Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a shell, two pole columns, a pole group and two connecting pieces. The pole is provided with a first boss; the pole group is arranged in the shell, and the pole group is provided with pole lugs which correspond to the pole columns and have the same polarity as the pole columns; the connecting sheet is arranged between the pole and the pole group and conductively connects the pole and the tab with the same polarity; the connecting piece comprises a pole connecting part and a tab connecting part, the pole connecting part is provided with an inserting hole, the first boss and the inserting hole are matched and inserted, and the outer peripheral wall of the first boss and the inner peripheral wall of the inserting hole are subjected to seam welding to realize conductive connection; and the two tab connecting parts are welded with the tabs with the corresponding polarities through the welding through holes. According to the utility model, the welding quality between the pole and the connecting sheet is good, the over-current area is large, the over-current capability is strong, the vibration can be effectively resisted, and the good over-current capability of the battery cell can still be ensured in a vibration working scene.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell and a battery pack. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles.

[0003] The connecting piece in the battery cell plays a role in conducting the electric energy of the electrode group to the electrode terminal. During the assembly of the battery cell, it is necessary to weld the connecting piece and the tab of the electrode group.

[0004] In the traditional battery cell solution, holes are opened in the cover plate, the electrode terminals and the connecting pieces are arranged on the cover plate, and the connecting pieces and the electrode terminals are welded to meet the over-current capacity of the battery cell. Since the electrode terminals and the connecting pieces are welded through penetration, the over-current capacity of the battery cell depends on the welding mark, the over-current area is small, and in the working scenario where the battery cell is vibrating, the welding surface between the electrode terminals and the connecting pieces is prone to looseness, resulting in poor over-current capacity and affecting the electrical conductivity. Summary of the Utility Model

[0005] In view of this, the utility model provides a battery cell and a battery pack to solve the problem of poor over-current capacity between the electrode terminal and the connecting piece in the working scenario where the battery cell is vibrating.

[0006] In a first aspect, the utility model provides a battery cell, which includes a housing, two electrode terminals, an electrode group and two connecting pieces. Two mounting holes and a welding through-hole are provided on the first side wall of the housing, and the welding through-hole is arranged between the two mounting holes; the two electrode terminals are respectively arranged in the two mounting holes; the electrode terminal is provided with a first boss; the electrode group is arranged in the housing, and the electrode group is provided with a tab having the same polarity as the electrode terminal corresponding to each electrode terminal; the connecting piece is arranged between the electrode terminal and the electrode group to conductively connect the electrode terminal and the tab with the same polarity; the connecting piece includes a pole connection part and an ear connection part, the pole connection part is provided with a socket hole, the first boss and the socket hole are matched and inserted, and the outer peripheral wall of the first boss and the inner peripheral wall of the socket hole are seam-welded to achieve conductive connection; both of the two ear connection parts are welded to the tab with the corresponding polarity through the welding through-hole.

[0007] Beneficial effects: For the battery cell provided by the present utility model, since the connecting piece is provided with a plugging hole and the pole post is provided with a first boss, the first boss and the plugging hole are plugged together to realize the assembly of the pole post and the connecting piece. The plugging fit between the first boss and the plugging hole can play a role in assembly limit, preventing the pole post and the connecting piece from shifting under the working scenario of vibration and affecting the over-current capacity. In addition, the outer peripheral wall of the first boss and the inner peripheral wall of the plugging hole are seam-welded to play the role of over-current between the pole post and the connecting piece. Due to the limiting effect between the first boss and the plugging hole and the use of seam-welding, the welding quality between the pole post and the connecting piece is ensured to be good, the over-current area is large, the over-current capacity is strong, and it can effectively resist vibration, ensuring that the battery cell still has good over-current capacity under the working scenario of vibration.

[0008] In an optional embodiment, when the outer peripheral wall of the first boss and the inner peripheral wall of the plugging hole are seam-welded, the penetration depth is D, D≥0.8mm, and the weld width is W, W≥1.2mm.

[0009] In an optional embodiment, the pole post includes a pole post body and a limiting convex edge provided on the outer surface of the pole post body. The pole post body is arranged in the mounting hole, the first boss is arranged on the inner surface of the pole post body, and the limiting convex edge is arranged on the outer end surface of the mounting hole.

