Battery

Abstract

The present invention relates to the technical field of batteries, and discloses a battery, which comprises a battery cell, the battery cell comprises: a battery cell body having a first surface and a second surface oppositely arranged along the thickness direction; the battery cell body comprises a plurality of layers of pole pieces which are laminated along the thickness direction and first tabs which extend out from at least one end of each pole piece; the second tab is welded with the first tab to form a connecting area, the connecting area forms a concave part on one surface, deviating from the first tab, of the second tab, and the connecting area forms a convex part on one surface, deviating from the second tab, of the first tab; the first colloid is bonded with the first surface, the first tab and the second tab, and the first colloid covers the concave part; the second colloid is bonded with the second surface, the first tab and the second tab, and the second colloid covers the protruding part; the thickness of the first colloid is t1, the thickness of the second colloid is t2, and t1 is smaller than t2. The first colloid is thinned, so that the overall thickness of the battery cell can be reduced, the energy density of the battery is improved, and the flatness of the battery cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to batteries. Background Art

[0002] Lithium-ion batteries, with their high energy density, excellent cycle performance, and smaller size, are widely used in consumer electronics, new energy vehicles, and energy storage power stations. With the deepening implementation of the "dual carbon" initiative, lithium-ion batteries are gradually moving towards faster charging, higher energy density, and higher safety.

[0003] Battery cells are typically affixed with various adhesives, such as wrapping adhesive for securing the cell in place along its thickness, adhesive for securing the cell to the membrane casing, and tab protection adhesive for covering the tabs. These adhesives can easily affect the thickness and energy density of the battery, and can also cause bulging on the battery surface after cycling, affecting the battery's flatness. Summary of the Invention

[0004] In view of this, the present invention provides a battery to solve the problem in the prior art that the colloid attached to the battery cell easily affects the thickness of the battery cell and the energy density of the battery, and causes bulging on the battery surface after the battery cell cyclically expands, affecting the flatness of the battery.

[0005] The present invention provides a battery, comprising a battery cell, wherein the battery cell comprises:

[0006] The battery cell body has a first surface and a second surface arranged opposite to each other in a thickness direction;

[0007] The battery cell body comprises a plurality of electrode sheets stacked along the thickness direction and a first electrode tab extending from at least one end of the electrode sheets;

[0008] a second tab connected to the first tab to form a connection region, wherein the connection region forms a recessed portion on a side of the second tab facing away from the first tab, and a protruding portion on a side of the first tab facing away from the second tab;

[0009] a first colloid bonded to the first surface, the first tab, and the second tab, wherein the first colloid covers the recessed portion;

[0010] a second colloid bonded to the second surface, the first tab, and the second tab, the second colloid covering the protrusion;

[0011] Wherein, the thickness of the first colloid is t1, the thickness of the second colloid is t2, and t1<t2. In an optional embodiment, the thickness t1 of the first colloid and the thickness t2 of the second colloid satisfy 1 / 5≤t1 / t2≤3 / 5; and / or,

[0012] The thickness t1 of the first colloid satisfies 10 μm≤t1≤30 μm; and / or,

[0013] The thickness t2 of the second colloid satisfies 20 μm≤t2≤50 μm.

[0014] In an optional embodiment, the battery cell further includes a fixed colloid, and the fixed colloid is at least partially attached to the first surface and the second surface;

[0015] In which, along the thickness direction, at the overlapping projections of the first colloid and the second colloid, the total thickness of the battery cell is h2; along the thickness direction, the fixed colloid located on the first surface has a first farthest point away from the first surface, and the fixed colloid located on the second surface has a second farthest point away from the second surface, and the distance between the first farthest point and the second farthest point in the thickness direction is h3, satisfying h2≤h3.

[0016] In an optional embodiment, the fixing colloid includes a third colloid, and the third colloid is bonded to the first surface, the end surface of the battery cell body along the thickness direction, and the second surface at the same time; and / or,

[0017] The fixed colloid includes a fourth colloid, which is attached to the first surface and / or the second surface. The battery also includes a membrane shell, at least part of the battery cell is located in the membrane shell, and the fourth colloid connects the battery cell body and the membrane shell.

[0018] In an optional embodiment, the thickness of the third colloid is t3, the thickness of the fourth colloid is t4, t3≤t4 is satisfied, and the fourth colloid is attached to at least the second surface; and / or,

[0019] The thickness of the third colloid is t3, which satisfies 10 μm≤t3≤30 μm; and / or,

[0020] The thickness of the fourth colloid is t4, which satisfies 20 μm≤t4≤50 μm; and / or,

[0021] The orthographic projections of the third colloid and the fourth colloid on the first surface do not overlap; and / or,

[0022] The third colloid includes a first segment, a second segment and a third segment that are sequentially connected, the first segment is attached to the first surface, the second segment is attached to the end face of the battery cell body along the thickness direction, and the third segment is attached to the second surface; along the width direction, the width of the first segment is L3, satisfying 2mm≤L3≤20mm; and / or, along the width direction, the width of the third segment is L4, satisfying 2mm≤L4≤20mm; and / or, along the thickness direction, the thickness of the battery cell body between the first segment and the third segment is L, the width of the second segment is L5, satisfying 1<L5 / L≤1.2.

[0023] In an optional embodiment, the electrode sheet includes a current collector and an active material layer arranged on the current collector, the active material layer includes a main area and a thinning area formed at one end close to the first electrode ear, along the thickness direction, the thickness of the thinning area is less than the thickness of the main area, the minimum thickness of the thinning area is t5, and the thickness of the main area is t6, satisfying 0.9≤t5 / t6≤0.98.

