Battery cell and battery pack

Abstract

The utility model relates to battery technology field discloses electric core and battery package, wherein the electric core, include: pole group, insulating film, casing and insulating plate, pole group outer periphery is covered with insulating film, casing plate material is bent and forms casing and forms two adjacent flanging, and the adjacent flanging all is equipped with the bending strengthening part that is concave along Z direction, and the adjacent bending strengthening part is welded and is connected, and the welding joint forms the weld, and the weld extends along X direction, and the pole group is installed in the casing, the insulating plate is fixed on the insulating film outside the pole group, and the insulating plate is set to the side that sets up the weld towards the casing, and is equipped with the recess of accommodating bending strengthening part and weld on the insulating plate, the utility model discloses in the process of pole group into the shell, and the recess on the insulating plate is accommodated in bending strengthening part and weld, can avoid the weld scratch damage insulating film, to avoid the pole group directly with the casing contact, that is, avoid short circuit risk. Moreover, still can improve the weld place periphery intensity, to improve the anti -deformation ability of casing.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to battery cells and battery packs. Background Technology

[0002] A battery cell typically consists of a casing and a cover plate forming a sealed space to house the electrode assembly. The casing is usually made of sheet metal that has been bent and then welded together.

[0003] Due to inherent defects in the welding process, it is inevitable that the height of the inner weld seam of the casing will exceed the inner surface of the casing. During the process of inserting the electrode assembly into the casing, the inner weld seam can easily scratch the insulating film on the outside of the electrode assembly, causing the electrode assembly to come into direct contact with the casing and creating a short circuit risk. Utility Model Content

[0004] In view of this, the present invention provides a battery cell and battery pack to solve the problem that the weld seam formed by the casing welding will scratch the insulating film outside the electrode assembly during the electrode assembly insertion process, causing the electrode assembly to directly contact the casing and cause a short circuit.

[0005] In a first aspect, this utility model provides a battery cell, comprising: The electrode assembly is surrounded by an insulating film. The shell plate is bent to form a shell and form two adjacent folded edges. Each of the adjacent folded edges is provided with a bending reinforcement portion that is concave in the Z direction. The adjacent bending reinforcement portions are welded together to form a weld at the welded joint. The weld extends in the X direction. The electrode assembly is installed in the shell. An insulating plate is fixed to the insulating film outside the electrode assembly. The insulating plate is disposed on the side of the housing where the weld is located, and the insulating plate is provided with a groove to accommodate the bent reinforcement and the weld.

[0006] Beneficial effects: The battery cell of this utility model, by setting an insulating plate on the side of the insulating film facing the housing where the weld is located, and setting a groove on the insulating plate, allows the bent reinforcement and the weld to be inserted into the groove along the X direction during the insertion of the electrode assembly into the housing. This avoids the weld scratching and damaging the insulating film, thus avoiding the risk of short circuit and improving the safety of the battery cell. Moreover, the welding connection at the bent reinforcement of the housing increases the strength around the weld, thereby improving the deformation resistance of the housing.

[0007] In one optional embodiment, the weld includes an outer weld located outside the bent reinforcement along the Z direction and an inner weld located inside the bent reinforcement, wherein the outer surface of the outer weld does not exceed the outer wall of the housing, and the inner weld is accommodated within the groove.

[0008] Beneficial effects: The outer surface of the outer weld does not exceed the outer wall of the shell, thus avoiding interference between the outer weld and the blue film on the outside of the shell. The inner weld is accommodated within the groove, which prevents the inner weld from scratching or damaging the insulating film during the insertion of the electrode assembly into the shell, thereby avoiding the risk of short circuit.

[0009] In one alternative embodiment, along the Z direction, the maximum dimension between the inner surface of the inner weld and the inner wall of the housing is L1, satisfying 0.1 mm ≤ L1 ≤ 0.5 mm.

[0010] Beneficial effects: By controlling L1 within a suitable range, it is possible to avoid the inner weld seam from protruding too much and occupying the internal space of the shell, while leaving enough space to ensure that the outer weld seam does not exceed the outer wall of the shell.

[0011] In one optional embodiment, the groove depth is T1, satisfying T1 > L1 and 0.15 mm ≤ T1 ≤ 0.55 mm.

[0012] Beneficial effects: By controlling T1 > L1, it is possible to avoid contact between the inner weld and the bottom of the groove. In addition, by controlling the groove depth T1 within a suitable range, it is possible to ensure that the groove has enough space to accommodate the bending reinforcement and the weld.

