Battery cell, battery cell manufacturing method, and vehicle

Abstract

The invention discloses a battery monomer, a battery monomer manufacturing method and a vehicle, the battery monomer comprises pole pieces, diaphragms and isolation rubber, the pole pieces comprise current collectors and tabs, the tabs are connected to one ends of the current collectors along a first direction, the diaphragms and the pole pieces are alternately arranged and laminated, the diaphragms exceed the end parts of the current collectors in the first direction, and the isolation rubber is arranged between the current collectors and the tabs. The isolation glue adheres to and wraps the edge of the end portion of the current collector in the first direction, the isolation glue can isolate the diaphragm from the edge of the current collector in the first direction, the risk that burrs at the edge of the current collector pierce the diaphragm can be reduced, and the isolation glue does not occupy the area, coated with the active material, of the surface of the current collector. And an enough active material coating area is reserved for the current collector, so that the battery capacity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell, a method for manufacturing a battery cell, and a vehicle. Background Art

[0002] During the cutting or punching process of the pole piece, burrs will be generated on the edge. The burrs may pierce the diaphragm, thereby causing a safety hazard of internal short circuit or even explosion of the battery. The related technology adopts the method of coating the surface of the pole piece with insulating coating to reduce the risk of short circuit caused by contact between the positive and negative electrodes after the burrs pierce the diaphragm. However, the insulating coating occupies the material coating area on the surface of the pole piece, resulting in a reduction in the coating area of ​​the active material of the pole piece and a reduction in the battery capacity. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a battery cell that can reduce the risk of burrs piercing the diaphragm and improve the battery capacity.

[0004] The invention also provides a method for manufacturing a battery cell.

[0005] The present invention also provides a vehicle having the battery cell, and a vehicle having the battery cell manufactured by the battery cell manufacturing method.

[0006] A battery cell according to a first aspect of the present invention includes:

[0007] A pole piece, comprising a current collector and a pole ear, wherein the pole ear is connected to one end of the current collector along a first direction, the length of the pole ear along a second direction is less than the length of the current collector along the second direction, and the first direction is perpendicular to the second direction;

[0008] A diaphragm, arranged alternately with the pole pieces and stacked, the diaphragm extending beyond the end of the current collector in the first direction;

[0009] An isolation glue is used to bond and wrap at least the edge of the current collector in the first direction.

[0010] The battery cell according to the embodiment of the present invention has at least the following beneficial effects:

[0011] In the present invention, the isolation glue is bonded to and wrapped around the edge of the end of the current collector in the first direction. The isolation glue can isolate the diaphragm from the edge of the current collector in the first direction, which can reduce the risk of burrs at the edge of the current collector piercing the diaphragm. The isolation glue does not occupy the area on the surface of the current collector where the active material is coated, and a sufficient active material coating area is reserved for the current collector, thereby improving the battery capacity.

[0012] According to some embodiments of the present invention, part of the isolation adhesive is bonded to and wraps the edge of the end of the current collector in the first direction, and part of the isolation adhesive is bonded to the end surface of the current collector in the first direction.

[0013] According to some embodiments of the present invention, adjacent diaphragms and the current collectors located between the diaphragms define a glue containing groove, part of the isolation glue is located in the glue containing groove, and is bonded to the opposite side of the adjacent diaphragms and the end face of the current collector in the first direction, and part of the isolation glue is located between the diaphragm and the current collector, and is bonded to the opposite side of the diaphragm and the current collector.

[0014] According to some embodiments of the present invention, the pole ears of adjacent pole pieces are respectively located on two opposite sides of the battery cell, and two opposite edges of the current collector in the first direction are wrapped with the isolation glue.

[0015] According to some embodiments of the present invention, one of the two adjacent pole pieces is a first pole piece, and the other is a second pole piece, the first pole piece includes a first current collector, the second pole piece includes a second current collector, the end of the first current collector along the first direction exceeds the second current collector, the isolation glue is provided on the opposite sides of the two diaphragms adjacent to the second current collector and located on opposite sides of the second current collector, and the isolation glue exceeds the end of the first current collector along the first direction.

[0016] According to some embodiments of the present invention, the pole piece further includes an active material layer, which is coated on a surface of the current collector in a thickness direction and extends to an edge of the current collector in the first direction.

[0017] A battery cell manufacturing method according to a second aspect of an embodiment of the present invention includes:

[0018] A pole piece and a diaphragm are provided, wherein the pole piece comprises a current collector and a pole ear, wherein the pole ear is connected to one end of the current collector along a first direction, and a surface of the diaphragm in a thickness direction is coated with a glue layer;

[0019] Alternately arranging the pole pieces and the diaphragms, so that the pole pieces and the diaphragms are stacked and formed into a stack, wherein the glue layer is provided on the opposite side of at least some of the adjacent diaphragms in the stack, and the glue layer is located between the current collector and the diaphragm, and at least one location outside the end of the current collector along the first direction;

[0020] Hot pressing the stacked body to heat and flow the adhesive layer, wherein the adhesive layer flows toward the end of the current collector along the first direction and wraps the edge of the end of the current collector in the first direction;

[0021] The adhesive layer is cured to form an isolation adhesive, and the isolation adhesive is bonded to the edge of the current collector in the first direction.

