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

Abstract

The anti-deformation stacked battery cell described in the present invention comprises a battery cell body composed of diaphragm bags encapsulating packaged electrode sheets and bare electrode sheets with different electrical polarity from the packaged electrode sheets, and a plastic support member at least partially connected to the diaphragm bag is provided between the diaphragm bags on both sides of at least one bare electrode sheet and protrudes from the edge of the bare electrode sheet. The plastic support member deforms after being subjected to heat pressing and diffuses to the surroundings to fill the diaphragm bags protruding from the edge of the bare electrode sheet, so as to achieve compact filling and deformation resistance of the edge of the diaphragm bag. The plastic support member of the present invention deforms and fills the gap between the diaphragm bag and the electrode sheet, and at the same time plays the role of connecting the diaphragm bag and supporting the gap between the diaphragm bag and the electrode sheet. In this way, when actually used, the formed battery cell body is placed in the outer shell, and the deformed plastic support member can effectively reduce the impact of the deformation of the plastic film 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 technical field of battery cells, and more specifically, to a deformation-resistant stacked cell 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 to 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 easy to deform, affecting the appearance of the battery, and even damaging the electrode sheet, and scrapping the battery. Summary of the invention

[0004] The primary purpose of the present invention is to provide a battery cell with compact filling of positive and negative electrodes and diaphragm joints, easy molding, improved deformation resistance and drop resistance in view of the above defects and shortcomings.

[0005] Another object of the present invention is to provide a unique method for preparing battery cells, by pasting hot melt adhesive on the edge or frame of the diaphragm bag, which can not only fill the gap, but also better fix the diaphragm bag and the electrode, prevent deviation, reduce thermal shrinkage of the diaphragm bag, solve the problem of easy deformation of the edge of the battery cell when falling or squeezed, and improve the pass rate of thermal shock and drop tests.

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

[0007] The deformation-resistant stacked battery cell described in the present invention includes a battery cell body composed of diaphragm bags encapsulating packaged electrode sheets and stacked in sequence with intervals, and bare electrode sheets with different electrical polarity from the packaged electrode sheets; a plastic support member at least partially connected to the diaphragm bag is provided between the diaphragm bags on both sides of at least one bare electrode sheet and protrudes from the edge of the bare electrode sheet. After being subjected to heat pressing, the plastic support member deforms and diffuses to the surroundings to fill the space between the diaphragm bags and protrude from the edge of the bare electrode sheet, thereby achieving tight filling and deformation resistance at the edge of the diaphragm bag.

[0008] The diaphragm bag in the present invention is a bag structure with edges pressed in advance, an electrode sheet is installed inside, and then the edges are sealed to obtain a bag. The electrode sheet can be a positive electrode sheet or a negative electrode sheet. Preferably, a positive electrode sheet is installed.

[0009] Preferably, the plastic support member comprises at least two plastic adhesive layers and a support layer arranged between the plastic adhesive layers.

[0010] Preferably, the plastic adhesive layer is composed of hot melt adhesive, and the hot melt adhesive is melted and deformed by heat, 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.

[0012] When the battery cell is actually manufactured, the room temperature adhesive layer is bonded to the diaphragm bag, and then the subsequent lamination process is carried out.

[0013] The pressed adhesive deformation layer used in this patent consists 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 and has stickiness at room temperature, and is adhered to the diaphragm, that is, the room temperature adhesive layer. The other side is sticky only when hot pressed, and will bond with the hot melt adhesive layer on the adjacent diaphragm, that is, the pressed adhesive deformation layer. The middle support layer is the PET film layer, which will not melt or deform during hot pressing, and plays a role in strength support, which can better resist deformation.

[0014] Preferably, the inner edge of the plastic support extends at least to the outer edge of the bare electrode sheet, and the outer edge of the plastic support extends at least to the outer edge of the diaphragm bag, so as to reduce consumables and achieve cost savings while ensuring support strength.

[0015] In the present invention, the diaphragm bag is made of a conventional material with a permeable porous structure on the surface, and the surface of the electrode sheet also has a permeable porous structure. These permeable porous structures are used for the electrolyte to penetrate the formed battery core.

[0016] Preferably, the plastic support member forms a frame structure along the peripheral edge of the diaphragm bag.

[0017] 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 bare electrode sheets between the diaphragm bags, and the diffusion space of the spacing parts with a large plastic volume exceeds that of the connecting parts.

[0018] Preferably, the spacer is formed between the diaphragm bags and has upper and lower side surfaces parallel to the diaphragm bags. When the upper and lower side surfaces are subjected to pressure, they fit well with the diaphragm bags and are subjected to uniform force.

