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 housing having an accommodating cavity with an open end; the cover plate covers the opening end, and two welding openings and two mounting openings are formed in the cover plate; the two pole columns are arranged in one-to-one correspondence with the two mounting openings; the pole group is arranged in the accommodating cavity, one side of the pole group is provided with a plurality of tab groups corresponding to the two welding openings, and each tab group comprises two tabs; each connecting piece is provided with a first connecting part and a second connecting part, each first connecting part is connected with the corresponding pole, a gap is formed between each second connecting part and the corresponding welding opening, each tab penetrates through the corresponding gap and then is bent to form a bent part, and each bent part and the corresponding second connecting part are welded through the corresponding welding opening; and a reinforcing structure is arranged on the second connecting part. During welding, only the tabs need to be bent, the connecting pieces do not need to be bent, the thickness of the connecting pieces and the tabs is reduced after the connecting pieces and the tabs are connected, and occupied space in the battery cell is reduced.

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] At present, in order to improve the energy density of power batteries and make more efficient use of the limited space inside passenger cars, the prior art usually makes the battery module larger. Specifically, there are two ways to achieve a large module. One is to stack multiple battery cells in a single row to form a long module, and the other is to stack multiple battery cells in two rows or multiple rows to form a wide module. The use of large modules can improve the energy density and space utilization rate of the battery, and can also improve the production speed of the module.

[0003] A conventional battery cell module is composed of a plurality of battery cells stacked together. The battery cell includes a housing, a cover plate, a pole group, etc. The positive and negative electrode plates are formed into a pole group by winding or laminating, and then the pole tabs of the pole group and the pole posts are effectively welded and transferred through a transfer piece to realize the connection of the positive and negative electrodes of the pole tabs and the positive and negative electrodes of the pole posts. After the preparation and stacking arrangement of the battery cells are completed, the series and parallel connection of multiple battery cells in the module are realized by welding jumper copper bars on the positive and negative electrode posts of the battery cells as required.

[0004] Usually, when the connecting piece and the electrode plate are connected, bending is required, which leads to a relatively thick thickness after the connecting piece and the pole tab are connected, occupying more internal space of the battery cell, and the utilization rate of the internal space of the battery cell is relatively low. 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 that when the connecting piece and the electrode plate are connected, bending is required, resulting in a relatively thick thickness after the connecting piece and the pole tab are connected and occupying more internal space of the battery cell.

[0006] In a first aspect, the utility model provides a battery cell, including: a housing having a receiving cavity with an open end; a cover plate covering the open end, and two spaced welding openings and two spaced mounting openings are provided on the cover plate; two pole posts corresponding to the two mounting openings one by one; a pole group disposed in the receiving cavity, and a plurality of pole tab groups corresponding to the two welding openings are provided on one side of the pole group, and each pole tab group includes two pole tabs; two connecting pieces, each connecting piece having a first connecting portion and a second connecting portion, the first connecting portion is connected to the corresponding pole post, a gap for the pole tab to pass through is formed between the second connecting portion and the corresponding welding opening, each pole tab passes through the gap and then is bent to form a bent portion, the bent portion is welded to the corresponding second connecting portion through the corresponding welding opening, and a strengthening structure is provided on the second connecting portion, and the strengthening structure is used to strengthen the structural strength of the connecting piece.

