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, the accommodating cavity having a first open end and a second open end; the first cover plate is arranged at the first opening end, and the first cover plate is provided with a welding through hole; the second cover plate is arranged at the second opening end; the first pole is arranged on the first cover plate; the second pole is arranged on the second cover plate; the pole group is arranged in the accommodating cavity, and one side of the pole group is provided with a pole lug; the connecting piece is provided with a pole connecting part and a tab connecting part, the pole connecting part is connected with the first pole, the tab connecting part is provided with a penetrating opening for the tab to penetrate through, the tab penetrates through the penetrating opening and then is bent to form a bent part, and the bent part and the tab connecting part are welded through a welding through hole; a reinforcing part is arranged on at least one of the pole connecting part and the tab 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] Due to the rise of the new energy industry, lithium batteries, which have large energy storage and fast charging, are naturally popular in the market. At present, the market demand for lithium batteries is increasing, so the requirements for the production capacity of lithium battery manufacturers are also getting higher and higher. Battery cells have been widely used in many fields due to their characteristics such as high energy density, long cycle life, and low self-discharge rate, such as consumer electronics, electric vehicle fields, energy storage fields, etc.

[0003] The outer shells of existing square lithium-ion / sodium-ion battery cells are mainly divided into two parts: a cover plate and a housing. The materials can be steel, aluminum (alloy) or hard plastic. Mainly by embedding the cover plate into the housing and then using laser welding or high-temperature fusion welding to connect the cover plate and the housing to obtain a sealing effect, providing a sealed working environment for the square lithium-ion / sodium-ion battery cell. The battery cell also includes a pole group arranged inside the outer shell. The pole group is housed inside the outer shell and is formed by winding or laminating positive and negative electrode plates and a separator. The pole tabs of the pole group are connected to the pole posts through connecting pieces, realizing the connection of the positive and negative poles of the pole tabs and the positive and negative poles of the pole posts.

[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 a first opening end and a second opening end; a first cover plate arranged at the first opening end, the first cover plate having a welding through hole; a second cover plate arranged at the second opening end; a first pole post arranged on the first cover plate; a second pole post arranged on the second cover plate; a pole group arranged in the receiving cavity, one side of the pole group having a pole tab; a connecting piece having a pole post connecting portion and a pole tab connecting portion, the pole post connecting portion being connected to the first pole post, a through hole for the pole tab to pass through being formed on the pole tab connecting portion, the pole tab passing through the through hole and then being bent to form a bent portion, the bent portion and the pole tab connecting portion being welded through the welding through hole, and at least one of the pole post connecting portion and the pole tab connecting portion being provided with a reinforcing portion for strengthening the structural strength of the connecting piece.

[0007] Beneficial effects: When welding the connection piece and the tab, first insert the electrode into the accommodation cavity of the housing and pass the tab through the through-hole. Then, after bending the tab, the bent portion is welded to the tab connection portion of the connection 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 connection piece. Compared with the connection method in the prior art where both the connection piece and the tab need to be bent during connection, the thickness after the connection piece and the tab are connected 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 connection piece is reduced, simplifying the manufacturing process, improving production efficiency, reducing production costs, and also reducing the potential damage or deformation risk caused by bending the connection piece. Without bending the connection piece, material waste can be reduced, saving costs. The arrangement of the welding through-hole avoids the bending equipment and the welding equipment, which not only facilitates bending the tab but also facilitates welding the tab and the connection piece, improving welding efficiency and reducing costs. A strengthening structure is provided on at least one of the pole connection portion and the tab connection portion to ensure that when the tab is welded to the connection piece, zero-gap contact between the connection piece and the tab can be ensured only by relying on the strength of the connection piece itself, 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 alternative embodiment, the through-hole is a notch provided on one side of the tab connection portion.

[0009] Beneficial effects: The through-hole extends to the side edge of the tab connection portion. When processing the connection piece, the connection piece is directly formed by cutting the sheet material, which is convenient for processing and manufacturing and reduces costs.

[0010] In an alternative embodiment, the strengthening portion is a reinforcing rib protruding towards one side. The reinforcing rib extends along the length direction of the first cover plate and is provided on the side of the tab connection portion and the pole connection portion away from the through-hole.

[0011] Beneficial effects: The strength and rigidity of the connection piece can be enhanced through the reinforcing rib. When the tab is welded to the connection piece, the upper part of the tab needs to be pressed by a tooling, and the lower part of the connection piece does not need tooling support, that is, the lower part of the connection piece does not need the support of auxiliary tooling, simplifying the welding process and improving welding efficiency. The structure of the reinforcing rib is simple and easy to implement, reducing costs.

