Battery cell, laminated battery and winding type battery

Abstract

The utility model discloses a battery cell, a laminated battery and a coiled battery, the battery cell comprises a first pole piece, a second pole piece and a diaphragm, the first pole piece, the diaphragm and the second pole piece are sequentially and alternately laminated to form a laminated structure or are laminated and coiled to form a coiled core structure; the first pole piece comprises a first current collector and a first active layer; the second pole piece comprises a second current collector and a second active layer; wherein the head part of the first pole piece is provided with a thinning area opposite to the second pole piece along the height direction of the battery cell, the head end of the first current collector does not exceed the head end of the second current collector, at least one side surface of the top of the battery cell along the thickness direction of the battery cell is provided with first insulating glue, and the first insulating glue is provided with second insulating glue along the height direction of the battery cell. The top end of the first insulation paste is not higher than the head end of the second current collector. The top thinning area of the battery cell is provided with the insulation paste, so that the thickness of the top thinning area is compensated, the stress consistency of the battery cell is improved, and the phenomena of black spots and lithium precipitation in the circulation process are avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery manufacturing technical field more specifically, relate to a kind of electric core, laminated battery and winding type battery. BACKGROUND

[0002] At present, when electric core is made, negative pole piece is usually longer than positive pole piece, to meet the demand of small volume, high safety performance and long service life of electric core, but the edge of positive pole piece is thin, and there is a problem of thinning in the top area of electric core.

[0003] The thinning in the top area of electric core will make the flatness of electric core low, leading to poor consistency of electric core under pressure, causing black spots and lithium precipitation phenomenon in the cycle process of electric core, thereby affecting battery performance and service life.

[0004] In summary, how to compensate the thinning area in the top of electric core to improve the consistency of electric core under pressure is a problem that needs to be solved by the technical personnel in the field. UTILITY MODEL CONTENT

[0005] Therefore, the utility model aims to provide an electric core, which has insulating glue in the thinning area in the top, compensates the thickness of the thinning area in the top, improves the consistency of electric core under pressure, and avoids black spots and lithium precipitation phenomenon in the cycle process.

[0006] Another object of the utility model is to provide a laminated battery and winding type battery comprising the above-mentioned electric core.

[0007] In order to achieve the above-mentioned object, the utility model provides the following technical scheme:

[0008] An electric core comprises a first pole piece, a second pole piece and a separator, the first pole piece, the separator and the second pole piece are alternately stacked in sequence to form a laminated structure or are stacked and wound to form a winding core structure;

[0009] The first pole piece comprises a first current collector and a first active layer coated on the surface of the first current collector, the head end of the first current collector is led out with a plurality of first pole tabs, and the plurality of first pole tabs are folded down along the thickness direction of the electric core and welded on the third pole tab in a folded layer;

[0010] The second pole piece comprises a second current collector and a second active layer coated on the surface of the second current collector, the head end of the second current collector is led out with a plurality of second pole tabs, and the plurality of second pole tabs are folded down along the thickness direction of the electric core and welded on the fourth pole tab in a folded layer;

[0011] The head of the first pole piece is provided with a thinning area opposite to the second pole piece along the height direction of the battery cell, and the head end of the first current collector does not exceed the head end of the second current collector along the thickness direction of the battery cell.

[0012] Preferably, the welding area of the first tab is provided with first solder joint protection glue, and the welding area of the second tab is provided with second solder joint protection glue.

[0013] The first insulation glue overlaps the first solder joint protection glue and the second solder joint protection glue along the height direction of the battery cell.

[0014] Preferably, the overlapping height of the first insulation glue, the first solder joint protection glue and the second solder joint protection glue along the height direction of the battery cell is H6, wherein H6 satisfies: 0mm≤H6≤8mm.

[0015] Preferably, the bottom of the battery cell is provided with second insulation glue, and the two sides of the second insulation glue are respectively arranged on the two opposite sides of the battery cell along the thickness direction, and the bending part of the second insulation glue is wrapped around the bottom of the battery cell.

[0016] Preferably, at least one side of the battery cell is provided with third insulation glue along the width direction of the battery cell, the two sides of the third insulation glue are respectively arranged on the two opposite sides of the battery cell along the thickness direction, the bending part of the third insulation glue is wrapped around the side of the battery cell, and the top end of the third insulation glue does not exceed the head end of the second current collector along the height direction of the battery cell.

[0017] Preferably, the upper side of the battery cell is the first pole piece along the thickness direction of the battery cell, and the upper side of the first pole piece includes the upper side of the first current collector and the first active layer coated on the lower side surface thereof, the top of the upper side surface of the upper side of the first current collector is pasted with the first insulation glue, and the top end of the first insulation glue does not exceed the head end of the upper side of the first current collector along the height direction of the battery cell.

[0018] And / or, the lower side of the battery cell is the first pole piece along the thickness direction of the battery cell, and the lower side of the first pole piece includes the lower side of the first current collector and the first active layer coated on the upper side surface thereof, the top of the lower side surface of the lower side of the first current collector is pasted with the second insulation glue, and the top end of the first insulation glue does not exceed the head end of the lower side of the first current collector along the height direction of the battery cell.

