Battery, battery box and electric automobile

Abstract

The invention relates to the technical field of batteries, and discloses a battery, a battery box and an electric automobile, and the battery comprises a battery cell which comprises a body part and a battery cell output part, and one end, connected with the body part, of the battery cell output part is a root part of the battery cell output part; the electrode terminal assembly is welded with the battery cell output part and forms a first connecting area, and the first connecting area is provided with a first edge close to the body part and a second edge far away from the body part in the first direction; wherein in the state that the battery cell output part is leveled in the first direction, the distance between the root part and the second edge is a, the distance between the root part and the first edge is b, the fault rate of the battery cell output part in the first connection area is c, and b / (a * c) is larger than or equal to 0.003 and smaller than or equal to 0.04. The over-current capability between the electrode terminal assembly and the battery core output part is ensured, the voltage jump of the battery is avoided, the reliability of the battery is ensured, the safety problems of thermal runaway of the battery and the like are avoided, and the safety performance of the battery is ensured.

Description

Technical Field

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

[0002] A battery generally includes an external battery structure and an internal battery structure. The external battery structure encloses a closed space, and the internal battery structure includes battery cells. The battery cells are arranged in the closed space, and the tabs of the battery cells are welded to the electrode terminal assemblies of the external battery structure, and current transmission is achieved through the electrode terminal assemblies. In order to ensure the voltage stability of the battery pack, the voltages of multiple batteries located in the same battery pack need to be maintained within a certain range during design. However, in the prior art, under certain working conditions, the battery is subject to vibration or manufacturing differences between batteries, which makes the voltage difference between multiple batteries in the battery pack large during use, resulting in poor consistency between multiple batteries, overcharging or over-discharging during the battery cycle, causing safety risks such as battery pack cycle life degradation or thermal runaway inside the battery. Summary of the Invention

[0003] In view of this, the present invention provides a battery, a battery box and an electric vehicle to solve the problem in the prior art that the voltage difference between multiple batteries inside the battery pack is large, resulting in poor consistency between the multiple batteries, overcharging or over-discharging during the battery cycle, causing safety risks such as battery pack cycle life degradation or thermal runaway inside the battery.

[0004] In a first aspect, the present invention provides a battery comprising: A battery cell, comprising a main body and a battery cell output portion extending from at least one end of the main body, wherein the end of the battery cell output portion connected to the main body is the root of the battery cell output portion; An electrode terminal assembly is welded to the cell output portion to form a first connection area, wherein along a first direction, which is a lead-out direction of the cell output portion, the first connection area has a first edge close to the body portion and a second edge away from the body portion; In the state where the battery cell output portion is flattened along the first direction, along the first direction, the distance between the root and the second edge is a, the distance between the root and the first edge is b, and the fault rate of the battery cell output portion in the first connection area is c, satisfying 0.003≤b / (a×c)≤0.04.

[0005] Beneficial effect: The distance a between the root and the second edge, the distance b between the root and the first edge, and the fault rate c of the battery output part in the first connection area satisfy 0.003≤b / (a×c)≤0.04, while ensuring the overcurrent capacity between the electrode terminal assembly and the battery output part, avoiding battery voltage jumps to ensure the reliability of the battery, and avoiding the occurrence of safety problems such as battery thermal runaway, thereby ensuring the safety performance of the battery. Specifically, if the value of b / (a×c) is too small, the first connection area will be easily subjected to tension from the main body when the battery vibrates, especially at the first edge position of the first connection area, the battery cell output part will be easily torn, resulting in excessive fault rate of the battery cell output part, resulting in a large pressure difference between batteries, a decrease in the overall cycle life of the battery pack, and overcharge and over-discharge of the battery, which will affect the use of the battery; if the value of b / (a×c) is too large, the current transmission path between the main body and the electrode terminal assembly will be too long, resulting in an increase in the internal resistance of the battery, and the welding area of ​​the first connection area will be too small, resulting in poor current flow capacity between the battery cell output part and the electrode terminal assembly, which will lead to excessively fast heating rate of the electrode terminal assembly, increasing the risk of thermal runaway of the battery and affecting the safety performance of the battery.

[0006] In a second aspect, the present invention also provides a battery box, comprising the above-mentioned battery, and also comprising a bottom plate and a frame, wherein the bottom plate is arranged on the periphery of the frame and fixedly connected to the frame, and the bottom plate and the frame enclose a accommodating space, and the battery is arranged in the accommodating space and fixedly connected to the bottom plate, and the batteries are connected in series or in parallel through conductive bars.

[0007] Beneficial effect: When the battery box is subjected to vibration, the voltage jump of the batteries in the battery box is avoided, thereby ensuring the overall consistency of the batteries during the charging and discharging process of the battery box, thereby ensuring the cycle life of the batteries, and avoiding the battery thermal runaway problem caused by local battery heat accumulation, thereby ensuring the safety performance of the battery box.

[0008] In a third aspect, the present invention further provides an electric vehicle comprising the above-mentioned battery box and chassis, wherein a side of the frame opposite to the bottom plate forms an opening surface, and the opening surface and the chassis are fixedly sealed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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.

[0010] Figure 1A schematic diagram of a welding method for a cell output portion and an electrode terminal assembly of a battery according to an embodiment of the present invention; Figure 2 for Figure 1 a top view of the battery shown; Figure 3 Schematic diagram of another welding method for the cell output portion and the electrode terminal assembly of a battery according to an embodiment of the present invention; Figure 4 for Figure 3 a top view of the battery shown; Figure 5 Schematic diagram of another welding method for the cell output portion and the electrode terminal assembly of a battery according to an embodiment of the present invention; Figure 6 for Figure 5 a top view of the battery shown; Figure 7 A top view of another welding method for the cell output portion and the electrode terminal assembly of the battery of an embodiment of the present invention; Figure 8 This is a schematic structural diagram of a bonding wire in the second connection area of ​​an embodiment of the present invention; Figure 9 This is a schematic structural diagram of another bonding wire in the second connection area of ​​an embodiment of the present invention; Figure 10 This is a schematic structural diagram of a bending area of ​​a battery cell output portion according to an embodiment of the present invention; Figure 11 This is a schematic structural diagram of another bending area of ​​the output portion of a battery cell according to an embodiment of the present invention; Figure 12 Schematic diagram of the structure of a pole piece with a raised portion according to an embodiment of the present invention; Figure 13 This is a schematic structural diagram of a pole piece with a chamfered structure according to an embodiment of the present invention; Figure 14 Schematic diagram of the structure of the tab layer and the isolation layer according to an embodiment of the present invention; Figure 15 This is a schematic diagram of a structure in which the ends of the tab layers are flush with each other according to an embodiment of the present invention; Figure 16 This is a schematic structural diagram of the staggered ends of the tab layer according to an embodiment of the present invention; Figure 17 This is a schematic structural diagram of an embodiment of the present invention in which the end of the tab layer is flush with the second edge; Figure 18 This is a structural schematic diagram of a battery cell output portion and an electrode terminal assembly having a third connection area according to an embodiment of the present invention; Figure 19 This is a schematic structural diagram of a battery cell output portion in a full-tab form according to an embodiment of the present invention; Figure 20 This is a schematic structural diagram of an embodiment of the present invention in which the main body and the cell output portion are eccentrically arranged; Figure 21 This is a structural diagram of the welding of the cell output portion and the electrode body according to an embodiment of the present invention; Figure 22 This is a structural diagram of the welding of the cell output portion and the adapter sheet according to an embodiment of the present invention; Figure 23 This is a schematic structural diagram of a tab layer fault at a first edge of an embodiment of the present invention; Figure 24 This is a structural schematic diagram of a battery cell output portion provided with a welding piece according to an embodiment of the present invention; Figure 25 This is a schematic diagram of the structure of the battery cell output part when it is output from the side according to an embodiment of the present invention; Figure 26 This is a structural diagram of the battery cell output portion when it is ejected according to an embodiment of the present invention; Figure 27 This is a schematic structural diagram of an embodiment of the present invention when the terminal body is located on the large surface of the battery; Figure 28 This is a schematic structural diagram of an adapter sheet having a first sheet and a second sheet before being bent according to an embodiment of the present invention; Figure 29 This is a schematic structural diagram of a first and second adapter plate connected to a cell output portion and a pole body according to an embodiment of the present invention; Figure 30 A schematic structural diagram of a battery according to an embodiment of the present invention, wherein one side of the battery is provided with a terminal body; Figure 31 A schematic structural diagram of a battery according to an embodiment of the present invention, wherein one side of the battery is provided with a terminal body and has two terminal bodies; Figure 32 This is a schematic structural diagram of an embodiment of the present invention in which the first projection is a circle; Figure 33 This is a schematic structural diagram of an embodiment of the present invention in which the first projection is a square; Figure 34 This is a schematic structural diagram of an embodiment of the present invention in which the first projection is an ellipse; Figure 35 This is a schematic structural diagram of an embodiment of the present invention in which the first projection is an oblong (racetrack-shaped) shape; Figure 36 for Figure 35 Schematic diagram of the matching structure of the electrode body and the battery shell shown; Figure 37 This is a schematic structural diagram of an embodiment of the present invention in which the protrusion and the cover plate are integrally formed; Figure 38This is a structural schematic diagram of the protrusion and the cover plate being welded together according to an embodiment of the present invention; Figure 39 This is a schematic diagram of a structure in which the folded edges are continuously arranged in the circumferential direction according to an embodiment of the present invention; Figure 40 This is a schematic structural diagram of a circumferentially segmented arrangement of the folded edge in an embodiment of the present invention; Figure 41 This is a structural diagram of an embodiment of the present invention in which the pole body is not inserted into the pole hole and the pole body is arranged on the cover plate; Figure 42 This is a structural schematic diagram of an embodiment of the present invention in which the pole body is not inserted into the pole hole and the pole body is arranged in the housing; Figure 43 This is a structural schematic diagram of a pole body partially inserted into a pole hole according to an embodiment of the present invention; Figure 44 This is a structural schematic diagram of an embodiment of the present invention in which the pole body is completely inserted into the pole hole; Figure 45 Schematic diagram of the structure of the tab layer according to an embodiment of the present invention; Figure 46 Schematic diagram of the structure of a first battery according to an embodiment of the present invention; Figure 47 for Figure 46 A front view of the battery shown; Figure 48 for Figure 47 Cross-sectional view in the AA direction; Figure 49 for Figure 48 A partial enlarged schematic diagram of point B in the middle; Figure 50 Schematic diagram of the structure of a second battery (housing not shown) according to an embodiment of the present invention; Figure 51 for Figure 50 a top view of the battery shown; Figure 52 for Figure 51 Cross-sectional view in CC direction; Figure 53 for Figure 52 A partial enlarged schematic diagram of point D in the middle; Figure 54 Schematic diagram of the structure of a third battery according to an embodiment of the present invention; Figure 55 for Figure 54 a top view of the battery shown; Figure 56 for Figure 55 Cross-sectional view in the EE direction; Figure 57 for Figure 56A partial enlarged schematic diagram of point F in the middle; Figure 58 is a schematic structural diagram of a fourth battery according to an embodiment of the present invention; Figure 59 for Figure 58 a top view of the battery shown; Figure 60 for Figure 59 Cross-sectional view in the GG direction; Figure 61 for Figure 60 A partial enlarged schematic diagram of the H in the middle; Figure 62 This is a schematic structural diagram of a battery with square poles according to an embodiment of the present invention; Figure 63 Schematic diagram of the structure of a battery with a racetrack-shaped pole according to an embodiment of the present invention; Figure 64 This is a schematic structural diagram of a battery box according to an embodiment of the present invention; Figure 65 This is a schematic structural diagram of an electric vehicle according to an embodiment of the present invention; Figure 66 This is the effect diagram of the welding area and non-welding area of ​​the battery cell output part and the electrode terminal assembly under CT.