[0012] In an alternative embodiment, the reinforcing rib protrudes towards the first cover plate, or the reinforcing rib protrudes towards the direction away from the first cover plate.

[0013] In an alternative embodiment, the thickness T of the connection piece is 0.6 mm - 2.5 mm.

[0014] Beneficial effects: By setting the thickness T of the connecting piece within a reasonable range, not only the strength of the connecting piece itself is ensured, and it is not easily bent during welding, but also it is ensured that the laser does not penetrate the connecting piece when welding the pole ear. Moreover, it 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.

[0015] In an optional implementation manner, the height H by which the reinforcing rib protrudes from the surface of the pole ear connecting portion is 0.5 - 3 times the thickness T of the connecting piece, and / or, the reinforcing rib forms a groove on the other side of the pole ear connecting portion, and the width W of the groove along the width direction of the first cover plate is 0.5 - 3 times the thickness T of the connecting piece.

[0016] Beneficial effects: By setting the height H within a reasonable range, not only the strength of the connecting piece itself is ensured, and it is not easily bent during welding, but also it 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. By setting the width of the reinforcing rib within a reasonable range, the strength and manufacturability of the connecting piece are ensured, the reliability and firmness of welding are improved, and it is also easy to process.

[0017] In an optional implementation manner, the length L of the pole ear connecting portion along the length direction of the first cover plate is greater than the length L1 of the pole ear along the length direction of the first cover plate.

[0018] Beneficial effects: The length L of the pole ear can be understood as the length of the welding area where the pole ear is welded to the connecting piece. By setting the length L of the reinforcing rib to be greater than the length of the welding area, the strength and stiffness of the connecting piece can be further enhanced, so that the connecting piece is not easily deformed during welding, and the welding quality is improved.

[0019] In an optional implementation manner, the battery cell further includes a sealing plate, and the sealing plate covers the welding through hole and is used to seal the welding through hole.

[0020] Beneficial effects: After the connecting piece and the pole ear are welded, the welding through hole can be effectively sealed by the sealing plate, 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 electrolyte inside the battery from leaking, reducing potential safety hazards.

[0021] In an optional implementation manner, the second cover plate is provided with a liquid injection hole and an explosion-proof valve.

[0022] Beneficial effects: The liquid injection hole is used to inject electrolyte into the inside of the battery cell. During the process of injecting electrolyte, gas may be generated inside the battery cell. The liquid injection hole can be used as a vent hole to release the gas and prevent the internal pressure of the battery cell from being too high. After the electrolyte injection is completed, the liquid injection hole is sealed by a sealing plug or the like to ensure the tightness of the internal environment of the battery cell and prevent electrolyte leakage or intrusion of external moisture. The explosion-proof valve can automatically open when the internal pressure of the battery cell exceeds the safety threshold to release the internal pressure and prevent the battery cell from exploding. The explosion-proof valve is in a closed state during the normal operation of the battery cell, which can effectively prevent electrolyte leakage, help maintain the tightness of the battery cell, and extend the service life of the battery cell. Both the explosion-proof valve and the liquid injection hole are arranged on the second cover plate, and operations are carried out on the same side of the housing, which can reduce the complexity on the production line and help improve production efficiency. It is convenient for maintenance personnel to maintain and detect when problems occur in the battery cell. By designing a heat dissipation channel or adding heat dissipation materials on the side where the liquid injection hole and the explosion-proof valve are located, the battery temperature can be controlled, thereby optimizing the thermal management inside the battery.

[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 use in 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.

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

[0026] Figure 2 It is Figure 1 A perspective view of the battery cell shown from a second perspective;

[0027] Figure 3 It is Figure 1 A perspective view of the first cover plate shown;

[0028] Figure 4 It is Figure 3 A sectional view of the first cover plate shown;

[0029] Figure 5 It is Figure 1 A perspective view of the connecting piece shown;

[0030] Figure 6 It is Figure 1 A top view of the connecting piece shown;

[0031] Figure 7Is Figure 6 The C-C direction cross-sectional view of the connecting piece shown;

[0032] Figure 8 Is Figure 1 The perspective view of the second cover plate shown;

[0033] Figure 9 Is Figure 8 The cross-sectional view of the second cover plate shown;

[0034] Figure 10 Is Figure 8 The perspective view of the second cover plate from another perspective shown;