[0019] Preferably, along the thickness direction of the battery cell, the upper side of the battery cell is the first pole piece, the upper side of the first pole piece comprises the upper side of the first current collector and the first active layer coated on the lower side surface thereof, and the side of the upper side of the first current collector is pasted with the first side of the third insulating adhesive, along the height direction of the battery cell, the top end of the first side of the third insulating adhesive is not lower than the head end of the upper side of the first current collector.

[0020] Preferably, along the thickness direction of the battery cell, the lower side of the battery cell is the first pole piece, the lower side of the first pole piece comprises the lower side of the first current collector and the first active layer coated on the upper side surface thereof, and the side of the lower side of the first current collector is pasted with the second side of the third insulating adhesive, along the height direction of the battery cell, the top end of the second side of the third insulating adhesive is not lower than the head end of the lower side of the first current collector.

[0021] Preferably, along the width direction of the battery cell, gaps are provided between the third insulating adhesive and the first insulating adhesive and the second insulating adhesive.

[0022] Preferably, along the height direction of the battery cell, the height of the top end of the first insulating adhesive from the head end of the second current collector is H1, wherein H1 satisfies: 0mm≤H1≤3.5mm.

[0023] Preferably, along the height direction of the battery cell, the height of the top end of the first insulating adhesive from the head end of the upper side of the first current collector and / or the head end of the lower side of the first current collector is H2, wherein H2 satisfies: 0mm≤H2≤3.5mm.

[0024] Preferably, along the width direction of the battery cell, the overlapping width of the third insulating adhesive with the upper side of the first current collector and the lower side of the first current collector is W1, wherein W1 satisfies: 2mm≤W1≤10mm.

[0025] Preferably, along the height direction of the battery cell, the height of the top end of the third insulating adhesive from the head end of the second current collector is H3, wherein H3 satisfies: 0mm≤H3≤3.5mm.

[0026] Preferably, along the height direction of the battery cell, the height of the top end of each of the two sides of the third insulating adhesive from the head end of the upper side of the first current collector is H4, wherein H4 satisfies: 0mm≤H4≤3.5mm.

[0027] Preferably, along the width direction of the battery cell, the gap between the third insulating adhesive and the first insulating adhesive and the second insulating adhesive is AW, wherein 2mm≤AW≤8mm.

[0028] And / or, along the width direction of the battery cell, the overlapping width of the two side portions of the second insulating adhesive with the first current collector on the upper side and the first current collector on the lower side is W2, wherein W2 satisfies: 4mm≤W2≤18mm.

[0029] And / or, along the height direction of the battery cell, the overlapping height of the two side portions of the second insulating adhesive with the first current collector on the upper side and the first current collector on the lower side is H5, wherein H5 satisfies: 2mm≤H5≤10mm.

[0030] Preferably, a plurality of through holes are arranged on the first insulating adhesive, the second insulating adhesive and the third insulating adhesive.

[0031] Preferably, the interval between two adjacent through holes is D1, wherein D1 satisfies: 2mm≤D1≤10mm.

[0032] And / or, the diameter of the through hole is D2, wherein D2 satisfies: 0.5mm≤D2≤4mm.

[0033] A laminated battery cell comprising the battery cell of any one of the above, wherein the first electrode sheet, the separator and the second electrode sheet are alternately stacked in sequence to form a laminated structure.

[0034] A wound battery cell comprising the battery cell of any one of the above, wherein the first electrode sheet, the separator and the second electrode sheet are alternately stacked in sequence and wound to form a wound core structure.

[0035] The battery cell provided by the utility model is formed by alternately stacking the first electrode sheet, the separator and the second electrode sheet in sequence to form a laminated structure or stacking and winding to form a wound core structure. In the thickness direction of the battery cell, the relative two side surfaces of the top of the battery cell (i.e. the upper side surface and the lower side surface of the top of the battery cell) are provided with insulating adhesive, the thickness of the top region of the battery cell is reduced, the flatness of the battery cell is improved, the consistency of the battery cell under pressure is improved, and the black spot and lithium precipitation phenomena in the circulation process are avoided. In addition, in the height direction of the battery cell, the top of the first insulating adhesive is not higher than the head end of the second electrode sheet, on the one hand, the tabs led out from the head end of the first electrode sheet and the second electrode sheet can be prevented from being welded on the insulating adhesive, and on the other hand, the insulating adhesive can be prevented from being damaged when the top of the battery cell is packaged, so that the insulating adhesive is not damaged, the stress uniformity of the battery cell is further ensured, and the black spot and lithium precipitation phenomena in the circulation process are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0037] Figure 1 A structure schematic view of a laminated cell provided by the present application;

[0038] Figure 2 A structure schematic view of a winding cell provided by the present application;

[0039] Figure 3 A schematic view of the cell with glue on all four sides provided by the present application;

[0040] Figure 4 A Figure 1 A sectional view of the laminated cell provided by the present application at B-B of embodiment one;

[0041] Figure 5 A Figure 1 A sectional view of the laminated cell provided by the present application at B-B of embodiment two;

[0042] Figure 6 A Figure 1 A sectional view of the laminated cell provided by the present application at A-A of embodiment one;

[0043] Figure 7 A Figure 1 A sectional view of the laminated cell provided by the present application at A-A of embodiment two;

[0044] Figure 8 A schematic view of the cell with glue on the side provided by the present application;

[0045] Figure 9 A schematic view of the cell with glue on the bottom provided by the present application;

[0046] Figure 10 A schematic view of the second insulating glue and the third insulating glue provided by the present application.

