Battery cell and battery pack

Abstract

The utility model relates to battery technical field discloses electric core and battery package, wherein the electric core, mainly include: casing, pole group, cover plate subassembly and insulating film, casing is equipped with opening at least one end, pole group is located in the casing, cover plate subassembly covers and is connected with the casing in the opening place, and the cover plate subassembly includes lower plastic part and side plate, and the side of lower plastic part is equipped with the clamping groove, insulating film is covered in the outside of pole group, and insulating film extends to the circumferential side of lower plastic part and is clamped between lower plastic part and side plate, and insulating film is equipped with through -hole with the clamping groove corresponding clamping groove, and the inside of side plate is equipped with the clamping portion of clamping groove and is inserted in the through -hole, and the clamping portion is clamped with clamping groove. The utility model opens the clamping groove in the side of lower plastic part, and the through -hole is opened in the insulating film, and the clamping portion of side plate is clamped with the through -hole and clamping groove, realizes the fixation of lower plastic part and insulating film, and is connected firm, and pole group and outside have no contact space, guarantee the insulating effect to the security of electric core is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to battery cells and battery packs. 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, and the requirements for the performance and safety of new energy batteries are becoming increasingly stringent.

[0003] In traditional new energy batteries, during the assembly process, an insulating film (such as Mylar film) is typically wrapped around the outside of the electrode assembly of the cell to protect it. Figure 1 and Figure 2 As shown, the insulating film 2' typically extends to the side of the lower plastic part 101' of the cover plate assembly 1' and forms an overlapping area with the side of the lower plastic part 101'. Multiple hot-melt points 3' are provided in the overlapping area, and the insulating film 2' is fixed to the lower plastic part 101' by hot-melt method.

[0004] However, after heat fusion, the actual heat fusion point differs significantly from the designed heat fusion point, which can easily lead to defects where the actual heat fusion point is smaller than the designed size. This can cause the heat fusion between the insulating film and the lower plastic part to fail, leaving a certain space between the bottom of the cover plate and the top of the insulating film, resulting in insulation failure, increasing the risk of short circuits, and ultimately affecting the safety performance of the battery cell. Utility Model Content

[0005] In view of this, the present invention provides a battery cell and battery pack to solve the problem that the existing method of fixing the lower plastic part and the insulating film by heat fusion is prone to heat fusion connection failure, resulting in poor safety of the battery cell.

[0006] In a first aspect, this utility model provides a battery cell, comprising: The housing has an opening at at least one end; The pole assembly is located within the housing; A cover plate assembly is provided on the opening and connected to the housing. The cover plate assembly includes a lower plastic part and a side plate. A snap-fit ​​groove is provided on the side of the lower plastic part. An insulating film is wrapped around the outside of the electrode assembly. The insulating film extends to the periphery of the lower plastic part and is sandwiched between the lower plastic part and the side plate. The insulating film has a through hole corresponding to the snap-fit ​​groove. The inner side of the side plate has a snap-fit ​​part that is inserted into the through hole and the snap-fit ​​groove. The snap-fit ​​part snaps into the snap-fit ​​groove.

[0007] Beneficial effects: The battery cell of this utility model has a snap-fit ​​groove on the side of the lower plastic part and a corresponding through hole on the insulating film. The snap-fit ​​part of the side plate passes through the through hole and snaps into the snap-fit ​​groove to fix the lower plastic part and the insulating film. Compared with the traditional hot-melt fixing method, the connection is more secure. In addition, the side plate can seal the gap between the insulating film and the cover plate assembly, so that the electrode group wrapped by the insulating film has no contact space with the outside world, ensuring the insulation effect of the insulating film, reducing the risk of short circuit, and thus improving the safety of the battery cell.

[0008] In one alternative embodiment, the cover assembly further includes a cover plate, the lower plastic member being disposed on the inner side of the cover plate along the Z direction, and the lower plastic member and the side plate being housed inside the housing.

[0009] Beneficial effects: By housing the lower plastic parts and side panels inside the housing, interference between the housing and the side panels can be avoided, thereby preventing the side panels from affecting the welding of the housing and cover plate assembly.

[0010] In one optional embodiment, the lower plastic part has extensions opposite to the cover plate at its two opposite ends along the X direction, the extensions extend along the Y direction, the extensions have a receiving space, and the snap-fit ​​groove is formed on the outside of the extensions along the X and / or Y directions and communicates with the receiving space.