[0035] Figure 11 Is Figure 1 The top view of the battery cell shown;

[0036] Figure 12 Is Figure 11 The A-A direction cross-sectional view of the battery cell shown;

[0037] Figure 13 Is Figure 11 The B-B direction cross-sectional view of the battery cell shown;

[0038] Figure 14 Is Figure 1 The partial perspective view of the electrode tab of the battery cell passing through the connecting piece shown;

[0039] Figure 15 Is Figure 14 The partial schematic view of the electrode group and the connecting piece shown;

[0040] Figure 16 Is Figure 14 The partial schematic view of the electrode tab bent 90° shown;

[0041] Figure 17 Is Figure 16 The partial schematic view of the electrode group and the connecting piece shown;

[0042] Figure 18 Is Figure 17 The top view of the electrode group and the connecting piece shown.

[0043] Explanation of reference numerals:

[0044] 1. Housing;

[0045] 201. First cover plate; 2011. Welding through-hole; 202. Second cover plate; 2021. Liquid injection hole; 2022. Explosion-proof valve;

[0046] 301. First pole column; 302. Second pole column;

[0047] 4. Electrode group; 401. Tab; 4011. Bent portion;

[0048] 5. Connecting piece; 501. Terminal connection part; 502. Tab connection part; 5021. Penetration opening; 503. Reinforcing rib;

[0049] 6. Sealing plate;

[0050] 7. Insulating part;

[0051] 8. First plastic part;

[0052] 9. Second plastic part;

[0053] 10. Sealing ring;

[0054] 11. Fixed block. Specific embodiments

[0055] 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. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0056] The following Figures 1 to 18 , describe the embodiments of the present utility model.

[0057] According to an embodiment of the present utility model, on the one hand, a battery cell is provided, including: a housing 1, a first cover plate 201, a second cover plate 202, a first terminal 301, a second terminal 302, an electrode group 4, and a connecting piece 5. The housing 1 has a receiving cavity with a first opening end and a second opening end; the first cover plate 201 is disposed at the first opening end and has a welding through hole 2011; the second cover plate 202 is disposed at the second opening end; the first terminal 301 is disposed on the first cover plate 201; the second terminal 302 is disposed on the second cover plate 202; the electrode group 4 is disposed in the receiving cavity, and one side of the electrode group 4 has a tab 401; the connecting piece 5 has a terminal connection part 501 and a tab connection part 502. The terminal connection part 501 is connected to the first terminal 301. A penetration opening 5021 for the tab 401 to penetrate is formed in the tab connection part 502. After the tab 401 passes through the penetration opening 5021, it is bent to form a bent portion 4011. The bent portion 4011 and the tab connection part 502 are welded through the welding through hole 2011. At least one of the terminal connection part 501 and the tab connection part 502 is provided with a reinforcing part for strengthening the structural strength of the connecting piece 5.

[0058] When applying the battery cell of this embodiment to weld the connecting piece 5 and the tab 401, first place the electrode group 4 into the accommodation cavity of the housing 1 and pass the tab 401 through the through-hole 5021. Then, after bending the tab 401, weld the bent portion 4011 and the tab connecting portion 502 of the connecting piece 5 together through welding processes such as laser welding or ultrasonic welding. Only the tab 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 5 and the tab 401 need to be bent during connection, the thickness after the connection of the connecting piece 5 and the tab 401 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, simplifying the manufacturing process, improving production efficiency, reducing production costs, and also reducing the potential damage or deformation risk caused by the bending of the connecting piece 5. Without bending the connecting piece 5, material waste can be reduced, saving costs.

[0059] Furthermore, the arrangement of the welding through-hole 2011 avoids the bending equipment and the welding equipment, which not only facilitates the bending of the tab 401 but also facilitates the welding of the tab 401 and the connecting piece 5, improving the welding efficiency and reducing costs. A strengthening structure is provided on at least one of the pole connection portion 501 and the tab connection portion 502 to ensure that when the tab 401 is welded to the connecting piece 5, zero-gap contact between the connecting piece 5 and the tab 401 can be ensured only by relying on the strength of the connecting piece 5 itself, ensuring the welding effect and achieving the purpose of saving space and improving the space utilization rate in the height direction of the battery.

[0060] In one embodiment, as Figure 5 shown, the through-hole 5021 is a notch provided on one side of the tab connection portion 502, that is, the through-hole 5021 extends to the side edge of the tab connection portion 502. When processing the connecting piece 5, the connecting piece 5 is directly formed by cutting a sheet material, which is convenient for processing and manufacturing and reduces costs.