[0047] Reference signs:

[0048] 1-first pole piece; 11-first pole lug; 2-second pole piece; 21-second pole lug; 3-separator; 4-first insulating glue; 5-second insulating glue; 6-third insulating glue; 7-first solder point protection glue; 8-second solder point protection glue; 9-third pole lug; 10-fourth pole lug; 12-through hole;

[0049] H is the height direction of the battery cell; W is the width direction of the battery cell; T is the thickness direction of the battery cell; and P is the thinning area. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0051] The core of the utility model provides a kind of battery cell, and the top thinning area of the battery cell has insulating glue, compensates the thickness of top thinning area, improves the consistency of battery cell under pressure, to avoid the phenomenon of black spot and lithium precipitation in the cycle process.

[0052] Another core of the utility model provides a kind of laminated battery and winding battery comprising the above battery cell.

[0053] It should be noted that in the present embodiment, the orientation or positional relationship indicated by "up", "down" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, "first", "second", "third", "fourth" are only used to describe the effect, and cannot be understood as indicating or implying relative importance.

[0054] Please refer to Figures 1 to 3 The present application provides a kind of battery cell, including first pole piece 1, second pole piece 2 and diaphragm 3, first pole piece 1, diaphragm 3 and second pole piece 2 are alternately stacked in sequence to form laminated structure or stacked and wound to form roll core structure.

[0055] The first pole piece 1 includes a first current collector and a first active layer applied on the surface of the first current collector, and the head end of the first current collector leads out a plurality of first tabs 11, and the plurality of first tabs 11 are folded down along the thickness direction of the battery cell and welded on the third tab 9.

[0056] The second pole piece 2 includes a second current collector and a second active layer applied on the surface of the second current collector, and the head end of the second current collector leads out a plurality of second tabs 21, and the plurality of second tabs 21 are folded down along the thickness direction of the battery cell and welded on the fourth tab 10.

[0057] The head of the first pole piece 1 is provided with a thinning area P opposite the second pole piece 2 along the height direction of the battery cell, and the head end of the first current collector does not exceed the head end of the second current collector along the thickness direction of the battery cell, and the top of the battery cell is provided with the first insulating glue 4 on at least one side along the thickness direction of the battery cell, and the top end of the first insulating glue 4 does not exceed the head end of the second current collector along the height direction of the battery cell.

[0058] It should be noted that the battery cell provided in the present application can be a laminated battery cell or a wound battery cell. The laminated battery cell is formed by alternately stacking the first pole piece 1, the separator 3 and the second pole piece 2 in sequence to form a laminated structure, and the wound battery cell is formed by alternately stacking the first pole piece 1, the separator 3 and the second pole piece 2 in sequence and then winding to form a wound core structure. The first pole piece 1 is a positive pole piece, the second pole piece 2 is a negative pole piece, and the separator 3 is located between the positive pole piece and the negative pole piece to isolate the positive and negative pole pieces and prevent short circuit caused by direct contact between the two levels.

[0059] It should be noted that the first tab 11 is cut from the end of the first current collector body, the remaining part of the first current collector body is the first current collector, the head end of the first current collector is adjacent to the first tab 11, and the third tab 9 is a positive tab for collecting the current of all the first tabs 11. The second tab 21 is cut from the end of the second current collector body, the remaining part of the second current collector body is the second current collector, the head end of the second current collector is adjacent to the second tab 21, and the fourth tab 10 is also a negative tab for collecting the current of all the second tabs 21.

[0060] As shown in Figure 4 , the head of the first pole piece 1 is provided with a thinning area P opposite the second pole piece 2, which will cause the top area of the battery cell to be thinned, resulting in low flatness of the battery cell, uneven stress on the battery cell, and concentrated stress in the local area of the battery cell during charging and discharging, which will cause lithium precipitation and damage the structure of the battery cell, forming black spots, resulting in poor safety performance and short service life of the battery cell.

[0061] The insulating glue is a composite glue with good electrical insulation performance, and the first insulating glue 4 is arranged in the top area of the battery cell to compensate for the thickness reduction of the top area of the battery cell.

[0062] The first insulating glue 4 has the following embodiments. In a first embodiment, the first insulating glue 4 is arranged on the upper side of the top of the battery cell along the thickness direction of the battery cell, as shown in Figure 4 and Figure 6 In a second embodiment, the first insulating glue 4 is arranged on the lower side of the top of the battery cell along the thickness direction of the battery cell, and in a third embodiment, the first insulating glue 4 is arranged on both the upper side and the lower side of the top of the battery cell along the thickness direction of the battery cell, as shown in Figure 5 and Figure 7 The thickness of the first insulating glue 4 in the above three embodiments is set according to the thickness reduction of the top area of the battery cell.

