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

Abstract

The anti-deformation laminated battery cell described in the present invention includes a battery cell body formed by stacking a diaphragm and electrode sheets in sequence; a plastic support member at least partially connected to the diaphragm is provided between the diaphragms on both sides of at least one electrode sheet and protrudes from the edge of the electrode sheet. The plastic support member is deformed after being subjected to heat pressing and diffuses to the surroundings to fill the diaphragm protruding from the edge of the electrode sheet, so as to achieve compact filling and deformation resistance of the diaphragm edge. The present invention causes the plastic support member to deform by pressing the external force applied, thereby filling the gap where the diaphragm exceeds the electrode sheet, and at the same time plays the role of connecting the diaphragm. After the plastic support member is deformed, the external force stops being applied, that is, the existing structure is maintained, and the gap can be supported from the inside to the outside. The formed battery cell body is placed in a shell and is easily deformed by external force. The plastic support member can effectively resist the impact of deformation on the internal battery cell, so that the battery cell is effectively protected and will not be scrapped.

Description

Technical Field

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

[0002] In the field of lithium-ion batteries, whether it is soft pack, cylindrical, or button cell production, winding or stacking is mostly adopted. The battery cell includes the positive electrode sheet, negative electrode sheet, and diaphragm, which follow the rule of increasing size in sequence. After the three are assembled, fixed, and welded with the pole ears, they are placed in an aluminum-plastic film shell or a steel shell, and then processed to form a lithium-ion battery cell.

[0003] The production of battery cells follows the rules of increasing sizes of positive electrode sheets, negative electrode sheets, and diaphragms. On the one hand, this is to meet the requirements of the positive and negative electrode capacity ratio, and on the other hand, it is to prevent the electrode sheets from deviating or misaligned during the production process and reserve error space to ensure that the diaphragm completely wraps the positive and negative electrodes, and the negative electrode completely wraps the positive electrode. However, this will cause a problem, that is, the part of the bare battery cell stack where the diaphragm exceeds the electrode sheet, that is, the head, tail or side of the battery cell will reserve more connection gaps, and the filling is not dense. When it falls or is squeezed, the battery cell is easily deformed, affecting the appearance of the battery, and even damaging the electrode sheet, and scrapping the battery. In order to prevent the battery from deformation and leakage, the Chinese invention patent with the publication number CN205882084U and the subject of a lithium-ion battery uses an insulating glue to surround and cover the bare battery cell to improve the mechanical properties of the battery. However, this method of wrapping the outside of the battery cell with a soft insulating glue is still easily deformed by external forces and fails to support the battery cell from the inside. In particular, the diaphragm gaps at the head and tail of the battery cell are prone to deformation when it falls or is impacted by external forces. Summary of the invention

[0004] The primary purpose of the present invention is to provide a bag-making laminated battery cell with enhanced structural strength from the inside, compact filling and anti-deformation in view of the above defects and shortcomings.

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

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

[0007] The deformation-resistant laminated battery cell described in the present invention comprises a battery cell body formed by stacking a diaphragm and electrode sheets in sequence; a plastic support member at least partially connected to the diaphragm is provided between the diaphragms on both sides of at least one electrode sheet and protrudes from the edge of the electrode sheet. The plastic support member deforms after heat pressing and diffuses to the surroundings to fill the diaphragm space and protrude from the edge of the electrode sheet, so as to achieve compact filling and deformation resistance of the diaphragm edge.

[0008] In the present invention, the surfaces of the separator and the electrode sheet have porous structures into which the electrolyte can penetrate, and the purpose of the injection process is to penetrate the electrolyte into these porous structures.

[0009] Preferably, the plastic support member comprises at least two plastic adhesive layers and a support layer disposed between the plastic adhesive layers, and the support layer can improve the support strength to achieve the purpose of anti-deformation.

[0010] Preferably, the plastic bonding layer is composed of hot melt adhesive, which is beneficial to subsequent molding and simplifies the molding process.

[0011] Preferably, at least one of the plastic adhesive layers is composed of cured hot melt adhesive. The cured hot melt adhesive layer has adhesion at room temperature, forming a room temperature adhesive layer.

[0012] Preferably, the plastic support member forms a frame structure along the edge of the diaphragm.

[0013] Preferably, the frame structure includes a frame 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 edges of the protruding electrode sheets between the diaphragms, and the diffusion space of the spacing parts with a large plastic volume exceeds that of the connecting parts.

[0014] Preferably, the spacer extends along the circumferential direction of the diaphragm to form a structure in which the upper and lower sides are parallel to the diaphragm. When the upper and lower sides are under pressure, they fit well with the diaphragm and are evenly stressed.

[0015] Preferably, the connecting portion is a flat strip formed by adjacent spacing portions.