[0061] It can be understood that in another embodiment, the through-hole 5021 is a through-hole with a certain distance from the side edges of the tab connection portion 502.

[0062] In one embodiment, as Figure 5 shown, the strengthening portion is a reinforcing rib 503 protruding towards one side. The reinforcing rib 503 extends along the length direction of the first cover plate 201 and is provided on the side of the tab connection portion 502 and the pole connection portion 501 away from the through-hole 5021. The strength and rigidity of the connecting piece 5 can be enhanced through the reinforcing rib 503. 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, the lower part of the connecting piece 5 does not need the support of auxiliary tooling, simplifying the welding process and improving the welding efficiency. The structure of the reinforcing rib 503 is simple and easy to implement, reducing costs.

[0063] It can be understood that in another embodiment, the strengthening structure is a strengthening flange or the like provided on the side of the tab connection portion 502.

[0064] In one embodiment, the reinforcing rib 503 protrudes towards the first cover plate 201. Specifically, the reinforcing rib 503 is formed by stamping the middle part of the tab connection portion 502. The stamping process can maximize the use of materials, reduce material waste, and is also convenient for processing and manufacturing, reducing the manufacturing difficulty.

[0065] It can be understood that in another embodiment, the reinforcing rib 503 protrudes in a direction away from the first cover plate 201.

[0066] In one embodiment, as Figure 3 and Figure 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 vertical dimension of the connecting piece 5 in Figure 7 . 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 means that the welding strength between the connecting piece 5 and the first pole 301 is weak, and thus the welding reliability between the connecting piece 5 and the first pole 301 cannot be guaranteed. 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, is not easily bent during welding, and ensures that the laser does not penetrate the connecting piece 5 when welding the tab 401, but also can reduce the space occupied inside the battery cell, contribute to improving the energy density of the battery cell, and enhance the utilization rate of the space inside the battery cell.

[0067] In one embodiment, as Figure 3 and Figure 7 shown, the height H of the reinforcing rib 503 protruding from the surface of the tab connection 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 of the reinforcing rib 503 protruding from the surface of the tab connection portion 502 is also Figure 7The vertical dimension between the upper surface of the reinforcing rib 503 and the upper surface of the tab connection portion 502, the height H should neither be too large nor too small. If the height H is too small, it means 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 first pole 301 cannot be ensured, and it is not easy to process. If the height H is too large, it means the height of the reinforcing rib 503 is relatively high, occupying a large 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 self-strength of the connecting piece 5 and is not easily bent during welding, but also can reduce the space occupied inside the battery cell, contribute to improving the energy density of the battery cell, and enhance the utilization rate of the space inside the battery cell.

[0068] In one embodiment, as Figure 3 and Figure 7 shown, the reinforcing rib 503 forms a groove on the other side of the tab connection portion 502. The width W of the groove along the width direction of the first cover plate 201 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 first cover plate 201 is also Figure 7 the lateral dimension inside the reinforcing rib 503 in

[0069] In one embodiment, as Figure 3 and Figure 18 shown, the length L of the tab connection portion 502 along the length direction of the first cover plate 201 is greater than the length L1 of the tab 401 along the length direction of the first cover plate 201. The length L of the reinforcing rib 503 is also Figure 18 the lateral dimension of the reinforcing rib 503 in Figure 18 and the length L1 of the tab 401 is also

[0070] In one embodiment, the battery cell further includes a sealing plate 6, which covers the welding through-hole 2011 and is used to seal the welding through-hole 2011. After the connecting piece 5 and the tab 401 are welded, the sealing plate 6 can effectively seal the welding through-hole 2011, preventing external moisture and pollutants 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.

[0071] Further, the sealing plate 6 generally adopts 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 first cover plate 201 to ensure a long-term sealing effect. The material of the sealing plate 6 can be metal materials such as stainless steel, aluminum, or aluminum alloy. It can be understood that the material of the sealing plate 6 can also be a composite material that combines metal and plastic, etc.

[0072] Specifically, the sealing plate 6 is formed by a sheet, which is convenient for processing and manufacturing and reduces the manufacturing cost. The sealing plate 6 is welded to the first cover plate 201, and the welding is firm and reliable, enhancing the overall structural strength.