[0063] Thus, in the case of the first insulating glue 4 on the top of the battery cell, the thickness of the top area of the battery cell can be reduced to improve the flatness of the battery cell, thereby improving the consistency of the battery cell under pressure, and further avoiding the black spot and lithium precipitation phenomenon in the cycle process.

[0064] Further, in the above three embodiments, the top end of the first insulating glue 4 is not higher than the head end of the second current collector along the height direction of the battery cell.

[0065] Specifically, as shown in Figure 3 , the height of the top end of the first insulating glue 4 is lower than the head end of the second current collector along the height direction of the battery cell, and H1 satisfies: 0mm≤H1≤3.5mm, the maximum value of H1 is adjusted according to the coverage value of the design of the first and second pole pieces 1 and 2, and does not exceed the height difference of the head end design of the first and second pole pieces 1 and 2. In addition, the value of H1 can also be any value in this range, for example, 1mm, 2mm or 3mm, etc.

[0066] Thus, on the one hand, the tabs led out by the head ends of the first and second pole pieces 1 and 2 can be prevented from being welded on the first insulating glue 4, and on the other hand, the first insulating glue 4 can be prevented from being damaged when the battery cell is packaged, that is, the shell is prevented from being squeezed, thereby improving the cycle performance and life of the battery cell, and ensuring that the first insulating glue 4 is not damaged, further ensuring that the battery cell is uniformly stressed, and avoiding the black spot and lithium precipitation phenomenon in the cycle process.

[0067] It should be noted that there is a certain height between the head end of the first current collector and the head end of the second current collector along the height direction of the battery cell, which will also cause the top of the battery cell to be uneven. Only extending the first insulating glue 4 along the height direction of the battery cell will not only cause the first insulating glue 4 to exceed the top of the second pole piece 2, but also cause the first insulating glue 4 to enter the welding area, and further cause the first insulating glue 4 to be folded.

[0068] To solve the problem of uneven top of the battery cell caused by the height difference between the head end of the first current collector and the head end of the second current collector, on the basis of the above embodiments, please refer to Figure 2 , Figure 6 and Figure 7 , the welding area of the plurality of first tabs 11 is provided with the first welding point protection glue 7, and the welding area of the plurality of second tabs 21 is provided with the second welding point protection glue 8; the first insulating glue 4 and the first and second welding point protection glues 7 and 8 are all overlapped along the height direction of the battery cell.

[0069] Specifically, first tabs 11 are cut out from the heads of several first current collectors. These first tabs 11 are bent downwards along the thickness of the battery cell and stacked and welded onto the third tab 9. First solder joint protective adhesive 7 covers the welding area of ​​the first tabs 11 and overlaps with the first insulating adhesive 4 on top of the battery cell. Similarly, second tabs 21 are cut out from the heads of several second current collectors. These second tabs 21 are bent downwards along the thickness of the battery cell and stacked and welded onto the fourth tab 10. Second solder joint protective adhesive 8 covers the welding area of ​​the second tabs 21 and overlaps with the first insulating adhesive 4 on top of the battery cell.

[0070] The overlap height between the first insulating adhesive 4 and the first solder joint protective adhesive 7 and the second solder joint protective adhesive 8 is H6. H6 satisfies: 0mm≤H6≤8mm, preferably 1mm≤H6≤4mm. The value of H6 can also be any value within this range, such as 1mm, 2mm, 4mm or 3mm.

[0071] Therefore, the above-mentioned arrangement of the first insulating adhesive 4 relative to the first solder joint protective adhesive 7 and the second solder joint protective adhesive 8 has the following advantages: First, it can effectively compensate for the thinning area at the top of the battery cell, ensuring not only the flatness of the top area of ​​the battery cell, but also avoiding the phenomenon of extending the first insulating adhesive 4 into the soldering area and the folding of the first insulating adhesive 4; Second, it can protect the solder joint from environmental corrosion and interference; Third, it can better fix the tabs and prevent safety problems caused by the tabs being inserted into the electrode plates during the battery cell's fall.

[0072] It should be noted that if the head of the first electrode 1 is thinned and the first electrode 1 is located on the upper and / or lower side of the cell, the head of the first electrode 1 is prone to bend under external force, which will lead to a shortened lifespan of the cell, a decrease in energy density, and a short circuit.

[0073] In one embodiment, please refer to Figure 3 , Figures 4 to 7 Along the thickness direction of the battery cell, the upper side of the battery cell is the first electrode 1. The upper side first electrode 1 includes an upper side first current collector and a first active layer coated on its lower side surface. The top of the upper side surface of the upper side first current collector is pasted with a first insulating adhesive 4. Along the height direction of the battery cell, the top of the first insulating adhesive 4 is not lower than the head end of the upper side first current collector.

[0074] Specifically, the upper side first current collector is coated with the first active material towards the lower side surface of the second tab 2 adjacent thereto, and is provided with the first insulating adhesive 4 away from the lower side surface of the second tab 2 adjacent thereto. Along the height direction of the battery cell, the top end of the first insulating adhesive 4 is higher than the head end of the upper side first current collector by a height H2, wherein H2 satisfies: 0mm≤H2≤3.5mm, and the maximum value of H2 is adjusted according to the coverage value designed for the first tab 1 and the second tab 2, and does not exceed the height difference designed for the head ends of the first tab 1 and the second tab 2. In addition, the value of H2 can also be any value within the range, for example, 1mm, 2mm or 3mm, etc.

