A deformation-resistant folded battery cell and its manufacturing method

Abstract

The anti-deformation folding battery cell described in the present invention includes a battery cell body composed of a folding diaphragm and an electrode sheet matched with the folding diaphragm; a plastic support member at least partially connected to the folding diaphragm is provided between the folding 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 space between the folding diaphragms and protrude from the edge of the electrode sheet, so as to achieve compact filling and deformation resistance of the edge of the folding diaphragm. The present invention deforms the plastic support member by applying external force through pressing, thereby filling the gap where the diaphragm exceeds the electrode sheet, and at the same time plays the role of connecting the diaphragm. The deformed plastic support member can effectively reduce the impact of the outer shell deformation or impact 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 cell manufacturing, and more specifically, to a deformation-resistant folding battery cell and a manufacturing method thereof. Background Art

[0002] Common methods for making battery cells include lamination and winding, among which the lamination method includes stacking and Z-folding of the electrode. In order to increase the connection strength of the laminated battery, hot melt adhesive can be used to bond the electrode. For example, the Chinese invention patent with publication number CN110459796A, which is a method for preparing a laminated battery, a laminated battery, a lamination device and a system, first adheres hot melt adhesive to the diaphragm, and after melting, it plays the role of bonding the electrode composite laminate.

[0003] Compared with stacked pole pieces, the Z-folded pole piece has a simpler process and lower equipment requirements for battery cells. However, there are gaps on the sides of the pole pieces and diaphragms, that is, the head and tail of the stacked battery cells. Such a structure will cause the battery cells to deform easily at the gaps during use, and even make the battery cells completely unusable and scrapped. Although the battery cells are wrapped in a shell when in use, some shells have low hardness and are easily deformed when dropped or impacted by other external forces, and are also likely to affect the internal battery cells and cause them to deform. Summary of the invention

[0004] The primary purpose of the present invention is to provide a folded electrode battery cell in response to the above defects and shortcomings, and fill a plastic support member in the gap between the electrode and the diaphragm, so that the battery cell is filled tightly and has high structural strength, thereby improving the drop resistance and impact resistance.

[0005] Another object of the present invention is to provide a method for manufacturing a folded electrode battery cell.

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

[0007] The anti-deformation folding battery cell described in the present invention includes a battery cell body composed of a folding diaphragm and an electrode sheet matched with the folding diaphragm; a plastic support member at least partially connected to the folding diaphragm is provided between the folding 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 heat pressing and diffuses to the surroundings to fill the space between the folding diaphragms and protrude from the edge of the electrode sheet, so as to achieve compact filling and deformation resistance of the edge of the folding 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 a cured hot melt adhesive. The plastic adhesive layer composed of the cured hot melt adhesive forms a room temperature adhesive layer.

[0011] The plastic adhesive 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 plastic adhesive 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.

[0012] 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 includes a positive electrode sheet band corresponding to the positive electrode sheet and a negative electrode sheet band corresponding to the negative electrode sheet, and the positive electrode sheet band is wider than the negative electrode sheet band, so as to save consumables while ensuring that the gap is filled tightly.

[0013] More preferably, the plastic support is a strip-shaped structure formed continuously along the length direction of the diaphragm strip, so as to facilitate the production of the battery cell body and the processing of the plastic support itself.

[0014] Preferably, the strip-type 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 edges of the protruding electrode sheets between the folded diaphragms, and the diffusion space of the spacing parts with a large plastic volume exceeds that of the connecting parts.

[0015] Preferably, the spacer is formed between the folded diaphragms and has upper and lower side surfaces parallel to the folded diaphragms. When the upper and lower side surfaces are pressed, they fit well with the folded diaphragms and are evenly stressed.

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

[0017] 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.

[0018] The method for manufacturing the deformation-resistant foldable battery cell described in the present invention includes placing a plastic support along the edge of a folded diaphragm, and then arranging a plurality of electrode sheets in sequence and staggered front and back on both sides of the folded diaphragm, and obtaining a basic battery cell body after folding and stacking, and the basic battery cell body is formed into a battery cell body after hot pressing.

[0019] Preferably, the basic battery cell body is hot pressed in a high temperature shaping process.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention adopts a plastic support member disposed at the gap where the folded diaphragm exceeds the edge of the electrode sheet. The external force applied by hot pressing causes the plastic support member to deform and fill the gap where the diaphragm exceeds the electrode sheet, and at the same time plays a role in connecting the diaphragm. After the plastic support member is deformed, the external force stops being applied, and the existing structure is maintained after being cooled, which can play a role in supporting the gap where the folded diaphragm exceeds the edge of the electrode sheet. In this way, in actual use, the formed battery body is placed in the outer shell. Because the material of some outer shells is relatively soft and easily deformed by external forces, when this happens, the deformed plastic support member can effectively reduce the impact of the outer shell deformation or impact on the internal battery cell, so that the battery cell is effectively protected and will not be scrapped.