[0011] Beneficial effect: The extension can provide support, and the snap-fit ​​slot is provided on the extension and snaps into the snap-fit ​​part without taking up extra space.

[0012] In one alternative embodiment, the end of the snap-fit ​​portion is accommodated within the accommodating space.

[0013] Beneficial effect: By accommodating the end of the snap-fit ​​part within the accommodating space, a hidden snap-fit ​​structure is formed, which can save installation space for the snap-fit ​​structure.

[0014] In one alternative embodiment, the snap-fit ​​portion is elastic, and the end of the snap-fit ​​portion is provided with a snap claw, which passes through the through hole and the snap-fit ​​groove and abuts against the inner wall of the extension portion.

[0015] Beneficial effects: During the assembly of the snap-fit ​​part and the snap-fit ​​groove, because the snap-fit ​​part is elastic, it can compress through the through hole on the insulating film and the snap-fit ​​groove on the lower plastic part, and after entering the receiving space of the extension part, it returns to its initial shape and abuts against the inner wall of the extension part to form an interference or barbed snap-fit ​​fit.

[0016] In one optional embodiment, the projected area of ​​the claw along the direction perpendicular to the side plate surface is greater than the opening area of ​​the locking groove.

[0017] Beneficial effects: After the claw enters the receiving space, because the area of ​​the claw is larger than the opening area of ​​the locking groove, the claw can be locked inside the extension, forming a stable locking structure that is not easy to fall off.

[0018] In one optional embodiment, the thickness of the side plate is T, which satisfies 0.1 mm ≤ T ≤ 0.2 mm.

[0019] Beneficial effects: Since the side plate needs to be installed inside the housing and the snap-fit ​​part is installed on the side plate, controlling the thickness of the side plate within a suitable range can ensure that the side plate has sufficient structural strength to snap-fit ​​with the lower plastic part, while avoiding the side plate occupying too much space inside the housing and affecting the energy density of the battery cell.

[0020] In one optional embodiment, the snap-fit ​​portion is provided at each of the opposite ends of the side plate along its length.

[0021] Beneficial effect: The side plate has snap-fit ​​parts at both ends along its length, which facilitates even force distribution.

[0022] In one optional embodiment, the side plate includes a first sub-side plate located on opposite sides of the lower plastic part along the X direction and a second sub-side plate located on opposite sides of the lower plastic part along the Y direction. Each of the first sub-side plates has a snap-fit ​​portion at opposite ends along the Y direction, and each of the second sub-side plates has a snap-fit ​​portion at opposite ends along the X direction.

[0023] Beneficial effects: The side panel adopts a split structure, which can form multiple snap-fit ​​fixing points with the lower plastic part, ensuring that the insulating film is evenly fixed and pressed around the perimeter, which helps to further improve the connection stability between the insulating film and the lower plastic part.

[0024] Secondly, the present invention also provides a battery pack, comprising: at least one of the above-mentioned battery cells.

[0025] Beneficial effects: Since the battery pack includes battery cells, it has the same effects as the battery cells, which will not be repeated here. Attached Figure Description

[0026] 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.

[0027] Figure 1 A schematic diagram showing the existing insulating film and the lower plastic part being fixed together by heat fusion; Figure 2 A schematic diagram from another perspective showing the use of heat fusion to fix the existing insulating film and the lower plastic part; Figure 3 This is a schematic diagram of the battery cell according to an embodiment of the present utility model; Figure 4 This is a schematic diagram showing the connection between the insulating film of the battery cell and the lower plastic part in an embodiment of this utility model. Figure 5 This is a schematic diagram of the cover plate assembly of the battery cell according to an embodiment of the present utility model; Figure 6 for Figure 5 Enlarged view of section A in the image; Figure 7 This is a schematic diagram of the structure of the battery cell's side plate and the lower plastic part snapping together according to an embodiment of the present utility model; Figure 8 This is a schematic diagram of the cover plate assembly of the battery cell according to another perspective of an embodiment of the present utility model; Figure 9 This is a schematic diagram of the side plate of the battery cell according to an embodiment of the present utility model; Figure 10 This is a schematic diagram of the insulating film of the battery cell in the unfolded state according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the insulating film of the battery cell in a folded state according to an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures: Existing technology: 1', cover plate assembly; 101', lower plastic part; 2', insulating film; 3', hot melt point; This application includes: 1. Cover plate assembly; 101. Lower plastic part; 1011. Extension; 1012. Receiving space; 102. Side plate; 103. Snap-fit ​​groove; 104. Snap-fit ​​part; 1041. Claw; 105. Cover plate; 2. Insulating film; 201. Through hole. Detailed Implementation

[0029] 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.

