Current collector, battery cell and battery pack

Abstract

The present application provides a current collector, which includes a connection part and a current collection part. The connection part has a first liquid injection hole, the current collection part has a second liquid injection hole, and the first liquid injection hole communicates with the second liquid injection hole. The current collection part has a first surface and a second surface arranged opposite to each other, and at least one first through hole penetrating the first surface and the second surface. The connection part is located on the first surface, and a groove is provided on the second surface. The groove communicates with the second liquid injection hole and at least one first through hole respectively. The present application also provides a battery cell and a battery pack. Among them, the battery cell includes a housing, an electrode assembly, an end cover and a current collector. The battery pack includes a box body and battery cells. The current collector, battery cell and battery pack provided by the present application can improve the liquid injection efficiency of the battery cell and the infiltration efficiency of the electrolyte, and improve the connection yield between the current collector in the battery cell and the electrode assembly, thereby improving the production efficiency and product yield of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of batteries, and particularly to a current collector, a battery cell and a battery pack. Background Art

[0002] During the production process of secondary batteries, it is necessary to inject electrolyte into the interior of the battery cell. The existing battery cells use a positive and negative pressure cycle for liquid injection. When the battery cell is in a negative pressure state, the air pressure inside the battery cell is less than the air pressure in the space where the electrolyte is located, and a pressure difference is formed between the inside of the battery cell and the space where the electrolyte is located. With the help of the pressure, the electrolyte is injected into the interior of the battery cell. In order to make the battery cell in a negative pressure state, it is necessary to evacuate the inside of the battery cell. Since the existing battery cell interior includes a current collector and an electrode assembly, the evacuation path inside the battery cell is tortuous and complex, and the evacuation efficiency is low, which in turn affects the liquid injection efficiency and production efficiency of the battery cell. Moreover, when the existing current collector is connected to the electrode assembly, the thickness at the connection is uneven, resulting in a low connection yield of the battery cell. Summary of the Invention

[0003] In view of the above problems, embodiments of the present application provide a current collector, a battery cell and a battery pack, which can effectively shorten the evacuation path inside the battery cell, improve the liquid injection efficiency of the battery cell and the infiltration efficiency of the electrolyte, and improve the connection yield between the current collector and the electrode assembly inside the battery cell, thereby improving the production efficiency and product yield of the battery cell.

[0004] A first aspect embodiment of the present application provides a current collector, the current collector includes:

[0005] a connection part, the connection part has a first liquid injection hole; and

[0006] a current collecting part, the current collecting part has a second liquid injection hole, the first liquid injection hole is communicated with the second liquid injection hole, the current collecting part has a first surface and a second surface arranged opposite to each other, and at least one first through hole penetrating through the first surface and the second surface, the connection part is located on the first surface, and a groove is provided on the second surface, and the groove is communicated with the second liquid injection hole and the at least one first through hole respectively.

[0007] In the embodiments of the present application, by providing the first liquid injection hole and the second liquid injection hole on the current collector, the liquid injection positions of the battery cells are integrated on the current collector, making the overall structure of the battery cells more compact and facilitating the injection of electrolyte into the battery cells. By providing the at least one first through hole and the groove, the gas between the end cap and the current collecting part can directly enter the groove, the second liquid injection hole and the first liquid injection hole in sequence through the at least one first through hole, and be discharged from the battery cell. This can effectively shorten the air extraction path, improve the air extraction efficiency, and further improve the production efficiency of the battery cell. Moreover, by providing the groove, when injecting electrolyte into the battery cell, during the process of the electrolyte flowing out from the second liquid injection hole to the electrode assembly, the electrolyte will flow along the groove to the surface of the end of the electrode assembly close to the current collector, thus improving the efficiency of the electrolyte wetting the electrode assembly.

[0008] Further, the groove includes a first sub-groove and at least one second sub-groove. The first sub-groove communicates with the second liquid injection hole, and the at least one second sub-groove is provided on the periphery of the first sub-groove and communicates the first sub-groove and the at least one first through hole.

[0009] In the embodiments of the present application, by providing the first sub-groove and the second sub-groove, while ensuring the smooth flow of gas, it is possible to avoid reducing the structural strength of the current collecting part due to the over-large size of the groove.

[0010] Further, the current collecting part includes a plurality of first through holes, and the groove includes a plurality of the second sub-grooves. The plurality of second sub-grooves are circumferentially spaced along the first sub-groove, and the plurality of second sub-grooves communicate with the plurality of first through holes in a one-to-one correspondence.