[0073] In one embodiment, as Figure 13 shown, the battery cell further includes an insulating part 7. The insulating part 7 is arranged at the welding through-hole 2011, and the sealing plate 6 is arranged above the insulating part 7. The insulating part 7 is used to isolate the sealing plate 6 from charged components such as the tab 401 to prevent short circuits, and can also support internal battery components such as the tab 401 to keep its position stable and avoid displacement during transportation or use.

[0074] Further, the material of the insulating part 7 is all plastic. Plastic has the advantages of electrical insulation, light weight, corrosion resistance, high structural strength, easy processing, strong plasticity, good thermal stability, etc.

[0075] In one embodiment, as Figure 8 and Figure 9As shown in the figure, the second cover plate 202 is provided with a liquid injection hole 2021 and an explosion-proof valve 2022. The liquid injection hole 2021 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 2021 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 2021 is sealed with a sealing plug or the like to ensure the tightness of the internal environment of the battery cell and prevent electrolyte leakage or external moisture intrusion. The explosion-proof valve 2022 can automatically open when the pressure inside the battery cell exceeds the safety threshold to release the internal pressure and prevent the battery cell from exploding. The explosion-proof valve 2022 is in a closed state during the normal operation of the battery cell, which can effectively prevent electrolyte leakage, help maintain the tightness of the battery cell, and extend the service life of the battery cell. By arranging both the explosion-proof valve 2022 and the liquid injection hole 2021 on the second cover plate 202 and operating on the same side of the housing 1, the complexity of the production line can be reduced, which helps improve production efficiency. It is convenient for maintenance personnel to maintain and detect when problems occur in the battery cell. By designing a heat dissipation channel or adding heat dissipation materials on the side where the liquid injection hole 2021 and the explosion-proof valve 2022 are located, the battery temperature can be controlled, thereby optimizing the thermal management inside the battery.

[0076] In one embodiment, as Figures 13 to 18 shown, the electrode group 4 has an electrode tab 401, and a welding through-hole 2011 corresponds to an electrode tab 401. The electrode tab 401 is bent toward the side where the reinforcing rib 503 is located. When bending the electrode tab 401, the bending head of the bending device can occupy the bending space before the bending of the electrode tab 401, and it is not necessary to open a too large welding through-hole 2011 on the first cover plate 201 for avoidance. The utilization rate of the battery width direction can be maximally improved, and the width of the welding through-hole 2011 of the first cover plate 201 can be minimized.

[0077] In one embodiment, as Figure 12As shown in the figure, the battery cell further includes two first plastic parts 8, two second plastic parts 9, two sealing rings 10 and two fixing blocks 11. The first cover plate 201 has a first mounting hole, and the second cover plate 202 has a second mounting hole. The first pole 301 is installed at the first mounting hole through a first plastic part 8, a sealing ring 10 and a fixing block 11. The second pole 302 is installed at the second mounting hole through a first plastic part 8, a sealing ring 10 and a fixing block 11. One second plastic part 9 is arranged on the inner surface of the first cover plate 201, and the other second plastic part 9 is arranged on the inner surface of the second cover plate 202. The first plastic part 8 is sleeved on the outside of the corresponding pole and assembled at the corresponding mounting hole. The first plastic part 8 can completely isolate the pole and the cover plate, prevent short circuit between the pole and the cover plate, and ensure electrical isolation between the pole and the cover plate. The second plastic part 9 is located inside the corresponding cover plate, used to isolate the cover plate from the charged components such as the tab 401 inside the battery to prevent short circuit; it can also support the internal components of the battery, such as the tab 401, to keep its position stable and avoid displacement during transportation or use. One sealing ring 10 is sleeved on the outside of the first pole 301 and is in sealing fit with the first cover plate 201 and the pole connection part 501. The other sealing ring 10 is sleeved on the outside of the second pole 302 and is in sealing fit with the second cover plate 202. The two sealing rings 10 are 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.

[0078] Further, the first pole 301 is a positive pole, and the second pole 302 is a negative pole, or the first pole 301 is a negative pole, and the second pole 302 is a positive pole. The materials of the positive pole and the negative pole are metals. Generally, the material of the negative pole is copper, aluminum, etc., and the material of the positive pole is aluminum, etc.

[0079] It should be noted that before welding the connecting piece 5 and the tab 401, the first pole 301, the first plastic part 8, the second plastic part 9, and the sealing ring 10 have been assembled on the first cover plate 201, and the pole connection part 501 of the connecting piece 5 has been fixed on the first pole 301.

[0080] In one embodiment, the welding through hole 2011 is rectangular. It can be understood that the welding through hole 2011 can also be other shapes and is not limited thereto.

