A kind of anti-deformation winding battery core and its manufacturing method

Abstract

The anti-deformation wound battery cell described in the present invention includes a battery cell body, wherein the battery cell body includes at least two electrode units of different electrical polarities formed by winding at intervals; the electrode unit includes a wound diaphragm, and a wound electrode covered by the wound diaphragm and arranged on one side of the wound diaphragm; at least a portion of a plastic support is provided between the wound diaphragms of at least one group of adjacent electrode units, which protrudes from the edge of the wound electrode. The plastic support deforms after being subjected to heat pressing and diffuses to the surroundings to fill the space between the wound diaphragms and protrude from the edge of the wound electrode, so as to achieve compact filling and deformation resistance of the edge of the wound diaphragm. In the present invention, the plastic support undergoes plastic deformation to fill the gap, so as to improve the defects of the existing battery cell body, which has weak structures at the head and tail, and is easily deformed by external forces. At the same time, after being pressed, the plastic support generates an adhesive force to tightly connect the adjacent diaphragms, and the structural connection strength is high.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and more specifically, to a deformation-resistant wound battery cell and a manufacturing method thereof. Background Art

[0002] Usually, the production methods of battery cells include lamination and winding. The lamination production method produces batteries with various shapes, such as round, square, fan-shaped, U-shaped, etc., which has advantages in high-rate discharge; the winding production method generally produces square or cylindrical batteries, which has advantages in capacity.

[0003] In order to overcome the problem that the core of the existing wound battery body is prone to shaking during transportation, module assembly, etc. after the lithium-ion battery is finished, the structural stability of the core is destroyed due to the relative displacement of the cap, the inner wall of the shell and the bottom. In serious cases, it will cause safety hazards during the use of the battery. For example, the Chinese invention patent with the publication number CN106410265A, which is a cylindrical lithium-ion battery, adopts a hot melt adhesive that can be molten under the action of heating within a set temperature range on the surface of the winding end of the battery body, and reduces the shaking of the battery body through the adhesion of the sol and the shell. Although this technical solution can effectively reduce the shaking of the battery body and protect the battery body, because the battery shell is often made of flexible material, when encountering strong external forces, such as falling and impact, the deformation of the shell causes the deformation of the internal battery body, affecting the use of the battery or even damaging the battery body and scrapping it. In particular, the head and tail positions of the battery body after winding are very susceptible to deformation due to external forces. Summary of the invention

[0004] The primary purpose of the present invention is to provide a deformation-resistant wound battery cell with enhanced structural strength at the head and tail positions of the wound battery cell body, strong adhesion, and tight filling in order to address the above-mentioned defects and shortcomings.

[0005] Another object of the present invention is to provide a method for manufacturing a deformation-resistant wound battery cell.

[0006] In order to achieve the above object, the specific technical solution adopted by the present invention is:

[0007] The deformation-resistant wound battery cell of the present invention comprises a battery cell body, wherein the battery cell body comprises at least two electrode units of opposite polarities formed by winding at intervals; the electrode unit comprises a wound diaphragm and a wound electrode covered by the wound diaphragm and arranged on one side of the wound diaphragm; at least a partially plastic support member is provided between the wound diaphragms of at least one group of adjacent electrode units and protrudes from the edge of the wound electrode. The plastic support member is deformed after being subjected to heat pressing and diffuses to the surroundings to fill the space between the wound diaphragms and protrude from the edge of the wound electrode, so as to achieve compact filling and deformation resistance of the edge of the wound diaphragm.

[0008] Preferably, the plastic support member comprises at least two plastic adhesive layers and a support layer arranged between the plastic adhesive layers.

[0009] Preferably, the plastic adhesive layer is composed of hot melt adhesive, which is used to melt the adhesive diaphragm and deform to fill the gap during hot pressing.

[0010] Preferably, at least one of the plastic adhesive layers is composed of cured hot melt adhesive.

[0011] The plastic support member used in the present invention is composed of three parts, a hot melt adhesive layer (sis), a PET film layer, and a hot melt adhesive layer (sis). The hot melt adhesive layer on one side is matured to become a matured plastic adhesive layer, which is sticky at room temperature and adheres to the diaphragm, i.e., a room temperature adhesive layer. The other side is sticky only when hot pressed, and will adhere to the hot melt adhesive layer on this side of the adjacent other diaphragm, i.e., an unripened plastic adhesive layer. The middle support layer is a PET film layer that will not melt or deform during hot pressing, and plays a strength support role, which can better resist deformation.

[0012] Preferably, the plastic support is provided on one side or both sides of the wound diaphragm.

[0013] Preferably, the plastic support member forms a strip structure along the winding direction of the wound diaphragm.