[0011] In the embodiments of the present application, by providing a plurality of the first through holes and a plurality of the second sub-grooves, gas can flow into the second liquid injection hole through the plurality of first through holes to further improve the air extraction efficiency. And the electrolyte can flow from the second liquid injection hole to the periphery of the surface of one end of the electrode assembly through the plurality of second sub-grooves, and the electrolyte wetting effect is better.

[0012] Further, the depth H of the groove satisfies: H≥D / 3, where D is the thickness of the current collecting part.

[0013] In the embodiments of the present application, by setting the depth H of the groove to satisfy H≥D / 3, it can ensure the smooth flow of gas in the battery cell to improve the air extraction efficiency.

[0014] In some embodiments of the present application, the current collector further has at least one electrical connection portion for connecting the electrode assembly. The electrical connection portion protrudes from the second surface in a direction away from the connection portion. The electrical connection portion is spaced apart from the groove and extends in a circumferential direction of the current collector from the second liquid injection hole. The current collector further has at least one second through hole penetrating the first surface and the second surface, and the at least one second through hole communicates with the electrical connection portion.

[0015] In an embodiment of the present application, by providing the at least one second through hole and the at least one second through hole communicating with the electrical connection portion, materials can flow out of the first surface through the at least one second through hole, thereby avoiding uneven thickness of the electrical connection portion caused by material accumulation, and further improving the connection reliability between the electrical connection portion and the electrode assembly. When the electrical connection portion and the electrode assembly are connected by welding, by providing the at least one second through hole communicating with the electrical connection portion, the welding yield can be improved.

[0016] Further, the current collector has two second through holes located at one end of the electrical connection portion close to the second liquid injection hole along the extending direction of the electrical connection portion, and the two second through holes are symmetrically arranged with respect to the electrical connection portion.

[0017] In an embodiment of the present application, by providing the two second through holes at one end close to the second liquid injection hole, the efficiency of materials flowing out of the first surface can be improved, ensuring that the thickness of the electrical connection portion is more uniform. And the two symmetrically arranged second through holes can further improve the efficiency of materials flowing out of the first surface and further ensure the uniform thickness of the electrical connection portion.

[0018] Further, the current collector has a plurality of electrical connection portion groups. Each electrical connection portion group includes one electrical connection portion and at least one second through hole, and the plurality of electrical connection portion groups are arranged at intervals around the second liquid injection hole.

[0019] In an embodiment of the present application, by arranging the plurality of electrical connection portion groups at intervals around the second liquid injection hole, the connection area between the current collector and the electrode assembly can be increased, thereby improving the connection stability between the two and the overcurrent effect of the battery cell.

[0020] Further, the aperture d1 of the at least one second through hole satisfies: 1.5 mm ≤ d1 ≤ 4 mm.

[0021] In an embodiment of the present application, by setting the aperture of the at least one second through hole within this range, the at least one second through hole can ensure the outflow effect of materials while ensuring the smooth forming of the electrical connection portion.

[0022] Furthermore, the current collecting part has at least one third through hole, and the electrical connection part has a first side, a second side, a third side, and a fourth side that are sequentially bent and connected end to end. Among them, the direction from the first side to the third side is the extending direction of the electrical connection part, and the at least one third through hole is spaced from the direction from the second side to the fourth side of the electrical connection part, and the minimum distance d2 between the at least one third through hole and the direction from the second side to the fourth side of the electrical connection part satisfies: d2≥1.5 mm.

[0023] In the embodiment of the present application, by arranging the at least one third through hole on the side of the electrical connection part, objects can also flow out of the first surface through the at least one third through hole, thereby avoiding uneven thickness of the electrical connection part caused by material accumulation, and further improving the connection reliability between the electrical connection part and the electrode assembly. And by setting the minimum distance d2 between the at least one third through hole and the direction from the second side to the fourth side of the electrical connection part to satisfy: d2≥1.5 mm, it can be avoided that the at least one third through hole affects the forming of the electrical connection part.

[0024] Furthermore, the current collecting part has two sets of through hole groups, each set of the through hole groups includes a plurality of third through holes, and the plurality of third through holes in each set are spaced along the extending direction of the electrical connection part, and the two sets of through hole groups are symmetrically arranged with respect to the electrical connection part in the direction from the second side to the fourth side.

[0025] In the embodiment of the present application, the two sets of through hole groups can further improve the efficiency of the material flowing out of the first surface and further ensure the uniform thickness of the electrical connection part.

[0026] Furthermore, the aperture d3 of the at least one third through hole satisfies: d3≥1.5 mm.