[0007] Beneficial effects: When welding the connecting piece and the tab, first insert the pole into the accommodating cavity of the housing and pass the tab through the corresponding gap. Then, after bending the tab, the bent portion is welded to the second connecting portion of the connecting piece by welding processes such as laser welding or ultrasonic welding. Only the tab needs to be bent, and there is no need to bend the connecting piece. Compared with the existing connection method where both the connecting piece and the tab need to be bent during connection, the thickness after connection of the connecting piece and the tab becomes thinner, which can reduce the space occupied inside the battery cell, contribute to improving the energy density of the battery cell, and enhance the space utilization rate inside the battery cell. Moreover, the bending process of the connecting piece is reduced, the manufacturing process is simplified, the production efficiency is improved, the production cost is reduced, and the potential damage or deformation risk caused by bending the connecting piece is also reduced. Since the connecting piece does not need to be bent, material waste can be reduced and costs can be saved. The setting of the welding opening avoids the bending equipment and the welding equipment, which not only facilitates bending the tab but also facilitates welding the tab and the connecting piece, improves the welding efficiency, and reduces the cost. The two welding openings are arranged at intervals so that the cover plate is not completely disconnected in the middle, enhancing the self-strength of the cover plate and further enhancing the structural strength of the battery cell. A reinforcing structure is provided on the second connecting portion to ensure that when the tab is welded to the connecting piece, only relying on the strength of the connecting piece itself can ensure zero-gap contact between the connecting piece and the tab, ensuring the welding effect and achieving the purpose of saving space and improving the space utilization rate in the height direction of the battery.

[0008] In an optional implementation manner, the reinforcing structure is a reinforcing rib provided on the surface of the second connecting portion and protruding toward one side.

[0009] Beneficial effects: The strength and rigidity of the connecting piece can be enhanced through the reinforcing rib. When the tab is welded to the connecting piece, the upper part of the tab needs to be pressed by a tooling, and the lower part of the connecting piece does not need to be supported by a tooling, that is, the lower part of the connecting piece does not need the support of an auxiliary tooling, simplifying the welding process and improving the welding efficiency. The structure of the reinforcing rib is simple and easy to implement, reducing costs.

[0010] In an optional implementation manner, the reinforcing rib protrudes toward the cover plate, or the reinforcing rib protrudes in a direction away from the cover plate.

[0011] In an optional implementation manner, the reinforcing rib extends along the length direction of the cover plate and divides the second connecting portion into two connecting sub-portions, and the two connecting sub-portions are respectively welded to the two tabs of a corresponding tab group one by one.

[0012] Beneficial effects: By arranging the reinforcing rib between the two connecting sub-portions, the strength and stiffness of the second connecting portion are enhanced, and it will not interfere with the area where the tab is welded on the second connecting portion.

[0013] In an optional implementation manner, the length L of the reinforcing rib along the length direction of the cover plate is greater than the length L1 of the tab along the length direction of the cover plate.

[0014] Beneficial effects: The length L1 of the tab can be understood as the length of the welding area where the tab is welded to the connecting piece. Setting the length L of the reinforcing rib to be greater than the length of the welding area can further strengthen the strength and stiffness of the connecting piece, making the connecting piece less likely to deform during welding and improving the welding quality.

[0015] In an alternative embodiment, the thickness T of the connecting piece is 0.6 mm - 2.5 mm.

[0016] Beneficial effects: Setting the thickness T of the connecting piece within a reasonable range not only ensures the strength of the connecting piece itself, making it not easily bent during welding, but also ensures that the laser does not penetrate the connecting piece when welding the tab, and can also reduce the space occupied inside the battery cell, contributing to improving the energy density of the battery cell and enhancing the space utilization rate inside the battery cell.

[0017] In an alternative embodiment, the height H by which the reinforcing rib protrudes from the surface of the second connecting portion is 0.5 - 3 times the thickness T of the connecting piece.

[0018] Beneficial effects: Setting the height H within a reasonable range not only ensures the strength of the connecting piece itself, making it not easily bent during welding, but also can reduce the space occupied inside the battery cell, contributing to improving the energy density of the battery cell and enhancing the space utilization rate inside the battery cell.

[0019] In an alternative embodiment, the reinforcing rib forms a groove on the other side of the second connecting portion, and the width W of the groove along the width direction of the cover plate is 0.5 - 3 times the thickness T of the connecting piece.

[0020] Beneficial effects: Setting the width of the reinforcing rib within a reasonable range ensures the strength and manufacturability of the connecting piece itself, improves the reliability and firmness of welding, and is also easy to process.