[0011] Description of reference numerals: 1. Cell; 11. Main body; 111. Sheet; 12. Cell output; 121. Root; 122. Seventh edge; 123. Eighth edge; 124. Bending area; 1241. Crease; 125. Tab layer; 1251. Insulation layer; 1252. Metal layer; 1253. Raised portion; 13. Pole piece; 131. Chamfered structure; 14. Isolation layer; 2. Electrode terminal assembly; 21. Pole body; 211. First projection; 2111. Straight segment; 2112. Arc segment; 22. Transition Sheet; 221, first sheet; 222, second sheet; 3, first connection area; 31, first edge; 32, second edge; 33, third edge; 34, fourth edge; 4, second connection area; 41, welding wire; 42, fifth edge; 43, sixth edge; 5, third connection area; 6, welding sheet; 7, outer shell; 71, protrusion; 711, folded edge; 712, connection edge; 72, shell; 73, cover; 731, pole hole; 100, battery box; 110, battery; 1000, electric vehicle. DETAILED DESCRIPTION

[0012] 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.

[0013] The following combination Figures 1 to 66 , describing embodiments of the present invention.

[0014] According to an embodiment of the present invention, on the one hand, a battery 110 is provided, comprising: a battery cell 1, comprising a main body 11 and a battery cell output portion 12 led out from at least one end of the main body 11, wherein the end of the battery cell output portion 12 connected to the main body 11 is a root 121 of the battery cell output portion 12; an electrode terminal assembly 2, welded to the battery cell output portion 12 and forming a first connection area 3, along a first direction, which is the lead-out direction of the battery cell output portion 12, the first connection area 3 has a first edge 31 close to the main body 11 and a second edge 32 away from the main body 11; wherein, when the battery cell output portion 12 is flattened along the first direction, along the first direction, the distance between the root 121 and the second edge 32 is a, the distance between the root 121 and the first edge 31 is b, and the fault rate of the battery cell output portion 12 in the first connection area 3 is c, satisfying 0.003≤b / (a×c)≤0.04.

[0015] By applying the battery 110 of this embodiment, the distance a between the root 121 and the second edge 32, the distance b between the root 121 and the first edge 31, and the fault rate c of the battery output portion 12 in the first connection area 3 satisfy 0.003≤b / (a×c)≤0.04. While ensuring the overcurrent capacity between the electrode terminal assembly 2 and the battery output portion 12, avoiding the voltage jump of the battery 110 to ensure the reliability of the battery 110, it also avoids the occurrence of safety problems such as thermal runaway of the battery 110, thereby ensuring the safety performance of the battery 110.

[0016] Specifically, if the value of b / (a×c) is too small, the first connection area 3 will be easily subjected to the pulling force from the main body 11 when the battery 110 vibrates, especially at the first edge 31 of the first connection area 3, the battery cell output part 12 will be easily torn, resulting in an excessively large fault rate of the battery cell output part 12, resulting in a large pressure difference between the batteries 110, a decrease in the overall cycle life of the battery pack, and overcharge and over-discharge of the battery 110, affecting the use of the battery 110; if the value of b / (a×c) is too large, the current transmission path between the main body 11 and the electrode terminal assembly 2 is too long, resulting in an increase in the internal resistance of the battery 110, and also causing the welding area of ​​the first connection area 3 to account for too small a proportion, resulting in poor current flow capacity between the battery cell output part 12 and the electrode terminal assembly 2, and further causing the electrode terminal assembly 2 to heat up too quickly, increasing the risk of thermal runaway of the battery 110 and affecting the safety performance of the battery 110.

[0017] Optionally, the value of b / (a×c) is any value of 0.003, 0.005, 0.006, 0.008, 0.009, 0.01, 0.013, 0.015, 0.018, 0.02, 0.023, 0.025, 0.028, 0.03, 0.032, 0.033, 0.035, 0.036, 0.038, or 0.04, or a value between any two values.

[0018] It is worth noting that the welding reliability of the cell output portion 12 and the electrode terminal assembly 2 is a key factor affecting the voltage of the battery 110. In the related art, when the cell output portion 12 and the electrode terminal assembly 2 are welded and a weld mark is formed, pores will form inside the weld mark, especially at the intersection of the weld mark and the adjacent non-weld area (see Figure 66 ), therefore, after the battery 110 is subjected to force, the battery cell output part 12 is easily caused to fault at the intersection of the weld mark and the non-weld area under the action of the pulling force, resulting in an increase in the impedance between the battery cell output part 12 and the electrode terminal assembly 2, and a decrease in the current flow capacity between the battery cell output part 12 and the electrode terminal assembly 2, causing a voltage drop in the battery 110, that is, causing a voltage jump in the battery 110.

[0019] Therefore, in this embodiment, by limiting the value of b / (a×c) of the relationship between the distance a between the root 121 and the second edge 32, the distance b between the root 121 and the first edge 31, and the fault rate c of the battery output part 12 in the first connection area 3, the tension from the main body 11 on the first connection area 3 is reduced, the fault risk of the battery output part 12 is reduced, and the overcurrent capacity between the battery output part 12 and the electrode terminal assembly 2 is avoided from being affected, thereby avoiding the occurrence of voltage jump phenomenon of the battery 110.

[0020] It is worth noting that during the production process of the battery 110, the cell output portion 12 may need to be bent before being welded to the electrode terminal assembly 2. However, in this embodiment, when measuring the distance a between the root portion 121 and the second edge 32 and the distance b between the root portion 121 and the first edge 31, the cell output portion 12 needs to be flattened along the first direction, that is, the cell output portion 12 needs to be extended along the first direction.

[0021] It should be further explained that in this embodiment, the first direction (x-direction) is the length of the cell output portion 12; accordingly, the second direction (y-direction) is the width of the cell output portion 12, and the third direction (z-direction) is the thickness of the cell output portion 12. The connection between the side edge of the main body 11 and the cell output portion 12 is the root portion 121.

[0022] It is understood that in this embodiment, please refer to Figure 15 The battery cell output part 12 includes several tab layers 125 stacked along a third direction. The battery cell output part 12 and the electrode terminal assembly 2 are stacked along the third direction. The battery cell output part 12 and the electrode terminal assembly 2 are welded from the side of the battery cell output part 12 away from the electrode terminal assembly 2.

[0023] It should be noted that the fault rate refers to the ratio of the number of layers of the cell output portion 12 that are not connected to the first connection area 3 at the position of the first edge 31 to the total number of layers of the cell output portion 12. Figure 23 The total number of layers of the cell output portion 12 is 8, and the number of layers of the cell output portion 12 not connected to the first connection area 3 at the position of the first edge 31 is 2, and the fault rate c=2 / 8=0.25.

