Battery cell and battery pack

Abstract

The application relates to the technical field of batteries, and discloses a battery cell and a battery pack, which comprise the following steps: at least one end of a battery cell shell is formed into an opening, a cover plate is arranged at the opening, the cover plate comprises a cover plate body, a lower plastic is arranged below the cover plate, an insulating film is arranged on the lower plastic, the cover plate accommodating section has an inclined step surface, the thickness of the cover plate accommodating section is e1, the thickness of the pole group accommodating section is e2, the thickness of the cover plate is t, the thickness of the cover plate body is h1, the gap between the cover plate body and the cover plate accommodating section is w1, the distance between the pole group accommodating section and the lower plastic is w2, the distance between the insulating film and the cover plate is h2, and the included angle between the step surface of the connecting section and the extension surface of the cover plate accommodating section is a, and the following conditions are met: 0 < a < 90 DEG, 0 < e1 < 0.5 mm, 0 < e2 < 0.5 mm, 0 < t < 0.5 mm, 0 < h1 < 0.5 mm, 0 < w1 < 0.5 mm, 0 < w2 < 0.5 mm, 0 < h2 < 0.5 mm, and 0 < h2 + 0.5 mm.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a battery cell and battery pack. Background Technology

[0002] With the increasing maturity of new energy battery technology, new energy batteries are widely used as power batteries in electric vehicles and energy storage fields. Therefore, the requirements for the performance and safety of new energy batteries are becoming increasingly stringent. Traditional new energy batteries, such as prismatic lithium-ion cells, involve covering the outer periphery of the electrode assembly with an insulating film, then inserting the electrode assembly into the cell casing. A cover plate is then assembled and welded to the cell casing for sealing, thus encapsulating the electrode assembly inside the cell casing. The insulating film serves to prevent short circuits between the electrode assembly and the cell casing, providing insulation and withstand voltage protection. The cell then uses the cover plate to lead out the positive and negative terminals for charging and discharging.

[0003] However, during the production of battery cells, the assembly process parameters between the cell casing, cover plate, and insulating film were not effectively defined for different sizes of cells. This resulted in a high rate of welding defects during the cell production process, causing some cells to be scrapped, which led to low cell production efficiency and wasted manufacturing costs. Summary of the Invention

[0004] In view of this, the present invention provides a battery cell and a battery pack to solve the problem of high welding defect rate during the battery cell production process, which leads to low battery cell production efficiency.

[0005] In a first aspect, the present invention provides a battery cell, comprising:

[0006] A battery cell housing, wherein at least one end of the battery cell housing forms an opening, the battery cell housing includes a cover plate receiving section, a connecting section and an electrode group receiving section, the connecting section having an inclined stepped surface;

[0007] A cover plate, wherein the cover plate is disposed at the opening, the cover plate comprising a cover plate body, and located within the installation space enclosed by the cover plate receiving section;

[0008] The lower plastic, along the Z direction, is disposed below the cover plate and within the installation space enclosed by the electrode assembly receiving section;

[0009] An insulating film is disposed on the lower plastic and located between the electrode assembly receiving section and the lower plastic;

[0010] The thickness of the cover plate receiving section along the X direction is e1, the thickness of the electrode assembly receiving section along the X direction is e2, the thickness of the cover plate along the Z direction is t, the thickness of the cover plate body along the Z direction is h1, the gap between the cover plate body and the cover plate receiving section along the X direction is w1, the distance between the electrode assembly receiving section and the lower plastic along the X direction is w2, the distance between the insulating film and the cover plate along the Z direction is h2, and the angle between the stepped surface of the connecting section and the extended surface of the cover plate receiving section is α, satisfying 0 < α. ≤h2+0.5mm.