[0021] In an alternative embodiment, the battery cell further includes two sealing members, and the two sealing members are arranged in one-to-one correspondence with the two welding openings, and each sealing member seals the corresponding welding opening.

[0022] Beneficial effects: After the connecting piece and the tab are welded, the sealing member can effectively seal the welding opening, preventing external moisture and contaminants from entering the battery interior, ensuring the long-term performance and reliability of the battery, and also helping to prevent the leakage of the electrolyte inside the battery and reducing potential safety hazards.

[0023] In a second aspect, the present utility model further provides a battery pack, including: the above-mentioned battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 A perspective view of a battery cell according to an embodiment of the present utility model;

[0026] Figure 2 For Figure 1 A top view of the battery cell shown;

[0027] Figure 3 For Figure 2 A sectional view taken along the A-A direction of the battery cell shown;

[0028] Figure 4 For Figure 3 A partial enlarged view of the battery cell shown;

[0029] Figure 5 For Figure 1 A perspective view of two connecting tabs of the battery cell shown;

[0030] Figure 6 For Figure 5 A top view of one of the connecting tabs shown;

[0031] Figure 7 For Figure 6 A sectional view taken along the B-B direction of the connecting tab shown;

[0032] Figure 8 For Figure 1 A perspective view of the electrode tab of the battery cell passing through the connecting tab shown;

[0033] Figure 9 For Figure 8 A perspective view of the cell body and the connecting tab shown;

[0034] Figure 10 For Figure 8 A perspective view of the electrode tab bent 90° shown;

[0035] Figure 11 For Figure 10 A perspective view of the cell body and the connecting tab shown;

[0036] Figure 12 For Figure 11 A top view of the cell body and the connecting tab shown;

[0037] Figure 13 For Figure 12Partial cross-sectional view of the core body and the connecting piece in the C-C direction as shown.

[0038] Description of the reference numerals:

[0039] 1. Housing;

[0040] 2. Cover plate; 201. Welding opening; 202. Liquid injection hole;

[0041] 3. Terminal post;

[0042] 4. Electrode group; 401. Tab; 4011. Bent portion;

[0043] 5. Connecting piece; 501. First connecting portion; 502. Second connecting portion; 503. Reinforcing rib;

[0044] 6. Sealing member; 601. Limit groove;

[0045] 7. Insulating sheet; 701. Limit protrusion;

[0046] 8. First plastic part;

[0047] 9. Second plastic part;

[0048] 10. Sealing ring. Detailed implementation manners

[0049] 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.

[0050] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 13 , describing the embodiments of the present utility model.

[0051] According to an embodiment of the present utility model, on the one hand, a battery cell is provided, including: a housing 1, a cover plate 2, two pole posts 3, a pole group 4 and two connecting pieces 5. The housing 1 has a receiving cavity with an open end; the cover plate 2 is covered at the open end, and two spaced welding openings 201 and two spaced installation openings are provided on the cover plate 2; the two pole posts 3 are arranged in one-to-one correspondence with the two installation openings; the pole group 4 is arranged in the receiving cavity, and one side of the pole group 4 has a plurality of pole ear groups corresponding to the two welding openings 201, and each pole ear group includes two pole ears 401; each connecting piece 5 has a first connecting portion 501 and a second connecting portion 502. The first connecting portion 501 is connected to the corresponding pole post 3, and there is a gap for the pole ear 401 to pass through between the second connecting portion 502 and the corresponding welding opening 201. After each pole ear 401 passes through the gap, it is bent into a bent portion 4011, and the bent portion 4011 is welded to the corresponding second connecting portion 502 through the corresponding welding opening 201. A strengthening structure is provided on the second connecting portion 502, and the strengthening structure is used to strengthen the structural strength of the connecting piece 5.