[0024] Furthermore, the fault rate test method is as follows: 1. Remove the welding part of the battery cell output part and the electrode terminal assembly, cut the sample in half with the gel-cured sample, and grind the sample clearly without visible scratches. First, use 800-grit sandpaper for coarse grinding, and then use 2000-grit sandpaper for fine grinding. The grinding time is about 2-3 minutes. 2. Measure the number of fracture layers at the junction of the welding pool and the tab layers on both sides. Black cracks and black pores are fractures. 3. The total number of fracture layers on the left side of the welding pool is C1, and the total number of fracture layers on the right side of the welding pool is C2. The fault rate = (C1 + C2) / (total number of tab layers × 2) × 100%.

[0025] In addition, for the regulation of the fault rate, when preparing sample batteries, batch tests can be conducted to control and adjust multiple factors such as oil stains and impurities on the surface of the tab foil, welding power control, and material selection. Batch tests can also be conducted to calculate the relationship between the fault rate and the above-mentioned influencing factors, so that the fault rate can be regulated in the process.

[0026] Specifically, in one embodiment, the distance a between the root portion 121 and the second edge 32 and the distance b between the root portion 121 and the first edge 31 satisfy 0.17≤b / a≤0.8. This configuration reduces the pulling force on the first connection area 3 while shortening the current transmission path between the body portion 11 and the electrode terminal assembly 2.

[0027] It is worth noting that if the value of b / a is too large, the current transmission path between the main body 11 and the electrode terminal assembly 2 will be too long, resulting in an increase in the internal resistance of the battery 110. It will also cause the welding area of ​​the first connection area 3 to be too small, resulting in poor current flow capacity between the battery cell output part 12 and the electrode terminal assembly 2, and then causing the electrode terminal assembly 2 to heat up and generate heat seriously, increasing the risk of thermal runaway of the battery 110 and affecting the safety performance of the battery 110. If the value of b / a is too small, the first connection area 3 will be subjected to a large pulling force from the main body 11 when the battery 110 vibrates, especially at the first edge 31 of the first connection area 3, the battery cell output part 12 is prone to tearing, resulting in an excessively large fault rate of the battery cell output part 12, affecting the overcurrent capacity between the battery cell output part 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump when in use, affecting the use of the battery 110; it will also cause the welding area of ​​the first connection area 3 to be too large. In order to accommodate the first connection area 3, the space occupied by the electrode terminal assembly 2 will increase, and the space utilization of the battery 110 will be reduced, affecting the energy density of the battery 110.

[0028] Optionally, the value of b / a is any value among 0.17, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, or a value between any two values.

[0029] In one embodiment, Figures 3 to 9As shown, the cell output portion 12 is also provided with a second connection area 4, which is at least partially located between the main body 11 and the first connection area 3. The second connection area 4 welds at least a portion of the cell output portion 12 along the third direction. In other words, the second connection area 4 can be used to gather and weld at least a portion of the tab layer 125. This arrangement can reduce the pulling of the main body 11 on the first connection area 3 through the cell output portion 12, reducing the risk of faults in the cell output portion 12, thereby ensuring the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, and preventing voltage jumps in the battery 110.

[0030] It is worth noting that the first connection area 3 and the second connection area 4 are arranged along the first direction at the cell output portion 12 , and the second connection area 4 is arranged closer to the main body 11 than the first connection area 3 .

[0031] It should be further explained that the first connection area 3 and the second connection area 4 can be set at intervals or overlap with each other. Specifically, the edges of the first connection area 3 and the second connection area 4 can overlap, or partial areas can overlap, or the first connection area 3 can be completely located in the second connection area 4.

[0032] In one embodiment, Figure 8 As shown, the second connection area 4 includes a continuous welding line 41, that is, a continuous welding method is adopted when welding to form the second connection area 4. Or, as Figure 9 As shown, the second connection area 4 includes a plurality of welding wires 41 , and the plurality of welding wires 41 are intermittently arranged, that is, a segmented welding method is adopted when welding to form the second connection area 4 .

[0033] It is worth noting that, in the process of welding the multi-layer tab layer 125, segmented welding can reduce cracks and faults caused by uneven thermal stress and rapid cooling by effectively controlling heat input and cooling rate compared to continuous welding.

[0034] It should be noted that each welding line 41 can form a welding mark, so the second connection area 4 can include only one complete welding mark, or it can be divided into multiple welding marks, which are arranged at intervals. Furthermore, the shape of the welding mark can be rectangular, circular, triangular, spiral, etc.

[0035] In a first embodiment of the second connection area 4, as Figure 3 and Figure 4As shown, the second connection area 4 welds the cell output portion 12 and the electrode terminal assembly 2. With this arrangement, when the battery 110 is subjected to stress, the pulling force applied by the main body 11 to the cell output portion 12 will first act on the second connection area 4, sharing the stress on the first connection area 3 through the second connection area 4, thereby protecting the first connection area 3. This improves the tensile strength of the weld area between the cell output portion 12 and the electrode terminal assembly 2 under vibration stress, reduces the risk of fracture in the cell output portion 12, and thus ensures the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, preventing the occurrence of voltage jumps in the battery 110.

[0036] It is worth noting that the first connection area 3 and the second connection area 4 are utilized to increase the flow area between the battery cell output portion 12 and the electrode terminal assembly 2 , thereby improving the flow capacity of the battery cell output portion 12 .

[0037] In this embodiment, if Figure 3 As shown, along the first direction, the distance d between the root portion 121 and the edge of the second connection area 4 near the body portion 11 satisfies 5mm≤d≤15mm. This arrangement reduces the pulling force on the second connection area 4 while shortening the current transmission path between the body portion 11 and the electrode terminal assembly 2.

[0038] It is worth noting that if the value of d is too large, the current transmission path between the body 11 and the electrode terminal assembly 2 is too long, resulting in an increase in the internal resistance of the battery 110, which in turn leads to poor current flow between the cell output portion 12 and the electrode terminal assembly 2. This in turn causes the battery 110 to generate more heat during use, increasing the risk of thermal runaway of the battery 110 and affecting the safety performance of the battery 110. If the value of d is too small, the second connection area 4 is too close to the body 11. This can cause the second connection area 4 to be subjected to a large pulling force from the body 11 when the battery 110 vibrates. In particular, the cell output portion 12 is prone to tearing at the edge of the second connection area 4 near the body 11, resulting in an excessively high fault rate of the cell output portion 12, affecting the current flow between the cell output portion 12 and the electrode terminal assembly 2, and causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110.

[0039] Optionally, the value of d is any value of 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, or 15mm, or a value between any two values.

[0040] In this embodiment, if Figure 4As shown, along the second direction, which is parallel to the surface of the cell output portion 12 and perpendicular to the first direction, the width of the first connection area 3 is e, and the width of the second connection area 4 is f, satisfying f>e. With this arrangement, when the battery 110 is subjected to stress, the second connection area 4 can share a larger amount of the stress, thereby improving the protection of the first connection area 3.

[0041] Furthermore, in this embodiment, Figure 4 As shown, along the second direction, the first connection area 3 has a third edge 33 and a fourth edge 34 disposed opposite each other, the second connection area 4 has a fifth edge 42 and a sixth edge 43 disposed opposite each other, and the cell output portion 12 has a seventh edge 122 and an eighth edge 123 disposed opposite each other. The third edge 33 and the fifth edge 42 are disposed adjacent to the seventh edge 122, and the fourth edge 34 and the sixth edge 43 are disposed adjacent to the eighth edge 123. Along the second direction, the fifth edge 42 is disposed closer to the seventh edge 122 than the third edge 33, and the sixth edge 43 is disposed closer to the eighth edge 123 than the fourth edge 34. That is, along the second direction, both side edges of the second connection area 4 extend outward beyond both side edges of the first connection area 3. This arrangement allows the second connection area 4 to fully protect the first connection area 3, further enhancing the protective effect of the first connection area 3.

[0042] Furthermore, in this embodiment, Figure 4 As shown, along the second direction, the distance between the fifth edge 42 and the third edge 33 is g, and the distance between the sixth edge 43 and the fourth edge 34 is h, satisfying |gh|≤2mm. That is, along the second direction, the two side edges of the second connection area 4 extend outwardly beyond the two side edges of the first connection area 3 by substantially the same amount, and the centerline of the second connection area 4 along the second direction is collinear with the centerline of the first connection area 3 along the second direction. With this arrangement, the pulling force applied by the main body 11 to the battery cell output portion 12 is shared by the second connection area 4, and the pulling force transmitted to the first connection area 3 is more balanced, which in turn makes the force applied to the first connection area 3 more balanced, reducing the risk of the battery cell output portion 12 fracturing at the first edge 31.

[0043] Optionally, the value of |gh| is any value of 0, 0.1mm, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, or a value between any two values.

[0044] In this embodiment, if Figure 4As shown, along the second direction, the fifth edge 42 is spaced apart from the seventh edge 122, and the sixth edge 43 is spaced apart from the eighth edge 123. With this arrangement, the relatively loose tab layer 125 between the fifth edge 42 and the seventh edge 122, and between the sixth edge 43 and the eighth edge 123, is used to buffer the force applied to the second connection area 4, thereby preventing the edge of the second connection area 4 from being directly subjected to force and thereby increasing the risk of fracture. Furthermore, since the second connection area 4 is not welded to the edge of the cell output portion 12, the welding yield of the second connection area 4 can be improved, the occurrence of cold solder joints can be avoided, and the overcurrent capacity of the cell output portion 12 can be ensured.