[0011] Beneficial effects: By reasonably setting the thickness e1 of the cover plate receiving section, the thickness e2 of the electrode receiving section, the thickness t of the cover plate, the thickness h1 of the cover plate body, the gap w1 between the cover plate body and the cover plate receiving section, the distance w2 between the electrode receiving section and the lower plastic, the distance h2 between the insulating film and the cover plate, and the angle α between the stepped surface of the connecting section and the extended surface of the cover plate receiving section, the above parameters are made to satisfy 0 < ≤h2+0.5mm, thus ensuring that the distance between the cell housing and the lower plastic and the distance between the cover plate and the insulating film are within a suitable range. When welding between the cell housing and the cover plate, it avoids the upper end of the lower insulating film being burned by the laser reflected from the stepped surface of the connection section, preventing the release of foreign gas that could cause weld spatter between the cell housing and the cover plate. This improves the welding yield between the cell housing and the cover plate, enhances the sealing between the cell housing and the cover plate, ensures the production quality of the cell, and ultimately improves the cell production efficiency.

[0012] In one alternative implementation, w2 satisfies 0.5mm≤w2≤5mm.

[0013] In one optional implementation, h2 satisfies 0.5mm≤h2≤10mm.

[0014] In one optional implementation, e1 satisfies 0.2mm≤e1≤1mm, and e2 satisfies e1+0.1mm≤e2≤e1+0.5mm.

[0015] In one optional implementation, t satisfies 1mm≤t≤5mm; h1 satisfies 0.5mm≤h1≤4.8mm, h1<t.

[0016] In one alternative implementation, w1 satisfies 0.03mm≤w1≤0.5mm.

[0017] In one alternative implementation, 'a' satisfies 15° ≤ a ≤ 45°.

[0018] In one alternative embodiment, along the Z direction, the lower surface of the cover plate body is provided with a boss, the boss having a guide portion in the circumferential direction, and the boss extending into the cell housing through the opening.

[0019] In one alternative embodiment, the battery cell further includes an electrode assembly disposed within an installation space enclosed by the electrode assembly receiving section.

[0020] Secondly, the present invention also provides a battery pack, comprising:

[0021] Box;

[0022] Multiple battery cells as described above are housed within the housing.

[0023] Beneficial effects: The battery pack also includes a housing, which houses multiple battery cells. The housing prevents liquids or other foreign objects from affecting the charging or discharging of the cells. Moreover, placing multiple battery cells inside the battery pack's housing can increase the overall energy density of the battery pack and improve its performance. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 An enlarged diagram of A in the diagram.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100. Cell housing; 110. Cover plate receiving section; 120. Connecting section; 121. Stepped surface; 130. Electrode group receiving section; 200. Cover plate; 210. Cover plate body; 220. Boss; 221. Guide part; 300. Lower plastic; 400. Insulating film. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The following is combined with Figures 1 to 2 The following describes embodiments of the present invention.

[0031] According to an embodiment of the present invention, in one aspect, in conjunction with [see also...] Figures 1 to 2 A battery cell is provided, comprising: a battery cell housing 100, at least one end of which forms an opening; the battery cell housing 100 includes a cover plate receiving section 110, a connecting section 120, and an electrode group receiving section 130; the connecting section 120 having an inclined stepped surface 121; a cover plate 200 disposed at the opening; the cover plate 200 includes a cover plate body 210 located within an installation space enclosed by the cover plate receiving section 110; a lower plastic 300 disposed below the cover plate 200 along the Z direction within the installation space enclosed by the electrode group receiving section 130; and an insulating film 400 disposed on the lower plastic 300. Located between the electrode assembly receiving section 130 and the lower plastic 300; the thickness of the cover plate receiving section 110 along the X direction is e1, the thickness of the electrode assembly receiving section 130 along the X direction is e2, the thickness of the cover plate 200 along the Z direction is t, the thickness of the cover plate body 210 along the Z direction is h1, the gap between the cover plate body 210 and the cover plate receiving section 110 along the X direction is w1, the distance between the electrode assembly receiving section 130 and the lower plastic 300 along the X direction is w2, the distance between the insulating film 400 and the cover plate 200 along the Z direction is h2, and the angle between the step surface 121 of the connecting section 120 and the extended surface of the cover plate receiving section 110 is α, satisfying 0 < α. ≤h2+0.5mm.