[0022] The battery cell manufacturing method according to the embodiment of the present invention has at least the following beneficial effects:

[0023] In the present invention, a glue layer is pre-arranged on the surface of the diaphragm. The glue layer flows after hot pressing and wraps the edge of the current collector. After curing, an isolation glue is formed. The isolation glue can isolate the diaphragm from the edge of the current collector in the first direction, and can reduce the risk of burrs at the edge of the current collector piercing the diaphragm. The isolation glue does not occupy the area on the surface of the current collector where the active material is coated, and a sufficient active material coating area is reserved for the current collector, thereby improving the battery capacity.

[0024] According to some embodiments of the present invention, one of the surfaces in the thickness direction of the diaphragm is provided with the glue layer; the pole piece includes a first pole piece and a second pole piece, the first pole piece includes a first current collector, the second pole piece includes a second current collector, and the length of the first current collector is greater than the length of the second current collector;

[0025] When forming the stack, the first pole pieces and the second pole pieces are arranged alternately, the diaphragm is located between the adjacent first pole pieces and the second pole pieces, the side of the diaphragm provided with the adhesive layer faces the second pole piece adjacent to the diaphragm, the end of the first current collector along the first direction exceeds the second current collector, and the adhesive layer exceeds the end of the first current collector along the first direction.

[0026] According to some embodiments of the present invention, before performing the hot pressing step, the thickness of the adhesive layer gradually increases in a direction close to an end of the diaphragm in the first direction;

[0027] and / or, before the hot pressing step, the length difference between the first current collector and the second current collector is L, the glue layer has a slope portion and a platform portion, the platform portion is located on a side of the slope portion facing the edge of the diaphragm along the first direction, the thickness of the slope portion gradually decreases in a direction away from the platform portion, and the length of the platform portion along the first direction is b, wherein: 0<2b-L<1 mm;

[0028] and / or, before the hot pressing step, the adhesive layer has a slope portion and a platform portion, the platform portion is located on a side of the slope portion facing an edge of the diaphragm along the first direction, the thickness of the slope portion gradually decreases away from the platform portion, and the length of the slope portion along the first direction is c, 1.5 mm ≤ c ≤ 3 mm;

[0029] And / or, the surface of the current collector in the thickness direction is coated with an active material layer, the thickness of the active material layer is d, and before the hot pressing step, the maximum thickness of the glue layer is a, a<d.

[0030] The vehicle according to the third aspect of the present invention comprises the battery cell according to the first aspect and / or the battery cell manufactured in the second aspect.

[0031] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0033] Figure 1 A schematic diagram of an embodiment of a battery cell in the present invention;

[0034] Figure 2 is a schematic diagram of another embodiment of a battery cell in the present invention;

[0035] Figure 3 It is a schematic diagram of the position coordination of the pole piece and the isolation glue and the pole piece;

[0036] Figure 4 Schematic diagram of the isolation glue wrapped around the edge of the current collector in different states;

[0037] Figure 5 Schematic diagram of the position coordination of the glue layer before hot pressing and the glue layer on the diaphragm with the diaphragm and the current collector after hot pressing;

[0038] Figure 6 Schematic diagram of the position of the glue layer in different embodiments;

[0039] Figure 7 Schematic diagram of the lamination of the pole piece and the diaphragm;

[0040] Figure 8 is a schematic diagram of an embodiment of an isolation membrane;

[0041] Fig. 9 A cross-sectional view of an embodiment of a diaphragm.

[0042] Reference numerals:

[0043] The pole piece 100, the current collector 110, the first current collector 110a, the second current collector 110b, the pole ear 120, the active material layer 130; the diaphragm 200, the first diaphragm 200a, the second diaphragm 200b, the glue layer 210, the slope portion 211, the platform portion 212; the isolation glue 300; and the glue containing groove 400. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0045] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0046] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If described, "the second" is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0047] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0048] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0049] A battery cell is provided in an embodiment of the present invention, and the battery cell can be charged and discharged, that is, the battery cell can continue to be used by activating the active material by charging after discharge; the battery cell can be constructed as a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a nickel-hydrogen battery, a lead-acid battery, etc.; the battery cell can also be constructed as a square shell battery, a blade battery, etc.

[0050] Reference Figure 1 and Figure 2The battery cell includes a pole piece 100 and a diaphragm 200, which are alternately arranged and stacked, that is, the pole piece 100 and the diaphragm 200 are stacked in the thickness direction, and a diaphragm 200 is provided between adjacent pole pieces 100, and the pole piece 100 is located between adjacent diaphragms 200. The diaphragm 200 can be set as a solid electrolyte, which plays a role in isolating the positive and negative electrodes and providing active ions (such as lithium ions) of adjacent pole pieces 100 to be embedded and removed back and forth between the positive and negative electrodes. The diaphragm 200 can be a single-layer film or a multi-layer composite film made of glass fiber, polyethylene, polypropylene and other materials.

[0051] Reference Figure 3 The pole piece 100 includes a current collector 110 and a pole ear 120. The surface of the current collector 110 in the thickness direction is used to coat the active material. The current collector 110 can be made of a metal foil or a composite current collector 110. For example, the positive electrode current collector 110 using a metal foil can be made of copper, stainless steel, nickel, titanium and other materials; the composite current collector 110 can be formed by forming a metal material such as aluminum, nickel, titanium, silver on a substrate of a polymer material such as polypropylene, polystyrene, polyethylene, etc.; the whole machine current collector 110 using a metal foil can be made of aluminum, stainless steel, nickel, titanium and other materials with silver plated on the surface.