[0024] In an optional embodiment, the thickness t1 of the first colloid, the thickness t2 of the second colloid, the thickness t3 of the third colloid, the thickness t4 of the fourth colloid, the minimum thickness t5 of the thinning area, and the thickness t6 of the main area satisfy t1+t2+t5≤t3+t4+t6; and / or,

[0025] Along the length direction, the orthographic projection of the first colloid on the first surface is located within the orthographic projection of the thinning area on the first surface; and / or,

[0026] Along the length direction, the orthographic projection of the second colloid on the second surface is located within the orthographic projection of the thinning area on the second surface; and / or,

[0027] Along the length direction, the length of the projection of the first colloid on the first surface is L1, which satisfies 2mm≤L1≤10mm; and / or,

[0028] Along the length direction, the length of the projection of the second colloid on the second surface is L2, which satisfies 2mm≤L2≤10mm; and / or,

[0029] The thickness t2 of the second colloid and the thickness t4 of the fourth colloid satisfy t2≥t4; and / or,

[0030] Along the thickness direction, the distance between the second surface and the side of the second colloid away from the second surface is Δh, the thickness of the fourth colloid is t4, and Δh≤t4 is satisfied; and / or,

[0031] The plurality of layers of electrode sheets include two outermost electrode sheets and an inner electrode sheet located between the two outermost electrode sheets, the outermost electrode sheet includes a current collector and an active material layer arranged on one side surface of the current collector along the thickness direction, the active material layer is arranged toward the inner electrode sheet, and the first colloid and the second colloid are attached to the other side surface of the current collector along the thickness direction.

[0032] In an optional embodiment, the first electrode tab includes a gathering portion, a merging portion, and a first bent portion connected in sequence, wherein a first end of the gathering portion is connected to an end of the battery cell body, and along the thickness direction, the merging portion is disposed close to the second surface, and a second end of the first bent portion is disposed close to the first surface;

[0033] The second electrode tab includes a second bent portion and a third bent portion that are connected to each other. The second bent portion is in contact with a surface of the first bent portion facing the battery cell body. The third bent portion is arranged at a predetermined angle to the second bent portion. The third bent portion extends in a direction away from the battery cell body.

[0034] In an optional embodiment, the angle between the confluence portion and the second bending portion is α, which satisfies α≤90°; and / or,

[0035] The first colloid comprises a first adhesive segment, a second adhesive segment, a third adhesive segment, and a fourth adhesive segment connected in sequence, wherein the first adhesive segment is attached to the first surface, the second adhesive segment is attached to the gathered portion and / or the converging portion, the third adhesive segment is attached to the second bent portion, and the fourth adhesive segment is attached to the third bent portion; and / or;

[0036] The second colloid includes a fifth adhesive segment, a sixth adhesive segment, a seventh adhesive segment and an eighth adhesive segment connected in sequence, the fifth adhesive segment is attached to the second surface, the sixth adhesive segment is attached to the gathered portion and / or the converging portion, the seventh adhesive segment is attached to the first bending portion, and the eighth adhesive segment is attached to the third bending portion.

[0037] In an optional embodiment, along the thickness direction, a distance between a side of the fourth bonding section away from the third bending portion and a side of the second bonding section away from the confluence portion is h1, and at the first bonding section and the fifth bonding section, a total thickness of the battery cell is h2, satisfying h1≤h2.

[0038] The technical solution of this application has the following advantages:

[0039] By thinning the first colloid, the overall thickness of the battery cell can be reduced, thereby improving the energy density of the battery, and avoiding the positions of the first colloid and the second colloid from becoming the maximum points of the battery cell thickness after the battery cell cyclically expands, that is, avoiding the formation of bulges, thereby improving the flatness of the battery cell; and the first colloid is used to cover the recessed portion of the connection area, and the second colloid is used to cover the protruding portion of the connection area. Therefore, even if the thickness of the first colloid is thinned relative to the thickness of the second colloid, the connection area will not puncture the first colloid, and the second colloid is kept of sufficient thickness, so that even the protruding portion of the connection area will not puncture the second colloid, thereby ensuring the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 is a schematic cross-sectional view of a battery cell according to an embodiment of the present invention;

[0042] Figure 2 for Figure 1 A schematic structural diagram of a portion of the battery cell shown;

[0043] Figure 3 for Figure 2 Schematic diagram of the dimensions of the battery cell shown;

[0044] Figure 4 for Figure 1 A schematic structural diagram of another part of the battery cell shown;

[0045] Figure 5 This is a schematic structural diagram of a third colloid and a battery cell body according to an embodiment of the present invention;

[0046] Figure 6 This is a schematic structural diagram of a pole piece according to an embodiment of the present invention;

[0047] Figure 7 for Figure 6 The diagram of the cooperation between the electrode and the second colloid is shown;

[0048] Figure 8 This is a schematic structural diagram of another pole piece according to an embodiment of the present invention;

[0049] Figure 9 This is a schematic diagram of a first arrangement of the third colloid on the first surface according to an embodiment of the present invention;

[0050] Figure 10 for Figure 9 A schematic diagram of the third colloid shown on the second surface;

[0051] Figure 11 This is a schematic diagram of a second arrangement of the third colloid on the first surface according to an embodiment of the present invention;

[0052] Figure 12 for Figure 11 A schematic diagram of the third colloid shown on the second surface;

[0053] Figure 13 This is a schematic diagram of a third arrangement of the third colloid on the first surface according to an embodiment of the present invention;

[0054] Figure 14 for Figure 13 A schematic diagram of the third colloid shown on the second surface;

[0055] Figure 15 This is a schematic diagram of a fourth arrangement of the third colloid on the first surface according to an embodiment of the present invention;

[0056] Figure 16 for Figure 15 A schematic diagram of the third colloid shown on the second surface;

[0057] Figure 17 This is a schematic diagram of a fifth arrangement of the third colloid on the first surface according to an embodiment of the present invention;

[0058] Figure 18 for Figure 17 A schematic diagram of the third colloid shown on the second surface;

[0059] Figure 19 This is a schematic diagram of a sixth arrangement of the third colloid on the first surface according to an embodiment of the present invention;

[0060] Figure 20 for Figure 19 A schematic diagram of the third colloid shown on the second surface;

[0061] Figure 21 is a schematic diagram of a fourth colloid on a first surface according to an embodiment of the present invention;

[0062] Figure 22 FIG. 4 is a schematic diagram of a fourth colloid on a second surface according to an embodiment of the present invention.