[0032] In this embodiment, the X direction is the length direction of the battery cell, and the Z direction is the height direction of the battery cell. At least one end of the battery cell housing 100 forms an opening. The battery cell housing 100 includes a cover plate receiving section 110, a connecting section 120, and an electrode assembly receiving section 130. The cover plate receiving section 110 is located near the opening, and the electrode assembly receiving section 130 encloses an installation space for placing the electrode assembly, allowing the electrode assembly to pass through the opening and enter the installation space within the battery cell housing 100, thus accommodating the electrode assembly. The connecting section 120 is located between the cover plate receiving section 110 and the electrode assembly receiving section 130. The cover plate 200 includes a cover plate body 210, which is disposed at the opening of the battery cell housing 100. The connecting section 120 has an inclined stepped surface 121. Along the Z direction, the thickness of the connecting section 120 gradually decreases from bottom to top, thereby forming a stepped surface 121 inclined downwards along the X direction on the inner side of the battery cell housing 100. When the cover plate 200 is assembled with the cell housing 100, the cover plate 200 can be supported on the stepped surface 121 of the connecting section 120, preventing the cover plate 200 from falling into the installation space. Furthermore, the stepped surface 121 of the connecting section 120 can guide the installation of the cover plate 200. The cell housing 100 and the cover plate 200 are connected by laser welding.

[0033] Along the Z-direction, a lower plastic 300 is provided below the cover plate 200, on the side of the cover plate 200 facing the installation space. The lower plastic 300 is located within the installation space enclosed by the electrode assembly receiving section 130. The lower plastic 300 is an insulating material. By providing the lower plastic 300 below the cover plate 200, the cover plate 200 and the electrode assembly can be isolated, preventing short circuits between the electrode assembly and the cover plate 200. An insulating film 400 is also provided on one side of the lower plastic 300, positioned between the electrode assembly receiving section 130 and the lower plastic 300, thereby enhancing the insulation effect between the cell housing 100 and the electrode assembly and preventing short circuits between the electrode assembly and the cell housing 100.

[0034] By reasonably setting the following parameters: the thickness e1 of the cover plate receiving section 110 along the X direction, the thickness e2 of the electrode assembly receiving section 130 along the X direction, the thickness t of the cover plate 200 along the Z direction, the thickness h1 of the cover plate body 210 along the Z direction, the gap w1 between the cover plate body 210 and the cover plate receiving section 110 along the X direction, the distance w2 between the electrode assembly receiving section 130 and the lower plastic 300 along the X direction, the distance h2 between the insulating film 400 and the cover plate 200 along the Z direction, and the angle α between the step surface 121 of the connecting section 120 and the extended surface of the cover plate receiving section 110, the above parameters are made to satisfy 0 < 0. ≤h2+0.5mm, thus ensuring that the distance between the cell housing and the lower plastic and the distance between the cover plate and the insulating film are within a suitable range; when welding between the cell housing 100 and the cover plate 200, it avoids the upper end of the insulating film 400 being burned by the laser reflected from the stepped surface 121 of the connecting section 120, so as to prevent the release of foreign gas and the occurrence of solder blasts between the cell housing 100 and the cover plate 200, thereby improving the welding yield between the cell housing 100 and the cover plate 200, improving the sealing between the cell housing 100 and the cover plate 200, ensuring the production quality of the cell, and thus improving the cell production efficiency.

[0035] In one embodiment, w2 satisfies 0.5mm≤w2≤5mm.