[0045] Furthermore, in this embodiment, Figure 4 As shown, along the second direction, the distance between the fifth edge 42 and the seventh edge 122 is i, and the distance between the sixth edge 43 and the eighth edge 123 is j, satisfying |ij| ≤ 5 mm. This arrangement can further improve the uniformity of the force applied to the second connection area 4 at the fifth edge 42 and the sixth edge 43, thereby avoiding the increased risk of fracture caused by concentrated force at the edges of the second connection area 4.

[0046] Optionally, the value of |ij| is any value among 0, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or a value between any two values.

[0047] Specifically, in this embodiment, the width e of the first connection area 3 and the width f of the second connection area 4 satisfy 1.2≤f / e≤3. This configuration ensures that the second connection area 4 protects the first connection area 3 while preventing the second connection area 4 from being torn.

[0048] It is worth noting that if the value of f / e is too large, the pulling force shared by the second connection area 4 is too great, which can easily cause the cell output portion 12 to tear at the edge of the second connection area 4 near the main body 11. This can lead to an excessively high fault rate of the cell output portion 12, affecting the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110. If the value of f / e is too small, the pulling force shared by the second connection area 4 is limited, and the pulling force transmitted to the first connection area 3 is still large. There is still a risk of the cell output portion 12 tearing at the first edge 31, and the protection effect on the first connection area 3 is insufficient.

[0049] Optionally, the value of f / e is any value among 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, or a value between any two values.

[0050] In this embodiment, if Figure 4As shown, along the first direction, the first connection area 3 and the second connection area 4 are spaced apart, and the distance between the first connection area 3 and the second connection area 4 is k, which satisfies 1mm≤k≤15mm. This arrangement ensures the welding quality between the battery cell output portion 12 and the electrode terminal assembly 2 while preventing the second connection area 4 from being torn.

[0051] It is worth noting that if the value of k is too small, the first connection area 3 and the second connection area 4 are likely to overlap, which can easily cause welding defects and affect the connection strength and flow capacity between the battery cell output portion 12 and the electrode terminal assembly 2. If the value of k is too large, the second connection area 4 is likely to be too close to the main body 11, which will cause the second connection area 4 to be subjected to a large pulling force from the main body 11 when the battery 110 vibrates. In particular, the battery cell output portion 12 is likely to tear at the edge of the second connection area 4 on one side close to the main body 11, resulting in an excessively high fault rate of the battery cell output portion 12, affecting the flow capacity between the battery cell output portion 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110.

[0052] Optionally, the value of k is any value among 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, or a value between any two values.

[0053] In a second embodiment of the second connection area 4, as Figure 5 As shown, the second connection area 4 is welded to the cell output portion 12. That is, the entire tab layer 125 is welded through the second connection area 4, while the second connection area 4 does not necessarily weld the cell output portion 12 to the electrode terminal assembly 2. This arrangement reinforces and pre-welds the cell output portion 12, improving its structural strength, reducing the pulling of the main body 11 on the first connection area 3 through the cell output portion 12, and reducing the risk of faults in the cell output portion 12. This ensures the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, preventing voltage jumps in the battery 110.

[0054] Specifically, in this embodiment, one of the first connection area 3 and the second connection area 4 is formed by laser welding, and the other of the first connection area 3 and the second connection area 4 is formed by ultrasonic welding.

[0055] Furthermore, in this embodiment, Figure 5 and Figure 6As shown, the first connection area 3 is at least partially disposed in the second connection area 4. The cell output portion 12 is pre-welded through the second connection area 4, and then the cell output portion 12 formed as a whole through the second connection area 4 is welded to the electrode terminal assembly 2 to improve welding strength.

[0056] Furthermore, in this embodiment, Figure 5 As shown, along the first direction, the distance L1 between the root portion 121 and the edge of the second connection area 4 near the main body 11 satisfies 5mm≤L1≤20mm. This arrangement reduces the pulling force on the first connection area 3 while preventing the cell output portion 12 from wrinkling and deformation.

[0057] It is worth noting that if the value of L1 is too small, the distance between the second connection area 4 and the first connection area 3 and the main body 11 is too close, and the cell output part 12 has a poor buffering effect on the pulling force, which can easily cause the first connection area 3 to be directly subjected to force, resulting in an increased risk of the cell output part 12 being fractured at the first edge 31, affecting the flow capacity between the cell output part 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110. If the value of L1 is too large, the cell output part 12 between the main body 11 and the second connection area 4 is too long, resulting in an increase in consumables and waste of materials, and easily causing the cell output part 12 to wrinkle and deform, making it easy for the cell output part 12 to overlap with the main body 11 or other structural components, causing a short circuit risk.

[0058] Optionally, the value of L1 is any value among 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, or a value between any two values.

[0059] Of course, as an alternative embodiment, Figure 7 As shown, the projection of the first connection area 3 on the cell output portion 12 along the third direction completely falls within the projection of the second connection area 4 on the cell output portion 12 along the third direction. The third direction is perpendicular to both the first and second directions. This arrangement further ensures the welding quality between the cell output portion 12 and the electrode terminal assembly 2, improving the flow capacity between the cell output portion 12 and the electrode terminal assembly 2.

[0060] In one embodiment, Figure 10 and Figure 11 As shown, a bend region 124 is formed on the cell output portion 12 between the first connection region 3 and the main body 11. The bend region 124 can provide a buffer for the forces acting on the first connection region 3, reducing the forces acting on the first edge 31 and lowering the risk of the cell output portion 12 fracturing at the first edge 31. This ensures the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, thus preventing voltage jumps in the battery 110.

[0061] Specifically, in one embodiment, along the first direction, the length of the bending zone 124 is L2, satisfying 0.2≤L2 / b≤0.8. This configuration ensures the buffering effect of the bending zone 124 while preventing the bending zone 124 from being overheated and causing safety risks.

[0062] It is worth noting that if the value of L2 / b is too small, the length of the bending zone 124 will be short, and the buffering effect provided by the bending zone 124 on the first connection area 3 will be insignificant, and the risk of faults in the battery cell output portion 12 will still exist. If the value of L2 / b is too large, the length of the bending zone 124 will be too long, which will lead to an excessively long overall length of the battery cell output portion 12. The battery cell output portion 12 will generate excessive heat and dissipate it poorly, which may easily lead to the risk of thermal runaway of the battery 110.

[0063] Optionally, the value of L2 / b is any value among 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or a value between any two values.

[0064] Specifically, in one embodiment, the bending area 124 has a fold 1241 (see Figure 10 ) or a plurality of folds 1241 are arranged at intervals along the first direction (see Figure 11 ). That is, the cell output portion 12 between the main body portion 11 and the first connection area 3 can be bent once or multiple times. It can be understood that each bend forms a crease 1241, for example, Figure 10 The bending area 124 shown has a fold 1241. Figure 11 The bending zone 124 shown has three folds 1241 .

[0065] Furthermore, in one embodiment, Figure 11 As shown, along the first direction, the distance between the fold 1241 closest to the first connection area 3 and the first edge 31 is m, satisfying 2mm≤m≤5mm. This arrangement provides a buffering effect for the first connection area 3 while ensuring the heat dissipation effect of the battery cell output part 12.

[0066] It is worth noting that if the value of m is too small, the heat dissipation capacity of the bending area 124 is poor. When the bending area 124 is too close to the first connection area 3, the heat of the bending area 124 and the heat of the first connection area 3 are superimposed, resulting in poor heat dissipation of the battery cell output portion 12, increasing the risk of thermal runaway of the battery 110 and affecting the safety performance of the battery 110. If the value of m is too large, the distance between the bending area 124 and the first connection area 3 is too far, and the buffering effect of the bending area 124 on the first connection area 3 is insufficient, resulting in the battery cell output portion 12 still being prone to tearing at the first edge 31, resulting in an excessively high fault rate of the battery cell output portion 12, affecting the flow capacity between the battery cell output portion 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110.

[0067] Optionally, the value of m is any value of 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, or a value between any two values.

[0068] Furthermore, in one embodiment, Figure 11 As shown, along the first direction, the distance n between the fold 1241 closest to the main body 11 and the root 121 satisfies 0.5mm≤n≤3mm. This arrangement ensures the quality and safety of the battery 110 while preventing the output portion 12 from wrinkling and deformation.

[0069] It is worth noting that if the value of n is too large, the cell output portion 12 between the main body 11 and the bending zone 124 will be too long, resulting in an increase in consumables and material waste, and it is easy for the cell output portion 12 to wrinkle and deform, making it easy for the cell output portion 12 to overlap with the main body 11 or other structural parts, causing a short circuit risk. If the value of n is too small, the main body 11 and the bending zone 124 are too close. When the cell output portion 12 is bent and deformed to form the bending zone 124, it is easy to cause the sheet 111 of the main body 11 to be deformed due to force, there is a risk of the active layer of the sheet 111 falling off. The falling active layer material falling into the interior of the battery 110 can easily cause a safety accident of the battery 110.

[0070] Optionally, the value of n is any value among 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, or a value between any two values.

[0071] In one embodiment, Figure 12As shown, the cell output portion 12 includes a plurality of tab layers 125 stacked along a third direction, and at least one tab layer 125 is provided with a protrusion 1253. By providing the protrusion 1253 on the tab layer 125, the structural strength of the cell output portion 12 can be improved, the pulling of the main body 11 on the first connection area 3 through the cell output portion 12 can be reduced, and the risk of faulting of the cell output portion 12 can be reduced. In addition, the overcurrent capacity between the cell output portion 12 and the electrode terminal assembly 2 is ensured, and the occurrence of voltage jump in the battery 110 is avoided.