[0010] In an optional embodiment, the height H of the inner surface of the first boss protruding from the inner surface of the pole post body is H≥1.2mm. The first boss is a cylindrical structure, and the radius R of the first boss is R≥1.5mm.

[0011] In an optional embodiment, the pole post connecting portion includes a connecting piece body and a second boss provided on the outer surface of the connecting piece body. The plugging hole penetrates through the second boss of the connecting piece.

[0012] In an optional embodiment, an enlarged groove is formed at the position on the inner surface of the connecting piece body corresponding to the second boss.

[0013] In an optional embodiment, a welding groove surrounding the plugging hole is provided on the inner surface of the second boss; the outer surface of the second boss abuts against the inner surface of the pole post body, and the second boss and the pole post body are penetration-welded through the welding groove.

[0014] In an optional embodiment, the pole group is provided with two pole tabs corresponding to the pole posts of each polarity respectively. The two pole tabs are respectively located on both sides of the pole tab connecting portion. The pole tab includes a root portion and a bent portion. The bent portion is perpendicular to the root portion. The bent portion is arranged on the outer surface of the pole tab connecting portion and is welded to the pole tab connecting portion.

[0015] In an alternative embodiment, the two pole columns are a positive pole column and a negative pole column respectively. The positive pole column is an integrally formed structure made of aluminum, and the negative pole column includes a first structural member made of aluminum and a second structural member made of copper. The first structural member and the second structural member are fixedly connected. The first structural member includes a limiting flange, and the second structural member includes a first boss.

[0016] In a second aspect, the present utility model further provides a battery pack, including a plurality of battery cells according to any one of the above technical solutions.

[0017] Beneficial effects: Since the battery pack includes battery cells, it has the same effects as the battery cells, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic structural diagram of a pole column in a battery cell according to an embodiment of the present utility model;

[0020] Figure 2 For Figure 1 a sectional view of the pole column shown along its axial direction;

[0021] Figure 3 It is a schematic structural diagram of a first perspective of a connecting piece in a battery cell according to an embodiment of the present utility model;

[0022] Figure 4 For Figure 3 a top view of the connecting piece shown;

[0023] Figure 5 For a sectional view along Figure 4 A-A in

[0024] Figure 6 For Figure 3 a schematic structural diagram of a second perspective of the connecting piece shown;

[0025] Figure 7 It is a schematic structural diagram of a battery cell in a first assembly state according to an embodiment of the present utility model;

[0026] Figure 8 It is a schematic structural diagram of a battery cell in a second assembly state according to an embodiment of the present utility model;

[0027] Figure 9A schematic structural diagram of a battery cell in the third assembly state provided by an embodiment of the present utility model;

[0028] Figure 10 is Figure 9 a top view of the battery cell shown;

[0029] Figure 11 is Figure 10 a cross-sectional view taken along line B-B in

[0030] Figure 12 is Figure 11 a partial enlarged view in

[0031] Figure 13 a schematic structural diagram of the negative electrode terminal.

[0032] Explanation of reference numerals:

[0033] 1. Housing; 101. First side wall; 102. Welding through hole; 2. Terminal; 21. Positive electrode terminal; 22. Negative electrode terminal; 221. First structural member; 222. Second structural member; 201. Terminal body; 202. First boss; 203. Limiting flange; 3. Electrode group; 301. Tab; 3011. Bent portion; 4. Connecting piece; 401. Terminal connecting portion; 4011. Connecting piece body; 4012. Second boss; 4013. Insertion hole; 4014. Expansion groove; 4015. Welding groove; 402. Tab connecting portion; 5. Sealing ring; 6. First plastic part; 7. Second plastic part; 8. Weld seam; 9. Sealing plate. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0035] Next, with reference to Figures 1 to 13 , the embodiments of the present utility model will be described.