[0052] The pole tab 120 is connected to one end of the current collector 110 along the first direction, and is used to lead out the positive and negative electrodes of the battery. The length of the pole tab 120 along the second direction is less than the length of the current collector 110 along the second direction, and the first direction is perpendicular to the second direction; in some embodiments, the first direction is the length direction of the pole piece 120, and the second direction is the width direction of the pole piece 120. The pole tab 120 is connected to the end of the length direction of the current collector 110, and the width of the pole tab 120 is less than the width of the current collector 110. In some embodiments, the pole tab 120 is formed by cutting the pole piece 100. During the cutting process of the pole piece 100, burrs are easily formed on the edge of the current collector 110, and the burrs are easy to pierce the diaphragm 200, resulting in direct contact between the positive and negative electrodes and causing internal short circuits in the battery.

[0053] In one embodiment of the present invention, Figure 1 and Figure 2, the length of the diaphragm 200 in the first direction is greater than the length of the current collector 110 in the first direction, the diaphragm 200 exceeds the end of the current collector 110 in the first direction, and the battery cell further includes an isolating glue 300, the isolating glue 300 at least adheres to and wraps the edge of the end of the current collector 110 in the first direction, and fixes the isolating glue 300 between the diaphragm 200 and the edge of the current collector 110. It can be understood that the isolating glue 300 can isolate the diaphragm 200 from the edge of the current collector 110 in the first direction, so as to reduce the risk of burrs at the edge of the current collector 110 piercing the diaphragm 200, and the isolating glue 300 does not occupy the area on the surface of the current collector 110 where the active material is coated, and a sufficient active material coating area is reserved for the current collector 110, thereby improving the battery capacity.

[0054] It should be noted that the above-mentioned “edge of the end of the current collector 110 along the first direction” refers to the corner area of ​​the end of the current collector 110 in the first direction (such as Figure 4 As shown in Figure (r) in the figure); the burrs located in the corner area of ​​the end of the current collector 110 are closer to the diaphragm 200 and are easier to pierce the diaphragm 200. Wrapping the edge of the end of the current collector 110 with the isolation glue 300 can effectively isolate the burrs from the diaphragm 200 and reduce the risk of the burrs piercing the diaphragm 200.

[0055] In some embodiments, the isolation glue 300 may also be bonded to other areas of the end of the current collector 110, such as Figure 4 In Figures (m), (n), and (h), part of the isolation glue 300 is bonded to and wrapped around the edge of the end of the current collector 110 in the first direction, and part of the isolation glue 300 is bonded to the end surface of the end of the current collector 110, so that the isolation glue 300 can wrap around the burrs at various locations on the edge of the current collector 110, and the isolation glue 300 can more thoroughly isolate the burrs from the diaphragm 200.

[0056] In one embodiment, the burrs on the edge of the current collector 110 are wrapped by the isolation glue 300 by hot pressing the preset glue layer 210 on the diaphragm 200, specifically: Figure 5 As shown in Figure (x), a glue layer 210 is pre-arranged on the surface of the diaphragm 200 in the thickness direction. The glue layer 210 has the characteristics of being solid at room temperature and being able to melt and flow during hot pressing. After the diaphragm 200 and the pole piece 100 are stacked, the diaphragm 200 and the pole piece 100 are hot pressed. The glue layer 210 is heated to be in a highly viscous and flowing state, and wraps the burrs (such as the burrs on the edge of the current collector 110) during the flow process. Figure 5(y) in the figure), the burrs are kept away from the diaphragm 200, and the high-viscosity and flowing glue layer 210 prevents the burrs from moving toward the diaphragm 200 during the hot pressing process, thereby reducing the risk of the diaphragm 200 piercing the diaphragm 200; after the hot pressing is completed, the glue layer 210 is cured, and the cured glue layer 210 forms a solid isolation glue 300, which is bonded to the opposite side of the adjacent diaphragm 200 and the edge of the current collector 110.

[0057] The isolation glue 300 can be made of materials such as polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), etc. The isolation glue 300 has the properties of bonding and porous structure. On the one hand, the isolation glue 300 can be fixed between the edge of the diaphragm 200 and the current collector 110. On the other hand, the isolation glue 300 allows the electrolyte to pass through. The active material coated on the area of ​​the current collector 110 wrapped by the isolation glue 300 is not affected by the isolation glue 300 and can perform ion exchange normally. The active material coated on any area of ​​the surface of the current collector 110 can participate in the charge and discharge reaction of the battery, which helps to improve the battery capacity and energy density.

[0058] In such Figure 3 In the illustrated embodiment, the pole piece 100 further includes an active material layer 130, which is coated on the surface of the current collector 110 in the thickness direction and extends to the edge of the current collector 110 in the first direction, so that the surface of the current collector 110 in the thickness direction can be fully coated with active material to maximize the use of the coating space of the current collector 110 and improve the battery capacity.

[0059] As an example, the positive electrode active material layer 130 can be made of one or more materials such as lithium cobalt oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, and lithium nickel oxide. The negative electrode active material layer 130 can be made of carbon materials such as graphite, soft carbon, hard carbon, or silicon-based materials, or other metal composite oxides (such as lithium titanate).

[0060] It can be understood that after the active material is coated on the surface of the pole piece 100, the pole ear 120 is formed by cutting, and the active material layer 130 extends to the edge of the current collector 110 in the first direction. After the pole piece 100 is cut, burrs remain on the end of the pole piece 100 where the pole ear 120 is set, that is, the burrs on the pole piece 100 are mainly located at the edge of the current collector 110 along the first direction. After the glue layer 210 on the diaphragm 200 is hot-pressed, it flows to the edge of the current collector 110 and wraps the burrs on the edge of the current collector 110 and the active material near the end of the current collector 110. Therefore, the isolation glue 300 can isolate the burrs from the diaphragm 200, reduce the risk of the burrs piercing the diaphragm 200, and can provide ion exchange to increase the battery capacity.

