An electric cell and a method of manufacturing the same

Abstract

The application discloses a kind of battery and its manufacturing method, battery includes shell and the core of setting in shell, the core is at least provided with two groups, each side of the core is provided with positive tab, the other side of each core is provided with negative tab, the positive tab and negative tab of same core are opposite, at least two groups of two groups of core are stacked to form core group, the side surface of any adjacent two groups of core is contacted, and the core group is set in the shell, the shell has the first opening and the second opening of shell, one end of each group of core is provided with positive cover plate and negative cover plate, at least two groups of the positive cover plate located on the same side of shell are connected and seal the first opening of shell, and at least two groups of negative cover plate located on the same side of shell are connected and seal the second opening of shell.The application can effectively reduce the amount of shell, reduce the space ratio of structural member, and then the energy density of lithium ion battery can be improved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery assembly technology, and in particular to a battery cell with tabs extending from both sides of a thick battery and its manufacturing method. Background Technology

[0002] With the development of lithium-ion battery technology, the requirements for capacity and energy density of lithium-ion batteries are becoming increasingly stringent. Increasing the thickness of the battery cell during manufacturing can, to some extent, reduce the amount of related structural components used. Simultaneously, thicker cells can reduce the space occupied by structural components during module assembly, thereby increasing the energy density of the battery pack.

[0003] In the assembly of existing thick battery cells, a larger tab length is required to ensure welding feasibility. This undoubtedly increases the production difficulty of upstream processes and consequently affects the overall yield. To reduce the tab length, thick battery cells generally need to have connecting tabs on at least the positive or negative side. This adds a welding process to the connecting tabs, making the production process cumbersome. Furthermore, the scrap caused during the welding process also affects the overall yield. In addition, the connecting tabs occupy internal space in the battery cell and increase the overall weight of the battery cell, thus affecting the energy density of the battery cell. Summary of the Invention

[0004] To address the technical problems existing in the background art, the present invention proposes a battery cell and its manufacturing method.

[0005] The present invention discloses a battery cell comprising a housing and stacked cores disposed within the housing. The stacked cores are provided in at least two sets, each stacked core having a positive electrode tab and a negative electrode tab. The positive and negative electrode tabs of the same stacked core are arranged opposite to each other. At least two sets of stacked cores are stacked to form a stacked core group, with the opposing side surfaces of any two adjacent sets of stacked cores in contact. The stacked core group is fitted inside a housing having a first opening and a second opening. Each set of stacked cores has a positive electrode cover plate and a negative electrode cover plate at one end. At least two sets of positive electrode cover plates located on the same side of the housing are connected to and seal the second opening of the housing, and at least two sets of negative electrode cover plates located on the same side of the housing are connected to and seal the first opening of the housing.

[0006] In some preferred embodiments, any two adjacent sets of the positive electrode cover plates are welded to form a positive electrode cover plate group, and the positive electrode cover plate group is welded to the outer casing.

[0007] In some preferred embodiments, any two adjacent sets of negative electrode cover plates are welded to form a negative electrode cover plate group, and the negative electrode cover plate group is welded to the outer shell.

[0008] In some preferred embodiments, an insulating film is wound around the outer side of the stacked core assembly.

[0009] Preferably in some embodiments, the end face of the stack is provided with a stopper fixed on the insulation film, the stopper is in contact with the inner side of the shell, and the positive or negative tab extends out of the stopper.

[0010] Preferably in some embodiments, the stopper is provided with two groups, one group of the stopper is arranged on one end face of the stack, the positive tab extends out of one stopper, the negative tab extends out of the other stopper, and the positive cover plate group is in contact with one stopper, and the negative cover plate is in contact with the other stopper, thereby achieving the fixation of the stack in the shell.

[0011] Preferably in some embodiments, the bottom support plate is further provided on the insulation film, a plurality of through holes are formed on the bottom support plate, the bottom support plate is located between the stack and the insulation film, and the bottom support plate is opposite to the contact line of any two adjacent stacks.

[0012] Preferably in some embodiments, any two adjacent positive cover plates are defined as a first positive cover plate and a second positive cover plate, a positioning groove is formed in the middle of the side face opposite to the second positive cover plate of the first positive cover plate, a positioning protrusion is arranged in the middle of the side face opposite to the first positive cover plate of the second positive cover plate, and the positioning protrusion is matched with the positioning groove.

[0013] In order to facilitate the positioning and fixation of the adjacent two negative cover plates and the sealing performance, preferably, the positioning mode of any two adjacent negative cover plates is the same as that of any two adjacent positive cover plates, both of which adopt the structure mode of positioning groove and positioning protrusion.