[0063] Description of reference numerals:

[0064] 10. Cell; 1. Cell body; 11. First surface; 12. Second surface; 13. Pole piece; 131. Thinning area; 132. Main body area; 133. Current collector; 134. Active material layer; 14. Outermost pole piece; 15. Inner pole piece; 16. First side; 17. Second side; 18. Third side; 19. Fourth side; 2. First tab; 21. Gathering portion; 22. Junction; 23. First bend; 3. Second tab; 31. Second bend 32. Third bend; 4. Connecting area; 41. Recessed portion; 42. Protruding portion; 5. First colloid; 51. First bonding section; 52. Second bonding section; 53. Third bonding section; 54. Fourth bonding section; 6. Second colloid; 61. Fifth bonding section; 62. Sixth bonding section; 63. Seventh bonding section; 64. Eighth bonding section; 7. Fixing colloid; 71. Third colloid; 711. First subsection; 712. Second subsection; 713. Third subsection; 72. Fourth colloid. DETAILED DESCRIPTION

[0065] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0066] The following combination Figures 1 to 22 , describing embodiments of the present invention.

[0067] According to an embodiment of the present invention, a battery is provided, including a battery cell 10. The battery cell 10 includes: a battery cell body 1 having a first surface 11 and a second surface 12 disposed opposite each other along a thickness direction; the battery cell body 1 including a plurality of electrode sheets 13 stacked along the thickness direction and a first electrode tab 2 extending from at least one end of the electrode sheet 13; a second electrode tab 3 connected to the first electrode tab 2 to form a connection region 4, wherein the connection region 4 forms a recessed portion 41 on a side of the second electrode tab 3 facing away from the first electrode tab 2, and a protruding portion 42 on a side of the first electrode tab 2 facing away from the second electrode tab 3; a first colloid 5 bonded to the first surface 11, the first electrode tab 2, and the second electrode tab 3, with the first colloid 5 covering the recessed portion 41; and a second colloid 6 bonded to the second surface 12, the first electrode tab 2, and the second electrode tab 3, with the second colloid 6 covering the protruding portion 42. The first colloid 5 has a thickness t1, and the second colloid 6 has a thickness t2, satisfying the condition t1 < t2.

[0068] In the battery of this embodiment, by thinning the first colloid 5, the overall thickness of the battery cell 10 can be reduced, thereby improving the energy density of the battery, and avoiding the positions of the first colloid 5 and the second colloid 6 from becoming the maximum points of the thickness of the battery cell 10 after the battery cell cyclic expansion, that is, avoiding the formation of bulges, thereby improving the flatness of the battery cell; and the first colloid 5 is used to cover the recessed portion 41 of the connecting area 4, and the second colloid 6 is used to cover the protruding portion 42 of the connecting area 4. Therefore, even if the thickness of the first colloid 5 is thinned relative to the thickness of the second colloid 6, the connecting area 4 will not puncture the first colloid 5, and the second colloid 6 is kept of sufficient thickness, so that even the protruding portion of the connecting area 4 will not puncture the second colloid 6, thereby ensuring the safety performance of the battery.

[0069] It is worth noting that, by providing the first colloid 5 and the second colloid 6 , the first electrode tab 2 and the second electrode tab 3 can be protected, insulated, and fixed, and the connection area 4 can be protected.

[0070] It should be noted that in the related art, the thickness of the first colloid 5 and the thickness of the second colloid 6 are usually set to the same thickness. Although this can make the second colloid 6 have a sufficient thickness to avoid being punctured by the raised portion of the connection area 4, it can also cause the thickness of the first colloid 5 to be too thick, resulting in the thickness of the battery cell 10 being too thick, affecting the energy density of the battery. Moreover, during the battery's charge and discharge cycles, it is easy to cause the location of the first colloid 5 to expand and bulge, becoming the maximum point of the thickness of the battery cell 10, affecting the flatness of the battery. Therefore, in this embodiment, considering that the first colloid 5 covers the location of the recessed portion 41 of the connection area 4, even if the thickness of the first colloid 5 is reduced, it will not cause the first colloid 5 to be punctured. Therefore, in this embodiment, the thickness of the first colloid 5 is made thinner than the thickness of the second colloid 6, which can not only improve the energy density of the battery, but also improve the flatness of the battery surface, and also ensure the safety performance of the battery.

[0071] Specifically, in one embodiment, the first tab 2 is a soft tab, and the second tab 3 is a hard tab. The soft tab and the hard tab have an overlapping position, and the soft tab and the hard tab are connected by welding at the overlapping position. Furthermore, welding is performed from the side of the hard tab away from the soft tab, so that at the connection area 4, the surface of the hard tab away from the soft tab has a depression to form a depression 41, and the surface of the soft tab away from the hard tab has a protrusion to form a protrusion.

[0072] It should be noted that after the soft tab and the hard tab are welded and the first colloid 5 and the second colloid 6 are pasted, the soft tab and the hard tab need to be bent to form a predetermined shape structure. Therefore, in this embodiment, by thinning the first colloid 5, the bending of the tab can be more facilitated.

[0073] In one embodiment, Figure 3 As shown, the thickness t1 of the first colloid 5 and the thickness t2 of the second colloid 6 satisfy 1 / 5≤t1 / t2≤3 / 5. This arrangement improves the energy density of the battery and the flatness of the battery surface while ensuring the protection effect of the first colloid 5 on the tabs and the connection area 4.

[0074] It is worth noting that if the value of t1 / t2 is too small, the first colloid 5 is too thin and easily damaged, and the protection effect on the tab and the connection area 4 is poor, affecting the safety performance of the battery. Alternatively, the second colloid 6 is too thick, which can easily lead to an excessive thickness of the battery cell 10, affecting the energy density of the battery. If the value of t1 / t2 is too large, the first colloid 5 is too thick, which can easily lead to an excessive thickness of the battery cell 10, affecting the energy density of the battery, and can easily cause the location of the first colloid 5 to swell and bulge, becoming the maximum point of the thickness of the battery cell 10, affecting the flatness of the battery. Alternatively, if the second colloid 6 is too thin, it can easily be punctured by the protrusion of the connection area 4, and there is a risk of puncturing the aluminum-plastic film, affecting the safety performance of the battery.