[0061] In addition, adjacent pole sheets 100 are configured to have different polarities, that is, one of the adjacent pole sheets 100 is a positive pole sheet and the other is a negative pole sheet, the positive pole ears 120 of all the positive pole sheets are located on the same side of the positive pole sheets, and the negative pole ears 120 of all the negative pole sheets are located on the same side of the negative pole sheets. In one embodiment, the pole ears 120 of adjacent pole sheets 100 are located on the same side of the battery cell, that is, the positive pole ear 120 and the negative pole ear 120 are located on the same side of the battery cell, then the isolation glue 300 can be arranged on one side of the current collector 110 along the first direction, and arranged on the same side as the positive pole ear 120 and the negative pole ear 120. In this case, the positive pole ear 120 and the negative pole ear 120 are staggered along the second direction, and the second direction is perpendicular to the first direction and the thickness direction of the pole sheet 100. Or, in another embodiment, as Figure 5 As shown, the pole ears 120 of adjacent pole pieces 100 are respectively located on opposite sides of the battery cell, that is, the positive pole ear 120 and the negative pole ear 120 are respectively located on opposite sides of the battery cell, then an isolation glue 300 can be provided at both opposite ends of the current collector 110 along the first direction. In this case, the positive pole ear 120 and the negative pole ear 120 are respectively arranged at both ends of the long side of the battery cell, so that the battery cell is suitable for being constructed as a blade battery.

[0062] like Figure 5 As shown, in the case where the pole ears 120 of adjacent pole pieces 100 are located on opposite sides of the battery cell, the two edges of the current collector 110 in the first direction are wrapped with the isolation glue 300, and the isolation glue 300 at each edge extends to the edge of the current collector 110 along the second direction, so that the isolation glue 300 wraps the edge of the current collector 110 more thoroughly. Figure 3 As shown, one end of the pole tab 120 close to the current collector 110 is the root of the pole tab 120 , and the root of the pole tab 120 is also covered with an isolation glue 300 , which can reduce the risk of short circuit caused by abnormal deformation of the pole tab 120 and contact with the current collector 110 .

[0063] Since the pole piece 100 is located between adjacent diaphragms 200 and the diaphragm 200 exceeds the end of the current collector 110 in the first direction, the adjacent diaphragms 200 and the current collector 110 located between the adjacent diaphragms 200 define a glue containing groove 400 on the outer side of the end of the current collector 110 along the first direction. The glue containing groove 400 can accommodate the isolation glue 300, provide a flow space for the glue layer 210, prevent the glue layer 210 from overflowing during the hot pressing process, and increase the bonding area between the isolation glue 300 and the current collector 110 and between the isolation glue 300 and the diaphragm 200, so that the isolation glue 300 can wrap the end of the current collector 110 more thoroughly, further reducing the risk of burrs piercing the diaphragm 200.

[0064] In one embodiment, part of the isolation glue 300 is located in the glue containing groove 400, and the isolation glue 300 is bonded to the opposite side of the adjacent diaphragm 200 and the end face of the current collector 110 in the first direction. Part of the isolation glue 300 is located between the diaphragm 200 and the current collector 110, and is bonded to the opposite side of the current collector 110 and the diaphragm 200, so that the corner transition position between the end face of the end of the current collector 110 and the surface in the thickness direction, and the end face of the current collector 110 are all wrapped by the isolation glue 300, the isolation glue 300 isolates the burrs more thoroughly, and because the isolation glue 300 is also bonded to the opposite sides of the diaphragm 200, the bonding between the isolation glue 300 and the diaphragm 200 is more stable.

[0065] like Figure 1 In the illustrated embodiment, the edge of each current collector 110 is wrapped with an isolating glue 300, that is, the isolating glue 300 is bonded to both opposite sides of the diaphragm 200 in the thickness direction, wherein the isolating glue 300 on one side is bonded to the edge of the current collector 110 of the positive electrode sheet, and the isolating glue 300 on the other side is bonded to the edge of the current collector 110 of the negative electrode sheet. The burrs on the edge of the current collector 110 of each electrode sheet 100 are wrapped with the isolating glue 300 and isolated from the diaphragm 200, reducing the risk of the burrs piercing the diaphragm 200 and causing a battery short circuit.

[0066] like Figure 2 In the illustrated embodiment, the current collectors 110 of adjacent pole pieces 100 are arranged to have different lengths, and the isolation glue 300 is bonded to the edge of the current collector 110 with a shorter length to isolate the burrs on the edge of the current collector 110 in the same layer and reduce the risk of the burrs on the current collectors 110 of adjacent layers piercing the diaphragm 200. Specifically, one of the two adjacent pole pieces 100 is a first pole piece, and the other is a second pole piece. The current collector 110 of the first pole piece is a first current collector 110a, and the current collector 110 of the second pole piece is a second current collector 110b. The length of the first current collector 110a along the first direction is greater than the length of the second current collector 110b along the first direction, and the end of the first current collector 110a along the first direction exceeds the end of the second current collector 110b. An isolation glue 300 is provided on the opposite sides of the two diaphragms 200 adjacent to the second current collector 110b and located on opposite sides of the second current collector 110b, and the isolation glue 300 exceeds the end of the first current collector 110a along the first direction, that is, the isolation glue 300 is only located at the two opposite ends of the second current collector 110b along the first direction, and the isolation glue 300 is not provided at the two opposite ends of the first current collector 110a along the first direction, which can reduce the material consumption of the isolation glue 300.