[0081] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including: the above-mentioned battery cell.

[0082] In the related art, two downward bending parts are formed by bending the two sides of the connecting piece. A pair of tabs pass through between the two downward bending parts and are bent on the corresponding downward bending parts. When welding the connecting piece and the tab, bending is required, which results in a relatively thick thickness after the connecting piece and the tab are connected, occupying more internal space of the battery, and the process is also complex.

[0083] In this embodiment, cover plates are respectively arranged at two opposite open ends of the housing 1. The two cover plates are the first cover plate 201 and the second cover plate 202 respectively. A welding through hole 2011 is provided on the first cover plate 201. The welding through hole 2011 serves as a channel for welding the connecting piece 5 and the electrode tab 401. An explosion-proof valve 2022 and a liquid injection hole 2021 are arranged on the second cover plate 202. The electrode group 4 is first welded to the second cover plate 202, then placed into the housing 1. Next, the first cover plate 201 and the vertical electrode tab 401 are assembled together. Then, after the electrode tab 401 is bent by 90°, welding processes such as laser welding or ultrasonic welding are used to weld the connecting piece 5 and the electrode tab 401 through the welding through hole 2011. Finally, the welding through hole 2011 of the first cover plate 201 is hermetically welded by the sealing plate 6 to achieve sealing, reducing the bending process of the connecting piece 5, improving the space utilization rate inside the battery, and enhancing the production efficiency.

[0084] Specifically, the connecting piece 5 is divided into a pole column connecting portion 501 and an electrode tab connecting portion 502. The pole column connecting portion 501 is welded to the first pole column 301. Reinforcing ribs 503 protruding towards the first cover plate 201 or protruding away from the first cover plate 201 are arranged on the same side of the pole column connecting portion 501 and the electrode tab connecting portion 502, ensuring the strength of the connecting piece 5. When the electrode tab 401 is welded to the connecting piece 5, the upper part of the electrode 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, without 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 electrode 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.

[0085] Furthermore, the welding through hole 2011 is a stepped hole. The stepped surface of the welding through hole 2011 facilitates fixing the sealing plate 6. The upper surface of the electrode tab connecting portion 502 is coplanar with the upper surface of the pole column connecting portion 501.

[0086] It should be noted that the upper surface of the bending portion 4011 forms a welding area (such as Figure 16 and Figure 17 the grid-like area shown).

[0087] 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 a first open end and a second open end; A first cover plate disposed at the first open end, the first cover plate having a welding through-hole; A second cover plate disposed at the second open end; A first terminal post disposed on the first cover plate; A second terminal post disposed on the second cover plate; A pole group disposed in the receiving cavity, one side of the pole group having a tab; A connecting piece having a terminal post connecting portion and a tab connecting portion, the terminal post connecting portion being connected to the first terminal post, a through-hole for the tab to pass through being formed in the tab connecting portion, the tab passing through the through-hole and being bent to form a bent portion, the bent portion and the tab connecting portion being welded through the welding through-hole, at least one of the terminal post connecting portion and the tab connecting portion being provided with a reinforcing portion for strengthening the structural strength of the connecting piece.

2. The battery cell according to claim 1, wherein The through-hole is a notch disposed on one side of the tab connecting portion.

3. The cell according to claim 2, wherein, The reinforcing portion is a reinforcing rib protruding towards one side, the reinforcing rib extending along the length direction of the first cover plate and being disposed on the side of the tab connecting portion and the terminal post connecting portion away from the through-hole.

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

5. The battery cell according to claim 3, wherein, The thickness T of the connecting piece is 0.6 mm - 2.5 mm.

6. The cell according to claim 5, characterized in that, The height H of the reinforcing rib protruding from the surface of the tab connecting portion is 0.5 - 3 times the thickness T of the connecting piece, and / or, the reinforcing rib forms a groove on the other side of the tab connecting portion, and the width W of the groove along the width direction of the first cover plate is 0.5 - 3 times the thickness T of the connecting piece.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The length L of the tab connecting portion along the length direction of the first cover plate is greater than the length L1 of the tab along the length direction of the first cover plate.

8. The battery cell according to any one of claims 1 to 6, characterized in that, The battery cell further includes a sealing plate covering the welding through-hole and used for sealing the welding through-hole.

9. The battery cell according to any one of claims 1 to 6, characterized in that, The second cover plate is provided with a liquid injection hole and an explosion-proof valve.

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

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