[0030] In embodiments of this utility model, a "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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The following is combined Figures 3 to 11 The following describes embodiments of the present invention.

[0035] According to embodiments of the present invention, on the one hand, such as Figure 3 and Figure 4As shown, a battery cell is provided, including: a housing, an electrode assembly, a cover plate assembly 1, and an insulating film 2. The housing has an opening at at least one end. The electrode assembly is disposed within the housing. The cover plate assembly 1 covers the opening and is connected to the housing. The cover plate assembly 1 includes a lower plastic part 101 and a side plate 102. A snap-fit ​​groove 103 is formed on the side of the lower plastic part 101. The insulating film 2 covers the outer side of the electrode assembly, extends to the periphery of the lower plastic part 101, and is sandwiched between the lower plastic part 101 and the side plate 102. The insulating film 2 has a through hole 201 corresponding to the snap-fit ​​groove 103. The inner side of the side plate 102 has a snap-fit ​​portion 104 inserted into the through hole 201 and the snap-fit ​​groove 103, and the snap-fit ​​portion 104 snaps into the snap-fit ​​groove 103.

[0036] Therefore, the battery cell provided in this embodiment of the present invention has a snap-fit ​​groove 103 on the side of the lower plastic part 101 and a corresponding through hole 201 on the insulating film 2. The snap-fit ​​part 104 of the side plate 102 passes through the through hole 201 and snaps into the snap-fit ​​groove 103, thereby fixing the lower plastic part 101 and the insulating film 2. Compared with the traditional heat-fusion fixing method, the fixing connection between the lower plastic part 101 and the insulating film 2 in this embodiment is more secure. Furthermore, the side plate 102 can seal the gap between the insulating film 2 and the cover plate assembly 1, so that the electrode group wrapped by the insulating film 2 has no contact space with the outside world, ensuring the insulation effect of the insulating film 2, reducing the risk of short circuit, and thus improving the safety of the battery cell. Moreover, the side plate 102 can also be used to protect the insulating film 2.

[0037] Specifically, the insulating film 2 covers the outside of the electrode assembly, and its material can be Mylar (polyester film) or other suitable insulating materials. The insulating film 2 protects the electrode assembly and provides insulation. After covering the electrode assembly, the upper end of the insulating film 2 extends to the periphery of the lower plastic part 101, and a through hole 201 is pre-formed in the extended area. The side plate 102 can be made of insulating plastic. The inner side of the side plate 102 refers to the side closest to the insulating film 2.

[0038] In one embodiment, such as Figure 5 and Figure 6 As shown, the cover assembly 1 also includes a cover 105. A lower plastic part 101 is disposed on the inner side of the cover 105 along the Z direction, and the lower plastic part 101 and the side plate 102 are housed inside the housing. By housing the lower plastic part 101 and the side plate 102 inside the housing, interference between the housing and the side plate 102 can be avoided, thereby preventing the side plate 102 from affecting the welding between the housing and the cover assembly 1.

[0039] Specifically, the lower plastic part 101 is sheet-shaped and fixedly connected to the cover plate 105, for example, by adhesive bonding. The cover plate 105 covers the opening and is welded and fixedly connected to the housing. After the cover plate 105 is welded to the housing, the cover plate 105 is located on the outside, the lower plastic part 101 is located on the inside, and the lower plastic part 101 is located between the electrode assembly and the cover plate 105.

[0040] Specifically, in the Z direction, such as Figure 3 and Figure 4 Arrow Z in the diagram indicates the height direction of the battery cell.

[0041] It should be noted that the present invention does not limit the specific snap-fit ​​structure of the snap-fit ​​part 104 and the snap-fit ​​groove 103, and any existing snap-fit ​​method can be selected as needed.

[0042] Furthermore, there are no restrictions on the shape of the through hole 201. Any existing shape can be selected as needed. For example, the through hole 201 can be a round hole, a strip hole, a square hole, an elliptical hole, etc.

