppositely arranged straight edge segments and a circular arc segment connecting the two straight edge segments, and the straight edge segments are arranged along the X direction. The material of the pole post is pure copper or pure aluminum.

3. The electric cell of claim 1, wherein, The pole post bottom plate comprises a bottom plate main body and a bottom plate column segment protruding from the bottom plate main body, the pole post column and the bottom plate column segment are integrally connected, the pole post bottom plate is made of copper material, and the pole post column is made of aluminum material.

4. The electric cell of claim 1, wherein, The cover plate assembly further comprises:

5. The electric cell of claim 1, wherein, A riveting block provided with a number of second pole post mounting holes corresponding to the pole post columns; the riveting block is arranged on the second surface of the cover plate body; A first insulating piece provided with a number of third pole post mounting holes corresponding to the pole post columns; the first insulating piece is arranged between the riveting block and the second surface of the cover plate body, and insulatingly connects the riveting block and the cover plate body. ​ A second insulating piece is provided with a corresponding number of fourth pole post mounting holes corresponding to the pole post bodies; the second insulating piece is arranged between the first surface of the cover plate body and the pole post bottom plate, and insulatingly connects the cover plate body and the pole post bottom plate; The pole post bodies pass through the fourth pole post mounting holes, the first pole post mounting holes, the third pole post mounting holes and the second pole post mounting holes in sequence, and are riveted or welded with the riveting blocks.

6. The electric cell of claim 1, wherein, Further comprising a shell having a receiving cavity, the shell being provided with at least one open end communicating with the receiving cavity; The pole group is arranged in the receiving cavity, and the pole group has positive and negative pole ears; The cover plate assembly is arranged at the open end of the shell, and the pole group is encapsulated in the shell; the pole posts include positive and negative pole posts, the positive pole posts are welded with the positive pole ears, and the negative pole posts are welded with the negative pole ears.

7. A battery pack, characterized by, A plurality of the battery cell according to any one of claims 1-6 are electrically connected between each other.

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