[0075] Optionally, the value of t1 / t2 is any value among 1 / 5, 2 / 5, 1 / 2, 3 / 5, or a value between any two values.

[0076] Furthermore, in one embodiment, Figure 3 As shown, the thickness t1 of the first colloid 5 satisfies 10 μm≤t1≤30 μm. This configuration improves the energy density of the battery and the flatness of the battery surface while ensuring the protective effect of the first colloid 5 on the tabs and the connection area 4.

[0077] It is worth noting that if the value of t1 is too small, the first colloid 5 is too thin, the first colloid 5 is easily damaged, and the protection effect on the tabs and the connection area 4 is poor, affecting the safety performance of the battery; if the value of t1 is too large, the first colloid 5 is too thick, which can easily lead to an excessive thickness of the overall battery cell 10, affecting the energy density of the battery, and easily causing the position of the first colloid 5 to swell and become the maximum point of the thickness of the battery cell 10, affecting the flatness of the battery.

[0078] Optionally, the value of t1 is any value among 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, or a value between any two values.

[0079] Furthermore, in one embodiment, Figure 3 As shown, the thickness t2 of the second colloid 6 satisfies 20 μm≤t2≤50 μm. This configuration improves the energy density of the battery while ensuring the safety performance of the battery.

[0080] It is worth noting that if the value of t2 is too small, the second colloid 6 is too thin, which may easily cause the second colloid 6 to be punctured by the protrusion of the connection area 4, affecting the safety performance of the battery; if the value of t2 is too large, the second colloid 6 is too thick, which may easily cause the overall thickness of the battery cell 10 to be too large, affecting the energy density of the battery.

[0081] Optionally, the value of t2 is any value among 20μm, 22μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 42μm, 45μm, 48μm, 50μm, or a value between any two values.

[0082] In one embodiment, Figure 4 As shown, the battery cell 10 further includes a fixed colloid 7, which is at least partially attached to the first surface 11 and the second surface 12; wherein, along the thickness direction, at the overlapping projections of the first colloid 5 and the second colloid 6, the total thickness of the battery cell 10 is h2; along the thickness direction, the fixed colloid 7 located on the first surface 11 has a first farthest point away from the first surface 11, and the fixed colloid 7 located on the second surface 12 has a second farthest point away from the second surface 12, and the distance between the first farthest point and the second farthest point in the thickness direction is h3, satisfying h2≤h3. By providing the fixing colloid 7, the fixation of the electrode 13 of the battery cell 10 and the connection and fixation with the membrane shell are satisfied, and the total thickness of the battery cell 10 corresponding to the fixing colloid 7 is not less than the total thickness of the battery cell 10 corresponding to the first colloid 5 and the second colloid 6, avoiding the position of the first colloid 5 and the second colloid 6 becoming the maximum point of the thickness of the battery cell 10, thereby reducing the overall thickness of the battery and improving the battery energy density. In addition, after the battery charge and discharge cycle, it is avoided that the thickness of the first adhesive tape and the second adhesive tape exceeds the thickness of the fixing colloid 7 due to the expansion of the battery cell 10, thereby ensuring the flatness of the battery.

[0083] Specifically, in one embodiment, Figure 4 and Figure 5 As shown, the fixing colloid 7 includes a third colloid 71, which is bonded to the first surface 11, the end surface of the battery cell body 1 along the thickness direction, and the second surface 12. In other words, the third colloid 71 is a wrap-around adhesive that limits the position of the multiple layers of electrode sheets 13 along the thickness direction, thereby preventing delamination of the battery cell 10.

[0084] It is worth noting that if Figures 9 to 20As shown, the third colloid 71 is attached to the four edges of the battery cell body 1. Specifically, the battery cell body 1 has a square structure, including a first side 16 extending from the first electrode tab 2, a second side 17 spaced apart from the first side 16, and a third side 18 and a fourth side 19 connected between the first side 16 and the second side 17. The third colloid 71 is provided on at least one of the first side 16, the second side 17, the third side 18, and the fourth side 19. In addition, one third colloid 71 can be provided on the side, or several third colloids 71 ​​can be provided at intervals. In addition, the third colloid 71 can be provided near the middle of the side, or near the connection between the two sides (i.e., the corner of the square structure).

[0085] Specifically, in one embodiment, Figure 4 As shown, the fixing colloid 7 further includes a fourth colloid 72, which is attached to the first surface 11 and / or the second surface 12. The battery further includes a membrane shell, and at least a portion of the battery cell 10 is located within the membrane shell. The fourth colloid 72 connects the battery cell body 1 and the membrane shell. In other words, the fourth colloid 72 adheres and secures the large surface of the battery cell 10 to the membrane shell, thereby restricting the position of the battery cell 10 within the membrane shell and improving the reliability and safety of the battery.

[0086] It is worth noting that, please refer to Figure 20 and Figure 21 The fourth colloid 72 may be disposed only on the first surface 11 , or only on the second surface 12 , or on both the first surface 11 and the second surface 12 . Specifically, in this embodiment, the fourth colloid 72 is disposed only on the second surface 12 .

[0087] It should be noted that, in this embodiment, Figure 4 As shown, h2 is the sum of the thickness of the battery cell body 1 corresponding to the first colloid 5 and the second colloid 6, the thickness of the first colloid 5, and the thickness of the second colloid 6; h3 is the distance in the thickness direction between the first farthest point of the third colloid 71 located on the first surface 11 away from the first surface 11 and the second farthest point of the fourth colloid 72 located on the second surface 12 away from the second surface 12, and is further the sum of the thickness of the battery cell body 1 corresponding to the fixed colloid 7, the thickness of the third colloid 71, and the thickness of the fourth colloid 72.