[0014] Preferably in some embodiments, the outer side of the shell is provided with an explosion-proof valve.

[0015] Preferably in some embodiments, the stack is a cuboid.

[0016] A method for manufacturing an electric core, comprising the following steps:

[0017] S1: a positive tab is arranged on one side of each stack, and a negative tab is arranged on the other side of each stack, both of which are collected together by ultrasonic welding, and the positive tab is opposite to the negative tab;

[0018] S2: at least two stacks after welding of the positive tab and the negative tab are stacked together to form a cuboid stack, and the opposite side faces of any two adjacent stacks are in contact;

[0019] S3: the insulation film is wound on the outer side of the stack;

[0020] S4: Fix the stop frame on the insulating film, the stop frame is provided with two groups, one group of stop frame is arranged on the positive lug side of the core stack, and the other group of stop frame is arranged on the negative lug side of the core stack, the stop frame is in contact with the end face of the core stack, and the positive lug extends out of one group of stop frames, and the negative lug extends out of the other group of stop frames;

[0021] S5: Place the core stack wound with the insulating film and provided with the stop frame in the shell with two openings, the stop frame is in contact with the inner side of the shell, and the positive lug and the negative lug extend out of the shell;

[0022] S6: Connect a positive cover plate with the positive lug of a core and weld the side of the positive cover plate with the end face of the shell, each core is welded with a positive cover plate, any two adjacent positive cover plates are welded, at least two groups of positive cover plates form a positive cover plate group, and the positive cover plate group seals one opening of the shell;

[0023] Connect a negative cover plate with the negative lug of a core and weld the side of the negative cover plate with the other end face of the shell, each core is welded with a negative cover plate, any two adjacent negative cover plates are welded, at least two groups of negative cover plates form a negative cover plate group, and the negative cover plate group seals the other opening of the shell, and the positive cover plate group and the negative cover plate group are opposite.

[0024] In the application, the proposed battery cell and its manufacturing method do not need to be provided with a connecting sheet, and the assembly of the positive lug and the negative lug extending out of the core on both sides can be realized through the connection of at least two positive cover plates and the connection of at least two negative cover plates, thereby avoiding the problem of high manufacturing difficulty caused by the long length of the lug (including the positive lug and the negative lug) of the traditional at least two core groups, and simultaneously, the amount of shell can be effectively reduced, the space ratio of the structural member can be reduced, and the energy density of the lithium ion battery can be improved.

[0025] Additional aspects and advantages of the application will be made apparent in the following description, some of which will be evident to those skilled in the art, or will be learned from the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of the battery cell structure of the application;

[0027] Figure 2 It is a schematic diagram of the explosion structure of the battery cell of the application

[0028] Figure 3 It is a schematic diagram of the core structure of the application;

[0029] Figure 4 It is a schematic diagram of the structure of the core stack wound with the insulating film and provided with the stop frame of the application;

[0030] Figure 5 This is a schematic diagram of the stacked core assembly of the present invention placed behind the outer shell;

[0031] Figure 6 This is a schematic diagram of the structure after the positive electrode cover plate and negative electrode cover plate are placed in this invention;

[0032] Figure 7 This is a schematic diagram of the structure after disassembling the two adjacent positive electrode cover plates of the present invention;

[0033] Figure 8 This is a schematic diagram of the bent electrode structure of the battery cell of the present invention;

[0034] Figure 9 For the present invention Figure 8 Enlarged view of a portion of area A;

[0035] In the diagram: 1. Core stack; 2. Outer shell; 3. Negative electrode tab; 4. Positive electrode tab; 5. Negative electrode cover plate; 50. Positioning groove; 51. Positioning protrusion; 6. Positive electrode cover plate; 7. Insulating film; 8. Stop frame; 9. Base plate; 900. Through hole; 10. Explosion-proof valve; 11. Liquid injection hole; 12. Liquid guiding channel. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] like Figures 1-2 The battery cell shown includes an aluminum alloy casing 2 and stacked cores 1 disposed within the casing 2. The stacked cores 1 have at least two sets. Each set of stacked cores 1 has a negative electrode tab 3 on one side and a positive electrode tab 4 on the other side. The negative electrode tab 3 and positive electrode tab 4 on the same stacked core are arranged opposite each other. At least two sets of stacked cores 1 are stacked to form a stacked core group. The negative electrode tabs 3 of at least two sets of stacked cores 1 in the stacked core group are located on the same side. Preferably, the stacked core group is a cuboid, and any two adjacent sets of stacked cores 1... The opposite sides are in surface contact. The stacked cores are fitted inside the outer shell 2. The outer shell 2 has a first opening and a second opening. Each stacked core 1 is provided with a negative electrode cover plate 5 and a positive electrode cover plate 6. The negative electrode cover plate 5 is connected to the negative electrode tab 3 of the stacked core 1, and the positive electrode cover plate 6 is connected to the positive electrode tab 4. At least two sets of negative electrode cover plates 5 of the stacked core 1 are welded together and close the first opening. Each set of positive electrode tabs 4 of the stacked core 1 is connected to a positive electrode cover plate 6. At least two sets of positive electrode cover plates 6 are connected and seal the second opening of the outer shell.