[0027] In the embodiment of the present application, by setting the aperture of the at least one third through hole within this range, the material can smoothly flow out of the at least one third through hole, thereby ensuring the uniform thickness of the electrical connection part.

[0028] The second aspect of the embodiment of the present application provides a battery cell, and the battery cell includes:

[0029] A housing, the housing includes a receiving cavity and an opening communicating with the receiving cavity;

[0030] An electrode assembly, the electrode assembly is received in the receiving cavity;

[0031] An end cap, the end cap covers the opening; and

[0032] A current collector, the connecting portion is connected to the end cap, and the second surface of the current collector is connected to the electrode assembly. For the current collector, please refer to the introductions of the previous embodiments and will not be elaborated here.

[0033] In the embodiments of the present application, by adopting a current collector provided with the first through hole and the groove, the battery cell can effectively shorten the gas extraction path, improve the gas extraction efficiency, and further improve the production efficiency of the battery cell.

[0034] Further, the end cap is provided with a mounting hole; the connecting portion includes a first sub-connecting portion and a second sub-connecting portion. The first sub-connecting portion is inserted into the mounting hole to be connected to the end cap, and at least part of the surface of the first sub-connecting portion is exposed outside the end cap. One end of the second sub-connecting portion close to the first sub-connecting portion abuts against the end cap, and the end of the second sub-connecting portion far from the first sub-connecting portion is connected to the current collecting portion, so that a pressure relief space is formed between the current collecting portion and the end cap, and the pressure relief space communicates with the first through hole.

[0035] In the embodiments of the present application, by setting at least part of the surface of the first sub-connecting portion to be exposed outside the end cap, on the one hand, the first liquid injection hole is communicated with the outside of the battery cell, which is convenient for directly injecting electrolyte into the battery cell through the first liquid injection hole to improve the liquid injection efficiency. On the other hand, when the current collector and the end cap are connected by welding, at least part of the surface of the first section is exposed outside the end cap, so that the welding position of the current collector and the end cap is located outside the battery cell, which is convenient to confirm the welding position of the current collector and the end cap, thereby improving the welding efficiency and welding effect.

[0036] By providing the pressure relief space, when the battery cell undergoes thermal runaway, the gas generated by the electrode assembly can enter the pressure relief space through the first through hole, thereby realizing pressure release.

[0037] By communicating the pressure relief space with the first through hole, when the battery cell is evacuated, the gas in the pressure relief space can directly pass through the first through hole and the groove, and then enter the second liquid injection hole and the first liquid injection hole, and the gas in the pressure relief space is discharged to the outside of the battery cell from the first liquid injection hole, thereby improving the gas extraction efficiency.

[0038] The third aspect of the embodiments of the present application provides a battery pack, which includes:

[0039] A box body, and

[0040] A battery cell, which is accommodated in the box body. For the battery cell, please refer to the introductions of the previous embodiments and will not be elaborated here.

[0041] In the embodiments of the present application, by adopting the battery cells described in the various embodiments of the present application, the production efficiency, production yield, and safety are effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0043] Figure 1 A three-dimensional schematic diagram of a current collector provided in an embodiment of the present application;

[0044] Figure 2 For Figure 1 The bottom view of the provided current collector;

[0045] Figure 3 For Figure 2 The sectional schematic diagram of the current collector along the line I-I in ;

[0046] Figure 4 For Figure 3 The enlarged schematic diagram at A in ;

[0047] Figure 5 For Figure 1 The top view of the provided current collector;

[0048] Figure 6 A three-dimensional schematic diagram of a battery cell provided in an embodiment of the present application;

[0049] Figure 7 For Figure 6 The three-dimensional exploded view of the provided battery cell;

[0050] Figure 8 For Figure 6 The top view of the provided battery cell;

[0051] Figure 9 For Figure 8 The sectional schematic diagram of the battery cell along the line J-J in ;

[0052] Figure 10 For Figure 9 The enlarged schematic diagram at B in ;

[0053] Figure 11 A three-dimensional schematic diagram of a battery pack provided in an embodiment of the present application.