[0075] Therefore, the phenomenon of the first tab 1 on the upper side of the battery cell being folded over can be prevented, thereby ensuring that the battery cell has a long service life, a high energy density and is not prone to short circuit to cause safety hazards.

[0076] In another embodiment, referring to Figure 3 , Figures 4 to 7 , along the thickness direction of the battery cell, the lower side of the battery cell is the first tab 1, and the upper side of the battery cell is the first tab 1. The lower side first current collector includes a lower side first current collector and a first active layer coated on the upper side surface thereof. The top of the lower side surface of the lower side first current collector is pasted with the first insulating adhesive 4, and along the height direction of the battery cell, the top end of the first insulating adhesive 4 is not lower than the head end of the lower side first current collector.

[0077] Specifically, the lower side first current collector is coated with the first active material towards the upper side surface of the second tab 2 adjacent thereto, and is provided with the first insulating adhesive 4 away from the lower side surface of the second tab 2 adjacent thereto. Along the height direction of the battery cell, the top end of the first insulating adhesive 4 is higher than the head end of the lower side first current collector by a height H2, wherein H2 satisfies: 0mm≤H2≤3.5mm, and the maximum value of H2 is adjusted according to the coverage value designed for the first tab 1 and the second tab 2, and does not exceed the height difference designed for the head ends of the first tab 1 and the second tab 2. In addition, the value of H2 can also be any value within the range, for example, 1mm, 2mm or 3mm, etc.

[0078] Therefore, the phenomenon of the first tab 1 on the lower side of the battery cell being folded over can be prevented, thereby ensuring that the battery cell has a long service life, a high energy density and is not prone to short circuit to cause safety hazards.

[0079] On the basis of the above embodiments, referring to Figure 3 and Figure 8 , along the width direction of the battery cell, at least one side of the battery cell is provided with the third insulating adhesive 6. The two sides of the third insulating adhesive 6 are respectively provided on the two sides of the battery cell in the thickness direction. The bending part of the third insulating adhesive 6 is wrapped around the side of the battery cell, and along the height direction of the battery cell, the top end of the third insulating adhesive 6 is not higher than the head end of the second current collector.

[0080] It can be understood that the first side of the third insulating glue 6 is pasted on the upper side of the side of the battery cell, and the second side is pasted on the lower side of the side of the battery cell in the thickness direction of the battery cell, forming a U-shaped encapsulation of the side of the battery cell. This arrangement has the following effects: first, it improves the adhesion of the pole piece and the diaphragm 3, reduces the distance of the lithium ion transmission channel, and avoids the appearance of black spots and lithium precipitation during the cycle process; second, wrapping the side of the battery to restrain the pole piece is beneficial to improving the impact resistance of the side of the battery cell, thereby improving the drop resistance and rolling resistance of the battery cell; third, it compensates for the problem of inconsistent thickness of the side of the battery cell caused by the misalignment of the first pole piece 1 and the second pole piece 2 in the width direction, increases the consistency of the stress on the side of the battery cell, and avoids the appearance of black spots and lithium precipitation during the cycle process; fourth, wrapping the side of the battery can prevent the angle crack caused by the expansion of the pole piece pressing the film shell during the cycle process.

[0081] It is particularly noted that in the height direction of the battery cell, the top of the third insulating glue 6 is not higher than the head end of the second current collector. On the one hand, it can avoid the welding of the tabs led out from the head end of the first pole piece 1 and the second pole piece 2 on the third insulating glue 6, and on the other hand, it can avoid the pressure damage to the third insulating glue 6 when the battery cell is packaged at the top, thereby ensuring that the third insulating glue 6 is not damaged, further ensuring that the stress on the battery cell is uniform, and avoiding the appearance of black spots and lithium precipitation during the cycle process.

[0082] Specifically, as shown in Figure 8 Taking the upper side and the lower side of the battery cell as examples, the overlapping width of the third insulating glue 6 with the upper side first current collector and the lower side first current collector in the width direction of the battery cell is W1, wherein W1 satisfies: 2mm≤W1≤10mm, preferably 4mm≤W1≤6mm, and the maximum value of W1 is designed according to the width of the battery cell. In addition, the value of W1 can also be any value within this range, for example, 4mm, 5mm or 6mm, etc.

[0083] In the height direction of the battery cell, the height of the top end of the third insulating glue 6 is lower than the head end of the second current collector, which is H3, wherein H3 satisfies: 0mm≤H3≤3.5mm, and the maximum value of H3 is adjusted according to the coverage value designed for the first pole piece 1 and the second pole piece 2, and does not exceed the height difference value designed for the head end of the first pole piece 1 and the second pole piece 2. In addition, the value of H3 can also be any value within this range, for example, 1mm, 2mm or 3mm, etc.