[0088] Furthermore, in this embodiment, the fourth colloid 72 is hot melt adhesive. Of course, as an alternative embodiment, the fourth colloid 72 can also be other types of colloids, such as solid adhesive or liquid adhesive.

[0089] Furthermore, in this embodiment, the membrane shell is an aluminum-plastic film, that is, the battery is a soft-pack battery. Of course, as an alternative embodiment, the membrane shell can also be a metal shell, that is, the battery is a hard shell battery, such as an aluminum shell, a steel shell, etc.

[0090] It is worth noting that by providing the second colloid 6 with a relatively large thickness, it is possible to prevent the protrusions of the connection area 4 from scratching the PP layer of the aluminum-plastic film, thereby preventing contact with the aluminum layer and causing a micro short circuit.

[0091] In one embodiment, Figure 4 As shown, the thickness of the third colloid 71 is t3, and the thickness of the fourth colloid 72 is t4, satisfying t3≤t4. At least the second surface 12 is attached with the fourth colloid 72. This arrangement allows the thicker second colloid 6 and the fourth colloid 72 to be placed corresponding to the second surface 12, ensuring the flatness of the battery on the second surface 12.

[0092] Furthermore, in one embodiment, Figure 4 As shown, the thickness of the third colloid 71 is t3, which satisfies 10 μm≤t3≤30 μm. This arrangement ensures the limiting effect of the electrode 13 while improving the energy density of the battery.

[0093] It is worth noting that if the value of t3 is too small, the third colloid 71 is too thin, which makes the third colloid 71 easily damaged, and then easily causes the fixation failure of several layers of electrode sheets 13, resulting in low safety and reliability of the battery; if the value of t3 is too large, the third colloid 71 is too thick, which easily causes the overall thickness of the battery cell 10 to be too large, affecting the energy density of the battery.

[0094] Optionally, the value of t3 is any value among 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, or a value between any two values.

[0095] Furthermore, in one embodiment, Figure 4 As shown, the thickness of the fourth colloid 72 is t4, which satisfies 20 μm≤t4≤50 μm. This arrangement ensures the position stability of the battery cell 10 while improving the energy density of the battery.

[0096] It is worth noting that if the value of t4 is too small, the fourth colloid 72 is too thin, and the fixing effect on the battery cell 10 is poor, which may easily cause the battery cell to move in the membrane shell, and thus easily cause battery safety problems; if the value of t4 is too large, the fourth colloid 72 is too thick, which may easily cause the overall thickness of the battery cell 10 to be too large, affecting the energy density of the battery.

[0097] Optionally, the value of t4 is any value among 20μm, 22μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 42μm, 45μm, 48μm, 50μm, or a value between any two values.

[0098] In one embodiment, the orthographic projections of the third colloid 71 and the fourth colloid 72 on the first surface 11 do not overlap. That is, the third colloid 71 and the fourth colloid 72 do not overlap, thereby preventing the thickness of the third colloid 71 and the fourth colloid 72 from overlapping and causing the battery cell 10 to be locally too thick, thereby ensuring the energy density of the battery and the flatness of the battery surface.

[0099] In one embodiment, Figure 5 As shown, the third colloid 71 includes a first segment 711, a second segment 712, and a third segment 713, which are sequentially connected. The first segment 711 is attached to the first surface 11, the second segment 712 is attached to the end face of the battery cell body 1 along the thickness direction, and the third segment 713 is attached to the second surface 12. In the width direction, the width of the first segment 711 is L3, satisfying 2mm≤L3≤20mm; the width of the third segment 713 is L4, satisfying 2mm≤L4≤20mm; in the thickness direction, the thickness of the battery cell body 1 between the first segment 711 and the third segment 713 is L, and the width of the second segment 712 is L5, satisfying 1<L5 / L≤1.2. This arrangement ensures the stability of the third colloid 71's adhesion to the battery cell body 1 while reserving sufficient area for the second colloid 6, thereby ensuring the energy density of the battery.

[0100] It is worth noting that if the values ​​of L3 and / or L4 are too small, the width of the third colloid 71 bonded to the first surface 11 and / or the second surface 12 is too short, and the bonding strength between the third colloid 71 and the battery cell body 1 is weak, which may easily cause the third colloid 71 to separate from the battery cell body 1, and then easily cause the fixation of several layers of electrode sheets 13 to fail, resulting in low safety and reliability of the battery; if the values ​​of L3 and / or L4 are too large, the area occupied by the third colloid 71 on the first surface 11 and / or the second surface 12 is too large. In order to ensure that the third colloid 71 and the fourth colloid 72 do not overlap, the setting area of ​​the fourth colloid 72 will be too small, resulting in poor fixation effect on the battery cell 10, and easily causing the battery cell to move in the membrane shell, which may easily cause battery safety problems.

[0101] Optionally, the values ​​of L3 and L4 can be any value among 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, or a value between any two values.

[0102] It's worth noting that L5 is the distance between the side of the first segment 711 facing away from the first surface 11 and the side of the third segment 713 facing away from the second surface 12, or L5 = L + 2 × t3. Therefore, the attachment of the third colloid 71 to both the first and second surfaces 11, 12 results in L5 being greater than L. Furthermore, the thickness of the third colloid 71 need not be excessive; it only needs to be sufficient to prevent it from breaking during battery expansion during cycling. Furthermore, excessive thickness should be avoided, as it could negatively impact the battery's energy density.

[0103] In one embodiment, Figure 6 As shown, the electrode 13 includes a current collector 133 and an active material layer arranged on the current collector 133. The active material layer includes a main area 132 and a thinning area 131 formed at one end close to the first electrode tab 2. Along the thickness direction, the thickness of the thinning area 131 is less than the thickness of the main area 132.

[0104] It is worth noting that the plurality of electrode sheets 13 include a plurality of positive electrode sheets 13 and a plurality of negative electrode sheets 13. In this embodiment, the plurality of positive electrode sheets 13 and the plurality of negative electrode sheets 13 are all provided with thinning regions 131. As an alternative embodiment, if the negative electrode adopts the ZTZ process, the thinning regions 131 may be provided only on the plurality of positive electrode sheets 13, while the negative electrode sheets 13 are not provided with the thinning regions 131.