[0036] In this embodiment, along the X direction, the distance w2 between the electrode housing section 130 and the lower plastic 300 can be any value or a value between any two of the following: 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, and 5mm. If the distance w2 between the electrode housing section 130 and the lower plastic 300 is too small, such as less than 0.5mm, during welding between the cell housing 100 and the cover plate 200, the laser may be reflected from the stepped surface 121 of the connecting section 120 onto the lower plastic 300, causing the lower plastic 300 to be burned and releasing foreign gas, resulting in solder joint explosions between the cell housing 100 and the cover plate 200, causing the seal between the cell housing 100 and the cover plate 200 to fail. Although the burn resistance of the lower plastic 300 is better than that of the insulating film 400, it is still necessary to control the distance w2 to attenuate the laser power and reduce the impact of the laser on the lower plastic 300.

[0037] If w2 is too large, exceeding 5mm, the excessive gap will encroach on the installation space of the electrode assembly, forcing a reduction in the electrode assembly size and directly decreasing the battery's capacity and energy density. Furthermore, the battery cell will experience vibration and temperature changes during charging, discharging, transportation, or use. An excessively large w2 will also increase the movement space of the lower plastic 300 within the electrode assembly housing section 130, potentially causing displacement, shaking, or deviation from its preset position, leading to insulation failure of the lower plastic 300. Setting w2 to less than or equal to 5mm ensures the stability of the lower plastic 300's position. By properly setting the w2 parameter, it is ensured that the laser will not burn the lower plastic 300 during welding between the cell housing 100 and the cover plate 200, thus ensuring the welding effect between the cell housing 100 and the cover plate 200.

[0038] In one embodiment, h2 satisfies 0.5mm≤h2≤10mm.

[0039] In this embodiment, along the Z-direction, the distance h2 between the insulating film 400 and the cover plate 200 can be any value or a value between any two of the following: 0.5mm, 1.5mm, 2.5mm, 3.5mm, 4.5mm, 5.5mm, 6.5mm, 7.5mm, 8.5mm, 9.5mm, and 10mm. By setting the insulating film 400, a short circuit between the electrode assembly and the cell housing 100 can be prevented. Setting the distance h2 between the insulating film 400 and the cover plate 200 to be greater than 0.5mm also prevents the laser from reflecting off the stepped surface 121 of the connecting section 120 onto the insulating film 400 during welding, which could cause the insulating film 400 to be burned and emit foreign gases, resulting in weld spatter between the cell housing 100 and the cover plate 200, thus causing a seal failure between the cell housing 100 and the cover plate 200. If the distance h2 between the insulating film 400 and the cover plate 200 is too large, such as greater than 10mm, it will force the electrode assembly size to be compressed, directly reducing the cell's capacity and energy density. If h2 is too large, the distance between the cover plate 200 and the lower insulating film 400 and the electrode assembly will be too far, which may cause the cover plate 200 to easily shake inside the cell housing 100, affecting the sealing performance between the cell housing 100 and the cover plate 200. By reasonably setting the parameter h2, the welding yield between the cell housing 100 and the cover plate 200 can be ensured, and the connection stability between the cell housing 100 and the cover plate 200 can be guaranteed.

[0040] In one embodiment, e1 satisfies 0.2mm≤e1≤1mm, and e2 satisfies e1+0.1mm≤e2≤e1+0.5mm.

[0041] In this embodiment, along the X direction, the thickness e1 of the cover plate receiving section 110 can be any value or a value between any two of 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1mm. The thickness e2 of the pole group receiving section 130 can be any value or a value between any two of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, and 1.5mm.

[0042] The cover plate receiving section 110 is the opening of the cell housing 100 and needs to withstand the pressure during assembly and the internal tension of the cell during operation. By setting e1 to be greater than or equal to 0.2 mm, the cover plate receiving section 110 has sufficient rigidity to prevent deformation or cracking of the cell housing 100 due to its thinness when the cover plate 200 is laser welded to it. If e1 is too large, such as greater than 1 mm, it will increase the overall weight of the cell housing 100, leading to increased material consumption. Setting e1 to be less than or equal to 1 mm allows for lightweighting and efficient space utilization of the cell housing 100 while maintaining its strength.