[0084] To further prevent the phenomenon of folding of the first pole piece 1 on the upper side of the battery cell, on the basis of the above embodiment, please refer to Figure 8, along the thickness direction of the battery cell, the upper side of the battery cell is the first pole piece 1, the upper side of the first pole piece 1 includes the upper side of the first current collector and the first active layer coated on the lower side surface thereof, and the side of the upper side surface of the upper side of the first current collector is pasted with the first side of the third insulating adhesive 6, along the height direction of the battery cell, the top end of the first side of the third insulating adhesive 6 is not lower than the head end of the upper side of the first current collector.

[0085] Specifically, along the height direction of the battery cell, the height of the top end of the first side of the third insulating adhesive 6 is higher than the head end of the upper side of the first current collector, and the height is H4, wherein H4 satisfies: 0mm≤H4≤3.5mm, the maximum value of H4 is adjusted according to the coverage value of the design of the first pole piece 1 and the second pole piece 2, and does not exceed the height difference value of the head end design of the first pole piece 1 and the second pole piece 2. In addition, the value of H4 can also be any value in this range, for example, 1mm, 2mm or 3mm, etc.

[0086] Therefore, the phenomenon of the first pole piece 1 on the upper side of the battery cell being folded can be further prevented, thereby ensuring that the service life of the battery cell is long, the energy density is high, and the safety hazard caused by short circuit is not easy to occur.

[0087] In order to further prevent the phenomenon of the first pole piece 1 on the lower side of the battery cell being folded, on the basis of the above embodiment, along the thickness direction of the battery cell, the lower side of the battery cell is the first pole piece 1, the lower side of the first pole piece 1 includes the lower side of the first current collector and the first active layer coated on the upper side surface thereof, and the side of the lower side surface of the lower side of the first current collector is pasted with the second side of the third insulating adhesive 6, along the height direction of the battery cell, the top end of the second side of the third insulating adhesive 6 is not lower than the head end of the lower side of the first current collector.

[0088] Specifically, along the height direction of the battery cell, the height of the top end of the second side of the third insulating adhesive 6 is higher than the head end of the lower side of the first current collector, and the height is H4, wherein H4 is taken from the value range of the above, which will not be discussed here.

[0089] Therefore, the phenomenon of the first pole piece 1 on the lower side of the battery cell being folded can be further prevented, thereby ensuring that the service life of the battery cell is long, the energy density is high, and the safety hazard caused by short circuit is not easy to occur.

[0090] On the basis of the above embodiment, please refer to Figure 3 and Figure 9 The bottom of the battery cell is provided with the second insulating adhesive 5, the two sides of the second insulating adhesive 5 are respectively arranged on the two opposite sides of the battery cell along the thickness direction, and the bending part of the second insulating adhesive 5 is wrapped around the bottom of the battery cell.

[0091] It can be understood that the first side of the second insulating glue 5 is pasted on the upper side of the bottom of the battery cell, and the second side is pasted on the lower side of the bottom of the battery cell in the thickness direction of the wire, forming a U-shaped encapsulation on the bottom of the battery cell. This setting has the following effects: first, it can avoid the folding of the first pole piece 1 on the upper and lower sides of the battery cell; second, it improves the adhesion of the pole piece and the diaphragm 3, reduces the distance of the lithium ion transmission channel, and avoids the appearance of black spots and lithium precipitation during the cycle process; third, wrapping the bottom of the battery to bind the pole piece is beneficial to improve the impact resistance of the bottom of the battery cell, thereby improving the drop resistance and rolling resistance of the battery cell; third, it makes up for the problem of inconsistent thickness of the bottom of the battery cell caused by the misalignment of the first pole piece 1 and the second pole piece 2 in the height direction, increases the consistency of the force on the bottom of the battery cell, and avoids the appearance of black spots and lithium precipitation during the cycle process.

[0092] Specifically, as shown in Figure 9 , along the width direction of the battery cell, the overlapping width of the two side portions and the upper side first current collector and the lower side first current collector of the second insulating glue 5 is W2, wherein W2 satisfies: 4mm≤W2≤18mm, preferably 4mm≤W2≤10mm. In addition, the value of W2 can also be any value within this range, for example, 5mm, 6mm or 8mm, etc. Along the height direction of the battery cell, the overlapping height of the two side portions and the upper side first current collector and the lower side first current collector of the second insulating glue 5 is H5, wherein H5 satisfies: 2mm≤H5≤10mm, preferably 4mm≤H5≤6mm. In addition, the value of H5 can also be any value within this range, for example, 4mm, 5mm or 6mm, etc.

[0093] On the basis of the above embodiments, please refer to Figure 10 , along the width direction of the battery cell, gaps are provided between the third insulating glue 6 and the first insulating glue 4 and the second insulating glue 5.

[0094] Specifically, along the width direction of the battery cell, the gap between the third insulating glue 6 and the first insulating glue 4 and the second insulating glue 5 is AW, wherein 2mm≤AW≤8mm, preferably 2mm≤AW≤4mm. In addition, the value of AW can also be any value within this range, for example, 2mm, 3mm or 4mm, etc.

[0095] Thus, gaps can be reserved between the insulating glue located at the four peripheral edges of the battery cell, which is beneficial to the entry of electrolyte into the battery cell and improves the adsorption capacity of the battery cell.