[0072] Preferably, a protrusion 1253 is provided on each tab layer 125 .

[0073] It is worth noting that, please refer to Figure 12 In one embodiment, the tab layer 125 is provided with a plurality of raised portions 1253 spaced apart along the second direction, each raised portion 1253 extending along the first direction. Of course, in other alternative embodiments, the raised portions 1253 may also have other shapes, such as wavy lines, sawtooth shapes, etc.

[0074] Furthermore, in one embodiment, Figure 12 As shown, along the first direction, the distance between the protrusion 1253 and the root 121 is o, which satisfies 0.5mm≤o≤2mm. This arrangement ensures the quality and safety of the battery 110 while preventing the battery output portion 12 from being torn at the root 121.

[0075] It is worth noting that if the value of o is too large, the structural strength of the cell output portion 12 near the root 121 is still low, which can easily cause the cell output portion 12 to tear at the root 121. If the value of o is too small, the protrusion 1253 is connected to the root 121 near the cell output portion 12, and the structural strength of the cell output portion 12 near the root 121 is too high, which can easily cause the active layer of the sheet 111 to fall off. The fallen active layer material falls into the interior of the battery 110 and may cause a safety accident of the battery 110.

[0076] Optionally, the value of o is any value among 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, or a value between any two values.

[0077] In one embodiment, Figure 13As shown, the battery cell 1 includes several layers of electrode sheets 13 stacked along a third direction. Each electrode sheet 13 includes a sheet body 111 and a tab layer 125 extending from at least one end of the sheet body 111. The several layers of sheet body 111 form the main body 11, and the several layers of tab layers 125 form the battery cell output portion 12. The connection between the edges of the sheet body 111 and the edges of the tab layers 125 has a chamfered structure 131. This arrangement can reduce stress concentration at the root 121 of the battery cell output portion 12, prevent the battery cell 1 from tearing at the root 121 of the battery cell output portion 12, and ensure the safety performance of the battery 110.

[0078] Furthermore, in one embodiment, Figure 13 As shown, the radius of the chamfer structure 131 is R, which satisfies 1mm≤R≤5mm. This configuration reduces stress concentration at the root 121 of the cell output portion 12 of the battery cell 1 and facilitates assembly of the battery 110.

[0079] It is worth noting that if the value of R is too large, the width of the connection between the main body 11 and the cell output portion 12 along the second direction will be too large, making it difficult to bend the cell output portion 12, making it difficult to assemble the battery 110. If the value of R is too small, there is still a risk of stress concentration at the root 121 of the cell output portion 12, and the risk of the battery cell 1 tearing at the root 121 of the cell output portion 12 is still high.

[0080] Optionally, the value of R is any value among 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or a value between any two values.

[0081] Specifically, in one embodiment, Figure 14 As shown, the battery cell 1 further includes an isolation layer 14, which is disposed between two adjacent electrode sheets 13. The isolation layer 14 extends from between adjacent sheets 111 to between adjacent tab layers 125. The isolation layer 14 can limit the position of the battery cell output portion 12 near the root 121, thereby preventing the battery cell output portion 12 from tearing, reducing vibration of the battery cell output portion 12, and reducing the force applied to the first connection area 3, thereby reducing the risk of faulting the battery cell output portion 12. This ensures the flow rate between the battery cell output portion 12 and the electrode terminal assembly 2, and prevents voltage jumps in the battery 110.

[0082] Furthermore, in one embodiment, Figure 14 As shown, along the first direction, the distance p between the end of the isolation layer 14 closest to the tab layer 125 and the connection end between the tab layer 125 and the sheet body 111 satisfies 0.5 mm ≤ p ≤ 4 mm. This configuration prevents tearing of the root portion 121 of the cell output portion 12 while also preventing interference with welding of the cell output portion 12.

[0083] It is worth noting that if the value of p is too small, the area of ​​the isolation layer 14 exerting a reaction force on the tab layer 125 when the cell output portion 12 is subjected to force is small, increasing the risk of tearing the tab layer 125. If the value of p is too large, the isolation layer 14 occupies too much area of ​​the tab layer 125, affecting the welding of the cell output portion 12 and the electrode terminal assembly 2.

[0084] Optionally, the value of p is any value among 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or a value between any two values.

[0085] It should be noted that the electrode sheet 13 includes a positive electrode sheet and a negative electrode sheet, which are alternately stacked in sequence, and the isolation layer 14 is disposed between the positive electrode sheet and the negative electrode sheet. Specifically, the isolation layer 14 is a diaphragm.

[0086] In one embodiment, Figure 15 As shown, the cell output portion 12 includes multiple tab layers 125 stacked along a third direction. Along the first direction, the distance between any two of the multiple tab layers 125, away from the end of the main body 11, does not exceed 1 mm. This arrangement facilitates the retraction of the cell output portion 12 during assembly of the battery 110 and prevents the ends of the tab layers 125 from being inserted backwards into the main body 11, thereby ensuring the safety of the battery 110.

[0087] Furthermore, in one embodiment, Figure 17 As shown, the cell output portion 12 is provided with a connection area, including a first connection area 3. Along a first direction, the edge of the connection area is flush with the end of the cell output portion 12 away from the main body 11. In other words, the connection area extends to the edge of the cell output portion 12. This arrangement allows the end of the cell output portion 12 to be gathered and fixed, reducing the risk of short circuits caused by overlapping between the cell output portion 12 and other components of the battery 110, thereby improving the safety performance of the battery 110.

[0088] It is worth noting that if the connection area does not reach the edge of the battery cell output part 12, several layers of the tab layer 125 are still in a loose state at the edge of the battery cell output part 12, which makes the end of the battery cell output part 12 easily deformed, and is therefore easy to overlap with other structural parts of the battery 110, causing a short circuit problem in the battery 110.

[0089] As an alternative embodiment, in one embodiment, Figure 16As shown, the cell output unit 12 includes several tab layers 125 stacked along the third direction. Along the first direction, several tab layers 125 are staggered away from one end of the body 11. This arrangement can improve the heat dissipation effect at the end of the cell output unit 12 and reduce the risk of thermal runaway of the battery 110.

[0090] Furthermore, in one embodiment, Figure 15 and Figure 16 As shown, the cell output portion 12 is provided with a connection area, including a first connection area 3. Along a first direction, the edge of the connection area is spaced from the end of the cell output portion 12 away from the main body 11. In other words, the connection area does not reach the edge of the cell output portion 12. This arrangement ensures the weld strength between the cell output portion 12 and the electrode terminal assembly 2 while improving the heat dissipation effect of the connection area during current transmission.

[0091] It is worth noting that by ensuring that the connection area is at a certain distance from the end of the battery cell output part 12, all the tab layers 125 can be welded to the electrode terminal assembly 2, thereby ensuring the welding strength between the battery cell output part 12 and the electrode terminal assembly 2, and ensuring the overcurrent capacity between the battery cell output part 12 and the electrode terminal assembly 2. In addition, utilizing the battery cell output part 12 in a loose state can be more conducive to heat dissipation, thereby avoiding the risk of thermal runaway caused by excessive temperature of the battery cell output part 12.

[0092] Specifically, in this embodiment, along the first direction, the distance L3 between the edge of the connection area and the end of the cell output portion 12 away from the main body portion 11 satisfies 0.5 mm ≤ L3 ≤ 3 mm. This arrangement improves the welding quality between the cell output portion 12 and the electrode terminal assembly 2 while reducing the risk of fracture in the cell output portion 12.

[0093] It is worth noting that if the value of L3 is too small, the edge of the connection area is too close to the other end of the cell output portion 12 opposite the root portion 121, which can easily affect the welding quality of the connection area and the heat dissipation performance of the cell output portion 12. If the value of L3 is too large, the connection area is likely to be too close to the root portion 121 of the cell output portion 12, thereby increasing the risk of fracture of the cell output portion 12 in the connection area.

[0094] Optionally, the value of L3 is any value among 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, or a value between any two values.

[0095] It should be noted that the connection area refers to all welding areas on the battery cell output part 12, that is, it may not only be the first connection area 3, but there may also be other welding areas, such as the pre-welding area (referring to the weld marks where several layers of the tab layers 125 are pre-welded together), etc.

[0096] In one embodiment, Figure 18 As shown, the cell output portion 12 is provided with a third connection area 5. Along the first direction, the third connection area 5 is located between the second edge 32 and the end of the cell output portion 12 away from the main body 11. The third connection area 5 welds at least a portion of the cell output portion 12 along the third direction. This arrangement can further improve the structural strength of the cell output portion 12.

[0097] As an alternative embodiment, the third connection region 5 may also be located on at least one side of the first connection region 3 in the second direction.

[0098] Furthermore, in one embodiment, Figure 18 As shown, the third connection area 5 is welded to the cell output portion 12 and the electrode terminal assembly 2. This arrangement can improve the current capacity between the cell output portion 12 and the electrode terminal assembly 2.

[0099] In one embodiment, Figure 2 and Figure 20 As shown, along the second direction, at least one side edge of the cell output portion 12 is spaced from the corresponding edge of the body portion 11. That is, the battery 110 adopts a multi-tab form, which is conducive to improving the energy density of the battery 110.

[0100] Specifically, along the second direction, the distance between at least one side edge of the cell output portion 12 and the corresponding edge of the main body 11 is L4, and the width of the main body 11 is L5, satisfying 0.1≤L4 / L5≤0.3. This arrangement ensures the connection strength between the cell output portion 12 and the main body 11 while minimizing the impact on the energy density of the battery 110.