[0043] The electrode assembly receiving section 130 is the main part of the cell housing 100 that encloses the electrode assembly. Setting the thickness e2 of the electrode assembly receiving section 130 to be slightly larger than the thickness e1 of the cover plate receiving section 110 can enhance the deformation resistance of the cell housing 100 by increasing the wall thickness, thus protecting the internal electrode assembly from damage. If the difference between e2 and e1 exceeds 0.5mm, it may significantly increase the weight and cost of the cell housing 100; it will also compress the effective receiving space of the electrode assembly, thereby reducing the cell capacity. By reasonably setting the parameters e1 and e2, the installation strength at the opening of the cell housing 100 can be ensured, and the overall weight of the cell housing 100 can be avoided, reducing the manufacturing cost of the cell housing 100.

[0044] In one embodiment, t satisfies 1mm≤t≤5mm; h1 satisfies 0.5mm≤h1≤4.8mm, h1<t.

[0045] In this embodiment, along the Z direction, the thickness t of the cover plate 200 can be any value of 1mm, 2mm, 3mm, 4mm, 5mm or any value between two of them, and the thickness h1 of the cover plate body 210 can be any value of 0.5mm, 1mm, 2mm, 3mm, 4mm, 4.8mm or any value between two of them.

[0046] The thickness of the cover plate 200 is set to be greater than or equal to 1 mm to ensure that the cover plate 200 has sufficient rigidity and resistance to deformation. This prevents the cover plate 200 from bending and forming gaps due to excessive thinness under stress, which could lead to cell sealing failure. If t is too large, such as greater than 5 mm, the cover plate 200 will occupy too much space within the cell housing 100, thereby compressing the electrode assembly volume and reducing the cell capacity. Moreover, an excessively thick cover plate 200 will also increase the overall weight of the cell.

[0047] The cover plate body 210 is the core part of the cover plate receiving section 110 where the cover plate 200 is embedded into the cell housing 100. If the thickness h1 of the cover plate body 210 is too small, such as less than 0.5 mm, the weld penetration between the cell housing 100 and the cover plate body 210 will be insufficient, resulting in low connection strength between the cell housing 100 and the cover plate body 210. If the thickness h1 of the cover plate body 210 is too large, such as greater than 4.8 mm, under the premise of a certain thickness of the cover plate 200, the thickness of the boss 220 will be too small, resulting in a small guide slope of the guide part 221, making it difficult to assemble the cover plate 200 into the cell housing 100. By reasonably setting the parameters t and h1, sufficient weld penetration can be achieved between the cell housing 100 and the cover plate 200, thereby ensuring the connection strength between the cell housing 100 and the cover plate 200; and the guide part 221 can also guide the installation of the cover plate 200, increasing the convenience of the cover plate 200 installation.

[0048] In one embodiment, w1 satisfies 0.03mm≤w1≤0.5mm.

[0049] In this embodiment, along the X direction, the gap w1 between the cover plate body 210 and the cover plate receiving section 110 can be any value or a value between any two of the following: 0.03mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.3mm, 0.4mm, and 0.5mm. If w1 is too small, such as less than 0.03mm, the cover plate 200 will not be able to be smoothly embedded into the cover plate receiving section 110, and stress will be generated due to tight compression after assembly, causing the battery cell to crack during subsequent use. If w1 is too large, such as greater than 0.5mm, the weld width between the battery cell housing 100 and the cover plate 200 will be too large, resulting in poor connection strength between the battery cell housing 100 and the cover plate 200; moreover, the large gap will increase the welding difficulty between the battery cell housing 100 and the cover plate 200, making it difficult to focus the laser energy to form an effective weld pool during laser welding, easily leading to burn-through or incomplete penetration. By setting the parameters of w1 appropriately, the weld width between the cell housing 100 and the cover plate 200 is ensured to be within a reasonable range, thereby enhancing the connection strength between the cell housing 100 and the cover plate 200.

[0050] In one embodiment, a satisfies 15°≤a≤45°.