[0014] Preferably, the strip structure includes a strip body, which includes connecting parts that are arranged in sequence at intervals, and spacing parts whose plastic volume exceeds that of adjacent connecting parts. After being subjected to heat pressing, the spacing parts and the connecting parts are simultaneously plastically deformed and diffused to the surroundings to fill the protruding edges of the wound electrodes between the wound diaphragms, and the diffusion space of the spacing parts with large plastic volume exceeds that of the connecting parts.

[0015] Preferably, the spacer is formed between the wound diaphragms and has upper and lower side surfaces parallel to the wound diaphragms. When the upper and lower side surfaces are subjected to pressure, they fit well with the wound diaphragms and are subjected to uniform force.

[0016] Preferably, the connecting portion is a flat strip formed by adjacent spacing portions.

[0017] Preferably, the wound electrode includes a positive electrode strip and a negative electrode strip; the wound separator and the positive electrode strip form a positive electrode unit, and the wound separator and the negative electrode strip form a negative electrode unit; the width of the positive electrode strip is narrower than that of the negative electrode strip.

[0018] Preferably, the thickness of the plastic support is 0.01-1 mm. The thickness can be selected according to the actual situation. If the plastic adhesive layer is too thin, it will not be enough to fill and support the gap at the edge of the diaphragm after melting; if the plastic adhesive layer is too thick, it will affect the molding after melting and increase the volume of the battery cell.

[0019] The method for manufacturing a deformation-resistant wound battery cell described in the present invention includes fixing a wound diaphragm and one end of a wound electrode to a rotating shaft, and the rotating shaft drives the wound diaphragm and the wound electrode to wind up a basic battery cell body; while winding, adding a plastic support member to the wound diaphragms between adjacent electrode units and protruding at the edge of the wound electrode; or, before winding, pre-connecting the plastic support member to the wound diaphragms between adjacent electrode units and protruding at the edge of the wound electrode, and then winding the plastic support member together with the wound electrode and the wound diaphragm; after winding, hot pressing the head and tail of the basic battery cell body to obtain the battery cell body.

[0020] Preferably, the basic battery cell body is obtained by heat pressing the battery cell body. Such a structure is conducive to the subsequent injection of liquid to penetrate smoothly into the diaphragm and the surface of the wound electrode.

[0021] The surfaces of the separator and the wound electrode in the present invention are no different from the existing structures, and both have porous structures that can penetrate the electrolyte. The purpose of the injection process is to penetrate the electrolyte into these porous structures.

[0022] Preferably, the basic battery cell body is first subjected to high temperature shaping and then pressed to obtain the battery cell body.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention uses a plastic support member to fill in the space between the wound diaphragms of adjacent electrode units and protrude from the edge of the wound electrode. After compression molding, the plastic support member is deformed to fill the edge gap, thereby overcoming the defects of the existing battery core body having weak head and tail structures and being easily deformed by external forces. At the same time, after being pressed, the plastic support member generates an adhesive force to tightly connect the adjacent diaphragms, and the structural connection strength is high.

[0025] The method for manufacturing a deformation-resistant wound battery cell adopted in the present invention is different from the prior art in that a plastic support is filled in when manufacturing the wound battery cell body. The plastic support can be filled in before winding or filled in while winding, so that the formed battery cell body has strong deformation resistance and high structural strength.

[0026] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the exploded structure of the battery cell body in a preferred embodiment of the present invention.

[0028] Figure 2 It is a schematic diagram of the top view structure of the battery core body in a preferred embodiment of the present invention.

[0029] Figure 3 It is a schematic diagram of the front view structure of the battery core body in a preferred embodiment of the present invention.

[0030] Figure 4 It is a schematic diagram of the cross-sectional structure of the plastic support member in a preferred embodiment of the present invention.

[0031] Figure 5 It is a schematic diagram of the structure of the plastic support member in a preferred embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 1 battery cell body, 2 electrode unit, 21 wound separator, 22 wound electrode, 23 gap, 24 plastic support, 2a positive electrode unit, 2b negative electrode unit, 221 positive electrode belt, 222 negative electrode belt, 241 room temperature adhesive layer, 242 support layer, 243 plastic adhesive layer, 6 strip body, 61 connecting part, 62 spacer. DETAILED DESCRIPTION

[0034] The present invention is further explained and illustrated by specific implementation modes below. It should be understood that the purpose of the following implementation modes is to make the technical solution of the present invention clearer and easier to understand, and does not limit the protection scope of the claims.