[0054] Description of the reference numerals:

[0055] 100 - Current collector, 110 - Connection part, 111 - First liquid injection hole, 112 - First sub - connection part, 113 - Second sub - connection part, 120 - Current collection part, 121 - Second liquid injection hole, 122 - First surface, 123 - Second surface, 1231 - Groove, 1231a - First sub - groove, 1231b - Second sub - groove, 124 - First through - hole, 125 - Electrical connection part, 1251 - First side, 1252 - Second side, 1253 - Third side, 1254 - Fourth side, 126 - Second through - hole, 127 - Electrical connection part group, 128 - Third through - hole, 129 - Through - hole group;

[0056] 200 - Battery cell, 210 - Housing, 211 - Accommodation cavity, 212 - Opening, 220 - Electrode assembly, 230 - End cap, 231 - Mounting hole, 240 - Pressure relief space;

[0057] 300 - Battery pack, 310 - Box body. Detailed implementation manners

[0058] In order to enable those skilled in the art to better understand the solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0059] The terms "first", "second", etc. in the specification, claims and the above - mentioned drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non - exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices. The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings.

[0060] It should be noted that for the convenience of description, in the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments.

[0061] Please refer to Figure 1 、 Figure 2 and Figure 3 , Figure 1 which is a three - dimensional schematic diagram of the current collector provided by an embodiment of this application; Figure 2 isFigure 1 Bottom view of the current collector provided Figure 3 is Figure 2 Schematic cross-sectional view of the middle current collector along line I-I. In the first aspect of the embodiments of the present application, a current collector 100 is provided. The current collector 100 includes a connection part 110 and a current collection part 120. The connection part 110 has a first liquid injection hole 111. The current collection part 120 has a second liquid injection hole 121, and the first liquid injection hole 111 communicates with the second liquid injection hole 121. The current collection part 120 has a first surface 122 and a second surface 123 arranged opposite to each other, and at least one first through hole 124 penetrating through the first surface 122 and the second surface 123. The connection part 110 is located on the first surface 122, and the second surface 123 is provided with a groove 1231, and the groove 1231 communicates with the second liquid injection hole 121 and the at least one first through hole 124 respectively.

[0062] Specifically, when the current collector 100 is applied to the battery cell 200 (please refer to Figure 9 ), the current collector 100 is respectively connected to the end cap 230 of the battery cell 200 and the electrode assembly 220 of the battery cell 200. Among them, the connection part 110 is connected to the end cap 230, and the current collection part 120 is connected to the electrode assembly 220. The first liquid injection hole 111 and the second liquid injection hole 121 communicate to form a liquid injection channel of the battery cell 200 for injecting electrolyte into the battery cell 200.

[0063] It can be understood that, on the one hand, by providing the first liquid injection hole 111 and the second liquid injection hole 121, the liquid injection channel of the battery cell 200 is integrated on the current collector 100, so that the overall structure of the battery cell 200 is more compact, and it is more convenient to inject electrolyte into the battery cell 200.

[0064] On the other hand, it can be assumed that, in the case where the at least one first through hole 124 and the groove 1231 are not provided, when it is necessary to inject electrolyte into the battery cell 200, the inside of the battery cell 200 is evacuated, and the gas between the end cap 230 and the current collector portion 120 needs to bypass the electrode assembly 220 to enter the second liquid injection hole 121 and the first liquid injection hole 111, and is discharged from the battery cell 200 through the first liquid injection hole 111. Therefore, by providing the at least one first through hole 124 and the groove 1231, the gas between the end cap 230 and the current collector portion 120 can directly enter the groove 1231, the second liquid injection hole 121, and the first liquid injection hole 111 through the at least one first through hole 124 in sequence, and is discharged from the battery cell 200. Thereby, the evacuation path can be effectively shortened, the evacuation efficiency can be improved, and further the production efficiency of the battery cell 200 can be improved. Moreover, by providing the groove 1231, when injecting electrolyte into the battery cell 200, during the process of the electrolyte flowing out from the second liquid injection hole 121 to the electrode assembly 220, the electrolyte will flow along the groove 1231 to the surface of the electrode assembly 220 near the end of the current collector 100, thereby improving the efficiency of the electrolyte wetting the electrode assembly 220.

[0065] Please refer to Figure 2 , Figure 3 and Figure 4 , wherein, Figure 4 is Figure 3 an enlarged schematic view of portion A in

[0066] Understandably, by providing the first sub-groove 1231a and the second sub-groove 1231b, while ensuring the smooth flow of gas, it is possible to avoid reducing the structural strength of the current collecting portion 120 due to the oversize of the groove 1231. In some embodiments of the present application, the first sub-groove 1231a may surround the second liquid injection hole 121, so that gas can flow into the second liquid injection hole 121 from any direction of the second liquid injection hole 121. The second sub-groove 1231b is a strip-shaped groove 1231 connecting the second liquid injection hole 121 and the at least one first through hole 124, to guide the gas flow direction and ensure the structural strength of the current collecting portion 120. Moreover, the strip-shaped groove 1231 also has the function of guiding the flow of the electrolyte, that is, guiding the electrolyte to flow from the second liquid injection hole 121 to the periphery of the surface of the electrode assembly 220 near one end of the current collecting member 100, so that the electrolyte evenly wets the electrode assembly 220 and further improves the electrolyte wetting rate.