[0101] It is worth noting that if the value of L4 / L5 is too large, the width of the cell output portion 12 will be too small, the connection strength between the cell output portion 12 and the main body 11 will be weak, and the current capacity of the cell output portion 12 will be affected. If the value of L4 / L5 is too small, the width of the cell output portion 12 will be too large, and the cell output portion 12 will occupy too much space, affecting the energy density of the battery 110. At the same time, the cell output portion 12 will be too redundant, which may easily lead to insulation risks such as reverse insertion.

[0102] Optionally, the value of L4 / L5 is any value among 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, or a value between any two values.

[0103] Furthermore, at this time, the connection strength between the battery cell output part 12 and the main body part 11 is relatively small, and the battery cell output part 12 is subjected to a relatively concentrated force, resulting in a relatively concentrated stress in the first connection area 3. Therefore, the values ​​of a, b, and c satisfy 0.008≤b / (a×c)≤0.04, thereby reducing the risk of fault in the battery cell output part 12, thereby ensuring the overcurrent capacity between the battery cell output part 12 and the electrode terminal assembly 2, and avoiding the occurrence of voltage jump phenomenon in the battery 110.

[0104] Furthermore, in one embodiment, Figure 2 As shown, the centerline of the cell output portion 12 in the second direction is collinear with the centerline of the main body 11 in the second direction. This arrangement positions the cell output portion 12 in the center of the main body 11, which facilitates current transmission within the main body 11. Furthermore, the tension exerted on the cell output portion 12 by the main body 11 is more uniform, preventing localized tearing of the cell output portion 12 due to excessive force. This reduces the risk of fracture in the cell output portion 12, thereby ensuring the current flow capacity between the cell output portion 12 and the electrode terminal assembly 2 and preventing voltage jumps in the battery 110.

[0105] Of course, as an alternative embodiment, Figure 20 As shown, the center line of the cell output portion 12 in the second direction is spaced apart from the center line of the body portion 11 in the second direction. That is, the cell output portion 12 is offset from the middle position of the body portion 11, which makes it easier to weld and assemble the cell output portion 12.

[0106] Furthermore, in one embodiment, Figure 20 As shown, along the second direction, the distance q between one edge of the first connection area 3 and the corresponding edge of the main body 11 satisfies 5mm≤q≤35mm. This arrangement reduces the risk of faults in the cell output portion 12 while preventing the current transmission path from being too long.

[0107] It is worth noting that if the value of q is too small, the tension exerted on the cell output portion 12 by the body portion 11 is relatively large, and the cell output portion 12 is prone to tearing at the first edge 31. This results in an excessively high fault rate of the cell output portion 12, affecting the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110. If the value of q is too large, the current transmission path between the body portion 11 and the electrode terminal assembly 2 is too long, resulting in an increased internal resistance of the battery 110. It also results in an excessively small welding area in the first connection region 3, resulting in poor flow capacity between the cell output portion 12 and the electrode terminal assembly 2. This in turn leads to increased heat generation during use of the battery 110, increasing the risk of thermal runaway of the battery 110 and affecting the safety performance of the battery 110.

[0108] Optionally, the value of q is any value among 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, or a value between any two values.

[0109] Additionally, in other alternative embodiments, Figure 19 As shown, along the second direction, the two side edges of the cell output portion 12 are flush with the two side edges of the main body 11. This means that the battery 110 utilizes a full-tab design, which enhances the structural strength of the cell output portion 12. It is worth noting that along the second direction, the cell output portion 12 occupies the entire width of the main body 11. This provides a relatively strong connection between the cell output portion 12 and the main body 11, increasing the stress-bearing area of ​​the cell output portion 12 and reducing stress concentration in the first connection area 3. Furthermore, by ensuring that the values ​​of a, b, and c satisfy 0.005 ≤ b / (a × c) ≤ 0.035, the risk of fracture in the cell output portion 12 is reduced while also improving the flow capacity between the cell output portion 12 and the electrode terminal assembly 2.

[0110] In one embodiment, Figure 21 As shown, the electrode terminal assembly 2 includes a pole body 21, which is directly welded to the cell output portion 12 to form a first connection area 3. That is, the cell output portion 12 is directly connected to the pole body 21 without the need for a transfer plate 22, reducing the resistance during current transmission to increase overcurrent.

[0111] Of course, as an alternative embodiment, Figure 22 As shown, the electrode terminal assembly 2 includes a pole body 21 and a transfer plate 22. The transfer plate 22 is welded to the cell output portion 12 to form a first connection area 3. The pole body 21 is connected to the transfer plate 22. That is, the electrical connection between the cell output portion 12 and the pole body 21 is achieved through the transfer plate 22. Welding multiple layers of tab layers 125 to the transfer plate 22 has better welding effects and increases welding strength.

[0112] In one embodiment, Figure 23 As shown, the fault rate c of the cell output portion 12 in the first connection area 3 satisfies 15%≤c≤75%. This configuration simplifies the welding process while ensuring the flow capacity between the electrode terminal assembly 2 and the cell output portion 12, further reducing the risk of voltage jumps in the battery 110.

[0113] It is worth noting that if the value of c is too large, the impedance during current transmission will be too large, affecting the flow capacity between the cell output portion 12 and the electrode terminal assembly 2. Furthermore, when the battery 110 is subjected to force, the risk of tearing of the cell output portion 12 increases, further increasing the fault rate of the cell output portion 12, and thus causing the output voltage of the battery 110 to jump during use, affecting the use of the battery 110. If the value of c is too small, the welding process and other requirements will be too high, increasing the processing difficulty and affecting production efficiency.

[0114] Optionally, the value of c is any value of 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or a value between any two values.

[0115] In one embodiment, the distance a between the root portion 121 and the second edge 32 satisfies 5 mm ≤ a ≤ 20 mm. This configuration ensures the safety performance of the battery 110 while avoiding affecting the energy density of the battery 110.

[0116] It is worth noting that if the value of a is too large, the length of the cell output portion 12 will be too large, and the cell output portion 12 will occupy too much space within the battery 110, which may easily affect the energy density of the battery 110. In addition, the cell output portion 12 may be too redundant, which may easily lead to insulation risks such as overlap. If the value of a is too small, the welding area of ​​the first connection area 3 may be too small, resulting in poor current flow capacity between the cell output portion 12 and the electrode terminal assembly 2, which in turn may cause the electrode terminal assembly 2 to heat up too quickly, increasing the risk of thermal runaway in the battery 110 and affecting the safety performance of the battery 110.

[0117] Optionally, the value of a is any value among 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, or a value between any two values.

[0118] In one embodiment, the distance b between the root portion 121 and the first edge 31 satisfies 3 mm ≤ b ≤ 10 mm. This arrangement ensures the flow capacity between the electrode terminal assembly 2 and the cell output portion 12, prevents the battery 110 from voltage jumps, and reduces the internal resistance of the battery 110.

[0119] It is worth noting that if the value of b is too large, the current transmission path between the main body 11 and the electrode terminal assembly 2 is too long, resulting in an increase in the internal resistance of the battery 110. If the value of b is too small, the first connection area 3 is likely to be subjected to tension from the main body 11 when the battery 110 vibrates, especially at the first edge 31 of the first connection area 3, which is prone to tearing of the cell output portion 12. This can lead to an excessively high fault rate of the cell output portion 12, a large pressure difference between the battery cells 110, a reduction in the overall cycle life of the battery pack, and the possibility of overcharging or over-discharging of the battery 110, thus affecting the use of the battery 110.

[0120] Optionally, the value of b is any value among 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or a value between any two values.

[0121] In one embodiment, Figure 24 As shown, a welding tab 6 is provided on the side of the cell output portion 12 facing away from the electrode terminal assembly 2. The provision of the welding tab 6 improves the welding effect and weld strength between the cell output portion 12 and the electrode terminal assembly 2, reduces the risk of tearing of the cell output portion 12 when the battery 110 is subjected to stress, and reduces the risk of faulting of the cell output portion 12. This ensures the flow capacity between the cell output portion 12 and the electrode terminal assembly 2, and prevents voltage jumps in the battery 110.

[0122] In one embodiment, Figure 25 and Figure 26 As shown, the end surface of the main body 11 leading out the cell output portion 12 is arranged opposite to the surface of the battery 110 provided with the pole body 21 .

[0123] Specifically, such as Figure 26 As shown, the cell output portion 12 is ejected, and the side of the battery 110 provided with the pole body 21 is the top surface of the battery 110; or, as shown Figure 25 As shown, the cell output portion 12 is side-out, and the side of the battery 110 provided with the pole body 21 is the side surface of the battery 110. For example, a cylindrical battery 110, a square shell battery 110, or a short knife battery 110.

[0124] It is worth noting that the battery cell output part 12 and the pole body 21 are arranged on the same side, and the force of the pole body 21 is directly transmitted to the battery cell output part 12, so that the battery cell output part 12 is subjected to greater force, resulting in an increased risk of tearing of the battery cell output part 12, and further an increased risk of fracture of the battery cell output part 12.

[0125] As an alternative embodiment, Figures 27 to 29 as well as Figures 46 to 53As shown, the end surface of the main body 11 leading out the cell output portion 12 is arranged adjacent to a surface of the battery 110 on which the pole body 21 is arranged.