[0052] When applying the battery cell of this embodiment to weld the connecting piece 5 and the pole ear 401, first place the pole group 4 into the receiving cavity of the housing 1 and pass the pole ear 401 through the corresponding gap. Then, after bending the pole ear 401, the bent portion 4011 and the second connecting portion 502 of the connecting piece 5 are welded together by welding processes such as laser welding or ultrasonic welding. Only the pole ear 401 needs to be bent, and there is no need to bend the connecting piece 5. Compared with the connection method in the prior art where both the connecting piece and the pole ear need to be bent during connection, the thickness of the connecting piece 5 and the pole ear 401 after connection becomes thinner, which can reduce the space occupied inside the battery cell, help improve the energy density of the battery cell, and enhance the space utilization rate inside the battery cell; moreover, the bending process of the connecting piece 5 is reduced, the manufacturing process is simplified, the production efficiency is improved, the production cost is reduced, and the potential damage or deformation risk caused by the bending of the connecting piece 5 is also reduced. Since the connecting piece 5 does not need to be bent, material waste can be reduced and costs can be saved.

[0053] Furthermore, the arrangement of the welding openings 201 avoids the bending equipment and the welding equipment, which not only facilitates the bending of the pole ear 401 but also facilitates the welding of the pole ear 401 and the connecting piece 5, improving the welding efficiency and reducing the cost. The two welding openings 201 are spaced apart, so that the cover plate 2 is not completely disconnected in the middle, enhancing the self-strength of the cover plate 2 and thus enhancing the structural strength of the battery cell. A strengthening structure is provided on the second connecting portion 502 to ensure that when the pole ear 401 is welded to the connecting piece 5, only relying on the strength of the connecting piece 5 itself can ensure zero-gap contact between the connecting piece 5 and the pole ear 401, ensuring the welding effect and achieving the purpose of saving space and improving the space utilization rate in the height direction of the battery.

[0054] In one embodiment, as Figures 5 to 7As shown, the reinforcement structure is a reinforcement rib 503 provided on the surface of the second connection portion 502 and protruding toward one side. The strength and rigidity of the connecting piece 5 can be enhanced by the reinforcement rib 503. When the pole tab 401 is welded to the connecting piece 5, the upper part of the pole tab 401 needs to be pressed by a tool, and the lower part of the connecting piece 5 does not need to be supported by a tool, that is, the lower part of the connecting piece 5 does not need to be supported by an auxiliary tool, which simplifies the welding process and improves welding efficiency. The reinforcement rib 503 has a simple structure, is easy to implement, and reduces costs.

[0055] It is understandable that, in another embodiment, the reinforcement structure is a reinforcement flange or the like provided on the side of the second connection portion 502 .

[0056] In one embodiment, the reinforcing rib 503 protrudes toward the cover plate 2. Specifically, the reinforcing rib 503 is formed by stamping the middle portion of the second connecting portion 502. The stamping process can maximize the use of materials, reduce material waste, and facilitate processing and manufacturing, reducing manufacturing difficulty.

[0057] It can be understood that, in another embodiment, the reinforcing rib 503 protrudes in a direction away from the cover plate 2 .

[0058] In one embodiment, the reinforcing rib 503 is extended along the length direction of the cover plate 2 and divides the second connection portion 502 into two connection sub-parts, and the two connection sub-parts are welded one-to-one with the two tabs 401 of a corresponding tab group. The reinforcing rib 503 is arranged between the two connection sub-parts to enhance the strength and rigidity of the second connection portion 502, and will not interfere with the area on the second connection portion 502 that is welded to the tab 401.

[0059] Furthermore, the reinforcing rib 503 is disposed in the middle of the second connecting portion 502, which provides a better reinforcing effect.

[0060] It is understandable that, in another embodiment, the reinforcing rib 503 may also be disposed on a side of the second connecting portion 502 away from the first connecting portion 501 .

