An electrode assembly for a lithium secondary battery

Abstract

The utility model discloses a kind of electric core winding devices, comprising: winding mechanism, for winding electric core material, electric core material includes anode sheet, cathode sheet and diaphragm, to form electric core roll body;Shaping mechanism, is located in the material inlet front end of winding mechanism, it includes two first extrusion pieces and at least one first driving piece being oppositely arranged, shaping space is formed between two first extrusion pieces;Hot-pressing mechanism, is located between the material outlet end of shaping mechanism and the material inlet end of winding mechanism, it includes two second extrusion pieces, at least one second driving piece and the heating component being set corresponding second extrusion piece, hot-pressing space is formed between two second extrusion pieces;Anode sheet and the two layers diaphragm located in the both sides of anode sheet constitute composite pole piece, composite pole piece passes shaping space and hot-pressing space in turn.The beneficial effects of the utility model are that the misplacement of diaphragm and electrode sheet and the phenomenon of diaphragm wrinkle can be avoided when winding.

Description

Technical Field

[0001] This utility model relates to a battery cell winding device, belonging to the field of battery cell manufacturing. Background Technology

[0002] Currently, the battery cell structure mainly consists of four layers: a separator, anode plate, and cathode plate. Cell winding is the core process in battery manufacturing, which involves winding the anode plate, cathode plate, and separator in a specific order to form a bare cell. The winding quality directly affects the battery's energy density, safety, and cycle life.

[0003] However, during the winding process, the separator needs to withstand dynamic tension, which can cause wrinkles in the separator or interlayer displacement between the separator and the electrode, thus affecting the quality and safety of the battery. Utility Model Content

[0004] The purpose of this invention is to provide a battery cell winding device that can prevent misalignment between the diaphragm and the electrode sheet and the formation of wrinkles in the diaphragm during winding.

[0005] This utility model is achieved through the following technical solution.

[0006] A battery cell winding device, comprising:

[0007] A winding mechanism for winding battery cell material, the battery cell material including an anode sheet, a cathode sheet and a separator, to form a battery cell roll;

[0008] A shaping mechanism is located at the feed front end of the winding mechanism. It includes two opposing first extruders and at least one first drive member. A shaping space is formed between the two first extruders. The second drive member is used to drive the two first extruders to move closer to or further away from each other.

[0009] A hot pressing mechanism is located between the discharge end of the shaping mechanism and the inlet end of the winding mechanism. It includes two opposing second extruders, at least one second driving member, and a heating member corresponding to the second extruders. A hot pressing space is formed between the two second extruders. The second driving member is used to drive the two second extruders to move closer or further apart from each other.

[0010] The anode sheet and the two diaphragms located on both sides of the anode sheet constitute a composite electrode sheet, which passes through the shaping space and the hot pressing space in sequence.

[0011] As a further improvement of this utility model, the second extruder has a hot-pressing surface for contacting the diaphragm, wherein at least one protrusion is provided on one of the hot-pressing surfaces; when the protrusion contacts the corresponding diaphragm, the diaphragm is partially deformed to form a recess, and the recess is embedded in the anode sheet.

[0012] As a further improvement of this utility model, the protrusions are provided in multiple ways, and the multiple protrusions are arranged in an array on the hot pressing surface.

[0013] As a further improvement of this utility model, the heating component has a heating surface for contacting the second extruder, and the second extruder is provided with a receiving groove for each heating component, and the heating component is embedded in the receiving groove.

[0014] As a further improvement of this utility model, each of the second extrusion members is provided with a plurality of heating components, and the plurality of heating components are evenly spaced along the circumference of the second extrusion member.

[0015] As a further improvement of this utility model, two first driving members are provided for each first extrusion member, and the two first driving members are respectively connected to the two ends of the first extrusion member.

[0016] As a further improvement of this utility model, two second driving members are provided for each second extrusion member, and the two second driving members are respectively connected to the two ends of the second pressure member.

[0017] As a further improvement of this utility model, the first driving member and the second driving member are configured as electric push rods or telescopic cylinders.

[0018] As a further improvement of this utility model, both the first extrusion member and the second extrusion member are configured as pressure rollers.