[0013] In one optional embodiment, the thickness of the insulating plate is T2, satisfying T2 > T1 and 0.3 mm ≤ T2 ≤ 1 mm.

[0014] Beneficial effects: By controlling the thickness T2 of the insulation board within a suitable range, it is possible to ensure that the insulation board has sufficient thickness to open grooves and accommodate the bending reinforcement and welds, while avoiding the insulation board being too thick and occupying the internal space of the battery cell, which would reduce the energy density of the battery cell.

[0015] In one alternative embodiment, the battery cell is a blade battery cell, and the insulating plate is disposed between the insulating film and the narrow side of the housing so that the insulating plate supports the electrode assembly.

[0016] Beneficial effects: In the case of blade cells, placing the insulating plate on the narrow side of the housing allows the electrode assembly to be directly supported by the insulating plate, thereby eliminating the side plate of traditional blade cells, simplifying the cell structure, reducing usage costs and improving cell manufacturing efficiency.

[0017] In one alternative embodiment, a gap is left between the insulating plate and the housing, and the insulating plate has at least one through hole along the Z direction.

[0018] Beneficial effects: By leaving a gap between the insulation board and the housing, and opening through holes in the insulation board, an exhaust channel can be formed between the housing and the electrode assembly. This allows the gas generated by the electrode assembly to be quickly discharged to the outside of the housing during normal use of the battery cell and in the event of thermal runaway, thereby improving the safety of the battery cell.

[0019] In one optional embodiment, a plurality of through holes are provided, and the plurality of through holes are spaced apart along the X direction on opposite sides of the groove.

[0020] Beneficial effects: By setting multiple through holes at intervals on opposite sides of the groove, multiple venting paths can be formed, which facilitates further venting and improves the safety of the battery cell.

[0021] In one optional embodiment, the thickness of the shell is T3, satisfying 0.15 mm ≤ T3 ≤ 1.5 mm.

[0022] Beneficial effects: By controlling the thickness T3 of the shell within a suitable range, it is possible to ensure that the bending reinforcement has sufficient strength to resist external impacts, avoid excessive weight and volume of the shell, and at the same time ensure that the shell has a suitable thickness for welding into a whole.

[0023] Secondly, the present invention also provides a battery pack, comprising: at least one of the above-mentioned battery cells.

[0024] Beneficial effects: Because the battery pack includes battery cells, it has the same effect as the battery cells. Specifically, by placing an insulating plate on the side of the insulating film facing the casing where the weld seam is located, and creating grooves on the insulating plate, the bending reinforcement and weld seam can be inserted into the grooves along the X-direction during the insertion of the electrode assembly into the casing. This prevents the weld seam from scratching and damaging the insulating film, thus avoiding the risk of short circuits and improving the safety of the battery cells. Furthermore, welding the bending reinforcement section of the casing increases the strength around the weld seam, thereby improving the casing's resistance to deformation. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present utility model; Figure 2 This is an exploded view of a battery cell according to an embodiment of the present utility model; Figure 3This is a side view of a battery cell according to an embodiment of the present utility model; Figure 4 for Figure 3 Sectional view at point AA; Figure 5 for Figure 4 A magnified view of a section at point B in the middle; Figure 6 This is a partial structural schematic diagram of the insulating plate of a battery cell according to an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures: 1. Electrode assembly; 2. Insulating film; 3. Housing; 301. Bending reinforcement; 302. Weld; 3021. External weld; 3022. Internal weld; 4. Insulating plate; 401. Groove; 402. Through hole; 5. Cover plate. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] In the embodiments of the utility model, the "battery pack" is formed by combining a certain number of battery cells into a battery module and placing them in a housing to protect the battery cells from external impacts, heat, vibration, etc. The battery pack also includes a battery management system (BMS), a thermal management system, an electrical connection system (high-voltage / low-voltage connectors, wiring harnesses, etc.), structural components (shell, brackets, etc.), and protective components, forming a complete functional unit that can directly output electrical energy.

[0030] Battery packs serve as a rechargeable power source in electrical devices. These devices include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric vehicles include pure electric vehicles, hybrid electric vehicles, and range-extended electric vehicles.