[0061] In one embodiment, Figure 5 and Figure 12 As shown, the length L of the reinforcing rib 503 along the length direction of the cover plate 2 is greater than the length L1 of the tab 401 along the length direction of the cover plate 2. Figure 12 The transverse dimension of the middle reinforcing rib 503 and the length L1 of the tab 401 are Figure 12 The lateral dimension of the middle pole ear 401, the length L1 of the pole ear 401 can be understood as the length of the welding area where the pole ear 401 is welded to the connecting piece 5. Setting the length L of the reinforcing rib 503 to be greater than the length of the welding area can further enhance the strength and rigidity of the connecting piece 5, making it less likely for the connecting piece 5 to deform during welding, thereby improving the welding quality.

[0062] In one embodiment, as Figures 5 to 7 shown, the thickness T of the connecting piece 5 is 0.6 mm - 2.5 mm. The thickness T of the connecting piece 5 is also the Figure 7 vertical dimension of the connecting piece 5 in . The thickness T of the connecting piece 5 should neither be too large nor too small. If the thickness T of the connecting piece 5 is too small, it indicates that the welding strength between the connecting piece 5 and the terminal post 3 is weak, and thus the welding reliability between the connecting piece 5 and the terminal post 3 cannot be ensured. If the thickness T of the connecting piece 5 is too large, it means that the connecting piece 5 is relatively thick, occupying a large amount of space inside the battery cell, and the utilization rate of the space inside the battery cell is low. Therefore, setting the thickness T of the connecting piece 5 within 0.6 mm - 2.5 mm, that is, setting the thickness T of the connecting piece 5 within a reasonable range, not only ensures the strength of the connecting piece 5 itself, making it not easy to bend during welding, but also ensures that the laser does not penetrate the connecting piece 5 when welding the tab 401, and can also reduce the space occupied inside the battery cell, contributing to improving the energy density of the battery cell and enhancing the utilization rate of the space inside the battery cell.

[0063] In one embodiment, as Figure 7 shown, the height H by which the reinforcing rib 503 protrudes from the surface of the second connecting portion 502 is 0.5 - 3 times the thickness T of the connecting piece 5, that is, H is 0.5T - 3T. The height H by which the reinforcing rib 503 protrudes from the surface of the second connecting portion 502 is also the Figure 7 vertical dimension between the upper surface of the reinforcing rib 503 and the upper surface of the second connecting portion 502 in . The height H should neither be too large nor too small. If the height H is too small, it indicates that the strengthening effect is limited, and the strength of the connecting piece 5 itself is small, and thus the welding reliability between the connecting piece 5 and the terminal post 3 cannot be ensured, and it is not easy to process either. If the height H is too large, it means that the height of the reinforcing rib 503 is relatively high, occupying a large amount of space inside the battery cell, and the utilization rate of the space inside the battery cell is low. Therefore, setting the height H within 0.5T - 3T, that is, setting the height H within a reasonable range, not only ensures the strength of the connecting piece 5 itself, making it not easy to bend during welding, but also can reduce the space occupied inside the battery cell, contributing to improving the energy density of the battery cell and enhancing the utilization rate of the space inside the battery cell.

[0064] In one embodiment, as Figure 7 shown, the reinforcing rib 503 forms a groove on the other side of the second connecting portion 502. The width W of the groove in the width direction of the cover plate 2 is 0.5 - 3 times the thickness T of the connecting piece 5, that is, W is 0.5T - 3T. The width W of the groove in the width direction of the cover plate 2 is also the Figure 7The lateral dimension inside the reinforcing rib 503, the width of the groove should neither be too large nor too small. If the width of the groove is too small, it indicates that the strengthening effect is limited, the self-strength of the connecting piece 5 is small, and thus the welding reliability between the connecting piece 5 and the terminal 3 cannot be guaranteed, nor is it easy to process. If the width of the groove is too large, it means that the span of the reinforcing rib 503 is large. With the width dimension of the connecting piece 5 unchanged, the welding area between the tab 401 and the connecting piece 5 is small, and the firmness of the welding cannot be guaranteed. Therefore, the width of the groove is set within 0.5T - 3T, that is, the width of the reinforcing rib 503 is set within a reasonable range, ensuring the self-strength and manufacturability of the connecting piece 5, improving the welding reliability and firmness, and being easy to process.