[0038] Through the butt welding of the cover plates (including the negative cover plate 5 and the positive cover plate 6), the assembly of the structure of the medium-thickness battery cell with the two-side tab (including the negative tab 3 and the positive tab 4) can be realized, and the problem of high manufacturing difficulty caused by the large length of the tab in the traditional thick battery cell can be avoided; at the same time, the amount of the shell can be effectively reduced, the space ratio of the structural member can be reduced, and then the energy density of the lithium ion battery can be improved.

[0039] In some embodiments, preferably, any two adjacent negative cover plates 5 are defined as a first negative cover plate and a second negative cover plate, a positioning groove 50 is formed in the middle of the side surface opposite to the first negative cover plate, and a positioning protrusion 51 is arranged on the middle of the side surface opposite to the second negative cover plate, and the positioning protrusion 51 matches the positioning groove 50.

[0040] In order to facilitate the positioning and fixing of the two adjacent positive cover plates 6 and avoid light leakage during laser welding, preferably, the positioning mode of any two adjacent positive cover plates 6 is the same as that of any two adjacent negative cover plates 5, and both adopt the structure mode of the positioning groove 50 and the positioning protrusion 51.

[0041] In some embodiments, preferably, any two adjacent groups of negative cover plates 5 are welded and fixed, and at least two groups of negative cover plates 5 form a negative cover plate group, and the negative cover plate group is welded and sealed with the first opening of the shell.

[0042] In some embodiments, preferably, any two adjacent groups of positive cover plates 6 are welded and fixed, and at least two groups of positive cover plates 6 form a positive cover plate group, and the positive cover plate group is welded and sealed with the second opening of the shell 2.

[0043] In some embodiments, preferably, the outer side of the stack group is wrapped with an insulating film 7, and the insulating film 7 is located in the shell, and the insulating film 7 can be a Mylar film.

[0044] In some embodiments, preferably, the end surface of the stack group is provided with a stop rack 8, the stop rack 8 is fixed on the insulating film 7, the stop rack 8 is in contact with the inner side of the shell, and the negative tab 3 or the positive tab 4 extends out of the stop rack 8. In some embodiments, preferably, the stop rack 8 is provided with two groups, one group of stop racks 8 is arranged on one end surface of the stack group, and the negative tab 3 extends out of one stop rack 8 and the positive tab 4 extends out of the other stop rack 8; specifically, the stop rack 8 can be installed on the insulating film 7 by hot pressing.

[0045] In some embodiments, preferably, a bottom support plate 9 is further arranged on the insulating film 7, a plurality of through holes 900 are formed in the bottom support plate 9, the bottom support plate 9 is opposite to the contact line of any adjacent stack 1, the bottom support plate 9 can be installed on the insulating film 7 by hot pressing, and the bottom support plate 9 is located between the stack 1 and the insulating film 7.

[0046] Preferably, the bottom plate 9 is not in contact with the stopper 8, further increasing the performance of the battery cell.

[0047] Preferably, in some embodiments, the outer shell 2 is provided with an explosion-proof valve 10, which is opposite to the bottom plate 9. The outer shell 2 is provided with a liquid injection hole 11.

[0048] A battery cell preparation method, comprising the following steps:

[0049] S1: On one side of each stack 1, a negative tab 3 is provided, and on the other side of each stack 1, a positive tab 4 is provided, which are all gathered together by ultrasonic welding. The negative tab 3 is opposite to the positive tab 4, and the formed stack 1 is as shown in Figure 3 ;

[0050] S2: At least two stacks 1 with welded negative tabs 3 and positive tabs 4 are stacked together to form a cuboid stack group. The opposite sides of any two adjacent stacks 1 are in surface contact, preferably in contact. Preferably, the sides with the largest surface area of the two stack groups are opposite, and the negative tabs 3 of the stacks 1 are on the same side, and the positive tabs 4 of the stacks 1 are on the same side.