[0031] In the embodiments of this utility model, "cell" refers to a single battery cell capable of independent charging and discharging. The components of a cell include a positive electrode, a negative electrode, a separator, an electrolyte, and a casing for encapsulating the positive electrode, negative electrode, separator, and electrolyte. The portions of the positive and negative electrode containing active material constitute the main body of the electrode assembly, while the portions of the positive and negative electrode without active material each constitute a tab. The tabs include positive and negative tabs, which may be located together at one end of the main body or at opposite ends of the main body.

[0032] This invention does not impose any particular limitations on the type or shape of the battery cell; it can be a blade cell or a prismatic cell, etc. The battery cell in this invention can be a lithium-ion cell, a potassium-ion cell, a sodium-ion cell, a lithium-sulfur cell, etc., with lithium-ion cells being particularly preferred. The electrode assembly process is a crucial step in the battery cell manufacturing process, directly affecting the cell's performance and safety.

[0033] The following is combined with Figures 1 to 6 The following describes embodiments of the present invention.

[0034] According to embodiments of the present invention, on the one hand, such as Figure 1 and Figure 2 As shown, a battery cell is provided, mainly comprising: an electrode assembly 1, an insulating film 2, a housing 3, and an insulating plate 4. The electrode assembly 1 is covered with the insulating film 2. The housing sheet is bent to form the housing 3 and forms two adjacent folded edges. Each adjacent folded edge is provided with a bending reinforcement 301 that is concave in the Z direction. The adjacent bending reinforcements 301 are welded together to form a weld 302 at the welded joint. The weld 302 extends in the X direction. The electrode assembly 1 is installed in the housing 3. The insulating plate 4 is fixed to the insulating film 2 outside the electrode assembly 1. The insulating plate 4 is positioned on the side of the housing 3 where the weld 302 is located, and the insulating plate 4 is provided with a groove 401 to accommodate the bending reinforcement 301 and the weld 302.

[0035] Therefore, the battery cell provided in this embodiment of the present invention, by providing an insulating plate 4 on the side of the insulating film 2 facing the housing 3 where the weld seam 302 is located, and providing a groove 401 on the insulating plate 4, allows the bending reinforcement 301 and the weld seam 302 to be inserted into the groove 401 in the X direction during the insertion of the electrode assembly 1 into the housing 3. This avoids the weld seam 302 scratching and damaging the insulating film 2, thus avoiding the risk of short circuit and improving the safety of the battery cell. Moreover, by welding the bending reinforcement 301 of the housing 3, the bending reinforcement 301 can improve the periphery strength at the weld seam 302, thereby improving the deformation resistance of the housing 3.

[0036] Specifically, in the Z direction, such as Figure 1 and Figure 2 As shown by arrow Z in the diagram, the X direction is as follows: Figure 1and Figure 2 As indicated by arrow X in the diagram. Electrode group 1 is formed by winding or stacking positive and negative electrode sheets, with a separator between the positive and negative electrode sheets. Insulating film 2 covers the outer periphery of electrode group 1 to protect electrode group 1 and prevent electrode group 1 from directly contacting housing 3.

[0037] In this embodiment of the invention, the "shell 3" is a component that provides a receiving space to house components such as the positive electrode, negative electrode, diaphragm, and electrolyte, and isolates them from the outside environment. The outer periphery of the shell 3 is generally covered with a blue film for insulation. The shell 3, formed by bending the shell sheet, has openings at both ends, with an internal receiving cavity communicating with the openings. The electrode assembly 1 is disposed within the receiving cavity. The bending reinforcement 301, formed by bending the shell sheet, acts as a reinforcing rib, increasing the strength of the sheet material near the weld 302, thereby improving the resistance of the area near the weld 302 to external forces. Without the bending reinforcement 301, external forces would easily concentrate on the weaker sides of the weld 302, causing the weld 302 to crack. The weld 302 is the trace formed by welding the bending reinforcement 301.

[0038] In embodiments of this utility model, such as Figure 1 and Figure 2 As shown, the battery cell also includes a cover plate 5, which is placed over the opening and welded to the housing 3 to form a sealed cavity for accommodating the electrode group 1. The cover plate 5 is also provided with a terminal post, which is electrically connected to the tab of the electrode group 1.

[0039] It should be noted that the shell 3 can also be formed by welding multiple shell plates together, which will form multiple welds 302. The number and position of the bending reinforcement 301 and the groove 401 can be set accordingly.

[0040] It should be noted that the materials of the insulating board 4 and the insulating film 2 are not limited in this embodiment of the invention, as long as they can achieve the insulation effect. For example, both the insulating board 4 and the insulating film 2 can be PP (Polypropylene) films, and the insulating board 4 and the insulating film 2 can be fixed into a whole by heat fusion.