[0096] On the basis of any of the above embodiments, please refer to Figure 3 , a plurality of through holes 12 are provided on the first insulating glue 4, the second insulating glue 5 and the third insulating glue 6, and preferably, the plurality of through holes 12 are arranged at equal intervals.

[0097] Specifically, the interval between two adjacent through holes 12 is D1, wherein D1 satisfies: 2mm≤D1≤10mm, and D1 can also be any value within the range, for example, 2mm, 5mm, 6mm or 10mm, etc. The diameter of the through hole 12 is D2, wherein D2 satisfies: 0.5mm≤D2≤4mm, and D2 can also be any value within the range, for example, 1mm, 2mm, 3mm or 4mm, etc.

[0098] Therefore, the insulating glue located at the edges of the four sides of the battery cell is provided with the through hole 12, which can accelerate the absorption of the electrolyte by the battery cell and improve the liquid absorption amount.

[0099] In summary, the battery cell four-side pasting glue provided by the application has the following beneficial effects:

[0100] (1) The pasting glue area improves the problem of inconsistent thickness of the edges of the four sides of the battery cell, improves the consistency of the pressure on the battery cell, and thus avoids the black spot and lithium precipitation phenomenon in the cycle process.

[0101] (2) Improves the adhesion of the pole piece and the diaphragm 3, reduces the distance of the lithium ion transmission channel, and thus avoids the black spot and lithium precipitation phenomenon in the cycle process.

[0102] (3) Prevents the single-sided area pole piece from being raised / folded.

[0103] (4) Prevents the four-corner diaphragm 3 from being wrinkled / folded / leaking negative, reduces the risk of short circuit, and improves the safety performance.

[0104] (5) Wraps and binds each layer of pole piece, improves the drop resistance and rolling resistance of the battery cell, and thus solves the problem of battery cell drop / rolling test, and improves the safety performance.

[0105] (6) Prevents the shell from being squeezed, improves the cycle performance and service life of the battery cell, and improves the long cycle corner cracking and pole piece fracture problem.

[0106] The utility model also provides a laminated battery, the laminated battery includes the battery cell disclosed by the above embodiment, wherein the first pole piece 1, the diaphragm 3 and the second pole piece 2 are alternately and sequentially stacked to form a laminated structure.

[0107] The utility model also provides a winding type battery, the winding type battery includes the battery cell disclosed by the above embodiment, wherein the first pole piece 1, the diaphragm 3 and the second pole piece 2 are alternately and sequentially stacked and wound to form a winding core structure.

[0108] It should be noted that in the present specification, relational terms such as first and second are used only to distinguish one entity from another, and do not necessarily require or imply that there is any such actual relationship or order between these entities.

[0109] The various embodiments are described in the specification by way of progression, each building on the last to facilitate ease of understanding. The same or similar reference numerals are used in the drawings and description to refer to the same or like parts, components and operations.

[0110] The above has carried out the detailed introduction to the electric core, the electric core provided by the utility model, the electric pile and the winding type battery. The principle and implementation mode of the utility model are described in this paper by applying specific examples. The above embodiment is only used to help understand the method and core idea of the utility model. It should be pointed out that for ordinary skilled person in the art, without departing from the principle of the utility model, the utility model can be improved and modified in several ways. These improvements and modifications also fall within the protection scope of the utility model claims.

Claims

1. A battery cell, characterized in that, It includes a first electrode (1), a second electrode (2) and a diaphragm (3), wherein the first electrode (1), the diaphragm (3) and the second electrode (2) are stacked alternately to form a stacked structure or stacked and wound to form a core structure; The first electrode (1) includes a first current collector and a first active layer coated on the surface of the first current collector. A plurality of first tabs (11) are led out from the head end of the first current collector, and the plurality of first tabs (11) are bent and folded downward along the thickness direction of the battery cell and welded to the third tab (9). The second electrode (2) includes a second current collector and a second active layer coated on the surface of the second current collector. A number of second electrode tabs (21) are led out from the head end of the second current collector, and the number of second electrode tabs (21) are bent and folded downward along the thickness direction of the battery cell and welded to the fourth electrode tab (10). Along the height direction of the battery cell, the head of the first electrode (1) is provided with a thinning area (P) opposite to the second electrode (2), and the head end of the first current collector does not exceed the head end of the second current collector. Along the thickness direction of the battery cell, at least one side of the top of the battery cell is provided with a first insulating adhesive (4), and along the height direction of the battery cell, the top end of the first insulating adhesive (4) is not higher than the head end of the second current collector.

2. The battery cell according to claim 1, characterized in that, A first weld point protective adhesive (7) is applied to the welding area of ​​several first electrode tabs (11), and a second weld point protective adhesive (8) is applied to the welding area of ​​several second electrode tabs (21). Along the height direction of the battery cell, the first insulating adhesive (4) overlaps with the first solder joint protective adhesive (7) and the second solder joint protective adhesive (8).

3. The battery cell according to claim 2, characterized in that, Along the height direction of the battery cell, the overlap height of the first insulating adhesive (4), the first solder joint protective adhesive (7), and the second solder joint protective adhesive (8) is H6, wherein H6 satisfies: 0mm≤H6≤8mm.