[0067] Please continue to refer to Figure 2 , further, the current collecting portion 120 includes a plurality of first through holes 124, the groove 1231 includes a plurality of the second sub-grooves 1231b, the plurality of second sub-grooves 1231b are circumferentially spaced along the first sub-groove 1231a, and the plurality of second sub-grooves 1231b communicate with the plurality of first through holes 124 in one-to-one correspondence.

[0068] Understandably, by providing the plurality of first through holes 124 and the plurality of second sub-grooves 1231b, gas can flow into the second liquid injection hole 121 through the plurality of first through holes 124, so as to further improve the air extraction efficiency. And the electrolyte can flow from the second liquid injection hole 121 to the periphery of the surface of one end of the electrode assembly 220 through the plurality of second sub-grooves 1231b, and the electrolyte wetting effect is better.

[0069] Please refer to Figure 4 , further, the depth H of the groove 1231 satisfies: H≥D / 3, where D is the thickness of the current collecting portion 120. Understandably, after the current collecting member 100 is connected to the electrode assembly 220, the gap between the two is very small, and during the use of the battery cell 200, the electrode assembly 220 will also expand, resulting in the extrusion of the current collecting member 100 and the electrode assembly 220, and the gap between the current collecting member 100 and the electrode assembly 220 is further reduced, affecting the flow of gas in the groove 1231 between the end cap 230 and the current collecting portion 120. Therefore, by setting the depth H of the groove 1231 to satisfy: H≥D / 3, it is possible to ensure the smooth flow of gas in the battery cell 200 to improve the air extraction efficiency.

[0070] Please refer to Figure 5 , Figure 5 the top view of the current collector provided Figure 1 . In some embodiments of the present application, the current collector portion 120 further has an electrical connection portion 125 for connecting to the electrode assembly 220. The electrical connection portion 125 protrudes from the second surface 123 in a direction away from the connection portion 110. The electrical connection portion 125 is spaced apart from the groove 1231 and extends in a direction from the second liquid injection hole 121 towards the periphery of the current collector portion 120. The current collector portion 120 further has at least one second through hole 126 penetrating through the first surface 122 and the second surface 123, and the at least one second through hole 126 communicates with the electrical connection portion 125. Specifically, the electrical connection portion 125 can be formed by stamping, so that the electrical connection portion 125 forms a protrusion on the second surface 123 in a direction away from the connection portion 110 for connection with the electrode assembly 220, and the electrical connection portion 125 forms a depression on the first surface 122. The electrical connection portion 125 is spaced apart from the groove 1231 to ensure the smooth forming of the current collector portion 120.

[0071] It can be understood that by setting the electrical connection portion 125 to extend in a direction from the second liquid injection hole 121 towards the periphery of the current collector portion 120, it can ensure the full connection between the electrical connection portion 125 and the electrode assembly 220 and ensure the overcurrent of the battery cell 200. Since the electrical connection portion 125 is prone to material accumulation on the first surface 122 during the stamping process, resulting in uneven thickness of the electrical connection portion 125 after forming. Therefore, by providing the at least one second through hole 126 and the at least one second through hole 126 communicating with the electrical connection portion 125, the material can flow out of the first surface 122 through the at least one second through hole 126, thereby avoiding uneven thickness of the electrical connection portion 125 caused by material accumulation, and further improving the connection reliability between the electrical connection portion 125 and the electrode assembly 220. When the electrical connection portion 125 is connected to the electrode assembly 220 by welding, by providing the at least one second through hole 126 communicating with the electrical connection portion 125, the welding yield can be improved.

[0072] Please continue to refer to Figure 5 , further, the current collector portion 120 has two second through holes 126, and the two second through holes 126 are located at one end of the electrical connection portion 125 close to the second liquid injection hole 121 along the extension direction of the electrical connection portion 125, and the two second through holes 126 are symmetrically arranged with respect to the electrical connection portion 125.

[0073] Understandably, since one end close to the second liquid injection hole 121 is a position where more materials accumulate, by arranging the two second through holes 126 at the end close to the second liquid injection hole 121, the efficiency of the material flowing out of the first surface 122 can be improved, ensuring that the thickness of the electrical connection part 125 is more uniform. Moreover, the two symmetrically arranged second through holes 126 can further improve the efficiency of the material flowing out of the first surface 122 and further ensure the uniform thickness of the electrical connection part 125.