[0041] In one embodiment, such as Figure 5As shown, weld 302 includes an outer weld 3021 located outside the bent reinforcement 301 along the Z direction and an inner weld 3022 located inside the bent reinforcement 301. The outer surface of the outer weld 3021 does not exceed the outer wall of the housing 3, and the inner weld 3022 is accommodated within the groove 401. The outer weld 3021 not exceeding the outer wall of the housing 3 prevents interference between the outer weld 3021 and the blue film outside the housing 3. The inner weld 3022 being accommodated within the groove 401 prevents the inner weld 3022 from scratching or damaging the insulating film 2 during the insertion of the electrode assembly 1 into the housing 3, thus avoiding the risk of short circuit.

[0042] Specifically, the shape of the groove 401 is adapted to the shape of the bent reinforcement 301 and the inner weld 3022 in order to accommodate the bent reinforcement and the weld 302. For example, the groove 401 can be a rectangular groove.

[0043] Furthermore, in one embodiment, such as Figure 5 As shown, along the Z-direction, the maximum dimension between the inner surface of the inner weld 3022 and the inner wall of the shell 3 is L1, satisfying 0.1 mm ≤ L1 ≤ 0.5 mm. By controlling L1 within a suitable range, it is possible to prevent the inner weld 3022 from protruding too much and occupying the internal space of the shell 3, while leaving sufficient space to ensure that the outer weld 3021 does not exceed the outer wall of the shell 3. If the value of L1 is too small, the strength of the bending reinforcement 301 will be too small, and the strength around the weld 302 will be low. If the value of L1 is too large, the inner weld 3022 will protrude too much and occupy the internal space of the shell 3.

[0044] For example, in this embodiment of the present invention, the value of L1 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc.

[0045] Furthermore, in one embodiment, such as Figure 5 As shown, the groove depth of groove 401 is T1, which satisfies T1 > L1 and 0.15mm ≤ T1 ≤ 0.55mm. By controlling the groove depth T1 of groove 401 within a suitable range, it can be ensured that groove 401 has sufficient space to accommodate the bent reinforcement 301 and the weld 302, and to prevent the inner weld 3022 from contacting the bottom of groove 401.

[0046] For example, in this embodiment of the present invention, T1-L1=0.05 mm, and the value of L1 can be 0.15 mm, 0.25 mm, 0.35 mm, 0.45 mm, 0.55 mm, etc.

[0047] Furthermore, in one embodiment, such as Figure 5As shown, the thickness of the insulating plate 4 is T2, which satisfies T2 > T1 and 0.3 mm ≤ T2 ≤ 1 mm. By controlling the thickness T2 of the insulating plate 4 within a suitable range, it can be ensured that the insulating plate 4 has sufficient thickness to open the groove 401 and accommodate the bending reinforcement 301 and the weld 302, while avoiding the insulating plate 4 being too thick and occupying the internal space of the battery cell, which would reduce the energy density of the battery cell.

[0048] For example, in this embodiment of the present invention, the value of T2 can be 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1 mm, etc.

[0049] In one embodiment, such as Figures 2 to 5 As shown, the battery cell is a blade battery cell, and the insulating plate 4 is disposed between the insulating film 2 and the narrow side of the housing 3 so that the insulating plate 4 supports the electrode group 1.

[0050] In traditional blade-type battery cells, a side plate is typically placed between the narrow side of the electrode assembly 1 and the housing 3 to support the electrode assembly 1. This embodiment of the invention places the insulating plate 4 on the narrow side of the housing 3, allowing the electrode assembly 1 to be directly supported by the insulating plate 4. This eliminates the need for the side plate found in traditional blade-type battery cells, simplifying the cell structure, reducing usage costs, and improving cell manufacturing efficiency.

[0051] In one embodiment, such as Figure 2 and Figure 6 As shown, a gap is left between the insulating plate 4 and the housing 3. Along the Z direction, the insulating plate 4 has at least one through hole 402. The gap between the insulating plate 4 and the housing 3, and the through hole 402 on the insulating plate 4, can form an exhaust channel between the housing 3 and the electrode group 1, so that the gas generated by the electrode group 1 can be quickly discharged to the outside of the housing 3 during normal use of the battery cell and in the event of thermal runaway, thereby improving the safety of the battery cell.