[0067] like Figure 2As shown in the figure, the outermost diaphragm 200 of the battery cell is defined as the first diaphragm 200a, and the other diaphragms 200 are defined as the second diaphragms 200b. The two opposite sides of the second diaphragm 200b in the thickness direction are respectively adjacent to the first current collector 110a and the second current collector 110b. The burrs on the edge of the second current collector 110b are wrapped by the isolation glue 300. The isolation glue 300 isolates the burrs from the second diaphragm 200b, which can reduce the risk of the second diaphragm 200b being pierced by the burrs on the edge of the second current collector 110b. Since the first current collector 110a exceeds the second The end of the current collector 110b, and the isolation glue 300 exceeds the end of the first current collector 110a, the end of the first current collector 110a corresponds to the isolation glue 300 in the thickness direction, that is, the ends of the adjacent first current collectors 110a and the second current collectors 110b are staggered along the first direction, even if the burrs on the edge of the first current collector 110a pierce the second diaphragm 200b, under the isolation effect of the isolation glue 300, the burrs on the edge of the first current collector 110a will not contact the second current collector 110b, thereby reducing the risk of internal short circuit of the battery.

[0068] Furthermore, in one embodiment, the first electrode sheet is configured as a negative electrode sheet, and the second electrode sheet is configured as a positive electrode sheet, that is, the length of the negative electrode current collector 110 is greater than the length of the positive electrode current collector 110, and the length of the active material layer 130 on the negative electrode current collector 110 is greater than the length of the active material layer 130 on the positive electrode current collector 110, so as to ensure that the negative electrode active material layer 130 has sufficient space to embed active ions released from the positive electrode, such as lithium ions, to avoid lithium plating, and improve the performance and cycle life of the battery.

[0069] In addition, the pole piece 100 located on the outermost side of the battery cell is the first pole piece, that is, the pole pieces 100 at the top and bottom of the battery cell are both negative pole pieces, so that the positive electrode collector 110 is completely wrapped by the negative electrode collector 110, so as to fully utilize the active material on the surface of the positive electrode collector 110 for charging and discharging, and improve the charging and discharging performance of the battery. The outermost layer of the battery cell is the diaphragm 200, that is, the top and bottom layers of the battery cell are both diaphragms 200, so as to isolate the pole piece 100 from external components (such as aluminum-plastic film, shell, etc.).

[0070] In the present invention, the pole piece 100 and the diaphragm 200 are stacked to form a laminated electrode assembly. The laminated battery cell can eliminate the R angle, reduce the internal resistance, increase the power, and has a high energy density and a long cycle life.

[0071] In some embodiments, the battery cell may further include a shell, the shell including an end cap and a shell, the shell is provided with an opening, and the end cap closes the opening to form a closed space inside the shell for accommodating the pole piece 100, the diaphragm 200, and electrolyte and other substances. The battery cell can also be constructed into a battery pack by being placed in a box.

[0072] The present invention also provides a method for manufacturing a battery cell, which specifically comprises the following steps:

[0073] The pole piece 100 and the diaphragm 200 are provided, the pole piece 100 includes a current collector 110 and a pole ear 120, the pole ear 120 is connected to one end of the current collector 110 along the first direction, and the surface of the diaphragm 200 in the thickness direction is coated with a glue layer 210; the pole piece 100 and the diaphragm 200 are alternately arranged so that the pole piece 100 and the diaphragm 200 are stacked and arranged to form a stack, and at least part of the adjacent diaphragms 200 in the stack are provided with a glue layer 210 on the side facing each other, and the glue layer 210 is located between the current collector 110 and the diaphragm 200 and on the outer side of the end of the current collector 110 along the first direction. at least one place on the side; the stack is hot-pressed, the adhesive layer 210 melts after being heated and presents a high-viscosity flow state, the adhesive layer 210 flows toward the end of the current collector 110 along the first direction and wraps the edge of the end of the current collector 110 in the first direction, so that the burrs at the edge of the current collector 110 are wrapped by the adhesive layer 210; finally, the adhesive layer 210 is cured, and the cured adhesive layer 210 becomes an isolation adhesive 300, and the isolation adhesive 300 is bonded to the edge of the current collector 110 in the first direction. The curing method of the adhesive layer 210 is not limited to moisture curing, UV curing, room temperature curing, etc.

[0074] In such Figure 6 In the embodiment shown in Figure (f), before the stack is hot-pressed, the glue layer 210 is located between the current collector 110 and the diaphragm 200. During the hot-pressing process of the stack, the glue layer 210 is melted by the heat and can flow. The glue layer 210 is pressed to flow toward the end of the current collector 110 in the first direction. Part of the glue layer 210 flows to the outside of the end of the current collector 110 in the first direction, and the glue layer 210 wraps the edge of the end of the current collector 110 in the first direction. After curing, the glue layer 210 adheres to the edge of the current collector 110 in the first direction to form an isolation glue 300.

[0075] In such Figure 6 In the embodiment shown in Figure (j), before the stack is hot-pressed, the glue layer 210 is located on the outside of the end of the current collector 110 along the first direction. During the hot-pressing process of the stack, the glue layer 210 is melted by the heat and can flow. The glue layer 210 is pressed to flow toward the end of the current collector 110 in the first direction. Part of the glue layer 210 penetrates between the diaphragm 200 and the current collector 110, so that the glue layer 210 wraps the edge of the end of the current collector 110 in the first direction; after curing, the glue layer 210 adheres to the edge of the current collector 110 in the first direction to form an isolation glue 300.