[0105] It should be noted that the electrode 13 includes a current collector 133 and an active material layer 134 provided on at least one surface of the current collector 133 along the thickness direction. The thinning area 131 is formed by thinning one end of the active material layer 134 close to the first electrode tab 2.

[0106] Specifically, in one embodiment, Figure 6 As shown, the minimum thickness of the thinning area 131 is t5, and the thickness of the main area 132 is t6, satisfying 0.9≤t5 / t6≤0.98.

[0107] Furthermore, in one embodiment, the thickness t1 of the first colloid 5, the thickness t2 of the second colloid 6, the thickness t3 of the third colloid 71, the thickness t4 of the fourth colloid 72, the minimum thickness t5 of the thinning area 131, and the thickness t6 of the main area 132 satisfy t1+t2+t5≤t3+t4+t6.

[0108] It is worth noting that the thickness of the cell body 1 corresponding to the main region 132 of the electrode 13 is the sum of the thicknesses of the main regions 132 of the electrode 13 in several layers, and the minimum thickness of the cell body 1 corresponding to the thinned region 131 of the electrode 13 is the sum of the minimum thicknesses of the thinned regions 131 in several layers. As can be seen from the above, the total thickness of the cell 10 at the first and second colloids 5 and 6 is h2, and the total thickness of the cell 10 at the fixed colloid 7 is h3, satisfying h2≤h3. Therefore, it can be seen that t1+t2+t5≤t3+t4+t6.

[0109] In one embodiment, along the length direction, the orthographic projection of the first colloid 5 on the first surface 11 is located within the orthographic projection of the thinning region 131 on the first surface 11. That is, the portion of the first colloid 5 located on the first surface 11 (i.e., the first bonding section 51 described below) is located within the thinning region 131, preventing the first colloid 5 from extending beyond the thinning region 131 along the length direction and adhering to the main body region 132, thereby further preventing the battery cell 10 from being too thick.

[0110] In one embodiment, along the length direction, the orthographic projection of the second colloid 6 on the second surface 12 is located within the orthographic projection of the thinning region 131 on the second surface 12. That is, the portion of the second colloid 6 located on the second surface 12 (i.e., the fifth bonding section 61 described below) is located within the thinning region 131, preventing the second colloid 6 from extending beyond the thinning region 131 along the length direction and adhering to the main body region 132, thereby further reducing the thickness of the battery cell 10.

[0111] Specifically, in one embodiment, Figure 3 As shown, along the length direction, the length of the projection of the first colloid 5 on the first surface 11 is L1, which satisfies 2 mm ≤ L1 ≤ 10 mm.

[0112] Specifically, in one embodiment, Figure 3 As shown, along the length direction, the length of the projection of the second colloid 6 on the second surface 12 is L2, which satisfies 2 mm ≤ L2 ≤ 10 mm.

[0113] It is worth noting that by limiting the values ​​of L1 and L2, the bonding strength between the first colloid 5 and the second colloid 6 and the battery cell body 1 is ensured while preventing the battery cell 10 from being too thick. Specifically, if the values ​​of L1 and / or L2 are too large, the first colloid 5 and / or the second colloid 6 may easily extend into the main body region 132, which may cause the battery cell 10 to be too thick. If the values ​​of L1 and / or L2 are too small, the length of the first colloid 5 and / or the second colloid 6 attached to the battery cell body 1 may be too small, which may lead to loose adhesion and detachment of the first colloid 5 and / or the second colloid 6, thus affecting the safety performance of the battery.

[0114] It should be further explained that the provision of the first colloid 5 and the second colloid 6 can compensate for the reduced thickness of the thinned area 131 to a certain extent, thereby improving the consistency of the pressure of the battery cell 10 during formation.

[0115] Optionally, the values ​​of L1 and L2 can be any value among 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or a value between any two values.

[0116] In one embodiment, the thickness t2 of the second colloid 6 and the thickness t4 of the fourth colloid 72 satisfy t2 ≥ t4. Since both the second colloid 6 and the fourth colloid 72 are attached to the second surface 12, and the second colloid 6 is located in the thinned area 131 and the fourth colloid 72 is located in the main area 132, setting the thickness of the second colloid 6 to be no less than the thickness of the fourth colloid 72 is more conducive to using the thickness of the second colloid 6 to compensate for the thinned thickness of the thinned area 131, which can further improve the flatness of the battery surface.

[0117] It should be noted that in this embodiment, the aluminum-plastic film includes a first film body and a second film body. The first film body has a pit, and the second film body is a planar structure. The first film body and the second film body are butted together so that the second film body covers the pit. The first film body and the second film body enclose a receiving space for accommodating the battery cell 10. Furthermore, the second colloid 6 and the fourth colloid 72 are both located on the pit surface.

[0118] Furthermore, in one embodiment, Figure 7 As shown, along the thickness direction, the distance between the side of the second colloid 6 away from the second surface 12 and the second surface 12 is Δh, and the thickness of the fourth colloid 72 is t4, satisfying Δh≤t4. That is, the thickness of the second colloid 6 extending beyond the second surface 12 is no greater than the thickness of the fourth colloid 72. This prevents the location of the first colloid 5 and the second colloid 6 from becoming the maximum thickness point of the battery cell 10 after cycling and expansion, thus preventing the formation of bulges and improving the flatness of the battery cell.

[0119] In one embodiment, Figure 6 and Figure 8 As shown, the plurality of electrode sheets 13 include two outermost electrode sheets 14 and an inner electrode sheet 15 located between the two outermost electrode sheets 14. The outermost electrode sheet 14 includes a current collector 133 and an active material layer 134 disposed on one side of the current collector 133 along the thickness direction. The active material layer 134 is disposed toward the inner electrode sheet 15. The first colloid 5 and the second colloid 6 are attached to the other side of the current collector 133 along the thickness direction. That is, the first colloid 5 and the second colloid 6 are attached to a single-sided foil.