[0016] More preferably, the electrode sheet includes a positive electrode sheet and a negative electrode sheet whose outer edge exceeds the positive electrode sheet; and the plastic support member is a frame structure whose inner edge extends at least to the outer edge of the positive electrode sheet.

[0017] More preferably, the plastic support is only provided in the gap formed by the positive electrode sheet and the separator.

[0018] Preferably, the thickness of the plastic support is 0.01-1 mm, and is used to form a suitable volume after melting to fill the protrusion between the diaphragms and the edge of the electrode sheet. The protrusion forms a gap when the plastic support is not provided.

[0019] The method for manufacturing the deformation-resistant laminated battery cell described in the present invention comprises firstly stacking electrode sheets, a plastic support member, and a diaphragm so that the plastic support member is located between the diaphragms and protrudes from the edge of the electrode sheets to obtain a basic battery cell body; and then hot pressing the edge of the basic battery cell body to shape it into a battery cell body.

[0020] Preferably, the pressing is performed by intermittent hot pressing, so as to leave an injection channel for facilitating subsequent injection.

[0021] Preferably, the basic battery cell body is first placed in a plastic shell and then pressed together to form a battery cell body.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention adopts a plastic support member disposed at the gap where the diaphragm exceeds the electrode sheet, and the plastic support member is deformed by the external force applied by pressure, so as to fill the gap where the diaphragm exceeds the edge of the electrode sheet, and at the same time plays the role of connecting the diaphragm. After the plastic deformation occurs, the external force stops being applied to the plastic support member, that is, the existing structure is maintained, and the gap where the diaphragm exceeds the edge of the electrode sheet can be supported from the inside to the outside. In this way, when it is actually used, the formed battery body is placed in the outer shell. If the outer shell is made of a soft plastic shell, it is easy to be deformed by external force. When this happens, the deformed plastic support member can effectively reduce the impact of the outer shell deformation on the internal battery cell, so that the battery cell is effectively protected and will not be scrapped.

[0024] The battery cell manufactured by the battery cell manufacturing method of the present invention has the performance of anti-drop, anti-impact and anti-deformation. Compared with the existing battery cells, it has better ability to cope with unexpected situations and effectively improves the internal structure strength and service life of the battery cell.

[0025] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the exploded structure of the battery cell body in a preferred embodiment of the present invention.

[0027] Figure 2 Schematic diagram of the structure of the battery cell in a preferred embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of the longitudinal section structure of the plastic support member in a preferred embodiment of the present invention.

[0029] Figure 4 It is a schematic diagram of the structure of the plastic support member in a preferred embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1 electrode sheet, 11 positive electrode sheet, 12 negative electrode sheet, 2 separator, 3 battery cell body, 4 gap, 5 plastic support, 51 room temperature adhesive layer, 52 support layer, 53 plastic adhesive layer, 6 frame body, 61 connecting part, 62 spacer. DETAILED DESCRIPTION

[0032] 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.

[0033] like Figures 1-2 As shown, the deformation-resistant laminated battery cell described in the present invention includes a battery cell body 3 formed by stacking at least two diaphragms 2 and a plurality of electrode sheets 1 covered by the diaphragms; the space outside the overlapping portion formed by stacking the diaphragms 2 and the electrode sheets 1 forms a gap 4, that is, a gap 4 is formed between the diaphragms 2 on both sides protruding from the edge of the electrode sheet 1, and at least part of the gap 4 is provided with a plastic support 5; during the pressing process, the plastic support 5 is deformed, bonded and fills the gap 4 between adjacent diaphragms to achieve the purpose of filling, compacting and preventing deformation. Among them, the thickness of the plastic support 5 is 0.01 to 1 mm, which is used to form a suitable volume after melting to fill the gap between the diaphragms. In order to simplify the production process and facilitate filling the gap, the plastic support 5 can also be formed into a frame structure along the edge of the diaphragm 2.

[0034] like Figure 3 As shown, in a preferred embodiment, the plastic support member 5 includes a room temperature adhesive layer 51, a support layer 52, and a plastic adhesive layer 53 connected in sequence, and the support layer can improve the support strength to achieve the purpose of anti-deformation. The plastic adhesive layer 53 is a hot melt adhesive layer, which is conducive to subsequent molding and simplifies the molding process by means of hot melt adhesive. The plastic support member 5 used in this embodiment is composed of three parts, a hot melt adhesive layer (sis), a PET film layer, and a hot melt adhesive layer (sis), wherein the hot melt adhesive layer on one side is ripened, has viscosity at room temperature, and is adhered to the diaphragm, i.e., the room temperature adhesive layer 51. The other side is only sticky when hot pressed, and will be bonded to the hot melt adhesive layer on this side of the adjacent other diaphragm, i.e., the plastic adhesive layer 53 is pressed. The middle support layer 52 is a PET film layer that will not melt and deform during hot pressing, and plays a strength support role, which can better resist deformation.