[0076] In such Figure 5In the embodiment shown in Figure (x), before the stack is hot-pressed, a glue layer 210 is provided on the outer side of the end of the current collector 110 along the first direction, and between the current collector 110 and the diaphragm 200. During the hot-pressing process of the stack, the colloid is melted by the heat and can flow. The glue layer 210 located between the current collector 110 and the diaphragm 200 flows toward the outer side of the end of the current collector 110, and the glue layer 210 located on the outer side of the end of the current collector 110 flows toward the end face of the current collector 110, so that the glue layer 210 can wrap the edge of the end of the current collector 110 in the first direction to completely isolate the burrs on the edge of the current collector 110 from the diaphragm 200.

[0077] Thus, the isolation glue 300 formed by the glue layer 210 can isolate the diaphragm 200 from the edge of the end of the current collector 110 in the first direction, thereby reducing the risk of burrs at the edge of the current collector 110 piercing the diaphragm 200, and the isolation glue 300 does not occupy the area on the surface of the current collector 110 where the active material is coated, and reserves sufficient active material coating area for the current collector 110, which can improve the battery capacity.

[0078] It should be noted that during the cutting process of the pole piece 100, burrs extending in different directions are randomly generated on the edge of the current collector 110, and for the burrs extending in the thickness direction of the current collector 110, it is very easy to pierce the diaphragm 200 adjacent to the current collector 110. The adhesive layer 210 in the present invention is in a highly viscous flow state during the hot pressing process. On the one hand, since the adhesive layer 210 is coated on the surface of the diaphragm 200, the adhesive layer 210 blocks the burrs from moving toward the diaphragm 200 due to hot pressing during the flow process. On the other hand, the flowing adhesive layer 210 takes away the burrs and keeps the burrs away from the diaphragm 200, or the adhesive layer 210 changes the extension direction of the burrs during the flow process to prevent the burrs from directly piercing the diaphragm 200 in the thickness direction, thereby reducing the risk of the burrs piercing the diaphragm 200.

[0079] In addition, in the stack, the two diaphragms 200 adjacent to the pole piece 100 are both provided with a glue layer 210 on the opposite sides. When the stack is hot pressed, the glue layers 210 on the two diaphragms 200 have a tendency to flow toward each other and toward the end of the current collector 110. If there are burrs extending along the thickness direction at the end of the current collector 110, the burrs are pressed by the two layers of glue layers 210 and are taken away from the diaphragm 200, or the extension direction is changed, and the diaphragm 200 cannot be punctured, thereby reducing the risk of internal short circuit in the battery.

[0080] It should be noted that the above-mentioned “at least some of the adjacent diaphragms 200 have a glue layer 210 on the side facing each other” means that a glue layer 210 is provided on the side facing each two adjacent diaphragms 200, that is, the edge of each current collector 110 along the first direction is wrapped by the isolation glue 300; or, a glue layer 210 is provided on the side facing each other of some adjacent diaphragms 200, and a glue layer 210 is not provided on the side facing each other of some adjacent diaphragms 200, that is, the edges of some current collectors 110 along the first direction are wrapped by the isolation glue 300, and the edges of some current collectors 110 along the first direction are not wrapped by the isolation glue 300.

[0081] In one embodiment, if Figure 1 As shown, a glue layer 210 is provided on opposite sides of the diaphragm 200 in the thickness direction, one of the adjacent pole pieces 100 is a first pole piece, and the other is a second pole piece, the diaphragm 200 is located between the first pole piece and the second pole piece, and in the stack, the edge of each current collector 110 is wrapped with an isolation glue 300, wherein the glue layer 210 on one side is bonded to the edge of the current collector 110 of the first pole piece after hot pressing, and the glue layer 210 on the other side is bonded to the edge of the current collector 110 of the second pole piece after hot pressing, and the burrs on the edge of the current collector 110 of each pole piece 100 are wrapped by the isolation glue 300 and isolated from the diaphragm 200.

[0082] In another embodiment, if Figure 2 As shown, one of the surfaces of the diaphragm 200 in the thickness direction is provided with a glue layer 210, one of the adjacent pole pieces 100 is a first pole piece, and the other is a second pole piece, the first pole piece includes a first current collector 110a, and the second pole piece includes a second current collector 110b, and the length of the first current collector 110a is greater than the length of the second current collector 110b; when forming a stack, the first pole pieces and the second pole pieces are arranged alternately, the diaphragm 200 is located between the adjacent first pole piece and the second pole piece, and the side of the diaphragm 200 provided with the glue layer 210 faces the second pole piece adjacent to the diaphragm 200, the end of the first current collector 110a along the first direction exceeds the second current collector 110b, and the glue layer 210 exceeds the end of the first current collector 110a along the first direction.

[0083] like Figure 2As shown, the two opposite sides of the second diaphragm 200b in the thickness direction are respectively adjacent to the first current collector 110a and the second current collector 110b. During hot pressing, a glue layer 210 is provided on the side of the second diaphragm 200b facing the second current collector 110b. The glue layer 210 wraps the burrs on the edge of the second current collector 110b. The glue layer 210 isolates the burrs on the edge of the second current collector 110b from the second diaphragm 200b, which can reduce the risk of the second diaphragm 200b being pierced by the burrs on the edge of the second current collector 110b. In addition Since the first current collector 110a exceeds the end of the second current collector 110b, and the isolation glue 300 exceeds the end of the first current collector 110a, the ends of the adjacent first current collectors 110a and the second current collectors 110b are staggered along the first direction. Even if the burrs on the edge of the first current collector 110a pierce the second diaphragm 200b, under the isolation effect of the isolation glue 300, the burrs on the edge of the first current collector 110a will not contact the second current collector 110b, thereby reducing the risk of internal short circuit of the battery.