[0043] In one embodiment, such as Figure 5 and Figure 6 As shown, the lower plastic part 101 has extensions 1011 at opposite ends along the X direction, opposite to the cover plate 105, and the extensions 1011 extend along the Y direction. An accommodating space 1012 is provided within the extension 1011, and a snap-fit ​​groove 103 is formed on the outer side of the extension 1011 along the X and / or Y directions and communicates with the accommodating space 1012. The accommodating space 1012 can be a cavity inside the extension 1011, or an inwardly opening accommodating groove provided at the extension 1011, which serves as the accommodating space 1012.

[0044] The existing lower plastic part 101 generally has support structures extending towards the electrode group at both ends in the length direction, namely extensions 1011. The snap-fit ​​groove 103 is provided on the extension 1011 and snap-fitted to the snap-fit ​​part 104, which does not occupy extra space and has little impact on the energy density of the battery cell.

[0045] Specifically, the X direction is as follows: Figure 3 As shown by arrow X in the diagram, the Y direction is as follows: Figure 4 As indicated by the arrow Y in the diagram.

[0046] Furthermore, in one embodiment, such as Figure 6 As shown, the end of the snap-fit ​​portion 104 is accommodated within the accommodating space 1012. Accommodating the end of the snap-fit ​​portion 104 within the accommodating space 1012 forms a concealed structure, which saves installation space for the snap-fit ​​structure.

[0047] Furthermore, in one embodiment, such as Figure 6As shown, the snap-fit ​​portion 104 is elastic, and a snap-fit ​​claw 1041 is provided at the end of the snap-fit ​​portion 104. Specifically, the snap-fit ​​claw 1041 can be a barb, a spiral, an X-shape, etc. The snap-fit ​​claw 1041 passes through the through hole 201 and the snap-fit ​​groove 103 and abuts against the inner wall of the extension portion 1011. During the assembly process of the snap-fit ​​portion 104 and the snap-fit ​​groove 103, since the snap-fit ​​portion 104 is elastic, the snap-fit ​​portion 104 can be compressed through the through hole 201 on the insulating film 2 and the snap-fit ​​groove 103 on the lower plastic part 101, and after entering the receiving space 1012 of the extension portion 1011, it returns to its initial shape and abuts against the inner wall of the extension portion 1011 (the wall surface forming the receiving space 1012, and this wall surface is close to the side plate 102), forming an interference or barb snap-fit ​​fit.

[0048] Furthermore, in one embodiment, the projected area of ​​the claw 1041 along the direction perpendicular to the surface of the side plate 102 is larger than the opening area of ​​the locking groove 103. After the claw 1041 enters the receiving space 1012, since the area of ​​the claw 1041 is larger than the opening area of ​​the locking groove 103, the claw 1041 can be locked inside the extension 1011, forming a stable locking structure that is not easy to fall off.

[0049] In one embodiment, such as Figure 6 As shown, the thickness of the side plate 102 is T, which satisfies 0.1 mm ≤ T ≤ 0.2 mm. Since the side plate 102 needs to be installed inside the housing, and the snap-fit ​​part 104 is installed on the side plate 102, controlling the thickness of the side plate 102 within a suitable range can ensure that the side plate 102 has sufficient structural strength to snap into the lower plastic part 101, while also avoiding the side plate 102 occupying too much space inside the housing, thus affecting the energy density of the battery cell.

[0050] For example, in the utility model embodiment, the thickness T of the side plate 102 can be 0.1 mm, 0.15 mm, 0.2 mm, etc.

[0051] In one embodiment, the thickness of the insulating film 2 is t, which satisfies 0.05 mm ≤ t ≤ 1 mm. This avoids the insulating film 2 being too thin, resulting in insufficient insulation withstand voltage and breakdown, and also avoids the insulating film 2 being too thick, making it difficult to bend and thus unable to effectively cover the electrode assembly.

[0052] For example, in the utility model embodiment, the thickness t of the insulating film 2 can be 0.05 mm, 0.5 mm, 1 mm, etc.

[0053] It should be noted that the present invention does not limit the number of snap-fit ​​parts 104 and snap-fit ​​slots 103.

[0054] In one embodiment, such as Figure 7 , Figure 8 and Figure 9 As shown, the side plate 102 has snap-fit ​​portions 104 at both ends along its length. The snap-fit ​​portions 104 at both ends along the length of the side plate 102 facilitate even force distribution. The insulating film 2 has through holes 201 corresponding to the positions and number of the snap-fit ​​portions 104; similarly, the lower plastic part 101 has corresponding snap-fit ​​grooves 103.