[0019] Preferably, the connecting portion is a flat strip formed by adjacent spacing portions.

[0020] Preferably, the bare electrode sheet is a negative electrode sheet, and the packaged electrode sheet is a positive electrode sheet; the outer edge of the negative electrode sheet exceeds the outer edge of the positive electrode sheet.

[0021] Preferably, the thickness of the plastic support is 0.01-1 mm, which is used to form a suitable volume after melting to fill the gap at the edge of the diaphragm bag. 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 bag after melting; if the plastic adhesive layer is too thin, it will affect the molding and increase the volume of the battery cell after melting.

[0022] The method for manufacturing the anti-deformation stacked battery cell of the present invention comprises the following steps:

[0023] S1. Stacking: stacking the bare electrode sheet, the diaphragm bag encapsulating the packaged electrode sheet, and the plastic support member so that the plastic support member is located between the diaphragm bag and protrudes from the edge of the bare electrode sheet to obtain a basic battery body;

[0024] S2. Compression molding: Hot-press the edges of the basic battery cell body so that it is formed into the battery cell body under the action of external force.

[0025] Preferably, the step S2. adopts interval hot pressing to leave an injection channel for facilitating subsequent injection.

[0026] Preferably, the steps S1. and S2. further include a step S3. of installing the outer shell: placing the battery cell body in the outer shell, and then hot-pressing the outer shell and the basic battery cell body as a whole into the battery cell body.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention uses a plastic adhesive layer disposed between the diaphragm bags and protruding from the edge of the bare electrode sheet. The external force applied by hot pressing causes the plastic support to deform and fill the gap between the diaphragm bag and the electrode sheet, and at the same time plays a role in connecting the diaphragm bag. After the plastic support is deformed, the external force stops being applied, and after being cooled, the existing structure is maintained, which can play a role in supporting the gap between the diaphragm bag and the electrode sheet. In this way, in actual use, the formed battery body is placed in the outer shell. If the material of the outer shell is relatively soft and easily deformed by external force, when this happens, the deformed plastic support 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.

[0029] 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 structural strength and service life of the battery cell.

[0030] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the diaphragm structure before and after bag making in a preferred embodiment of the present invention.

[0032] Figure 2 It is a schematic diagram of the exploded structure of the battery cell in a preferred embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the battery cell structure to be pressed in a preferred embodiment of the present invention.

[0034] Figure 4 It is a schematic diagram of the longitudinal cross-sectional structure of the plastic adhesive layer in a preferred embodiment of the present invention.

[0035] Figure 5 It is a schematic diagram of the structure of the plastic support member in a preferred embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1 electrode sheet, 11 bare electrode sheet, 12 packaged electrode sheet, 2 diaphragm bag, 3 battery cell body, 4 plastic support, 41 room temperature adhesive layer, 42 support layer, 43 plastic adhesive layer, 6 frame body, 61 connecting part, 62 spacer. DETAILED DESCRIPTION

[0038] 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.

[0039] Example 1

[0040] like Figures 1 to 3 As shown, the anti-deformation stacked battery cell described in the present invention is prepared by pressing the edge of the bag structure in advance to obtain a diaphragm bag 2, and the diaphragm bag 2 is equipped with an electrode sheet 12 inside. The electrode sheet 12 can be a positive electrode sheet or a negative electrode sheet. Preferably, a positive electrode sheet is installed. In the present invention, the diaphragm bag 2 is a conventional material with a permeable porous structure on the surface, and the surface of the electrode sheet 1 also has a permeable porous structure. These permeable porous structures are used for the electrolyte to penetrate the battery cell after forming.

[0041] The battery cell includes a battery cell body, and the battery cell body includes multiple electrode sheets 1, and the electrode sheets 1 include bare electrode sheets 11 and packaged electrode sheets 12. Multiple bare electrode sheets 11, and a diaphragm bag 2 is placed between the multiple bare electrode sheets 11 and sealed with the outer edge of the packaged electrode sheet 12 exceeding the bare electrode sheet 11. The bare electrode sheet 11 is connected to the edge of the diaphragm bag 2 through a plastic support 4. During the pressing process, the plastic support 4 is deformed and bonded to fill the gap between the adjacent diaphragm bags 2 that exceeds the bare electrode sheet 11 to achieve the purpose of filling, tightening and preventing deformation. The bare electrode sheet 11 is a negative electrode sheet, and the packaged electrode sheet 12 is a positive electrode sheet; the outer edge of the negative electrode sheet exceeds the outer edge of the positive electrode sheet.