[0051] S3: An insulating film 7 is wound on the outer side of the stack group. The insulating film 7 can be selected from Mylar film. Preferably, the outer side of the insulating film 7 is provided with a bottom plate 9, and the bottom plate 9 is provided with a plurality of through holes 900. The bottom plate 9 covers the contact lines of any two adjacent stacks 1, and the bottom plate 9 is located between the stack 1 and the insulating film 7.

[0052] S4: A stopper 8 is fixed on the insulating film 7. The stopper 8 is provided in two groups. One group of stoppers 8 is arranged on one side of the stack group, and the other group of stoppers 8 is arranged on the other side of the stack group. The stopper 8 is in contact with the end face of the stack group, and the negative tab 3 extends out of one group of stoppers 8, and the positive tab 4 extends out of the other group of stoppers 8, as shown in Figure 4 . In the embodiment provided with the bottom plate 9, the bottom plate 9 is not connected with the stopper 8;

[0053] S5: The stack group wound with the insulating film 7 and provided with the stopper 8 in the S4 step is placed in an outer shell with two openings. The stopper 8 is in contact with the inner side of the outer shell, and the negative tab 3 and the positive tab 4 extend out of the outer shell. The stopper 8 is in contact with the inner side of the outer shell 2, as shown in Figure 5 . In some embodiments, the stopper 8 is provided in two groups

[0054] It should be noted that in some embodiments, the bottom plate 9 is also placed in the outer shell together with the stack group;

[0055] S6: The stack group is placed in the outer shell as shown in Figure 6As shown, a negative electrode cover plate 5 is connected to the negative electrode tab 3 of a stacked core 1 and the side of the negative electrode cover plate 5 is welded to the end face of the outer shell 2. Each stacked core 1 is welded with a negative electrode cover plate 5. Any two adjacent negative electrode cover plates 5 are welded together, and at least two sets of negative electrode cover plates 5 form a negative electrode cover plate group. The negative electrode cover plate group seals an opening in the outer shell.

[0056] A positive electrode cover plate 6 is connected to the positive electrode tab 4 of a stacked core 1, and the side of the positive electrode cover plate 6 is welded to the other end face of the outer shell 2. Each stacked core 1 is welded with a positive electrode cover plate 6. Any two adjacent positive electrode cover plates 6 are welded together, and at least two sets of positive electrode cover plates 6 form a positive electrode cover plate group. The positive electrode cover plate group seals another opening in the outer shell. The positive electrode cover plate group and the negative electrode cover plate group are opposite each other. Finally, as shown... Figure 8 , Figure 1 As shown.

[0057] In some embodiments, an explosion-proof valve 10 is provided on the outside of the housing, the explosion-proof valve 10 is opposite to the bottom support plate 9, and an injection hole 11 is provided on the outer side of the housing 2.

[0058] like Figure 9 As shown, preferably, in some embodiments, both the positive electrode cover plate 6 and the negative electrode cover plate 5 abut against the end face of the stop frame 8, and the negative electrode cover plate 5 is welded to the outer shell by laser welding.

[0059] like Figure 7 , Figure 8 , Figure 9 As shown, any two adjacent negative electrode cover plates 5 are defined as the first positive electrode cover plate and the second positive electrode cover plate. The first positive electrode cover plate and the second positive electrode cover plate have a positioning groove 50 in the middle of their opposite sides. The second positive electrode cover plate and the first positive electrode cover plate have a positioning protrusion 51 in the middle of their opposite sides. The positioning protrusion 51 matches the positioning groove 50.

[0060] like Figure 9 , Figure 8 As shown, in order to improve the performance of the battery cell, there is a liquid guiding channel between the stacked core group and the negative electrode cover plate group, and there is also a liquid guiding channel 12 between the stacked core group and the positive electrode cover plate 6. The liquid guiding channel 12 is opposite to the contact surface of the two adjacent stacked core groups 1.