[0065] In one embodiment, as Figures 1 to 4 shown, the battery cell further includes two seals 6, and the two seals 6 are arranged in one-to-one correspondence with the two welding openings 201, and each seal 6 seals the corresponding welding opening 201. After the connecting piece 5 and the tab 401 are welded, the welding opening 201 can be effectively sealed through the seal 6, preventing external moisture and contaminants from entering the battery interior, ensuring the long-term performance and reliability of the battery, and also helping to prevent the leakage of the electrolyte inside the battery, reducing potential safety hazards.

[0066] Furthermore, the seal 6 generally uses materials with high heat resistance, good chemical stability, and excellent sealing performance. These materials need to be able to withstand the high-temperature and high-pressure environment during battery operation and be compatible with the material of the cover plate 2 to ensure long-term sealing effect. The material of the seal 6 can be metal materials such as stainless steel, aluminum, or aluminum alloy. It can be understood that the material of the seal 6 can also be a composite material that combines metal and plastic, etc.

[0067] Specifically, the seal 6 is a sealing plate, and the seal 6 is formed by a plate, which is convenient for processing and manufacturing and reduces the manufacturing cost. The sealing plate and the cover plate 2 are welded and connected, and the welding is firm and reliable, enhancing the overall structural strength.

[0068] In one embodiment, as Figure 4 shown, the battery cell further includes two insulating sheets 7, and the two insulating sheets 7 are arranged in one-to-one correspondence with the two welding openings 201, and the seal 6 is arranged above the insulating sheet 7. The insulating sheet 7 is used to isolate the seal 6 from charged components such as the tab 401 to prevent short circuits, and can also support internal components of the battery, such as the tab 401, to keep its position stable and avoid displacement during transportation or use.

[0069] Furthermore, the materials of the insulating sheets 7 are all plastics. Plastics have the advantages of electrical insulation, light weight, corrosion resistance, high structural strength, easy processing, strong plasticity, and good thermal stability.

[0070] In one embodiment, a limiting structure is provided between the insulating sheet 7 and the seal 6, and the limiting structure is used to limit the positions between the insulating sheet 7 and the seal 6. The limiting structure can ensure the relative positions between the insulating sheet 7 and the seal 6 and restrict the movement between the insulating sheet 7 and the seal 6, making the assembly more convenient during assembly and improving the assembly efficiency.

[0071] Further, the limiting structure includes a limiting protrusion 701 and a limiting groove 601. The limiting protrusion 701 is provided on one of the insulating sheet 7 and the seal 6, and the limiting groove 601 is provided on the other of the insulating sheet 7 and the seal 6. The cooperation of the limiting protrusion 701 and the limiting groove 601 realizes the rapid limiting between the insulating sheet 7 and the seal 6, simplifies the assembly process, and helps to improve the production efficiency.

[0072] In one embodiment, a liquid injection hole 202 is formed in the cover plate 2. The liquid injection hole 202 is used to inject electrolyte into the battery cell. During the process of injecting the electrolyte, gas may be generated inside the battery cell. The liquid injection hole 202 can serve as a vent hole to release the gas and prevent the pressure inside the battery cell from being too high. After the electrolyte injection is completed, the liquid injection hole 202 is sealed by a sealing plug or the like to ensure the tightness of the internal environment of the battery cell and prevent the leakage of the electrolyte or the intrusion of external moisture. Directly arranging the liquid injection hole 202 on the cover plate 2 facilitates welding the connection piece 5 and the tab 401 and injecting the electrolyte on the same side of the battery cell. Operating on the same side of the housing 1 can reduce the operation complexity.