[0084] In addition, in the process of setting the electrode 100, the first electrode is set as the negative electrode, and the second electrode is set as the positive electrode, that is, the length of the negative electrode collector 110 is greater than the length of the positive electrode collector 110, and the length of the active material layer 130 on the negative electrode collector 110 is greater than the length of the active material layer 130 on the positive electrode collector 110, so as to ensure that the negative electrode active material layer 130 has sufficient space to embed the active ions released from the positive electrode, such as lithium ions, to avoid lithium plating, and improve the performance and cycle life of the battery.

[0085] In addition, during the formation of the stack, the pole piece 100 located on the outermost side of the battery cell is set as the first pole piece, that is, the pole pieces 100 of the uppermost and lowermost layers of the battery cell are both negative pole pieces, so that the positive electrode collector 110 is completely wrapped by the negative electrode collector 110, so as to fully utilize the active material on the surface of the positive electrode collector 110 for charging and discharging, thereby improving the charging and discharging performance of the battery. In one embodiment, during the formation of the stack, the separator 200 is set at the outermost layer of the stack, that is, the uppermost and lowermost layers of the stack are both separators 200.

[0086] like Figure 7 and Figure 8 As shown, each layer of the separator 200 in the battery cell is formed by folding a whole separator in a "Z"-shaped stacking manner. The separator is in a roll shape, and a glue layer 210 is provided at the edge of the separator in the width direction. The width direction of the separator corresponds to the first direction of the current collector 110. The separator is folded along the second direction. Each layer of the separator forms a separator 200, and the positive electrode sheet and the negative electrode sheet are correspondingly compounded on both sides of the separator 200.

[0087] like Fig. 9As shown, in one embodiment, before the hot pressing step, the thickness of the glue layer 210 in the stack gradually increases along the direction close to the end of the diaphragm 200 in the first direction, so that the glue layer 210 located between the diaphragm 200 and the current collector 110 is thinner or less. On the one hand, it is convenient for the active material coated on the edge of the current collector 110 to perform ion exchange, thereby improving the capacity and ion exchange efficiency of the battery cell. On the other hand, it is prevented that during the hot pressing process, the glue layer 210 between the diaphragm 200 and the current collector 110 flows excessively to the outside of the end of the current collector 110 and causes glue overflow.

[0088] In one embodiment, when the pole piece 100 is provided, the length difference between the first current collector 110a and the second current collector 110b is set to be L. Figure 2 As shown, the length of the first current collector 110a along the first direction is greater than the length of the second current collector 110b along the first direction, one side of the first current collector 110a along the first direction exceeds the second current collector 110b by a length of L / 2, and the other side of the first current collector 110a along the first direction exceeds the second current collector 110b by a length of L / 2. In the laminate, the glue layer 210 has a slope portion 211 and a platform portion 212, and the platform portion 212 is located at one side of the slope portion 211 facing the edge of the diaphragm 200 along the first direction. On the side, the thickness of the slope portion 211 gradually decreases in the direction away from the platform portion 212, and the length of the platform portion 212 along the first direction is b, 0<2b-L<1mm, so as to limit the length of the platform portion 212 and avoid the platform portion 212 being too long and causing excessive overflow of the adhesive layer 210 during the hot pressing process; specifically, 2b-L can be set to 0.9mm, 0.8mm, 0.7mm, 0.75mm, 0.6mm, 0.5mm, 0.4mm, 0.3mm, 0.2mm, 0.1mm, etc.

[0089] In one embodiment, in the stack, the glue layer 210 has a slope portion 211 and a platform portion 212, the platform portion 212 is located on the side of the edge of the slope portion 211 facing the diaphragm 200 along the first direction, the thickness of the slope portion 211 gradually decreases along the direction away from the platform portion 212, and the length of the slope portion 211 along the first direction is c, 1.5mm≤c≤3mm, so as to avoid excessive flow of the glue layer 210 between the diaphragm 200 and the current collector 110 to the outside of the end of the current collector 110 and overflow due to the length of the slope portion 211 being too long, and to ensure that the glue layer 210 between the diaphragm 200 and the current collector 110 can wrap the edge of the end of the current collector 110 by flowing to isolate the burrs from the diaphragm 200. Specifically, c can be set to 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.85mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.5mm, 2.7mm, 2.8mm, 3mm, etc.

[0090] In one embodiment, the surface of the current collector 110 in the thickness direction is coated with an active material layer 130, and the thickness of the active material layer 130 is d. Before the hot pressing step, the maximum thickness of the glue layer 210 is a, and a<d. The thickness of the glue layer 210 is set to be no greater than the thickness of the active material layer 130, which can prevent the glue layer 210 from excessively flowing and overflowing during the hot pressing process due to the glue layer 210 being too thick.

[0091] It can be understood that after hot pressing, the diaphragm 200 and the pole piece 100 as well as the adjacent diaphragms 200 are bonded to each other to form an electrode assembly. In one embodiment, the manufacturing method of the battery cell also includes placing the electrode assembly into the outer shell and performing hot sealing, injecting electrolyte, and chemical formation.