[0074] Please continue to refer to Figure 5 , further, the current collector part 120 has a plurality of electrical connection part groups 127. Each electrical connection part group 127 includes an electrical connection part 125 and at least one second through hole 126. The multiple electrical connection part groups 127 are arranged at intervals around the second liquid injection hole 121.

[0075] Understandably, by arranging the multiple electrical connection part groups 127 at intervals around the second liquid injection hole 121, the connection area between the current collector part 120 and the electrode assembly 220 can be increased, thereby improving the connection stability between the two and the overcurrent effect of the battery cell 200.

[0076] Please continue to refer to Figure 5 , further, the aperture d1 of the at least one second through hole 126 satisfies: 1.5 mm ≤ d1 ≤ 4 mm. Specifically, it can be 1.5 mm, or 1.6 mm, or 1.7 mm, or 1.8 mm, or 1.9 mm, or 2 mm, or 3 mm, or 4 mm. Understandably, within this range, the at least one second through hole 126 can ensure the outflow effect of the material while ensuring the smooth formation of the electrical connection part 125. If the aperture d1 of the at least one second through hole 126 is less than 1.5 mm, the outflow speed and flow rate of the material will be affected; if the aperture d1 of the at least one second through hole 126 is greater than 4 mm, the formation of the electrical connection part 125 will be affected.

[0077] Please continue to refer to Figure 5, Further, the current collector portion 120 has at least one third through hole 128, and the electrical connection portion 125 has a first side 1251, a second side 1252, a third side 1253, and a fourth side 1254 that are sequentially bent and connected end to end. Among them, the direction from the first side 1251 to the third side 1253 is the extending direction of the electrical connection portion 125, and the at least one third through hole 128 is spaced from the direction of the electrical connection portion 125 from the second side 1252 to the fourth side 1254, and the minimum distance d2 between the at least one third through hole 128 and the direction of the electrical connection portion 125 from the second side 1252 to the fourth side 1254 satisfies: d2≥1.5 mm.

[0078] It can be understood that by providing the at least one third through hole 128 on the side of the electrical connection portion 125, objects can also flow out of the first surface 122 through the at least one third through hole 128, thereby avoiding uneven thickness of the electrical connection portion 125 caused by material accumulation, and further improving the connection reliability between the electrical connection portion 125 and the electrode assembly 220. And by setting the minimum distance d2 between the at least one third through hole 128 and the direction of the electrical connection portion 125 from the second side 1252 to the fourth side 1254 to satisfy: d2≥1.5 mm, it can be avoided that the at least one third through hole 128 affects the forming of the electrical connection portion 125. If the minimum distance between the at least one third through hole 128 and the electrical connection portion 125 is greater than 1.5 mm, the at least one third through hole 128 is too close to the electrical connection portion 125, affecting the forming of the electrical connection portion 125.

[0079] Please continue to refer to Figure 5 , Further, the current collector portion 120 has two sets of through hole groups 129. Each set of the through hole groups 129 includes a plurality of third through holes 128. The plurality of third through holes 128 in each set are spaced along the extending direction of the electrical connection portion 125, and the two sets of through hole groups 129 are symmetrically arranged with respect to the electrical connection portion 125 in the direction from the second side 1252 to the fourth side 1254. It can be understood that the two sets of through hole groups 129 can further improve the efficiency of material flowing out of the first surface 122 and further ensure the uniform thickness of the electrical connection portion 125.

[0080] Please continue to refer to Figure 5 , Further, the aperture d3 of the at least one third through hole 128 satisfies: d3≥1.5 mm. In this range, materials can flow out of the at least one third through hole 128 smoothly, thereby ensuring the uniform thickness of the electrical connection portion 125. If the aperture of the at least one third through hole 128 is less than 1.5 mm, the connection effect between the current collector portion 120 and the electrode assembly 220 is poor.

[0081] Please refer to Figure 6 and Figure 7 , Figure 6 which is a three-dimensional schematic diagram of a battery cell provided for an embodiment of the present application; Figure 7 is Figure 6 a three-dimensional exploded view of the battery cell provided. An embodiment of the second aspect of the present application provides a battery cell 200, and the battery cell 200 includes a housing 210, an electrode assembly 220, an end cap 230, and a current collector 100. The housing 210 includes a receiving cavity 211 and an opening 212 communicating with the receiving cavity 211. The electrode assembly 220 is received in the receiving cavity 211, and the end cap 230 covers the opening 212. A connecting portion 110 of the current collector 100 is connected to the end cap 230, and a second surface 123 of the current collector 100 is connected to the electrode assembly 220. For the current collector 100, please refer to the introductions of the previous embodiments, and details will not be repeated here.