[0035] like Figures 1 to 3 As shown, the deformation-resistant wound battery cell of the present invention comprises a battery cell body 1, wherein the battery cell body 1 comprises at least two electrode units 2 of opposite polarities formed by winding at intervals; the electrode unit 2 comprises a wound separator 21, and a wound electrode 22 covered by the wound separator 21 and arranged on one side of the wound separator 21; at least a partially plastic support member 24 is at least partially provided at a portion protruding from the edge of the wound electrode 22 between the wound separators 21 of at least one group of adjacent electrode units 2, and is used to connect adjacent wound separators 21 during press molding and to plastically deform and fill the protruding edge gap, so as to achieve the purpose of deformation resistance of the battery cell body 1 and improve the structural strength.

[0036] like Figure 4 As shown, in a preferred embodiment, the thickness of the plastic support 24 is 0.01 to 1 mm. The plastic support 24 includes a room temperature adhesive layer 241, a support layer 242, and a plastic adhesive layer 243 connected in sequence. The room temperature adhesive layer 241 is a room temperature adhesive layer, which is used to bond and fix on the wound diaphragm to facilitate the subsequent manufacturing process. The plastic support 24 is arranged on one side or both sides of the wound diaphragm 21. The wound electrode 22 includes a positive electrode belt 221 and a negative electrode belt 222; a positive electrode unit 2a composed of a wound diaphragm 21 and a positive electrode belt 221, and a negative electrode unit 2b composed of another wound diaphragm 21 and a negative electrode belt 222; the width of the positive electrode belt 221 is narrower than that of the negative electrode belt 222.

[0037] like Figure 5As shown, in a preferred embodiment, the plastic support member 24 forms a strip structure along the winding direction of the wound diaphragm 21. The strip structure includes a strip body 6, and the strip body 6 includes a connection portion 61 arranged in sequence and a spacer 62 whose plastic volume exceeds the adjacent connection portion 61. After the spacer 62 and the connection portion 61 are subjected to heat pressing, they are plastically deformed at the same time and diffused to the surroundings to fill the wound diaphragm 21 and protrude from the edge of the wound electrode 22. The diffusion space of the spacer 62 with a large plastic volume exceeds the connection portion 61. In order to bear the force evenly, the spacer 62 is formed between the wound diaphragms 21 to form a structure with upper and lower sides parallel to the wound diaphragm 21. When the upper and lower sides are pressed, they fit well with the wound diaphragm 21 and bear the force evenly. Alternatively, the connection portion 61 is formed into a flat strip between adjacent spacers 62.

[0038] The method for manufacturing a deformation-resistant wound battery cell described in the present invention comprises fixing one end of at least one positive electrode tape 221, at least one negative electrode tape 222, and a plurality of wound separators 21 cooperating with the positive electrode tape 221 and the negative electrode tape 222 to a rotating shaft, wherein the rotating shaft drives the positive electrode tape 221, the negative electrode tape 222, and the wound separator 21 to wind up a basic battery cell body; while winding, a plastic support member 24 is added to the wound separator 21 between adjacent electrode units 2 to protrude at the edge of the wound electrode 22, and a gap 23 exists at the protruding edge when the plastic support member 24 is not provided; or, before winding, the plastic support member 24 is pre-connected with the wound separator 21, and then the plastic support member 24 is wound together with the positive electrode tape 221, the negative electrode tape 222, and the wound separator 21; after winding, the head and tail of the basic battery cell body are pressed to obtain the battery cell body 1. The basic battery cell body is first subjected to high temperature shaping and then to hot pressing to obtain the battery cell body 1 .

[0039] In a preferred embodiment, the basic battery body is compressed by intervals to obtain the battery body 1. Such a structure is conducive to the subsequent injection of liquid into the surface of the separator 21 and the wound electrode 22. The surface of the separator and the wound electrode 22 in the present invention is no different from the existing structure, and both have a porous structure that can penetrate the electrolyte. The purpose of the injection process is to penetrate the electrolyte into these porous structures.

[0040] The working principle of the present invention is as follows:

[0041] The wound battery body 1 is formed by a long positive electrode sheet 221, a long negative electrode sheet 222 and two wound separators 21 rotating around a center. The battery body 1 is prepared by the winding method, and the width of the positive electrode sheet 221 is less than the width of the negative electrode sheet 222 and less than the width of the separator 21. This will cause a space gap 23 between the head and the tail of the battery body 1, which is easy to deform when dropped or pressed.

[0042] When winding, the positive electrode sheet 221, the negative electrode sheet 222 and one end of the winding separator 21 are fixed on the metal shaft of the equipment, and then the metal shaft rotates to drive the three to move. Hot melt adhesive strips can be added to both sides of the winding separator 21 at the same time. When the winding separator 21 moves forward, they are simultaneously pasted to the edge of the winding separator 21 and wound into the battery cell body 1. Alternatively, the hot melt adhesive room temperature adhesive layer 241 can be first pasted on the winding separator 21, and then used directly during winding. Among them, the plastic support member 24 on one side contacting the positive electrode sheet 221 is slightly wider than the one on the side contacting the negative electrode sheet 222.