[0092] The present invention also provides a vehicle, the vehicle includes the above-mentioned battery cell, and / or the battery cell manufactured by the above-mentioned battery cell manufacturing method, the battery cell supplies power to the vehicle, the battery cell can be directly installed in the vehicle, or it can be placed in a box to form a battery pack, and then the battery pack is installed in the vehicle. That is, the box can be used as a part of the vehicle chassis structure, or the box can be installed on the vehicle chassis structure.

[0093] The vehicle referred to in the present invention may be a private car, such as a sedan, SUV, MPV or pickup truck, etc. The vehicle may also be an operating vehicle, such as a van, bus or truck, etc. When the vehicle is a new energy vehicle, it may be a hybrid vehicle or a pure electric vehicle.

[0094] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A battery cell, characterized in that: include: A pole piece, comprising a current collector and a pole ear, wherein the pole ear is connected to one end of the current collector along a first direction, the length of the pole ear along a second direction is less than the length of the current collector along the second direction, and the first direction is perpendicular to the second direction; A diaphragm, arranged alternately with the pole pieces and stacked, the diaphragm extending beyond the end of the current collector in the first direction; An isolation glue is used to bond and wrap at least the edge of the end of the current collector in the first direction.

2. The battery cell according to claim 1, characterized in that: Part of the isolation adhesive is bonded to and wraps the edge of the end of the current collector in the first direction, and part of the isolation adhesive is bonded to the end surface of the current collector in the first direction.

3. The battery cell according to claim 2, characterized in that: The adjacent diaphragms and the current collectors located between the diaphragms define a glue containing groove, part of the isolation glue is located in the glue containing groove, and is bonded to the opposite side of the adjacent diaphragms and the end face of the current collector in the first direction, and part of the isolation glue is located between the diaphragm and the current collector, and is bonded to the opposite side of the diaphragm and the current collector.

4. The battery cell according to claim 1, characterized in that: The pole ears of the adjacent pole pieces are respectively located on two opposite sides of the battery cell, and the edges of the two opposite ends of the current collector in the first direction are both wrapped with the isolation glue.

5. The battery cell according to any one of claims 1 to 4, characterized in that: One of the two adjacent pole pieces is a first pole piece, and the other is a second pole piece. The first pole piece includes a first current collector, and the second pole piece includes a second current collector. The end of the first current collector along the first direction exceeds the second current collector. The isolation glue is provided on the opposite sides of the two diaphragms adjacent to the second current collector and located on opposite sides of the second current collector, and the isolation glue exceeds the end of the first current collector along the first direction.

6. The battery cell according to claim 1, characterized in that: The pole piece further includes an active material layer, which is coated on the surface of the current collector in the thickness direction and extends to the edge of the current collector in the first direction.

7. A method for manufacturing a battery cell, characterized in that: include: A pole piece and a diaphragm are provided, wherein the pole piece comprises a current collector and a pole ear, wherein the pole ear is connected to one end of the current collector along a first direction, and a surface of the diaphragm in a thickness direction is coated with a glue layer; Alternately arranging the pole pieces and the diaphragms, so that the pole pieces and the diaphragms are stacked and formed into a stack, wherein the glue layer is provided on the opposite side of at least some of the adjacent diaphragms in the stack, and the glue layer is located between the current collector and the diaphragm, and at least one location outside the end of the current collector along the first direction; Hot pressing the stacked body to heat and flow the adhesive layer, wherein the adhesive layer flows toward the end of the current collector along the first direction and wraps the edge of the end of the current collector in the first direction; The adhesive layer is cured to form an isolation adhesive, and the isolation adhesive is bonded to the edge of the end of the current collector in the first direction.

8. The method for manufacturing a battery cell according to claim 7, characterized in that: One of the surfaces in the thickness direction of the diaphragm is provided with the glue layer; the pole piece comprises a first pole piece and a second pole piece, the first pole piece comprises a first current collector, the second pole piece comprises a second current collector, and the length of the first current collector is greater than the length of the second current collector; When forming the stack, the first pole pieces and the second pole pieces are arranged alternately, the diaphragm is located between the adjacent first pole pieces and the second pole pieces, the side of the diaphragm provided with the adhesive layer faces the second pole piece adjacent to the diaphragm, the end of the first current collector along the first direction exceeds the second current collector, and the adhesive layer exceeds the end of the first current collector along the first direction.

9. The method for manufacturing a battery cell according to claim 7 or 8, characterized in that: Before the hot pressing step is performed, the thickness of the adhesive layer gradually increases in a direction close to the end of the diaphragm in the first direction; and / or, before the hot pressing step, the length difference between the first current collector and the second current collector is L, the glue layer has a slope portion and a platform portion, the platform portion is located on a side of the slope portion facing the edge of the diaphragm along the first direction, the thickness of the slope portion gradually decreases in a direction away from the platform portion, and the length of the platform portion along the first direction is b, wherein: 0<2b-L<1 mm; and / or, before the hot pressing step, the adhesive layer has a slope portion and a platform portion, the platform portion is located on a side of the slope portion facing an edge of the diaphragm along the first direction, the thickness of the slope portion gradually decreases away from the platform portion, and the length of the slope portion along the first direction is c, 1.5 mm ≤ c ≤ 3 mm; And / or, the surface of the current collector in the thickness direction is coated with an active material layer, the thickness of the active material layer is d, and before the hot pressing step, the maximum thickness of the glue layer is a, a<d.

10. A vehicle, characterized in that A battery cell comprising the battery cell according to any one of claims 1 to 6, and / or a battery cell manufactured by the battery cell manufacturing method according to any one of claims 7 to 9.

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