[0019] The beneficial effects of this utility model are:

[0020] Before winding the battery cell material, the composite electrode (anode sheet + two layers of separator) is first pre-pressed and shaped by two first extruders to eliminate initial wrinkles or misalignments of the anode sheet and separator, ensuring material flatness. Then, the composite electrode is further extruded by a heated second extruder. On the one hand, this makes the separator and anode sheet fit tightly together, and on the other hand, it softens the adhesive on the separator surface, which helps to increase the microscopic adhesion between the separator and anode sheet, improve the adhesion strength between the anode sheet and separator, and achieve stable adhesion between the anode sheet and separator. This avoids the phenomenon of wrinkles or interlayer slippage and misalignment of the composite electrode relative to the anode sheet caused by winding stress during winding. Attached Figure Description

[0021] The preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings to help understand the purpose and advantages of this utility model, wherein:

[0022] Figure 1 This is a schematic diagram of the structure of a battery cell winding device according to the present invention;

[0023] Figure 2 This is a schematic diagram of the shaping mechanism;

[0024] Figure 3 This is a schematic diagram of the hot pressing mechanism;

[0025] Figure 4 This is a side view of the second extrusion piece;

[0026] Figure 5 This is a front view of the second extrusion piece;

[0027] Figure 6 This is a schematic diagram of the composite electrode structure; Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0029] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the construction shown in the accompanying drawings. The terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0030] A battery cell winding device is used to wind battery cell material, the battery cell material including an anode sheet a1, a cathode sheet a2 and two diaphragms a3, the anode sheet a1 is located between the two diaphragms a3, the structure of the two diaphragms a3 is such that after winding, any adjacent anode sheet a1 and cathode sheet a2 are isolated by the diaphragms a3.

[0031] Reference Figures 1-6 The battery cell consists of a winding mechanism 1, a shaping mechanism 2, and a hot pressing mechanism 3. The winding mechanism 1 winds the battery cell material into a continuous multi-turn structure by rotation, forming a battery cell roll.

[0032] The shaping mechanism 2 is located at the feed front end of the winding mechanism 1. It includes two opposing first extrusion members 21 and at least one first driving member 22. The gap between the two first extrusion members 21 forms a shaping space. The second driving member 32 is used to drive the two first extrusion members 21 to move closer or further apart from each other.

[0033] The hot pressing mechanism 3 is located between the discharge end of the shaping mechanism 2 and the inlet end of the winding mechanism 1. It includes two opposing second extrusion members 31, at least one second driving member 32, and a heating member 33 for heating the second extrusion members 31. The gap between the two second extrusion members 31 forms a hot pressing space. The second driving member 32 is used to drive the two second extrusion members 31 to move closer or further apart from each other.

[0034] Before winding the cell material, the composite electrode a4 (anode a1 + two layers of separator a3) is first pre-pressed and shaped by two first extruders 21 to eliminate the initial wrinkles or misalignments of the anode a1 and separator a3 and ensure the flatness of the material. Then, the composite electrode a4 is further extruded by the heated second extruder 31. On the one hand, the separator a3 is tightly attached to the anode a1, and on the other hand, the adhesive on the surface of the separator a3 is softened, which helps to increase the micro-adhesion between the separator a3 and the anode a1, improve the adhesion between the anode a1 and the separator a3, and achieve stable adhesion between the anode a1 and the separator a3. This avoids interlayer slippage, misalignment or wrinkles caused by the winding stress of the separator a3 during winding.

[0035] It should be mentioned that adhesive is provided on the surfaces of both diaphragms a3 and anode plate a1 to ensure that diaphragm a3 and anode plate a1 are bonded and fixed after being squeezed into close contact.

[0036] In this embodiment, the second extruder 31 has a hot-pressing surface for contacting the diaphragm a3, wherein at least one protrusion 34 is provided on one of the hot-pressing surfaces, as shown in the figure. Figure 6 Correspondingly, the protrusions 34 on the hot-pressing surface come into contact with the diaphragm a3 under pressure, causing the diaphragm a3 to deform locally and form a recess 35. The recess 35 is embedded into the anode sheet a1, forming a mechanical interlocking structure similar to a mortise and tenon joint. This structure can effectively prevent relative displacement between the electrode sheet and the diaphragm a3 during winding or subsequent processes, reducing the risk of delamination. At the same time, there are multiple protrusions 34, which are arranged in an array on the hot-pressing surface. The multiple protrusions 34 help to disperse the stress on the composite electrode sheet a4 during winding.

[0037] In this embodiment, the heating element 33 can be a heating rod with a heating surface for contacting the second extruder 31. The second extruder 31 has a receiving groove for each heating element 33, and the heating element 33 is embedded in the receiving groove. When the heating element is working, it heats the second extruder 31. The receiving groove is located on the side of the second extruder 31 to facilitate the installation of the heating element 33. Furthermore, to improve the heating efficiency and uniformity of the second extruder 31, multiple heating elements 33 are provided for each second extruder 31, and the multiple heating elements 33 are evenly spaced along the circumference of the second extruder 31.