[0043] After winding, hot pressing is performed. To ensure that the subsequent liquid injection is not affected, the head and tail high-temperature glue are hot pressed at intervals. It can also be hot pressed in the subsequent high-temperature shaping section.

[0044] The present invention is described by way of embodiments, but does not constitute a limitation to the present invention. With reference to the description of the present invention, other changes to the disclosed embodiments are easily conceivable to professionals in the field, and such changes should fall within the scope defined by the claims of the present invention.

Claims

1. A deformation-resistant wound battery cell, characterized in that: The battery cell comprises a battery cell body (1), wherein the battery cell body (1) comprises at least two electrode units (2) of different electrical polarities formed by winding at intervals; The electrode unit (2) comprises a wound diaphragm (21), and a wound electrode (22) provided on one side of the wound diaphragm (21) and covered by the wound diaphragm (21); at least a portion of a plastic support member (24) is provided between the wound diaphragms (21) of at least one group of adjacent electrode units (2) and protruding from the edge of the wound electrode (22); the plastic support member (24) deforms after being subjected to heat and pressure and diffuses to the surroundings to fill the wound diaphragm (21) and protruding from the edge of the wound electrode (22), so as to achieve compact filling and deformation resistance of the edge of the wound diaphragm (21); The plastic support member (24) forms a strip structure along the winding direction of the wound diaphragm (21); the strip structure comprises a strip body (6), the strip body (6) comprises connection parts (61) arranged in sequence at intervals, and spacers (62) whose plastic volume exceeds that of adjacent connection parts (61); the spacers (62) and the connection parts (61) are plastically deformed at the same time after being subjected to heat pressing to diffuse to the surroundings and fill the wound diaphragm (21) and protrude from the edge of the wound electrode (22); the diffusion space of the spacers (62) with a large plastic volume exceeds that of the connection parts (61); the spacers (62) are formed between the wound diaphragms (21) with upper and lower side surfaces parallel to the wound diaphragms (21); when the upper and lower side surfaces are subjected to pressure, they fit well with the wound diaphragm (21) and are subjected to uniform force; the connection part (61) is formed into a flat strip between adjacent spacers (62).

2. The deformation-resistant wound battery cell according to claim 1, characterized in that: The plastic support member (24) comprises at least two plastic adhesive layers (243) and a support layer (242) disposed between the plastic adhesive layers (243).

3. The deformation-resistant wound battery cell according to claim 2, characterized in that: The plastic bonding layer (243) is composed of hot melt adhesive and is used to melt and bond the diaphragm and deform to fill the gap during hot pressing.

4. The deformation-resistant wound battery cell according to claim 3, characterized in that: At least one layer of the plastic adhesive layer (243) is composed of cured hot melt adhesive.

5. The deformation-resistant wound battery cell according to claim 1, characterized in that: The wound electrode (22) comprises a positive electrode strip (221) and a negative electrode strip (222); the wound separator (21) and the positive electrode strip (221) form a positive electrode unit (2a), and the wound separator (21) and the negative electrode strip (222) form a negative electrode unit (2b); the width of the positive electrode strip (221) is narrower than that of the negative electrode strip (222).

6. The deformation-resistant wound battery cell according to claim 1, characterized in that: The plastic support member (24) has a thickness of 0.01 to 1 mm.

7. A method for manufacturing a deformation-resistant wound battery cell according to any one of claims 1 to 6, characterized in that: The method comprises fixing one end of a wound separator (21) and a wound electrode (22) to a rotating shaft, and the rotating shaft drives the wound separator (21) and the wound electrode (22) to be wound to obtain a basic battery cell body; While winding, a plastic support member (24) is added to the protruding edge of the wound electrode (22) between the wound separators (21) of adjacent electrode units (2); or, before winding, the plastic support member (24) is pre-connected to the protruding edge of the wound electrode (22) between the wound separators (21) of adjacent electrode units (2), and then the plastic support member (24) is wound together with the wound electrode (22) and the wound separator (21); after winding, the head and tail of the basic battery cell body are hot pressed to obtain the battery cell body (1).

8. The method for manufacturing a deformation-resistant wound battery cell according to claim 7, characterized in that: The basic battery cell body is subjected to heat pressing to obtain a battery cell body (1).

9. The method for manufacturing a deformation-resistant wound battery cell according to claim 7, characterized in that: The basic battery cell body is first subjected to high temperature shaping and then pressed to obtain the battery cell body (1).

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