[0022] 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.

[0023] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the unfolded structure of the battery cell in a preferred embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the unfolded structure of the battery cell from another perspective in a preferred embodiment of the present invention.

[0026] Figure 3 Schematic diagram of the battery cell structure in a preferred embodiment of the present invention.

[0027] Figure 4 Schematic diagram of the cross-sectional structure of the plastic adhesive layer in a preferred embodiment of the present invention.

[0028] Figure 5 It is a schematic diagram of the folded diaphragm structure in a preferred embodiment of the present invention.

[0029] Figure 6 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 battery cell body, 11 folded separator, 12 electrode sheet, 121 positive electrode sheet, 122 negative electrode sheet, 13 plastic support, 131 room temperature adhesive layer, 132 support layer, 133 plastic adhesive layer, 134 positive electrode sheet strip, 135 negative electrode sheet strip, 14 gap, 15 stacking gap, 6 strip 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 to 5 As shown, the anti-deformation folding battery cell of the present invention comprises a battery cell body 1 composed of a folding diaphragm 11 and an electrode sheet 12 matched with the folding diaphragm 11; a plastic support 13 at least partially connected to the folding diaphragm 11 is provided between the folding diaphragms 11 on both sides of at least one electrode sheet 12 and protruding from the edge of the electrode sheet 12; it is used to deform and fill the edge gap between the folding diaphragms 11 during hot pressing through the plastic support 13 to achieve the purpose of improving structural strength and anti-deformation. An overlapping gap 15 is formed between the folding diaphragms 11. In the space of the overlapping gap 15, the folding diaphragm 11 protrudes from the edge of the electrode sheet 12, and when the plastic support 13 is not provided, there is a gap 14. The thickness of the plastic support 13 is 0.01 to 1 mm. The thickness can be selected according to actual conditions. If the plastic adhesive layer is too thin, it is not enough to fill and support the edge gap 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.

[0034] like Figure 4 As shown, in a preferred embodiment, the plastic support 13 includes a room temperature adhesive layer 131, a support layer 132, and a plastic adhesive layer 133 connected in sequence to the folding diaphragm 11, and the support layer can improve the support strength to achieve the purpose of anti-deformation. Wherein, the plastic adhesive layer 133 is a hot melt adhesive layer, which is used to melt the adhesive diaphragm and deform to fill the gap during hot pressing. The plastic adhesive layer used in this patent 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 ripened and has viscosity at room temperature, and is adhered to the diaphragm, that is, the room temperature adhesive layer. The other side is only sticky when hot pressing, and will be bonded to the hot melt adhesive layer on this side of the adjacent other diaphragm, that is, the plastic adhesive layer. The middle support layer 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] In a preferred embodiment, the electrode sheet 12 includes a positive electrode sheet 121, and a negative electrode sheet 122 whose outer edge exceeds the positive electrode sheet 121, and the plastic support member 13 includes a positive electrode sheet band 134 corresponding to the positive electrode sheet 121, and a negative electrode sheet band 135 corresponding to the negative electrode sheet 122, and the positive electrode sheet band 134 is wider than the negative electrode sheet band 135, so as to save consumables while ensuring that the gap is filled tightly.

[0036] On the basis of the above, the plastic support member 13 may also be a strip-shaped structure continuously formed along the length direction of the diaphragm strip 11 to facilitate the production of the battery cell body and the processing of the plastic support member itself.

[0037] like Figure 6 As shown, in a preferred embodiment, the strip-type structure includes a strip body 6, which includes connection parts 61 arranged at intervals in sequence, and spacers 62 whose plastic volume exceeds that of adjacent connection parts 61. After being hot-pressed, the spacers 62 and the connection parts 61 are plastically deformed at the same time and diffuse to the surroundings to fill the edges of the protruding electrode sheets 12 between the folded diaphragms 11, and the diffusion space of the spacers 62 with large plastic volume exceeds that of the connection parts 61. In order to bear force evenly, the spacers 62 are formed between the folded diaphragms 11 to form a structure with upper and lower sides parallel to the folded diaphragms 11. When the upper and lower sides are pressed, they fit well with the folded diaphragms 11 and bear force evenly. Alternatively, the connection part 61 is formed into a flat strip between adjacent spacers 61.

[0038] like Figures 1 to 3 As shown, the method for manufacturing the anti-deformation folding battery cell of the present invention comprises placing a plastic support 13 along the edge of the folding diaphragm 11, and then arranging multiple electrode sheets 12 on both sides of the folding diaphragm 11 in a sequentially spaced and staggered manner, and folding the stacked sheets to obtain a basic battery cell body, which is hot-pressed to form a battery cell body 1. Alternatively, the basic battery cell body is hot-pressed in a high-temperature shaping process.