[0055] In one embodiment, the side plate 102 includes first sub-side plates located on opposite sides of the lower plastic part 101 along the X direction and second sub-side plates located on opposite sides of the lower plastic part 101 along the Y direction. Each of the first sub-side plates has a snap-fit ​​portion 104 at its opposite ends along the Y direction, and each of the second sub-side plates has a snap-fit ​​portion 104 at its opposite ends along the X direction. The side plate 102 adopts a split structure, which can form multiple snap-fit ​​fixing points with the lower plastic part 101, ensuring that the insulating film 2 is uniformly fixed and pressed around its perimeter, thus further improving the connection stability between the insulating film 2 and the lower plastic part 101.

[0056] In one embodiment, the insulating film 2 has an unfolded state and a folded state. For example... Figure 10 As shown, in its unfolded state, the insulating film 2 is sheet-like. At this point, through holes 201 can be opened at corresponding positions around the insulating film 2 according to design requirements. By folding the insulating film 2, a folded state capable of covering the electrode assembly is formed, as shown... Figure 11 As shown.

[0057] In an embodiment of this utility model, the assembly process of the battery cell is as follows: The electrode assembly is covered with an insulating film 2, so that the end of the insulating film 2 extends to the periphery of the lower plastic part 101, and the through hole 201 of the insulating film 2 corresponds to the snap-fit ​​groove 103 on the periphery of the lower plastic part 101.

[0058] Align the snap-fit ​​parts 104 of each side plate 102 with the corresponding through holes 201 and snap-fit ​​grooves 103, and pass each snap claw 1041 through the through holes 201 and snap-fit ​​grooves 103 to form a snap-fit ​​engagement.

[0059] The electrode assembly covered with insulating film 2 is inserted into the housing, and the cover plate assembly 1 is closed onto the opening of the housing.

[0060] The cover plate 105 is welded to the housing.

[0061] According to an embodiment of the present invention, another aspect provides a battery pack comprising at least one of the aforementioned battery cells.

[0062] Since the battery pack includes battery cells and has the same effect as the battery cells, it will not be elaborated on here.

[0063] 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 housing has an opening at at least one end; The pole assembly is located within the housing; A cover plate assembly is provided on the opening and connected to the housing. The cover plate assembly includes a lower plastic part and a side plate. A snap-fit ​​groove is provided on the side of the lower plastic part. An insulating film is wrapped around the outside of the electrode assembly. The insulating film extends to the periphery of the lower plastic part and is sandwiched between the lower plastic part and the side plate. The insulating film has a through hole corresponding to the snap-fit ​​groove. The inner side of the side plate has a snap-fit ​​part that is inserted into the through hole and the snap-fit ​​groove. The snap-fit ​​part snaps into the snap-fit ​​groove.

2. The battery cell according to claim 1, characterized in that, The cover plate assembly further includes a cover plate, the lower plastic part is disposed on the inner side of the cover plate along the Z direction, and the lower plastic part and the side plate are accommodated inside the housing.

3. The battery cell according to claim 2, characterized in that, The lower plastic part has extensions opposite to the cover plate at both ends along the X direction. The extensions extend along the Y direction and have a receiving space inside. The snap-fit ​​groove is opened on the outside of the extensions along the X and / or Y directions and communicates with the receiving space.

4. The battery cell according to claim 3, characterized in that, The end of the snap-fit ​​portion is accommodated within the accommodating space.

5. The battery cell according to claim 4, characterized in that, The snap-fit ​​part is elastic, and the end of the snap-fit ​​part is provided with a snap claw. The snap claw passes through the through hole and the snap-fit ​​groove and abuts against the inner wall of the extension.

6. The battery cell according to claim 5, characterized in that, The projected area of ​​the claw along the direction perpendicular to the side plate surface is larger than the opening area of ​​the locking groove.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The thickness of the side plate is T, which satisfies 0.1 mm ≤ T ≤ 0.2 mm.

8. The battery cell according to any one of claims 1 to 6, characterized in that, The side plate is provided with the snap-fit ​​portion at each of its opposite ends along its length.

9. The battery cell according to claim 8, characterized in that, The side plate includes a first sub-side plate located on opposite sides of the lower plastic part along the X direction and a second sub-side plate located on opposite sides of the lower plastic part along the Y direction. Each of the first sub-side plates has a snap-fit ​​portion at opposite ends along the Y direction, and each of the second sub-side plates has a snap-fit ​​portion at opposite ends along the X direction.

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

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