4. The battery cell according to claim 1, characterized in that, The bottom of the battery cell is provided with a second insulating adhesive (5), and the two sides of the second insulating adhesive (5) are respectively provided on the two opposite sides of the battery cell along the thickness direction. The bent part of the second insulating adhesive (5) is wrapped around the bottom of the battery cell.

5. The battery cell according to claim 4, characterized in that, Along the width direction of the battery cell, at least one side of the battery cell is provided with a third insulating adhesive (6). The two sides of the third insulating adhesive (6) are respectively provided on the two opposite sides of the battery cell along the thickness direction. The bend of the third insulating adhesive (6) wraps around the side of the battery cell, and along the height direction of the battery cell, the top of the third insulating adhesive (6) is not higher than the head end of the second current collector.

6. The battery cell according to claim 5, characterized in that, Along the thickness direction of the battery cell, the upper side of the battery cell is the first electrode (1). The first electrode (1) on the upper side includes the first current collector on the upper side and the first active layer coated on its lower side surface. The top of the upper side surface of the first current collector on the upper side is pasted with the first insulating adhesive (4). Along the height direction of the battery cell, the top of the first insulating adhesive (4) is not lower than the head end of the first current collector on the upper side. And / or, along the thickness direction of the battery cell, the lower side of the battery cell is the first electrode (1), the lower side first electrode (1) includes the lower side first current collector and the first active layer coated on its upper side surface, the top of the lower side surface of the lower side first current collector is pasted with the first insulating adhesive (4), and along the height direction of the battery cell, the top of the first insulating adhesive (4) is not lower than the head end of the lower side first current collector.

7. The battery cell according to claim 6, characterized in that, Along the thickness direction of the battery cell, the upper side of the battery cell is the first electrode (1). The first electrode (1) on the upper side includes the first current collector on the upper side and the first active layer coated on its lower side surface. The first side of the third insulating adhesive (6) is pasted on the side of the upper side surface of the first current collector on the upper side. Along the height direction of the battery cell, the top end of the first side of the third insulating adhesive (6) is not lower than the head end of the first current collector on the upper side. And / or, along the thickness direction of the battery cell, the lower side of the battery cell is the first electrode (1), the lower side first electrode (1) includes the lower side first current collector and the first active layer coated on its upper side surface, the lower side surface of the lower side first current collector is attached with the second side of the third insulating adhesive (6), along the height direction of the battery cell, the top end of the second side of the third insulating adhesive (6) is not lower than the head end of the lower side first current collector.

8. The battery cell according to claim 7, characterized in that, Along the width direction of the battery cell, there are gaps between the third insulating adhesive (6) and the first insulating adhesive (4) and the second insulating adhesive (5).

9. The battery cell according to claim 8, characterized in that, Along the height direction of the battery cell, the height of the top end of the first insulating adhesive (4) below the head end of the second current collector is H1, wherein H1 satisfies: 0mm≤H1≤3.5mm; And / or, along the height direction of the cell, the height of the top of the first insulating adhesive (4) above the head end of the first current collector on the upper side and / or the head end of the first current collector on the lower side is H2, wherein H2 satisfies: 0mm≤H2≤3.5mm; And / or, along the width direction of the cell, the overlap width between the third insulating adhesive (6) and the first current collector on the upper side and the first current collector on the lower side is W1, wherein W1 satisfies: 2mm≤W1≤10mm; And / or, along the height direction of the cell, the top of the third insulating adhesive (6) is lower than the head of the second current collector by a height of H3, wherein H3 satisfies: 0mm≤H3≤3.5mm; And / or, along the height direction of the cell, the height of the top of both sides of the third insulating adhesive (6) above the head of the first current collector on the upper side is H4, wherein H4 satisfies: 0mm≤H4≤3.5mm; And / or, along the width direction of the battery cell, the gap between the third insulating adhesive (6) and the first insulating adhesive (4) and the second insulating adhesive (5) is ΔW, wherein 2mm≤ΔW≤8mm; And / or, along the width direction of the battery cell, the overlap width between the two sides of the second insulating adhesive (5) and the first current collector on the upper side and the first current collector on the lower side is W2, wherein W2 satisfies: 4mm≤W2≤18mm; And / or, along the height direction of the battery cell, the overlap height between the two sides of the second insulating adhesive (5) and the first current collector on the upper side and the first current collector on the lower side is H5, wherein H5 satisfies: 2mm≤H5≤10mm.

10. The battery cell according to any one of claims 5 to 9, characterized in that, The first insulating adhesive (4), the second insulating adhesive (5) and the third insulating adhesive (6) are each provided with multiple through holes (12).

11. The battery cell according to claim 10, characterized in that, The interval between two adjacent through holes (12) is D1, wherein D1 satisfies: 2mm≤D1≤10mm; And / or, the diameter of the through hole (12) is D2, wherein D2 satisfies: 0.5mm≤D2≤4mm.

12. A stacked battery, characterized in that, The battery cell includes any one of claims 1 to 11, wherein the first electrode (1), the separator (3) and the second electrode (2) are stacked alternately to form a stacked structure.

13. A wound battery, characterized in that, The battery cell includes any one of claims 1 to 11, wherein the first electrode (1), the separator (3) and the second electrode (2) are alternately stacked and wound to form a wound core structure.

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