[0073] In one embodiment, as Figures 10 to 13 shown, the electrode assembly 4 has 2 tab groups, and one welding opening 201 corresponds to one tab group. In each tab group, the bending directions of the two tabs 401 are opposite, that is, the two tabs 401 are bent towards each other. When bending the tabs 401, the bending head of the bending device can occupy the bending space before the tabs 401 are bent, and there is no need to open too large a welding opening 201 on the cover plate 2 for avoidance, which can maximize the utilization rate of the battery in the width direction and minimize the width of the welding opening 201 of the cover plate 2.

[0074] In one embodiment, as Figure 4As shown, the battery cell further includes two first plastic parts 8, a second plastic part 9, and two sealing rings 10. The number of pole columns 3 and connecting pieces 5 is two. Each pole column 3 is installed at the installation opening through a first plastic part 8 and a sealing ring 10. The second plastic part 9 is arranged on the inner surface of the cover plate 2. The first plastic part 8 is sleeved on the outside of the corresponding pole column 3 and assembled at the corresponding installation opening. The first plastic part 8 can completely isolate the pole column 3 and the cover plate 2, preventing a short circuit between the pole column 3 and the cover plate 2 and ensuring electrical isolation between the pole column 3 and the cover plate 2. The second plastic part 9 is located inside the cover plate 2 and is used to isolate the cover plate 2 from charged components such as the pole ear 401 inside the battery to prevent a short circuit. It can also support internal components of the battery, such as the pole ear 401, to keep its position stable and avoid displacement during transportation or use. The sealing ring 10 is sleeved on the outside of the pole column 3 and is in sealed cooperation with the cover plate 2 and the first connecting part 501, which is used to ensure the sealing performance of the battery, prevent electrolyte leakage, and at the same time prevent external moisture and impurities from entering the inside of the battery cell.

[0075] Further, the two pole columns 3 are respectively a positive pole column and a negative pole column, the two connecting pieces 5 are respectively a positive connecting piece and a negative connecting piece. The positive connecting piece is welded to the positive pole column, and the negative connecting piece is welded to the negative pole column. The materials of the positive pole column and the negative pole column are metals. Generally, the material of the negative pole column is copper, aluminum, etc., and the material of the positive pole column is aluminum, etc.

[0076] It should be noted that before welding the connecting piece 5 and the pole ear 401, the pole column 3, the first plastic part 8, the second plastic part 9, and the sealing ring 10 have been assembled on the cover plate 2, and the first connecting part 501 of the connecting piece 5 has been fixed on the pole column 3.

[0077] In one embodiment, the two welding openings 201 are located between the two installation openings.

[0078] It can be understood that in another embodiment, the two installation openings are located between the two welding openings 201.

[0079] In one embodiment, the welding opening 201 is rectangular. It can be understood that the welding opening 201 can also be other shapes and is not limited thereto.

[0080] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including: the above-mentioned battery cell.

[0081] In the related art, two downward bending parts are formed by bending the two sides of the connecting piece. A pair of pole ears pass through between the two downward bending parts and are bent on the corresponding downward bending parts. When the connecting piece and the pole ear are welded, bending is required, which results in a relatively thick thickness after the connecting piece and the pole ear are connected, occupying more internal space of the battery, and the process is also complex.

[0082] In this embodiment, the first plastic part 8, the second plastic part 9, the positive electrode post, the negative electrode post, the sealing ring 10, the connecting piece 5, etc. are arranged on the cover plate 2. Two welding openings 201 for welding the connecting piece 5 and the tab 401 are arranged on the cover plate 2. The vertical tab 401 of the electrode group 4 is first assembled above the connecting piece 5, and then bent 90°. Then, welding processes such as laser welding or ultrasonic welding are used to weld the connecting piece 5 and the tab 401 through the welding openings 201, reducing the bending process of the connecting piece 5, improving the space utilization rate inside the battery, and enhancing the production efficiency.