[0082] It can be understood that for the battery cell 200 of the present application, by adopting the current collector 100 provided with the first through hole 124 and the groove 1231, when it is necessary to evacuate the inside of the battery cell 200, the gas between the end cap 230 and the current collecting portion 120 can directly enter the groove 1231, the second liquid injection hole 121, and the first liquid injection hole 111 in sequence through the first through hole 124, and then discharge from the battery cell 200. Thereby, the evacuation path can be effectively shortened, the evacuation efficiency can be improved, and further the production efficiency of the battery cell 200 can be improved.

[0083] Please refer to Figures 7 to 10 , wherein Figure 8 is Figure 6 a top view of the battery cell provided; Figure 9 is Figure 8 a cross-sectional schematic diagram of the battery cell along the J-J line in Figure 10 is Figure 9 an enlarged schematic diagram at B in . Further, the end cap 230 is provided with a mounting hole 231; the connecting portion 110 includes a first sub-connecting portion 112 and a second sub-connecting portion 113. The first sub-connecting portion 112 is inserted into the mounting hole 231 to be connected to the end cap 230, and at least part of the surface of the first sub-connecting portion 112 is exposed outside the end cap 230. One end of the second sub-connecting portion 113 close to the first sub-connecting portion 112 abuts against the end cap 230, and the other end of the second sub-connecting portion 113 away from the first sub-connecting portion 112 is connected to the current collecting portion 120, so that a pressure relief space 240 is formed between the current collecting portion 120 and the end cap 230, and the pressure relief space 240 communicates with the first through hole 124.

[0084] Understandably, by setting at least part of the surface of the first sub-connection part 112 to be exposed to the end cap 230, on the one hand, the first liquid injection hole 111 is communicated with the outside of the battery cell 200, which is convenient for directly injecting electrolyte into the battery cell 200 through the first liquid injection hole 111 to improve the liquid injection efficiency. On the other hand, when the current collector 100 and the end cap 230 are connected by welding, at least part of the surface of the first section is exposed to the end cap 230, so that the welding position of the current collector 100 and the end cap 230 is located outside the battery cell 200, which is convenient to confirm the welding position of the current collector 100 and the end cap 230, thereby improving the welding efficiency and welding effect. Of course, in other embodiments, the connection manner between the current collector 100 and the end cap 230 may also be other manners other than welding, and here, it is not limited thereto.

[0085] Understandably, by providing the pressure relief space 240, when the battery cell 200 undergoes thermal runaway, the gas generated by the electrode assembly 220 can enter the pressure relief space 240 through the first through hole 124, thereby realizing the release of pressure. If the thermal runaway degree of the battery cell 200 is relatively mild and the amount of gas generated by the battery cell 200 is small, the gas entering the pressure relief space 240 can realize the release of pressure, thereby avoiding potential safety hazards caused by excessive internal pressure of the battery cell 200. If the thermal runaway degree of the battery cell 200 is relatively severe and the amount of gas generated by the battery cell 200 is large, the gas generated by the electrode assembly 220 passes through the pressure relief space 240, and when the internal pressure of the battery cell 200 is higher than the set threshold, the gas rushes out of the explosion-proof valve on the end cap 230 and is discharged to the outside of the battery cell 200 to release the internal pressure of the battery cell 200 and improve the safety of the battery cell 200.

[0086] By communicating the pressure relief space 240 with the first through hole 124, when the battery cell 200 is evacuated, the gas located in the pressure relief space 240 can directly pass through the first through hole 124 and the groove 1231, and then enter the second liquid injection hole 121 and the first liquid injection hole 111, and discharge the gas in the pressure relief space 240 to the outside of the battery cell 200 from the first liquid injection hole 111, thereby improving the evacuation efficiency.

[0087] Please refer to Figure 11 , Figure 11A three-dimensional schematic diagram of a battery pack provided by an embodiment of the present application. An embodiment of the third aspect of the present application provides a battery pack 300, which includes a box body 310 and at least one battery cell 200, and the battery cell 200 is accommodated in the box body 310. For the description of the battery cell 200, please refer to the introductions of the previous embodiments and will not be elaborated here. By adopting the battery cell 200 described in the various embodiments of the present application, the battery pack 300 effectively improves production efficiency, production yield and safety.