[0036] According to an embodiment of the present invention, on the one hand, a battery cell is provided, which includes a housing 1, two pole columns 2, a pole group 3, and two connecting pieces 4. Two mounting holes and a welding through-hole 102 are provided on the first side wall 101 of the housing 1, and the welding through-hole 102 is arranged between the two mounting holes; the two pole columns 2 are respectively arranged in the two mounting holes; the pole column 2 is provided with a first boss 202; the pole group 3 is arranged in the housing 1, and the pole group 3 is provided with a pole tab 301 having the same polarity as the pole column 2 corresponding to each pole column 2; the connecting piece 4 is arranged between the pole column 2 and the pole group 3 to conductively connect the pole column 2 and the pole tab 301 of the same polarity; the connecting piece 4 includes a pole-column connecting portion 401 and a pole-tab connecting portion 402, the pole-column connecting portion 401 is provided with a plugging hole 4013, the first boss 202 and the plugging hole 4013 are matched and plugged, and the outer peripheral wall of the first boss 202 and the inner peripheral wall of the plugging hole 4013 are seam-welded to achieve conductive connection; the two pole-tab connecting portions 402 are both welded to the pole tabs 301 of the corresponding polarity through the welding through-hole 102.

[0037] For the battery cell provided by the embodiment of the present invention, the pole column 2 of the positive electrode is welded to the pole-column connecting portion 401 of a connecting piece 4, and the pole tab 301 on the positive electrode side is welded to the pole-tab connecting portion 402 of this connecting piece 4. Similarly, the pole column 2 of the negative electrode is welded to the pole-column connecting portion 401 of the other connecting piece 4, and the pole tab 301 on the negative electrode side is welded to the pole-tab connecting portion 402 of this connecting piece 4. The pole column 2, the connecting piece 4 and other structures are arranged on the housing 1, and by providing a welding through-hole 102, the pole tabs 301 on the positive electrode side and the negative electrode side are both welded to the corresponding connecting pieces 4 through this welding through-hole 102, so that the welding processes on the positive electrode side and the negative electrode side are continuous, one welding process is reduced, and the production efficiency is improved.

[0038] For the battery cell provided by the embodiment of the present invention, since the connecting piece 4 is provided with a plugging hole 4013 and the pole column 2 is provided with a first boss 202, the first boss 202 and the plugging hole 4013 are plugged to realize the assembly of the pole column 2 and the connecting piece 4. The plugging fit between the first boss 202 and the plugging hole 4013 can play a role in assembly limit, preventing the pole column 2 and the connecting piece 4 from being displaced in a vibrating working scenario and affecting the over-current capacity. In addition, the outer peripheral wall of the first boss 202 and the inner peripheral wall of the plugging hole 4013 are seam-welded to obtain a weld seam 8, which plays the role of over-current between the pole column 2 and the connecting piece 4. Due to the limiting effect between the first boss 202 and the plugging hole 4013 and the use of seam welding, the welding quality between the pole column 2 and the connecting piece 4 is good, the over-current area is large, the over-current capacity is strong, and it can effectively resist vibration, ensuring that the battery cell still has good over-current capacity in a vibrating working scenario.

[0039] In some embodiments, when the outer peripheral wall of the first boss 202 and the inner peripheral wall of the plugging hole 4013 are seam-welded, the penetration depth is D, D≥0.8mm, and the weld width is W, W≥1.2mm.

[0040] When seam - welding the outer peripheral wall of the first boss 202 and the inner peripheral wall of the insertion hole 4013, the penetration depth D is controlled within a range greater than or equal to 0.8 mm, and the weld width W is controlled within a range greater than or equal to 1.2 mm, which can ensure the welding quality between the first boss 202 and the insertion hole 4013, and guarantee good welding quality and current - carrying capacity.

[0041] In some embodiments, the pole column 2 includes a pole - column body 201 and a limiting flange 203 provided on the outer surface of the pole - column body 201. The pole - column body 201 is arranged in the mounting hole, the first boss 202 is arranged on the inner surface of the pole - column body 201, and the limiting flange 203 is arranged on the outer end surface of the mounting hole.

[0042] By providing the limiting flange 203 on the outer surface of the pole - column body 201, the limiting flange 203 can press on the outer end surface of the mounting hole, that is, the outer surface of the first side wall 101 of the housing 1, and can form a limit to ensure the assembly accuracy between the pole column 2 and the housing 1.

[0043] In some embodiments, the height H by which the inner surface of the first boss 202 protrudes from the inner surface of the pole - column body 201 is such that H≥1.2 mm. The first boss 202 is of a cylindrical structure, and the radius of the first boss 202 is R, where R≥1.5 mm.