[0061] It should be understood that the orientation or positional relationship indicated by terms such as "central", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0062] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0063] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or communicate with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication or interaction relationship of two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0064] In the present application, unless otherwise specifically defined and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0065] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An electric cell comprising a housing (2) and a stack of cells (1) arranged in the housing (2), characterized in that, The stack core (1) is provided with at least two groups, each of the stack core (1) is provided with a negative tab (3) and a positive tab (4) arranged oppositely, at least two groups of the stack core (1) are stacked to form a stack core group, the opposite side surfaces of any two adjacent stack core groups (1) are in surface contact, the stack core group is sleeved in a shell (2) provided with a first opening and a second opening, one end of each of the stack core groups (1) is provided with a negative cover plate (5) and a positive cover plate (6), at least two groups of the negative cover plates (5) located on the same side of the shell (2) are connected and seal the first opening of the shell (2), at least two groups of the positive cover plates (6) located on the same side of the shell (2) are connected and seal the second opening of the shell (2); any two adjacent groups of the negative cover plates (5) are welded to form a negative cover plate group, and the negative cover plate group is welded to the shell (2); any two adjacent groups of the positive cover plates (6) are welded to form a positive cover plate group, and the positive cover plate group is welded to the shell (2); The stack core group and the negative cover plate group are provided with a liquid guide channel (12), the stack core group and the positive cover plate (6) are also provided with a liquid guide channel (12), the liquid guide channel (12) is opposite to the contact surface of the two adjacent stack core groups (1), each of the stack core groups (1) is welded to a negative cover plate (5), each of the stack core groups (1) is welded to a positive cover plate (6), and the outer side of the shell (2) is provided with a liquid injection hole (11).

2. The electric cell of claim 1, wherein, The outer side of the stack core group is wound with an insulating film (7).

3. The electric cell of claim 2, wherein, The end surface of the stack core group is provided with a stop frame (8), the stop frame (8) is fixed on the insulating film (7), the stop frame (8) is in contact with the inner side of the shell (2), and the negative tab (3) or the positive tab (4) extends out of the stop frame (8).

4. The electric cell of claim 3, wherein, The stop frame (8) is provided with two groups, the stop frame (8) is arranged on the tab side end surface of the stack core group, the negative tab (3) extends out of one of the stop frames (8), and the positive tab (4) extends out of the other stop frame (8).

5. The electric cell of claim 2, wherein, The insulating film (7) is further provided with a bottom supporting plate (9), a plurality of through holes (900) are formed in the bottom supporting plate (9), and the bottom supporting plate (9) is located between the stack core (1) and the insulating film (7).

6. The electric cell of claim 1, wherein, Any two adjacent negative cover plates (5) are defined as a first negative cover plate and a second negative cover plate, a positioning groove (50) is formed in the middle of the side surface opposite to the first negative cover plate and the second negative cover plate, a positioning protrusion (51) is arranged on the middle of the side surface opposite to the first negative cover plate and the second negative cover plate, and the positioning protrusion (51) is matched with the positioning groove (50).

7. The electric cell of claim 1, wherein, The stack core group is a cuboid.

8. A method of manufacturing an electric double layer capacitor, for use in the electric double layer capacitor according to any one of claims 1 to 6, characterized by, The method comprises the following steps: S1: a negative tab (3) is arranged on one side of each stack core (1), and a positive tab (4) is arranged on the other side of each stack core (1), and the negative tab (3) and the positive tab (4) are collected together by ultrasonic welding and are opposite to each other; S2: at least two stack cores (1) after welding of the negative tab (3) and the positive tab (4) are stacked together to form a cuboid stack core group, and the opposite side surfaces of any two adjacent stack cores (1) are in surface contact. S3: winding the insulation film (7) on the outer side of the stack of cores; S4: fixing the stop frame (8) on the insulation film (7), the stop frame (8) is provided with two groups, one group of stop frames (8) is arranged on the positive lug side of the stack of cores, and the other group of stop frames (8) is arranged on the negative lug side of the stack of cores, the stop frame (8) is in contact with the end face of the stack of cores, and the negative lug (3) extends out of one group of stop frames (8), and the positive lug (4) extends out of the other group of stop frames (8); S5: placing the stack of cores wound with the insulation film (7) and provided with the stop frame (8) in the shell (2) with two openings in the S4 step, the stop frame (8) is in contact with the inner side of the shell, and the negative lug (3) and the positive lug (4) extend out of the shell (2); S6: connecting a negative cover plate (5) with the negative lug (3) of a stack of cores (1) and welding the side of the negative cover plate (5) with the end face of the shell (2), each stack of cores (1) is welded with a negative cover plate (5), any two adjacent negative cover plates (5) are welded, at least two groups of negative cover plates (5) form a negative cover plate group, and the negative cover plate group seals one opening of the shell; connecting a positive cover plate (6) with the positive lug (4) of a stack of cores (1) and welding the side of the positive cover plate (6) with the other end face of the shell (2), each stack of cores (1) is welded with a positive cover plate (6), any two adjacent positive cover plates (6) are welded, at least two groups of positive cover plates (6) form a positive cover plate group, the positive cover plate group seals the other opening of the shell (2), and the positive cover plate group and the negative cover plate group are opposite.

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