[0120] In one embodiment, Figure 2As shown, the first electrode tab 2 includes a gathering portion 21, a converging portion 22 and a first bending portion 23 connected in sequence. The first end of the gathering portion 21 is connected to the end of the battery cell body 1, the second end of the gathering portion 21 is connected to the first end of the converging portion 22, and the second end of the converging portion 22 is connected to the first end of the first bending portion 23. Along the thickness direction, the converging portion 22 is arranged close to the second surface 12, and the first bending portion 23 is arranged at a predetermined angle to the converging portion 22, so that the second end of the first bending portion 23 is arranged close to the first surface 11.

[0121] Further, such as Figure 2 As shown, the second electrode tab 3 includes a second bending portion 31 and a third bending portion 32 that are connected to each other. The second bending portion 31 is in contact with the first bending portion 23 on one side facing the battery cell body 1. The third bending portion 32 is arranged at a predetermined angle to the second bending portion 31, and the third bending portion 32 extends in a direction away from the battery cell body 1.

[0122] It is worth noting that if Figure 2 As shown, the first tab 2 includes several layers of tab sheets stacked along the thickness direction, and the several layers of tab sheets are respectively connected to several layers of pole sheets 13. The several layers of tab sheets are gathered and merged, and then bent after merging, thereby forming a gathered portion 21, a merged portion 22 and a first bent portion 23.

[0123] Furthermore, in one embodiment, Figure 3 As shown, the angle between the junction 22 and the second bent portion 31 is α, which satisfies α≤90°. This configuration can further save space at the tab end of the battery cell 10 and further improve the energy density of the battery.

[0124] In one embodiment, Figure 2 As shown, the first colloid 5 includes a first adhesive segment 51, a second adhesive segment 52, a third adhesive segment 53, and a fourth adhesive segment 54, which are connected in sequence. The first adhesive segment 51 is attached to the first surface 11, the second adhesive segment 52 is attached to the gathered portion 21 and / or the converging portion 22, the third adhesive segment 53 is attached to the second bent portion 31, and the fourth adhesive segment 54 is attached to the third bent portion 32. With this arrangement, the first colloid 5 forms a substantially U-shaped or V-shaped portion between the gathered portion 21 and the second bent portion 31. In this embodiment, the first colloid 5 is thinned, thereby saving twice the space of the thinned thickness between the gathered portion 21 and the second bent segment, further saving space at the tab end of the battery cell 10, thereby further improving the energy density of the battery.

[0125] In one embodiment, Figure 2As shown, the second colloid 6 includes a fifth adhesive segment 61, a sixth adhesive segment 62, a seventh adhesive segment 63, and an eighth adhesive segment 64, which are connected in sequence. The fifth adhesive segment 61 is attached to the second surface 12, the sixth adhesive segment 62 is attached to the gathered portion 21 and / or the converging portion 22, the seventh adhesive segment 63 is attached to the first bend 23, and the eighth adhesive segment 64 is attached to the third bend. This arrangement allows both the first colloid 5 and the second colloid 6 to extend and adhere to the third bend, improving the protection of the first and second tabs 2 and 3 and preventing the foil from being exposed at the bend of the first and second tabs 2 and 3.

[0126] It is worth noting that the first colloid 5 and the second colloid 6 are located inside the aluminum-plastic film, thereby ensuring the sealing effect after the aluminum-plastic film is encapsulated.

[0127] In one embodiment, Figure 3 As shown, along the thickness direction, the distance between the side of the fourth bonding section 54 away from the third bend 32 and the side of the second bonding section 52 away from the junction 22 is h1. At the first bonding section 51 and the fifth bonding section 61, the total thickness of the battery cell 10 is h2, satisfying h1 ≤ h2. This arrangement prevents the battery cell 10 from being too thick on the tab side, preventing it from being encapsulated with aluminum-plastic film.

[0128] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: The invention comprises a battery core (10), wherein the battery core (10) comprises: A battery cell body (1) having a first surface (11) and a second surface (12) arranged opposite to each other along a thickness direction; The battery cell body (1) comprises a plurality of electrode sheets (13) stacked in a thickness direction and a first electrode tab (2) extending from at least one end of the electrode sheets (13); A second pole tab (3) is connected to the first pole tab (2) to form a connection area (4), wherein the connection area (4) forms a recessed portion (41) on a side of the second pole tab (3) facing away from the first pole tab (2), and a protruding portion (42) on a side of the first pole tab (2) facing away from the second pole tab (3); a first colloid (5) bonded to the first surface (11), the first tab (2), and the second tab (3), the first colloid (5) covering the recessed portion (41); a second colloid (6) bonded to the second surface (12), the first tab (2) and the second tab (3), the second colloid (6) covering the protrusion (42); The thickness of the first colloid (5) is t1, and the thickness of the second colloid (6) is t2, satisfying t1<t2.

2. The battery according to claim 1, characterized in that The thickness t1 of the first colloid (5) and the thickness t2 of the second colloid (6) satisfy 1 / 5≤t1 / t2≤3 / 5; and / or, The thickness t1 of the first colloid (5) satisfies 10 μm≤t1≤30 μm; and / or, The thickness t2 of the second colloid (6) satisfies 20 μm≤t2≤50 μm.

3. The battery according to claim 1 or 2, characterized in that The battery core (10) further includes a fixed colloid (7), wherein the fixed colloid (7) is at least partially attached to the first surface (11) and the second surface (12); Wherein, along the thickness direction, at the overlapping projection of the first colloid (5) and the second colloid (6), the total thickness of the battery cell (10) is h2; along the thickness direction, the fixed colloid (7) located on the first surface (11) has a first farthest point away from the first surface (11), and the fixed colloid (7) located on the second surface (12) has a second farthest point away from the second surface (12), and the distance between the first farthest point and the second farthest point in the thickness direction is h3, satisfying h2≤h3.