[0044] By controlling the height H by which the inner surface of the first boss 202 protrudes from the inner surface of the pole - column body 201 within a range greater than or equal to 1.2 mm, and controlling the radius of the first boss 202 within a range greater than or equal to 1.5 mm, not only can the self - strength of the pole column 2 be improved, but also the manufacturing difficulty of the first boss 202 can be reduced. At the same time, the self - strength of the pole column 2 can be improved to prevent deformation during welding. Also, the larger the radius of the first boss 202, the larger the seam - welding area between the first boss 202 and the insertion hole 4013, and the stronger the current - carrying capacity between the pole column 2 and the connecting piece 4.

[0045] In some embodiments, the pole - column connecting portion 401 includes a connecting - piece body 4011 and a second boss 4012 provided on the outer surface of the connecting - piece body 4011. The insertion hole 4013 penetrates through the second boss 4012 of the connecting piece 4.

[0046] With this setting, a stepped structure is formed between the second boss 4012 and the connecting - piece body 4011, which can improve the self - strength of the connecting piece 4 and enhance the ability of the connecting piece 4 to resist welding thermal deformation.

[0047] The insertion hole 4013 penetrates through the second boss 4012. The insertion hole 4013 cooperates with the first boss 202 of the pole column 2, and the first boss 202 is inserted into the insertion hole 4013 of the connecting piece 4. Further, the inner surface of the first boss 202 is flush with the inner surface of the second boss 4012.

[0048] In some embodiments, an expansion groove 4014 is formed at a position on the inner surface of the connecting piece body 4011 corresponding to the second boss 4012.

[0049] An expansion groove 4014 is formed at a position on the inner surface of the connecting piece 4 corresponding to the second boss 4012, which can reduce the material used for the whole connecting piece 4 and the space occupied by the whole pole column 2 and the connecting piece 4 inside the battery cell. By forming the expansion groove 4014, the filling of the electrolyte can be increased, which is beneficial to improving the energy density of the battery cell.

[0050] In some embodiments, a welding groove 4015 surrounding the insertion hole 4013 is provided on the inner surface of the second boss 4012; the outer surface of the second boss 4012 abuts against the inner surface of the pole column body 201, and the second boss 4012 and the pole column body 201 are penetration-welded through the welding groove 4015.

[0051] By providing the welding groove 4015 on the inner surface of the second boss 4012 and the welding groove 4015 surrounding the insertion hole 4013, it is convenient to perform penetration welding on the second boss 4012 and the pole column body 201 at the welding groove 4015 to realize the connection of the pole column connection part 401 of the pole column 2 and the connecting piece 4. The penetration welding at the welding groove 4015 can play a fixing role between the pole column 2 and the connecting piece 4, strengthen the overall structural strength of the pole column 2 and the connecting piece 4, improve the current-carrying capacity between the pole column 2 and the connecting piece 4, and can also use the connecting piece 4 to compress the sealing ring 5 arranged in the mounting hole to improve the sealing effect, which will be specifically introduced below.

[0052] In some embodiments, the pole group 3 is provided with two pole tabs 301 corresponding to each polarity of the pole column 2 respectively. The two pole tabs 301 are respectively located on both sides of the pole tab connection part 402. The pole tab 301 includes a root part and a bent part 3011. The bent part 3011 is perpendicular to the root part. The bent part 3011 is arranged on the outer surface of the pole tab connection part 402 and is welded to the pole tab connection part 402.

[0053] Specifically, the pole tabs 301 are located on both sides of the pole tab connection part 402 of the connecting piece 4. Through a single 90° flip, the pole tabs 301 are formed into bent parts 3011. The bent parts 3011 are pressed on the outer surface of the pole tab connection part 402 of the connecting piece 4, and then the bent parts 3011 of the pole tabs 301 and the pole tab connection part 402 of the connecting piece 4 are welded. In the traditional scheme, the connecting piece 4 needs to be bent towards the direction of the pole tab 301, and the pole tab 301 needs to be bent towards the direction of the connecting piece 4, and then the two are welded. In contrast, this embodiment can reduce the bending process of the connecting piece 4 and the pole tab 301, improve the production efficiency, and reduce the space occupied by the connecting piece 4 and the pole tab 301 in the thickness direction of the connecting piece 4, which is beneficial to increasing the capacity of the battery cell.