[0042] In a preferred embodiment, the thickness of the plastic support member 4 is 0.01-1 mm, and is used to form a suitable volume after melting to fill the edge gap of the diaphragm bag 2. If the plastic adhesive layer is too thin, it is not enough to fill and support the edge gap of the diaphragm bag 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.

[0043] like Figure 4 As shown, in a preferred embodiment, the plastic support member 4 includes at least two layers of plastic adhesive layers 43, and a support layer 42 disposed between the plastic adhesive layers 43, and the support layer 42 can improve the support strength to achieve the purpose of anti-deformation. The plastic adhesive layer 43 is composed of hot melt adhesive, and the hot melt adhesive is melted and deformed by heat, which is beneficial to subsequent molding and simplifies the molding process. At least one layer of plastic adhesive layer 43 is composed of matured hot melt adhesive. The plastic adhesive layer composed of matured sol is a room temperature adhesive layer 41.

[0044] When actually manufacturing the battery cell, the room temperature adhesive layer 41 is bonded to the diaphragm bag 2, and then the subsequent lamination process is performed. During the lamination process, the uncured plastic adhesive layer 43 is opposite, deformed and adhered under the action of external force.

[0045] The pressed adhesive deformation layer used in the present invention is composed of three parts, a matured hot melt adhesive layer (sis), a PET film layer, and a hot melt adhesive layer (sis) that will deform and adhere only after pressing. The hot melt adhesive layer on one side is matured and has adhesiveness at room temperature, and adheres to the diaphragm, that is, the room temperature adhesive layer 41. The other side is adhesive only when hot pressed, and will adhere to the hot melt adhesive layer on this side of the other adjacent diaphragm, that is, the pressed adhesive deformation layer 43. The middle support layer 42 is a PET film layer that will not melt or deform during hot pressing, and plays a role in strength support, which can better resist deformation.

[0046] like Figure 5As shown, in a preferred embodiment, the frame structure includes a frame body 6, and the frame body 6 includes connection parts 61 arranged in sequence and interval parts 62 whose plastic volume exceeds the adjacent connection parts 61. After the interval parts 62 and the connection parts 61 are subjected to heat pressing, they are plastically deformed and diffused to the surroundings to fill the diaphragm bags 2 and protrude from the edge of the bare electrode sheet 11. The diffusion space of the interval parts 62 with a large plastic volume exceeds the connection parts 61. In order to better bear the force, the interval parts 62 are formed by the diaphragm bags 2 to form a structure with upper and lower sides parallel to the diaphragm bags 2. When the upper and lower sides are pressed, they fit well with the diaphragm bags 2 and bear the force evenly. Alternatively, the connection part 61 is formed into a flat strip between adjacent interval parts 62.

[0047] In a preferred embodiment, the inner edge of the plastic support 4 extends to the outer edge of the bare electrode sheet 11, and the outer edge of the plastic support 4 extends to the outer edge of the diaphragm bag 2, so as to reduce consumables and achieve cost savings while ensuring support strength.

[0048] Example 2

[0049] like Figure 2 As shown, in the method for making the anti-deformation stacked battery cell described in the present invention, the positive electrode sheet 11 (or the negative electrode sheet 12) is placed between two diaphragm bags 2, and by pressing the edge of the diaphragm bag 2, a diaphragm bag of the same shape containing the positive electrode sheet 11 (or the negative electrode sheet 12) is made, and the diaphragm bag 2 part of the diaphragm bag will be slightly larger than the positive electrode sheet 11 (or the negative electrode sheet 12). On this basis, a frame 4 composed of a matured hot melt adhesive (normal temperature adhesive layer 41), a PET film (support layer 42), and a hot melt adhesive layer (plastic adhesive layer 43) that will deform and adhere only after pressing is prepared, the inner diameter of the frame 4 is the same as the length of the electrode sheet 11, and the outer diameter is the same as the length of the diaphragm bag 2, and then the sticky side 41 of the hot melt adhesive frame 4 at room temperature is pasted to the outer contour edges of both sides of the diaphragm bag 2 to form an electrode bag with hot melt adhesive. After the lamination is completed, the battery body is hot pressed, and the hot melt adhesive surface 42 is melted by heat and has stickiness, which sticks to the edge of the adjacent diaphragm bag 2, directly fixes the battery body, and fills the edge gap between the layers of the diaphragm bag 2. In this way, the thermal shrinkage of the diaphragm bag 2 can be reduced during thermal shock. If the lamination is directly hot pressed, the process of fixing the entire laminate body with adhesive tape after lamination can be omitted, making the entire battery more beautiful and saving cost and time. In order to ensure that the subsequent liquid injection is not affected, the hot pressing area does not necessarily have to be hot-pressed and sealed around the frame 4. The frame 4 around the frame 4 can be hot-pressed at intervals, or only the frame 4 at the head and tail of the battery body, or the frame 4 at the left and right can be hot-pressed. In addition, it is not necessary to hot press after the lamination process, and it can also be hot pressed at the same time as the shell, such as aluminum-plastic film, during the high-temperature shaping of the subsequent production of the battery. During the high-temperature shaping and hot pressing, the hot melt adhesive on the outer ring diaphragm bag 2 of the battery body will stick to the inner wall of the shell, which will better fix the battery body.