[0126] Specifically, such as Figure 27 and Figure 49 As shown, when the cell output portion 12 is flattened along a first direction, the surface of the cell output portion 12 is parallel to the side of the battery 110 where the terminal body 21 is located. For example, the terminal body 21 is located on the larger surface of the battery 110, and the cell output portion 12 is parallel to the larger surface of the battery 110 and connected to the terminal body 21. In this case, the force applied to the terminal body 21 is directly transmitted to the cell output portion 12, causing greater force on the cell output portion 12, increasing the risk of tearing of the cell output portion 12 and, in turn, the risk of fracture of the cell output portion 12.

[0127] Or, as Figure 28 、 Figure 29 and Figure 53 As shown, the adapter plate 22 includes a first plate 221 and a second plate 222 connected at a predetermined angle. The cell output portion 12 is bent to connect to the first plate 221. The second plate 222 is located opposite the side of the battery 110 where the pole body 21 is located and is connected to the pole body 21. In other words, the cell output portion 12 and the pole body 21 are located on opposite sides. The L-shaped adapter plate 22 connects the cell output portion 12 and the pole body 21. In this case, the force applied to the pole body 21 does not directly act on the cell output portion 12, which can reduce the force applied to the cell output portion 12 and reduce the risk of tearing of the cell output portion 12.

[0128] It is worth noting that the surface of the cell output portion 12 refers to the large surface of the cell output portion 12 , that is, the surface of the cell output portion 12 perpendicular to the third direction, that is, the surface enclosed by the first direction and the second direction.

[0129] In one embodiment, Figure 30 As shown, the battery 110 has a pole body 21 on one side thereof. For example, a short-blade battery 110 or a cylindrical battery 110.

[0130] Of course, in other alternative embodiments, such as Figure 31As shown, the battery 110 has two terminal bodies 21 on the same side where the terminal body 21 is provided. For example, in a prismatic battery 110, heat generation is concentrated in the cell output portion 12, and the internal gas of the battery 110 impacts the same side of the battery 110, causing significant stress on the cell output portion 12. Therefore, the values ​​of a, b, and c are set to satisfy 0.006 ≤ b / (a ​​× c) ≤ 0.032 to reduce the risk of fracture in the cell output portion 12, thereby ensuring the flow capacity between the cell output portion 12 and the electrode terminal assembly 2 and preventing voltage jumps in the battery 110.

[0131] In one embodiment, Figure 32 and Figure 54 As shown, the battery 110 further includes a housing 7 having a first surface. A terminal body 21 is disposed on the first surface. The terminal body 21 is at least partially located on a side of the housing 7 facing away from the main body 11. The orthographic projection of at least a portion of the terminal body 21 onto the first surface forms a first projection 211, which is circular. In other words, the terminal body 21 is cylindrical. A cylindrical terminal is more evenly stressed, and therefore, the force transmitted to the cell output portion 12 is also more evenly stressed, avoiding localized stress concentration on the cell output portion 12 and reducing the risk of tearing of the cell output portion 12.

[0132] As an alternative embodiment, in one embodiment, Figure 33 and Figure 62 As shown, the first projection 211 is a square. That is, the pole body 21 is a square pole, which has a higher assembly stability with the battery 110 housing 7, preventing the pole body 21 from twisting under force and causing the cell output part 12 to twist and deform, thereby reducing the risk of the cell output part 12 being torn.

[0133] As an alternative embodiment, in one embodiment, Figure 34 and Figure 35 As shown, the first projection 211 is in the shape of an elongated strip. This arrangement can increase the area of ​​the first projection 211 and improve the current carrying capacity of the pole body 21.

[0134] Specifically, in one embodiment, Figure 34 As shown, the first projection 211 is an ellipse.

[0135] Or, in one embodiment, Figure 35 and Figure 63 As shown, the outer contour of the first projection 211 includes two straight segments 2111 and two arc segments 2112. The two straight segments 2111 are spaced apart from each other, and the two arc segments 2112 are connected to the ends of the two straight segments 2111 on the same side. In other words, the first projection 211 is an oblong (also called a racetrack) shape.

[0136] Further, such as Figure 36 As shown, the straight line segment 2111 is arranged parallel to the long side of the battery 110 on which the pole body 21 is provided. Thus, the anti-deformation capability of the pole body 21 is improved and the deformation risk of the pole body 21 is reduced.

[0137] Furthermore, the elliptical pole and the racetrack-shaped pole increase the current output rate of the battery 110, increase the flow area, and reduce the internal resistance of the battery 110. Therefore, the values ​​of a, b, and c satisfy 0.003≤b / (a×c)≤0.036, further shortening the current transmission path between the main body 11 and the electrode terminal assembly 2.

[0138] In one embodiment, Figures 37 to 44 as well as Figures 54 to 61 As shown, the battery 110 further includes a housing 7 having a first surface, on which the terminal body 21 is disposed. The housing 7 includes a protrusion 71 disposed on the first surface. The protrusion 71 forms a folded edge 711 that snaps onto a side of the terminal body 21 away from the cell output portion 12. This arrangement allows the folded edge 711 to press and limit the terminal body 21, reducing vibration and other effects on the terminal body 21, thereby reducing the force transmitted to the cell output portion 12 and reducing the risk of tearing of the cell output portion 12.

[0139] Specifically, in one embodiment, Figure 37 and Figure 57 As shown, the housing 7 also includes a main body, and the protrusion 71 is integrally provided with the main body. This arrangement increases the connection strength between the protrusion 71 and the main body, and the protrusion 71 better limits the position of the pole body 21, which can further reduce the vibration of the pole body 21, thereby further reducing the force transmitted to the battery cell output part 12, and further reducing the risk of the battery cell output part 12 tearing.

[0140] Of course, in other alternative embodiments, such as Figure 38 and Figure 61 As shown, the housing 7 also includes a main body, to which the protrusion 71 is welded. The connection strength between the protrusion 71 and the main body is relatively low, resulting in a relatively poor positioning effect of the protrusion 71 on the terminal body 21. This can increase vibration of the terminal body 21, increasing the force on the cell output portion 12 and the risk of tearing. Furthermore, the values ​​of a, b, and c satisfy 0.009 ≤ b / (a ​​× c) ≤ 0.04.

[0141] It is worth noting that if Figure 37 、 Figure 38 、 Figure 57 and Figure 61As shown, the protrusion 71 includes a connecting edge 712 and a folded edge 711. The side of the connecting edge 712 close to the battery cell output part 12 is fixedly connected to the main body, and the side of the connecting edge 712 away from the battery cell output part 12 is fixedly connected to the side of the folded edge 711. The folded edge 711 and the connecting edge 712 are arranged at a predetermined angle so that the folded edge 711 at least partially covers the side of the pole body 21 away from the battery cell output part 12.

[0142] Furthermore, in one embodiment, Figure 39 As shown, the folded edge 711 is continuously arranged along the circumference of the side of the pole body 21 facing away from the cell output portion 12. That is, the protrusion 71 is annular in structure. Specifically, both the connecting edge 712 and the folded edge 711 are annular in structure. This arrangement allows the folded edge 711 to completely constrain the pole body 21 circumferentially. The protrusion 71 further restrains the pole body 21, further reducing vibration of the pole body 21, thereby further reducing the force transmitted to the cell output portion 12 and the risk of tearing of the cell output portion 12.

[0143] Or, in one embodiment, Figure 40 As shown, the folded edge 711 is arranged in segments along the circumference of the side of the pole body 21 away from the battery output portion 12. That is, the connecting edge 712 is annular, while the folded edge 711 is segmented, meaning that the folded edge 711 is arranged discontinuously along the circumference. This improves the heat dissipation of the pole body 21. However, the folded edge 711 limits the position of part of the pole body 21, making the protrusion 71 less effective at limiting the position of the pole body 21. This increases the vibration of the pole body 21, causing increased stress on the battery output portion 12 and a relatively higher risk of tearing of the battery output portion 12.

[0144] In one embodiment, Figures 41 to 44 As shown, the battery 110 further includes a housing 7 , which includes a shell 72 and a cover 73 . At least one end of the shell 72 has an opening, and the cover 73 is connected to the shell 72 and blocks the opening.

[0145] It is worth noting that the above-mentioned main body can be a shell 72 or a cover 73. That is, the protrusion 71 can be provided on the shell 72 (see Figure 42 ), can also be set on the cover 73 (see Figure 41 ).

[0146] Furthermore, in one embodiment, Figure 41As shown, the pole body 21 is set on the cover plate 73. It is worth noting that the cover plate 73 and the shell 72 are welded together, and the shell 72 has a poor restraining effect on the cover plate 73. There is a risk of deformation of the cover plate 73 and the pole body 21, which can easily cause stress on the battery output part 12, and the risk of tearing of the battery output part 12 is relatively increased.

[0147] Of course, as an alternative embodiment, Figure 42 As shown, the pole body 21 is disposed on the housing 72. It is worth noting that the pole body 21 is disposed on at least one side wall of the housing 72, and the side wall of the housing 72 and other adjacent walls are generally integrally formed. Therefore, the overall structural strength of the housing 72 is relatively high and not easily deformed. Therefore, the force applied to the pole body 21 is relatively small, and the force applied to the battery cell output portion 12 is relatively small, thereby reducing the risk of tearing of the battery cell output portion 12.