[0038] In this embodiment, each first extruder 21 is provided with two first driving members 22, which are respectively connected to both ends of the first extruder 21. Providing two first driving members 22 for each first extruder 21 facilitates adjustment of the gap between the two first extruders 21 and enables stable movement of the first extruder 21. Similarly, each second extruder 31 is provided with two second driving members 32, which are respectively connected to both ends of the second pressurizing member.

[0039] In this embodiment, the positions of the first driving member 22 and the second driving member 32 are fixed, and the first driving member 22 and the second driving member 32 are configured as electric push rods or telescopic cylinders. The movable end of the electric push rod or telescopic cylinder is connected to the first extrusion member 21 and the second extrusion member 31, thereby controlling the movement of the first extrusion member 21 and the second extrusion member 31.

[0040] In this embodiment, the first extruder 21 and the second extruder 31 can be a pressure block or a rotatably configured pressure roller. Specifically, when the first extruder 21 and the second extruder 31 are pressure blocks, their two relatively close surfaces move relative to each other to extrude the composite electrode sheet; when the first extruder 21 and the second extruder 31 are configured as rotating pressure rollers, the pressure rollers can provide continuous linear pressure by rotating to contact the anode sheet a1 and the diaphragm a3, thus avoiding local stress concentration caused by point contact.

[0041] In this embodiment, the winding mechanism 1 includes at least one rotatable winding needle, which rotates under the action of a driver, and during rotation, it drives the battery cell material to be wound to form a battery cell roll.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A battery cell winding device, characterized in that, include: A winding mechanism (1) is used to wind a battery cell material, the battery cell material including an anode sheet (a1), a cathode sheet (a2) and a separator (a3) ​​to form a battery cell roll; The shaping mechanism (2) is located at the feed front end of the winding mechanism (1), and includes two opposing first extrusion members (21) and at least one first driving member (22). The gap between the two first extrusion members (21) forms a shaping space, and the first driving member (22) is used to drive the two first extrusion members (21) to move closer or further away from each other. The hot pressing mechanism (3) is located between the discharge end of the shaping mechanism (2) and the inlet end of the winding mechanism (1). It includes two opposing second extruders (31), at least one second driving member (32), and a heating member (33) corresponding to the second extruders (31). The gap between the two second extruders (31) forms a hot pressing space. The second driving member (32) is used to drive the two second extruders (31) to move closer or further away from each other. The anode plate (a1) and the two layers of diaphragms (a3) ​​located on both sides of the anode plate (a1) constitute a composite electrode (a4), which passes through the shaping space and the hot pressing space in sequence.

2. The battery cell winding device according to claim 1, characterized in that, The second extruder (31) has a hot-pressed surface for contacting the diaphragm (a3), wherein at least one protrusion (34) is provided on the hot-pressed surface of the second extruder (31); when the protrusion (34) contacts the corresponding diaphragm (a3), the diaphragm (a3) ​​is driven to partially deform to form a recess (35), and the recess (35) is embedded in the anode sheet (a1).

3. The battery cell winding device according to claim 2, characterized in that, The protrusions (34) are provided in multiples, and the multiple protrusions (34) are arranged in an array on the hot pressing surface.

4. The battery cell winding device according to claim 1, characterized in that, The heating element (33) has a heating surface for contacting the second extruder (31), and the second extruder (31) has a receiving groove for each heating element (33), and the heating element (33) is embedded in the receiving groove.

5. A cell winding device according to claim 4, characterized in that, Each of the second extruders (31) is provided with a plurality of heating elements (33), and the plurality of heating elements (33) are evenly spaced along the circumference of the second extruders (31).

6. A cell winding device according to claim 1, characterized in that, Each of the first extrusion members (21) is provided with two first driving members (22), and the two first driving members are respectively connected to the two ends of the first extrusion member (21).

7. A battery cell winding device according to claim 1, characterized in that, Each of the second extrusion members (31) is provided with two second driving members (32), and the two second driving members (32) are respectively connected to the two ends of the second extrusion member.

8. A battery cell winding device according to claim 1, characterized in that, The first drive unit (22) and the second drive unit (32) are configured as electric push rods or telescopic cylinders.

9. A battery cell winding device according to claim 1, characterized in that, Both the first extrusion member (21) and the second extrusion member (31) are configured as pressure rollers.

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