[0052] It should be noted that after the electrode assembly 1 is covered with the insulating film 2, the gas generated by the electrode assembly 1 can pass through the insulating film 2, or pass through the gap between the electrode assembly 1 and the insulating film 2, and enter the gap between the insulating plate 4 and the housing 3 through the through hole 402, and finally be discharged to the outside of the housing 3.

[0053] It should be noted that the present invention does not limit the number of through holes 402, and one, two or more can be selected as needed.

[0054] In addition, there are no restrictions on the shape of the through hole 402. Regular holes or irregular holes can be selected. Regular holes include, but are not limited to, round holes, square holes, elliptical holes, etc.

[0055] In one embodiment, such as Figure 6As shown, multiple through holes 402 are provided, and the multiple through holes 402 are spaced apart along the X direction on opposite sides of the groove 401. The multiple through holes 402 spaced apart on opposite sides of the groove 401 can form multiple venting paths, thereby facilitating further venting and improving the safety of the battery cell.

[0056] In one embodiment, such as Figure 5 As shown, the thickness of the shell 3 is T3, which satisfies 0.15 mm ≤ T3 ≤ 1.5 mm. By controlling the thickness T3 of the shell 3 within a suitable range, it is possible to ensure that the bending reinforcement 301 has sufficient strength to resist external impacts, avoid the shell 3 becoming too heavy and increasing its weight and volume, and at the same time ensure that the shell 3 has a suitable thickness for welding into a whole.

[0057] For example, in this embodiment of the present invention, the value of T3 can be 0.15 mm, 0.3 mm, 0.45 mm, 0.6 mm, 0.8 mm, 1 mm, 1.25 mm, 1.5 mm, etc.

[0058] According to an embodiment of the present invention, another aspect provides a battery pack, comprising: at least one battery cell.

[0059] Because the battery pack includes battery cells, it has the same effect as the battery cells. Specifically, by providing an insulating plate 4 on the side of the insulating film 2 facing the housing 3 where the weld 302 is located, and by providing a groove 401 on the insulating plate 4, the bending reinforcement 301 and the weld 302 can be inserted into the groove 401 along the X direction during the insertion of the electrode assembly 1 into the housing 3. This prevents the weld 302 from scratching or damaging the insulating film 2, thus avoiding the risk of short circuits and improving the safety of the battery cells. Furthermore, the welding connection at the bending reinforcement 301 of the housing 3 increases the perimeter strength at the weld 302, thereby improving the deformation resistance of the housing 3.

[0060] Although 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, include: The electrode assembly is covered with an insulating film on its outer periphery; The shell plate is bent to form a shell and form two adjacent folded edges. Each of the adjacent folded edges is provided with a bending reinforcement portion that is concave in the Z direction. The adjacent bending reinforcement portions are welded together to form a weld at the welded joint. The weld extends in the X direction. The electrode assembly is installed in the shell. An insulating plate is fixed to the insulating film outside the electrode assembly. The insulating plate is disposed on the side of the housing where the weld is located, and the insulating plate is provided with a groove to accommodate the bent reinforcement and the weld.

2. The battery cell according to claim 1, characterized in that, The weld includes an outer weld located outside the bent reinforcement along the Z direction and an inner weld located inside the bent reinforcement. The outer surface of the outer weld does not exceed the outer wall of the shell, and the inner weld is accommodated within the groove.

3. The battery cell according to claim 2, characterized in that, Along the Z direction, the maximum dimension between the inner surface of the inner weld and the inner wall of the shell is L1, which satisfies 0.1 mm ≤ L1 ≤ 0.5 mm.

4. The battery cell according to claim 3, characterized in that, The groove depth is T1, satisfying T1>L1, 0.15 mm≤T1≤0.55 mm.

5. The battery cell according to claim 4, characterized in that, The thickness of the insulating plate is T2, which satisfies T2>T1 and 0.3mm≤T2≤1 mm.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The battery cell is a blade battery cell, and the insulating plate is disposed between the insulating film and the narrow side of the housing so that the insulating plate supports the electrode assembly.

7. The battery cell according to any one of claims 1 to 5, characterized in that, A gap is left between the insulating plate and the housing, and at least one through hole is formed in the insulating plate along the Z direction.

8. The battery cell according to claim 7, characterized in that, Multiple through holes are provided, and the multiple through holes are spaced apart along the X direction on opposite sides of the groove.

9. The battery cell according to any one of claims 1 to 5, characterized in that, The thickness of the shell is T3, which satisfies 0.15 mm ≤ T3 ≤ 1.5 mm.

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

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