[0083] Specifically, the connecting piece 5 is divided into a first connecting portion 501 and a second connecting portion 502. The first connecting portion 501 is welded to the electrode post 3. A reinforcing rib 503 protruding towards the cover plate 2 or protruding away from the cover plate 2 is arranged in the middle of the second connecting portion 502, ensuring the strength of the connecting piece 5. When the tab 401 is welded to the connecting piece 5, the upper part of the tab 401 needs to be pressed by a tooling, and the lower part of the connecting piece 5 does not need tooling support, that is, it does not need the support of auxiliary tooling. Only relying on the strength of the connecting piece 5 itself can ensure zero-gap contact between the connecting piece 5 and the tab 401, ensuring the welding effect and achieving the purpose of saving space and improving the space utilization rate in the height direction of the battery.

[0084] Furthermore, the welding opening 201 is a stepped hole. The stepped surface of the welding opening 201 is convenient for fixing the sealing plate. The upper surface of the second connecting portion 502 is higher than the upper surface of the first connecting portion 501, that is, the connecting piece 5 has a stepped structure. Since the surface of the tab 401 on the side close to the electrode plate of the electrode group 4 is convex, the stepped structure can adapt to the structure of the tab 401 on the side close to the electrode plate.

[0085] It should be noted that a welding area is formed on the upper surface of the bending portion 4011 (such as Figure 10 the grid-like area shown).

[0086] Although the embodiments of the present 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 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, Comprising: A housing having a receiving cavity with an open end; A cover plate covering the open end, with two spaced welding openings and two spaced mounting openings formed in the cover plate; Two pole columns, arranged in one-to-one correspondence with the two mounting openings; A pole group disposed in the receiving cavity, with a plurality of pole ear groups corresponding to the two welding openings on one side of the pole group, and each pole ear group includes two pole ears; Two connecting pieces, each connecting piece having a first connecting portion and a second connecting portion, the first connecting portion is connected to the corresponding pole column, a gap for the pole ear to pass through is formed between the second connecting portion and the corresponding welding opening, each pole ear forms a bent portion after passing through the gap, the bent portion is welded to the corresponding second connecting portion through the corresponding welding opening, and a strengthening structure is provided on the second connecting portion, and the strengthening structure is used to strengthen the structural strength of the connecting piece.

2. The battery cell according to claim 1, wherein, The strengthening structure is a reinforcing rib provided on the surface of the second connecting portion and protruding towards one side.

3. The battery cell according to claim 2, characterized in that, The reinforcing rib protrudes towards the cover plate, or the reinforcing rib protrudes in a direction away from the cover plate.

4. The cell according to claim 2, wherein The reinforcing rib extends along the length direction of the cover plate and divides the second connecting portion into two connecting sub-portions, and the two connecting sub-portions are welded to the two pole ears of the corresponding one pole ear group in one-to-one correspondence.

5. The battery cell according to claim 2, wherein, The length L of the reinforcing rib along the length direction of the cover plate is greater than the length L1 of the pole ear along the length direction of the cover plate.

6. The battery cell according to any one of claims 2 to 5, characterized in that, The thickness T of the connecting piece is 0.6 mm - 2.5 mm.

7. The battery cell according to claim 6, characterized in that, The height H of the reinforcing rib protruding from the surface of the second connecting portion is 0.5 - 3 times the thickness T of the connecting piece.

8. The battery cell according to claim 6, wherein, The reinforcing rib forms a groove on the other side of the second connecting portion, and the width W of the groove along the width direction of the cover plate is 0.5 - 3 times the thickness T of the connecting piece.

9. The battery cell according to any one of claims 1 to 5, characterized in that, The battery cell further includes two sealing members, the two sealing members are arranged in one-to-one correspondence with the two welding openings, and each sealing member seals the corresponding welding opening.

10. A battery pack, characterized in that, Comprising: The battery cell according to any one of claims 1 to 9.

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