4. The battery according to claim 3, characterized in that The fixed colloid (7) includes a third colloid (71), and the third colloid (71) is bonded to the first surface (11), the end surface of the battery cell body (1) along the thickness direction, and the second surface (12) at the same time; and / or, The fixed colloid (7) includes a fourth colloid (72), and the fourth colloid (72) is attached to the first surface (11) and / or the second surface (12). The battery also includes a membrane shell, and at least part of the battery cell (10) is located in the membrane shell. The fourth colloid (72) connects the battery cell body (1) and the membrane shell.

5. The battery according to claim 4, characterized in that The thickness of the third colloid (71) is t3, the thickness of the fourth colloid (72) is t4, t3≤t4 is satisfied, and at least the second surface (12) is attached with the fourth colloid (72); and / or, The thickness of the third colloid (71) is t3, which satisfies 10 μm≤t3≤30 μm; and / or, The thickness of the fourth colloid (72) is t4, which satisfies 20 μm≤t4≤50 μm; and / or, The orthographic projections of the third colloid (71) and the fourth colloid (72) on the first surface (11) do not overlap; and / or, The third colloid (71) comprises a first segment (711), a second segment (712), and a third segment (713) which are sequentially connected, the first segment (711) being attached to the first surface (11), the second segment (712) being attached to the end surface of the battery cell body (1) along the thickness direction, and the third segment (713) being attached to the second surface (12); Along the width direction, the width of the first segment (711) is L3, satisfying 2mm≤L3≤20mm; and / or, along the width direction, the width of the third segment (713) is L4, satisfying 2mm≤L4≤20mm; and / or, along the thickness direction, the thickness of the battery cell body (1) between the first segment (711) and the third segment (713) is L, and the width of the second segment (712) is L5, satisfying 1<L5 / L≤1.

2.

6. The battery according to claim 4, characterized in that The electrode sheet includes a current collector (133) and an active material layer arranged on the current collector (133), the active material layer includes a main region (132) and a thinning region (131) formed at one end close to the first electrode tab (2), along the thickness direction, the thickness of the thinning region (131) is less than the thickness of the main region (132), the minimum thickness of the thinning region (131) is t5, and the thickness of the main region (132) is t6, satisfying 0.9≤t5 / t6≤0.

98.

7. The battery according to claim 6, characterized in that The thickness t1 of the first colloid (5), the thickness t2 of the second colloid (6), the thickness t3 of the third colloid (71), the thickness t4 of the fourth colloid (72), the minimum thickness t5 of the thinning area (131), and the thickness t6 of the main area (132) satisfy t1+t2+t5≤t3+t4+t6; and / or, Along the length direction, the orthographic projection of the first colloid (5) on the first surface (11) is located within the orthographic projection of the thinning area (131) on the first surface (11); and / or, Along the length direction, the orthographic projection of the second colloid (6) on the second surface (12) is located within the orthographic projection of the thinning area (131) on the second surface (12); and / or, Along the length direction, the length of the projection of the first colloid (5) on the first surface (11) is L1, which satisfies 2mm≤L1≤10mm; and / or, Along the length direction, the length of the projection of the second colloid (6) on the second surface (12) is L2, which satisfies 2mm≤L2≤10mm; and / or, The thickness t2 of the second colloid (6) and the thickness t4 of the fourth colloid (72) satisfy t2≥t4; and / or, In the thickness direction, the distance between the second surface (12) and the side of the second colloid (6) away from the second surface (12) is Δh, the thickness of the fourth colloid (72) is t4, and Δh≤t4 is satisfied; and / or, The plurality of layers of pole pieces (13) include two outermost pole pieces (14) and an inner pole piece (15) located between the two outermost pole pieces (14); the outermost pole piece (14) includes a current collector (133) and an active material layer (134) arranged on one side surface of the current collector (133) along the thickness direction; the active material layer (134) is arranged toward the inner pole piece (15); the first colloid (5) and the second colloid (6) are attached to the other side surface of the current collector (133) along the thickness direction.

8. The battery according to claim 1 or 2, characterized in that The first electrode tab (2) comprises a gathering portion (21), a merging portion (22) and a first bending portion (23) connected in sequence, wherein the first end of the gathering portion (21) is connected to the end of the battery cell body (1), and along the thickness direction, the merging portion (22) is arranged close to the second surface (12), and the second end of the first bending portion (23) is arranged close to the first surface (11); The second pole lug (3) comprises a second bent portion (31) and a third bent portion (32) which are connected to each other; the second bent portion (31) is in contact with the first bent portion (23) on one side facing the battery cell body (1); the third bent portion (32) is arranged at a predetermined angle to the second bent portion (31); and the third bent portion (32) is extended in a direction away from the battery cell body (1).

9. The battery according to claim 8, characterized in that The angle between the converging portion (22) and the second bending portion (31) is α, which satisfies α≤90°; and / or, The first adhesive (5) comprises a first adhesive section (51), a second adhesive section (52), a third adhesive section (53) and a fourth adhesive section (54) connected in sequence, wherein the first adhesive section (51) is attached to the first surface (11), the second adhesive section (52) is attached to the gathered portion (21) and / or the converging portion (22), the third adhesive section (53) is attached to the second bent portion (31), and the fourth adhesive section (54) is attached to the third bent portion (32); and / or; The second colloid (6) comprises a fifth adhesive segment (61), a sixth adhesive segment (62), a seventh adhesive segment (63) and an eighth adhesive segment (64) connected in sequence, wherein the fifth adhesive segment (61) is attached to the second surface (12), the sixth adhesive segment (62) is attached to the gathered portion (21) and / or the converging portion (22), the seventh adhesive segment (63) is attached to the first bending portion (23), and the eighth adhesive segment (64) is attached to the third bending portion.

10. The battery according to claim 9, characterized in that Along the thickness direction, the distance between a side of the fourth bonding section (54) away from the third bending portion (32) and a side of the second bonding section (52) away from the confluence portion (22) is h1, and at the first bonding section (51) and the fifth bonding section (61), the total thickness of the battery cell (10) is h2, satisfying h1≤h2.

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