[0088] In the present application, the mention of "embodiment" and "embodiment mode" means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments. In addition, it should also be understood that the features, structures or characteristics described in the various embodiments of the present application can be combined arbitrarily without contradiction to form another embodiment that does not deviate from the spirit and scope of the technical solution of the present application.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A current collector, characterized in that, Comprising: A connecting part, the connecting part having a first liquid injection hole; And A current collecting part, the current collecting part having a second liquid injection hole, at least one electrical connection part and two second through holes, the first liquid injection hole communicating with the second liquid injection hole, the current collecting part having a first surface and a second surface arranged opposite to each other, and at least one first through hole penetrating through the first surface and the second surface, the connecting part being located on the first surface, the second surface being provided with a groove, the groove communicating with the second liquid injection hole and the at least one first through hole respectively, the electrical connection part being used for electrically connecting an electrode assembly, the electrical connection part protruding from the second surface in a direction away from the connecting part, the electrical connection part being spaced apart from the groove, and extending in a circumferential direction of the current collecting part from the second liquid injection hole; the second through hole penetrates through the first surface and the second surface, the second through hole communicating with the electrical connection part, the two second through holes being located at one end of the electrical connection part close to the second liquid injection hole along the extending direction of the electrical connection part, and the two second through holes being symmetrically arranged with respect to the electrical connection part, the second through hole being used for the material to flow out when the electrical connection part is stamped.

2. The current collector according to claim 1, characterized in that, The groove includes a first sub-groove and at least one second sub-groove, the first sub-groove communicating with the second liquid injection hole, the at least one second sub-groove being arranged on the periphery of the first sub-groove and communicating the first sub-groove and the at least one first through hole.

3. The current collector according to claim 2, characterized in that, The current collecting part includes a plurality of first through holes, the groove includes a plurality of the second sub-grooves, the plurality of second sub-grooves are circumferentially spaced apart along the first sub-groove, and the plurality of second sub-grooves communicate with the plurality of first through holes in a one-to-one correspondence.

4. The current collector according to claim 1, wherein The depth H of the groove satisfies: H≥D / 3, where D is the thickness of the current collecting part.

5. The current collector according to claim 1, characterized in that, The current collecting part has a plurality of electrical connection part groups, each group of electrical connection part groups including one electrical connection part and at least one second through hole, the plurality of groups of electrical connection part groups being arranged at intervals around the second liquid injection hole.

6. The current collector according to claim 1, wherein The aperture d1 of the at least one second through hole satisfies: 1.5mm≤d1≤4mm.

7. The current collector according to claim 1, characterized in that The current collecting part has at least one third through hole, the electrical connection part having a first side, a second side, a third side and a fourth side which are sequentially bent and connected end to end, wherein the direction from the first side to the third side is the extending direction of the electrical connection part, the at least one third through hole being spaced apart from the direction of the electrical connection part from the second side to the fourth side, and the minimum distance d2 between the at least one third through hole and the direction of the electrical connection part from the second side to the fourth side satisfying: d2≥1.5mm.

8. The current collector according to claim 7, characterized in that, The current collecting part has two groups of through hole groups, each group of through hole groups including a plurality of third through holes, the plurality of third through holes in each group being spaced apart along the extending direction of the electrical connection part, and the two groups of through hole groups being symmetrically arranged with respect to the electrical connection part in the direction from the second side to the fourth side.

9. The current collector according to claim 7, wherein The aperture d3 of the at least one third through hole satisfies: d3≥1.5mm.

10. A battery cell, characterized in that, The battery cell described above includes: A housing, the housing including a receiving cavity and an opening communicating with the receiving cavity; An electrode assembly, the electrode assembly being received in the receiving cavity; An end cap, the end cap covering the opening; and A current collector as described in any one of claims 1-9, the connecting portion being connected to the end cap, and the second surface of the current collector being connected to the electrode assembly.

11. The battery cell according to claim 10, characterized in that, The end cap is provided with a mounting hole; the connecting portion includes a first sub-connecting portion and a second sub-connecting portion, the first sub-connecting portion being inserted into the mounting hole to be connected to the end cap, and at least a part of the surface of the first sub-connecting portion being exposed from the end cap, one end of the second sub-connecting portion close to the first sub-connecting portion abuts against the end cap, and the other end of the second sub-connecting portion away from the first sub-connecting portion is connected to the current collecting portion, so that a pressure relief space is formed between the current collecting portion and the end cap, and the pressure relief space communicates with the first through hole.

12. A battery pack, characterized in that, Comprising: A box body, and At least one battery cell as described in claim 10 or 11, the battery cell being received in the box body.

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