[0051] In this embodiment, the included angle α between the stepped surface 121 of the connecting segment 120 and the extended surface of the cover plate receiving segment 110 can be any value of 15°, 20°, 25°, 30°, 35°, 40°, or 45°, or a value between any two of these values. If the included angle α between the stepped surface 121 of the connecting segment 120 and the extended surface of the cover plate receiving segment 110 is too small, such as less than 15°, then when the cover plate 200 is installed at the opening of the cell housing 100, the cover plate 200 will slide directly into the inside of the cell housing 100, thereby increasing the assembly difficulty of the cell housing 100. If the included angle α between the stepped surface 121 of the connecting segment 120 and the extended surface of the cover plate receiving segment 110 is too large, such as greater than 45°, then during the stamping process of the cell housing 100, the stress at the stepped surface 121 of the connecting segment 120 will be too high, leading to the cell housing 100 breaking, greatly increasing the stamping difficulty of the cell housing 100.

[0052] In one embodiment, along the Z direction, the lower surface of the cover body 210 is provided with a boss 220, the boss 220 has a guide portion in the circumferential direction, and the boss 220 extends into the cell housing 100 through the opening.

[0053] In this embodiment, the boss 220 is a protruding structure extending from the lower surface of the cover plate body 210 along the Z direction, i.e., towards the interior of the cell housing 100. By extending into the housing, the boss 220 provides a physical reference for the relative position of the cover plate 200 and the electrode assembly. The boss 220 can also abut against the electrode assembly through the lower plastic 300, thereby limiting the axial displacement of the electrode assembly within the cell housing 100. A guide portion is also provided circumferentially on the boss 220, i.e., the inclined surface of the edge of the boss 220. The guide portion can serve as a guiding ramp. During the installation of the cover plate 200, the guide portion can guide the cover plate 200 to be installed at the opening of the cell housing 100. Moreover, the inclined surface can automatically correct any slight offset of the cover plate 200, ensuring that the cover plate 200 is accurately installed at the preset position at the opening of the cell housing 100.

[0054] The following examples and comparative examples verify the influence of the parameters of the cell housing 100 and the cover plate 200 on its performance. The examples and comparative examples are shown in Table 1. The cell housing 100 and the cover plate 200 are designed with different parameters, and the cell is tested accordingly. The corresponding test results are recorded.

[0055] Table 1

[0056]

[0057] As shown in Table 1, in When the value exceeds the upper limit, solder joint defects appear at the weld between the cell housing 100 and the cover plate 200, and the insulating film 400 is found to be burned after disassembling the cell. When the included angle α between the stepped surface 121 of the connecting section 120 and the extended surface of the cover plate receiving section 110 is lower than the lower limit, the cover plate 200 slides into the cell housing 100 when it is installed at the opening of the cell housing 100. When the distance w2 between the electrode receiving section 130 and the lower plastic 300 is lower than the lower limit, solder joint defects appear at the weld between the cell housing 100 and the cover plate 200, and the lower plastic 300 is found to be burned after disassembling the cell.

[0058] According to an embodiment of the present invention, in a second aspect, a battery pack is also provided, comprising: a housing; and a plurality of battery cells as described above, wherein the plurality of battery cells are housed within the housing. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells; furthermore, arranging the plurality of battery cells within the housing of the battery pack can increase the overall energy density of the battery pack and improve its performance.

[0059] The battery pack mentioned in the embodiments of the present invention may include a single physical module of one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple cells are connected in series, parallel, or mixed through a busbar. Multiple battery cells can be directly assembled into a battery pack, or they can be first assembled into battery modules, and then the battery modules are assembled into a battery pack.

[0060] In some implementations, the battery pack housing can be part of the vehicle's chassis structure. For example, a portion of the housing can be at least part of the vehicle's floor, or a portion of the housing can be at least part of the vehicle's crossbeams and longitudinal beams.

[0061] In this embodiment of the invention, the battery cell can be a rechargeable battery cell, which refers to a battery cell that can be reactivated by charging after discharge and continue to be used. The battery cell can be a lithium-ion battery cell, sodium-ion battery cell, sodium-lithium-ion battery cell, lithium-sulfur battery cell, magnesium-ion battery cell, nickel-metal hydride battery cell, nickel-cadmium battery cell, lead-acid battery cell, etc., and this embodiment of the invention is not limited to this.