[0054] In some embodiments, the two pole columns 2 are respectively a positive pole column 21 and a negative pole column 22. The positive pole column 21 is an integrally formed structure made of aluminum material. The negative pole column 22 includes a first structural member 221 made of aluminum material and a second structural member 222 made of copper material. The first structural member 221 and the second structural member 222 are fixedly connected. The first structural member 221 includes a limiting flange 203, and the second structural member 222 includes a first boss 202.

[0055] Specifically, the positive pole column 21 is set as an integrally formed structure made of aluminum material, and the negative pole column 22 is set as a splicing structure with aluminum on the upper part and copper on the lower part, meeting the positive and negative pole characteristics of the battery cell.

[0056] In some embodiments, the battery cell further includes a first plastic part 6 and a second plastic part 7. The first plastic part 6 is pressed between the limiting flange 203 of the pole column 2 and the outer surface of the first side wall 101, insulatingly connecting the pole column 2 and the housing 1. The second plastic part 7 is arranged on the inner surface of the first side wall 101, insulatingly connecting the connecting piece 4 and the housing 1.

[0057] In some embodiments, the battery cell further includes a sealing plate 9. The sealing plate 9 is connected to the welding through hole 102 to package the first side wall 101, realizing the sealing of the battery cell.

[0058] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including a plurality of battery cells in any one of the above technical solutions.

[0059] Since the battery pack includes the battery cell and has the same effects as the battery cell, it will not be elaborated here.

[0060] Although the embodiments of the present invention are 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 present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: A shell, wherein a first side wall of the shell is provided with two mounting holes and a welding through hole, and the welding through hole is provided between the two mounting holes; Two poles, the two poles are respectively arranged at the two mounting holes; the poles are provided with a first boss; A pole group, the pole group is arranged in the shell, and each pole of the pole group is provided with a pole ear with the same polarity as the pole; Two connecting plates are arranged between the pole and the pole group to conductively connect the pole and the pole lug of the same polarity; the connecting plate includes a pole connecting portion and a pole lug connecting portion, the pole connecting portion is provided with a plug-in hole, the first boss and the plug-in hole are matched and plugged, and the outer peripheral wall of the first boss and the inner peripheral wall of the plug-in hole are seam welded to achieve conductive connection; the two pole lug connecting portions are welded to the pole lugs of corresponding polarity through the welding through holes.

2. The battery cell according to claim 1, characterized in that: The outer peripheral wall of the first boss and the inner peripheral wall of the plug hole have a penetration depth of D when seam welding, D≥0.8mm, and a penetration width of W, W≥1.2mm.

3. The battery cell according to claim 1 or 2, characterized in that: The pole comprises a pole body and a limiting convex edge arranged on the outer surface of the pole body, the pole body is arranged in the mounting hole, the first boss is arranged on the inner surface of the pole body, and the limiting convex edge is arranged on the outer end surface of the mounting hole.

4. The battery cell according to claim 3, characterized in that: The inner surface of the first boss protrudes from the inner surface of the pole body by a height H, H≥1.2mm. The first boss is a cylindrical structure, and the radius of the first boss is R, R≥1.5mm.

5. The battery cell according to claim 3, characterized in that: The pole connecting portion includes a connecting piece body and a second boss arranged on the outer surface of the connecting piece body, and the plug hole passes through the second boss of the connecting piece.

6. The battery cell according to claim 5, characterized in that: A capacity expansion groove is formed on the inner surface of the connecting piece body at a position corresponding to the second boss.

7. The battery cell according to claim 5, characterized in that: The inner surface of the second boss is provided with a welding groove surrounding the plug hole; The outer surface of the second boss abuts against the inner surface of the pole body, and the second boss and the pole body are penetrated and welded through the welding groove.

8. The battery cell according to claim 1 or 2, characterized in that: The pole group is provided with two pole ears corresponding to each polarity pole, and the two pole ears are respectively located on both sides of the pole ear connection part. The pole ear includes a root and a bending part, the bending part is perpendicular to the root, and the bending part is arranged on the outer surface of the pole ear connection part and welded to the pole ear connection part.

9. The battery cell according to claim 3, characterized in that: The two poles are respectively a positive pole and a negative pole, the positive pole is an integrally formed structure made of aluminum, the negative pole includes a first structural member made of aluminum and a second structural member made of copper, the first structural member and the second structural member are fixedly connected, the first structural member includes the limiting convex edge, and the second structural member includes the first boss.

10. A battery pack, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 9.

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