[0035] like Figure 1 As shown, in a preferred embodiment, the electrode sheet 1 includes a positive electrode sheet 11 and a negative electrode sheet 12 whose outer edge exceeds the positive electrode sheet 11. The plastic support member 5 is a frame structure whose inner edge extends at least to the outer edge of the positive electrode sheet 11. The plastic support member 5 is only provided at the gap 4 formed by the positive electrode sheet 11 and the diaphragm 2. A bag body is formed by two diaphragms 2, the positive electrode sheet 11 is encapsulated in the bag body, and the plastic support member 5 is provided at the edge gap 4 of the bag body.

[0036] like Figure 4As shown, in a preferred embodiment, the frame structure includes a frame body 6, and the frame body 6 includes a connection part 61 arranged in sequence and a spacer 62 whose plastic volume exceeds the adjacent connection part 61. After the spacer 62 and the connection part 61 are subjected to heat pressing, they are plastically deformed and diffused to the surroundings to fill the edge of the protruding electrode sheet 1 between the diaphragms 2. The diffusion space of the spacer 62 with a large plastic volume exceeds the connection part 61. In order to better bear the force, the spacer 62 extends along the circumferential direction of the diaphragm 2 to form a structure in which the upper and lower sides are parallel to the diaphragm 2. When the upper and lower sides are pressed, they fit well with the diaphragm 2 and bear the force evenly. It is also possible that the connection part 61 is formed into a flat strip between adjacent spacers 62.

[0037] The method for manufacturing the anti-deformation laminated battery cell of the present invention comprises firstly stacking the electrode sheet 1, the plastic support member 5, and the diaphragm 2, so that the plastic support member 5 is located at the gap 4, and obtaining the basic battery cell body; and then pressing the edge of the basic battery cell body so that it is formed into the battery cell body 3 under the action of external force. The pressing is interval pressing, which is used to facilitate the subsequent injection and leave an injection channel. The basic battery cell body is first placed in a plastic shell, and then pressed together to form the battery cell body 3. The pressing process is hot pressing.

[0038] 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 laminated battery cell, characterized in that: It comprises a battery cell body (3) formed by stacking a diaphragm (2) and electrode sheets (1) in sequence; A plastic support member (5) at least partially connected to the diaphragm (2) is provided between the diaphragms (2) on both sides of at least one electrode sheet (1) and protrudes from the edge of the electrode sheet (1). The plastic support member (5) is deformed after being subjected to heat and pressure and diffuses around to fill the space between the diaphragms (2) and protrudes from the edge of the electrode sheet (1), so as to achieve compact filling and deformation resistance of the edge of the diaphragm (2); The plastic support member (5) forms a frame structure along the peripheral edge of the diaphragm (2), and the frame structure comprises a frame body (6), the frame 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) being plastically deformed and diffused to the surroundings to fill the edge of the protruding electrode sheet (1) between the diaphragms (2) after being subjected to heat pressing, and 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 diaphragms (2) into a structure with upper and lower side surfaces parallel to the diaphragms (2), and the upper and lower side surfaces are well fitted with the diaphragm (2) when subjected to pressure, and the force is evenly applied; the connection parts (61) are formed into flat strips between adjacent spacers (62).

2. The anti-deformation laminated battery cell according to claim 1, characterized in that: The plastic support member (5) comprises at least two plastic adhesive layers (53) and a support layer (52) arranged between the plastic adhesive layers (53).

3. The deformation-resistant laminated battery cell according to claim 2, characterized in that: The plastic adhesive layer (53) is composed of hot melt adhesive.

4. The deformation-resistant laminated battery cell according to claim 3, characterized in that: At least one layer of the plastic adhesive layer (53) is composed of cured hot melt adhesive.

5. The deformation-resistant laminated battery cell according to claim 1, characterized in that: The plastic support (5) has a thickness of 0.01 to 1 mm and is used to form a suitable volume after melting to fill the space between the diaphragms and protrude from the edge of the electrode sheet.

6. A method for manufacturing a deformation-resistant laminated battery core according to any one of claims 1 to 5, characterized in that: The method comprises firstly stacking an electrode sheet (1), a plastic support member (5), and a diaphragm (2) so that the plastic support member (5) is located between the diaphragms (2) and protrudes from the edge of the electrode sheet (1) to obtain a basic battery cell body; and then hot pressing the edge of the basic battery cell body to form the battery cell body (3).

7. The method for manufacturing a deformation-resistant laminated battery core according to claim 6, characterized in that: The hot pressing is an interval hot pressing, which is used to facilitate subsequent liquid injection and leave a liquid injection channel.

8. The method for manufacturing a deformation-resistant laminated battery cell according to claim 6, characterized in that: The basic battery cell body is first placed in a plastic shell and then hot-pressed together to form a battery cell body (3).

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