[0062] In some implementations, the battery cell in the embodiments of the present invention can be a metal battery cell. Specifically, the metal battery cell may include a lithium metal secondary battery cell, a sodium metal battery cell, or a magnesium metal battery cell, etc. The embodiments of the present invention do not limit this.

[0063] The electrode assembly of a battery cell includes a positive electrode, a negative electrode, and an insulating component. During the charging and discharging process, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The insulating component, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0064] In some implementations, the positive electrode can be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0065] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0066] In some implementations, the negative electrode can be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0067] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0068] In some implementations, the separator is a separator membrane. This invention does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0069] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramic.

[0070] In some implementations, the separator is a solid electrolyte. The solid electrolyte is placed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0071] In some implementations, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This invention does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0072] In some implementations, the electrode group has tabs that allow current to be drawn out of the electrode group. The tabs include positive tabs and negative tabs.

[0073] The battery cells in this embodiment of the invention can be cylindrical cells, prismatic cells, pouch cells, or cells of other shapes. Among them, prismatic cells can include square cells, blade cells, or other multi-prismatic cells, such as hexagonal prismatic cells or octagonal prismatic cells, and this embodiment of the invention is not limited thereto.

[0074] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: A battery cell housing, wherein at least one end of the battery cell housing forms an opening, the battery cell housing includes a cover plate receiving section, a connecting section and an electrode group receiving section, the connecting section having an inclined stepped surface; A cover plate, wherein the cover plate is disposed at the opening, the cover plate comprising a cover plate body, and located within the installation space enclosed by the cover plate receiving section; The lower plastic, along the Z direction, is disposed below the cover plate and within the installation space enclosed by the electrode assembly receiving section; An insulating film is disposed on the lower plastic and located between the electrode assembly receiving section and the lower plastic; The thickness of the cover plate receiving section along the X direction is e1, the thickness of the electrode assembly receiving section along the X direction is e2, the thickness of the cover plate along the Z direction is t, the thickness of the cover plate body along the Z direction is h1, the gap between the cover plate body and the cover plate receiving section along the X direction is w1, the distance between the electrode assembly receiving section and the lower plastic along the X direction is w2, the distance between the insulating film and the cover plate along the Z direction is h2, and the angle between the stepped surface of the connecting section and the extended surface of the cover plate receiving section is α, satisfying 0 < α. ≤h2+0.5mm.

2. The battery cell according to claim 1, characterized in that, The w2 satisfies 0.5mm≤w2≤5mm.

3. The battery cell according to claim 1, characterized in that, The h2 satisfies 0.5mm≤h2≤10mm.

4. The battery cell according to claim 1, characterized in that, The condition e1 satisfies 0.2mm≤e1≤1mm, and the condition e2 satisfies e1+0.1mm≤e2≤e1+0.5mm.

5. The battery cell according to claim 1, characterized in that, The t satisfies 1mm≤t≤5mm; the h1 satisfies 0.5mm≤h1≤4.8mm, h1<t.

6. The battery cell according to claim 1, characterized in that, The condition w1 satisfies 0.03mm≤w1≤0.5mm.

7. The battery cell according to claim 1, characterized in that, The a condition satisfies 15°≤a≤45°.

8. The battery cell according to claim 1, characterized in that, Along the Z direction, the lower surface of the cover plate body is provided with a boss, the boss has a guide portion in the circumferential direction, and the boss extends into the cell housing through the opening.

9. The battery cell according to any one of claims 1-8, characterized in that, The battery cell also includes an electrode assembly, which is disposed within the installation space enclosed by the electrode assembly receiving section.

10. A battery pack, characterized in that, include: Box; A plurality of battery cells as described in any one of claims 1-9, wherein the plurality of battery cells are housed in the housing.

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