[0039] The working principle of the present invention is as follows:

[0040] The soft pack battery uses the Z-shaped stacking method to prepare the battery cell process, that is, when stacking, several positive plates, several negative plates and a separator are placed in a Z-shaped belt through the separator, and the negative plates and positive plates are placed in intervals on the left and right, and then stacked regularly. Among them, the number of positive plates and negative plates can have the following relationship: in the first case, it includes N positive plates and N+1 negative plates, where N is a non-zero natural number; in the second case, when making ultra-thin batteries, 1 positive plate and 1 negative plate are used to make the battery cell.

[0041] The Z-shaped lamination method is used to prepare battery cells, mainly because there is a space gap between the head and tail of the bare battery cell, which is easy to deform when it falls or is under pressure. In the present invention, a hot-melt adhesive tape with a PET film in the middle is pasted on the edges of both sides of the diaphragm tape along the length direction, and is directly stacked into the laminated body during lamination to fill the gap between the head and tail of the bare battery cell, fix the electrode sheet, and reduce the thermal shrinkage of the diaphragm during thermal shock. Among them, because the size of the positive electrode sheet < the negative electrode sheet < the diaphragm, the hot-melt adhesive tape corresponding to the positive electrode sheet is slightly wider than the hot-melt adhesive tape corresponding to the negative electrode sheet. Moreover, the electrode sheet is generally located in the middle of the diaphragm tape, so that there are gaps on both sides of the diaphragm tape, that is, the head and tail of the battery cell after molding. In order to prevent deformation, plastic support members are filled into these gaps.

[0042] After the lamination is completed, hot pressing is performed, or hot pressing can be performed in the subsequent high-temperature shaping section. Since the left and right sides of this lamination method will not be sealed, the different hot pressing methods will not affect the penetration of the electrolyte.

[0043] 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 foldable battery cell, characterized in that: The invention comprises a battery cell body (1) composed of a folded diaphragm (11) and an electrode sheet (12) matched with the folded diaphragm (11); a plastic support member (13) at least partially connected to the folded diaphragm (11) is provided between the folded diaphragms (11) on both sides of at least one electrode sheet (12) and protrudes from the edge of the electrode sheet (12); the plastic support member (13) deforms after being subjected to heat and pressure and diffuses to fill the folded diaphragm (11) and protrudes from the edge of the electrode sheet (12), so as to achieve compact filling and deformation resistance of the edge of the folded diaphragm (11); the plastic support member (13) is a strip-shaped structure continuously formed along the length direction of the diaphragm strip (11), so as to facilitate the manufacture of the battery cell body and the processing of the plastic support member itself; the strip The strip-shaped structure comprises a strip body (6), wherein 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); after being subjected to heat pressing, the spacers (62) and the connection parts (61) are simultaneously plastically deformed to diffuse to the surroundings to fill the edges of the protruding electrode sheets (12) between the folded diaphragms (11); 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 folded diaphragms (11) with upper and lower side surfaces parallel to the folded diaphragms (11); when the upper and lower side surfaces are subjected to pressure, they are well fitted with the folded diaphragms (11) and are subjected to uniform force; and the connection parts (61) are formed into a flat strip between adjacent spacers (62).

2. The anti-deformation foldable battery cell according to claim 1, characterized in that: The plastic support member (13) comprises at least two plastic adhesive layers (133) and a support layer (132) disposed between the plastic adhesive layers (133).

3. The anti-deformation foldable battery cell according to claim 2, characterized in that: The plastic bonding layer (133) 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 anti-deformation foldable battery cell according to claim 3, characterized in that: At least one layer of the plastic adhesive layer (133) is composed of cured hot melt adhesive.

5. The anti-deformation foldable battery cell according to claim 1, characterized in that: The electrode sheet (12) comprises a positive electrode sheet (121), and a negative electrode sheet (122) whose outer edge exceeds the positive electrode sheet (121); the plastic support member (13) comprises a positive electrode sheet band (134) corresponding to the positive electrode sheet (121), and a negative electrode sheet band (135) corresponding to the negative electrode sheet (122); the positive electrode sheet band (134) is wider than the negative electrode sheet band (135), so as to save consumables while ensuring that the gap is filled tightly.

6. The anti-deformation foldable battery cell according to claim 1, characterized in that: The plastic support member (13) has a thickness of 0.01 to 1 mm.

7. A method for manufacturing a deformation-resistant foldable battery cell according to any one of claims 1 to 5, characterized in that: The method comprises placing a plastic support member (13) along the edge of a folded diaphragm (11), and then arranging a plurality of electrode sheets (12) on both sides of the folded diaphragm (11) in a sequentially spaced and front-to-back staggered manner, folding and stacking the sheets to obtain a basic battery cell body, and hot pressing the basic battery cell body to form a battery cell body (1).

8. The method for manufacturing a deformation-resistant foldable battery cell according to claim 7, characterized in that: The basic cell body is hot pressed in a high temperature shaping process.

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