[0050] 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 stacked battery cell, characterized in that: It comprises a battery cell body (3) composed of diaphragm bags (2) stacked in sequence and encapsulating encapsulated electrode sheets (12), and bare electrode sheets (11) having an electrical polarity different from that of the encapsulated electrode sheets (12); A plastic support member (4) at least partially connected to the diaphragm bag (2) is provided between the diaphragm bags (2) on both sides of at least one bare electrode sheet (11) and protrudes from the edge of the bare electrode sheet (11). The plastic support member (4) is deformed after being heated and pressed and diffuses to the surroundings to fill the area between the diaphragm bags (2) and protruding from the edge of the bare electrode sheet (11), thereby achieving compact filling and deformation resistance of the edge of the diaphragm bag (2); The plastic support member (4) forms a frame structure along the peripheral edge of the diaphragm bag (2), the frame structure comprising a frame body (6), the frame body (6) comprising connection parts (61) arranged in sequence at intervals, and a spacing part (62) whose plastic volume exceeds that of an adjacent connection part (61).

2. The deformation-resistant stacked battery cell according to claim 1, characterized in that: The plastic support member (4) comprises at least two plastic adhesive layers (43) and a support layer (42) arranged between the plastic adhesive layers (43).

3. The deformation-resistant stacked battery cell according to claim 2, characterized in that: The plastic adhesive layer (43) is composed of hot melt adhesive, and the hot melt adhesive is melted and deformed by heat, which is beneficial to subsequent molding and simplifies the molding process.

4. The deformation-resistant stacked battery cell according to claim 3, characterized in that: At least one layer of the plastic adhesive layer (43) is composed of cured hot melt adhesive.

5. The deformation-resistant stacked battery cell according to claim 1, characterized in that: After being subjected to heat pressing, the spacer (62) and the connecting portion (61) are simultaneously plastically deformed to diffuse to the surroundings to fill the space between the diaphragm bags (2) and protrude from the edge of the bare electrode sheet (11). The diffusion space of the spacer (62) with a large plastic volume exceeds that of the connecting portion (61). The spacer (62) is formed by the diaphragm bags (2) to have an upper and lower side surface parallel to the diaphragm bag (2). When the upper and lower side surfaces are subjected to pressure, they fit well with the diaphragm bag (2) and are subjected to uniform force. The connecting portion (61) is formed by adjacent spacers (62) to form a flat strip.

6. The deformation-resistant stacked battery cell according to claim 1, characterized in that: The plastic support member (4) has a thickness of 0.01 to 1 mm and is used to form a suitable volume after deformation to fill the gap at the edge of the diaphragm bag (2).

7. A method for manufacturing a deformation-resistant stacked battery cell according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Stacking: stacking a bare electrode sheet (11), a diaphragm bag (2) encapsulating an encapsulated electrode sheet (12), and a plastic support member (4), so that the plastic support member (4) is located between the diaphragm bags (2) and protrudes from the edge of the bare electrode sheet (11), thereby obtaining a basic battery cell body; S2. Compression molding: Hot pressing the edges of the basic battery cell body to form the battery cell body under the action of external force.

8. The method for manufacturing a deformation-resistant stacked battery cell according to claim 7, characterized in that: The step S2 adopts interval hot pressing to facilitate subsequent liquid injection and leave a liquid injection channel.

9. The method for manufacturing a deformation-resistant stacked battery cell according to claim 7, characterized in that: The step S3 of installing the shell is further included between the steps S1 and S2: placing the battery cell body in the plastic shell, and then hot pressing the plastic shell and the basic battery cell body as a whole to form the battery cell body.

Images