[0148] Specifically, in one embodiment, the cover plate 73 is provided with a pole hole 731, and the pole body 21 is provided corresponding to the pole hole 731. Figure 41 As shown, the pole body 21 is located on the side of the cover plate 73 away from the pole ear; or, as shown Figure 43 As shown, the terminal body 21 is inserted into the terminal hole 731, and the end of the terminal body 21 close to the battery cell output portion 12 is located in the terminal hole 731. In other words, the terminal body 21 does not pass through the terminal hole 731, and the terminal body 21 does not occupy the internal space of the housing 72, thereby improving the space utilization of the battery 110 and further improving the energy density of the battery 110.

[0149] Furthermore, in one embodiment, Figures 41 to 43 As shown, part of the cell output portion 12 is located in the pole hole 731. This arrangement reduces the risk of the cell output portion 12 being inserted into the main body 11 backwards.

[0150] Of course, in other alternative embodiments, such as Figure 44 As shown, the cover plate 73 is provided with a pole hole 731, and the pole body 21 is arranged corresponding to the pole hole 731. The pole body 21 is inserted into the pole hole 731, and the end of the pole body 21 near the battery output portion 12 extends out of the pole hole 731. This arrangement makes it easier to connect and assemble the battery output portion 12 and the pole body 21.

[0151] In one embodiment, Figure 45As shown, the cell output portion 12 includes several layers of tab layers 125 stacked along a third direction. The tab layers 125 include an insulating layer 1251 and two metal layers 1252. The two metal layers 1252 are disposed on opposite sides of the insulating layer 1251 along the third direction. Specifically, the cell 1 includes several layers of pole pieces 13 stacked along the third direction. The pole pieces 13 include a current collector and an active material layer disposed on at least one side of the current collector along the third direction. Part of the current collector and the active material layer form a sheet 111, and part of the current collector extends to form the tab layer 125. Several layers of the sheet 111 form the main body 11, and several layers of the tab layers 125 form the cell output portion 12. The current collector includes an insulating layer 1251 and two metal layers 1252 to form a composite current collector. Thus, the flexibility of the current collector is improved, the risk of fault of the battery cell output part 12 is reduced, and the overcurrent capacity between the battery cell output part 12 and the electrode terminal assembly 2 is ensured, thereby avoiding the occurrence of voltage jump phenomenon of the battery 110.

[0152] Specifically, in one embodiment, Figure 45 As shown, along the third direction, the thickness of the insulating layer 1251 is t1, and the thickness of the metal layer 1252 is t2, satisfying 0.2≤t1 / t2≤0.5. This arrangement improves the flexibility of the current collector while ensuring its conductivity.

[0153] It is worth noting that if t1 / t2 is too large, the thickness of the metal layer 1252 is small, which is not conducive to electron transmission, the impedance of the battery 110 increases, and the voltage drop of the battery 110 increases; if t1 / t2 is too small, the thickness of the insulating layer 1251 is small, and the effect of improving the flexibility of the current collector is not obvious, and there is still a risk of fracture of the battery cell output part 12.

[0154] Optionally, the value of t1 / t2 is any value of 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, or a value between any two values.

[0155] Furthermore, in one embodiment, the metal layer 1252 includes copper or aluminum.

[0156] It's worth noting that the cell output portion is the area on the cell electrode not covered with active material. It serves as the current output terminal of the cell and is formed by gathering multiple single-layer current collectors. The multiple layers of current collectors can be welded together using at least one of the following welding methods: resistance welding, ultrasonic welding, and laser welding.

[0157] It should be further explained that the root portion 121 of the cell output portion 12 is the end portion of the electrode 13 where the active material is not coated.

[0158] It is understandable that the battery cell 1 is formed by a positive electrode sheet, a negative electrode sheet and a separator (ie, an isolation layer 14 ) disposed therebetween, by winding or stacking.

[0159] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material. The positive electrode current collector can be made of metal materials such as aluminum foil, nickel foil, stainless steel, or a composite foil formed by combining metal and insulating materials. The positive electrode active material includes a main positive electrode active material, a conductive agent, and a binder. The main positive electrode active material can include one or more lithium-containing positive electrode active materials such as lithium iron phosphate, a ternary material containing nickel, cobalt, and manganese, and lithium iron manganese phosphate.

[0160] Similarly, the negative electrode sheet consists of a negative electrode current collector and a negative electrode active material. The negative electrode current collector can be made of metal materials such as copper foil, aluminum foil, stainless steel, or a composite foil formed by combining metal and insulating materials. The negative electrode active material includes a negative electrode active main material, a conductive agent, and a binder. The negative electrode active main material can include one or more of artificial graphite, natural graphite, silicon carbon, silicon oxide, lithium titanate, and other negative electrode active main materials.

[0161] The diaphragm (also known as the isolation layer 14) is used to achieve insulation between adjacent positive and negative electrode sheets, and allows ions to shuttle back and forth for conduction, which can be lithium ions or sodium ions. The material of the isolation layer 14 includes a base film layer of PP or PE, and a ceramic layer and / or a glue layer can also be set on at least one surface of the base film layer. The ceramic layer plays a role in improving the high temperature resistance of the isolation layer 14, and the glue layer is used to improve the bonding strength between the base film layer and the electrode 13.

[0162] The battery 110 of this embodiment can be applied to many technical fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc.

[0163] In addition, the shape of the battery 110 can be cylindrical, quadrangular, hexagonal, soft-pack, etc., and the battery shell 7 is cylindrical or hexagonal. The battery shell 7 is evenly stressed, and the stress between the battery cell output part 12 and the electrode terminal assembly 2 is dispersed. Accordingly, the distance from the root 121 of the battery cell output part 12 to the connection area can be shortened, further improving the current transmission rate of the battery cell 1, reducing the internal heat generation of the battery 110, ensuring the thermal safety of the battery pack while shortening the charging and discharging time; when the battery 110 is a square shell battery, the vibration risk of the battery cell output part 12 and the electrode terminal assembly 2 is aggravated, and the deformation at the connection area is increased. Therefore, by increasing the distance from the root 121 of the battery cell output part 12 to the connection area and / or reducing the fault rate of the battery cell output part 12 in the connection area, the risk of deformation of the tab can be reduced, thereby reducing the risk of tearing of the battery cell output part 12 and avoiding the occurrence of voltage jump problems in the battery 110.

[0164] As the size of the battery 110 increases, especially in the length direction of the battery 110, the vibration of the connection area formed by the battery cell output part 12 and the electrode terminal assembly 2 increases. In particular, the effect of the size of the battery 110 along the lead-out direction of the battery cell output part 12 on the connection strength of the connection area is more significant. Therefore, the value range of b / (a×c) needs to be reasonably adjusted.

[0165] Furthermore, the length of the battery 110 ranges from 200 mm to 1000 mm, and preferably the length of the battery 110 is from 300 mm to 700 mm, so as to ensure the overall energy density of the single battery 110 while avoiding the current transmission path being too long, which would affect the overall rate performance of the battery 110 .

[0166] As for the size of the battery 110 in the direction perpendicular to the large surface of the electrode 13, that is, the thickness of the battery 110, the greater the thickness of the battery 110, the greater the heat generation, and the greater the impact of the gas inside the battery 110 on the battery cell output part 12. On the other hand, the smaller the thickness of the battery 110, the weaker the structural strength of the battery cell output part 12, and the greater the risk of the battery cell output part 12 being deformed by force. Therefore, it is also necessary to reasonably adjust the value range of b / (a×c).

[0167] Furthermore, in the direction perpendicular to the large surface of the pole piece 13 (ie, the third direction), the size (thickness) of the battery 110 ranges from 20 mm to 90 mm, preferably from 30 mm to 80 mm.

[0168] It is worth noting that the material of the battery shell 7 can be aluminum, aluminum alloy, steel, titanium, magnesium, nickel or other metal or alloy materials, and the battery cell 1 can be structurally protected by the material selection of the shell 7.

[0169] According to an embodiment of the present invention, on the other hand, a battery box 100 is provided. Figure 64 As shown, it includes the above-mentioned battery 110, and also includes a base plate and a frame. The base plate is arranged on the periphery of the frame and is fixedly connected to the frame. The base plate and the frame enclose a storage space. The battery 110 is arranged in the storage space and is fixedly connected to the base plate. The batteries 110 are connected in series or in parallel through conductive bars.

[0170] It is worth noting that in the relevant technology, when the battery box 100 is vibrated, the voltage of some batteries 110 in the battery box 100 jumps, causing the voltage difference between the batteries 110 and the batteries 110 in the battery box 100 to be too large, which in turn leads to poor overall consistency of the batteries 110 during the charging and discharging process of the battery box 100, affecting the cycle life of the batteries 110. The serious voltage jump of the batteries 110 will also cause heat accumulation in local batteries 110, leading to safety risks such as thermal runaway of the batteries 110.

[0171] By using the battery box 100 of this embodiment, the voltage of the batteries 110 in the battery box 100 can be prevented from jumping when the battery box 100 is subjected to vibration, thereby ensuring the overall consistency of the batteries 110 during the charging and discharging process of the battery box 100, thereby ensuring the cycle life of the batteries 110, and avoiding thermal runaway of the batteries 110 caused by heat accumulation in local batteries 110, thereby ensuring the safety performance of the battery box 100.

[0172] According to an embodiment of the present invention, on the other hand, an electric vehicle 1000 is provided. Figure 65 As shown, it includes the above-mentioned battery box 100 and the chassis, and the side of the frame opposite to the bottom plate forms an opening surface, and the opening surface and the chassis are fixed and sealed.

[0173] At this time, the chassis serves as the cover of the battery box 100, causing the deformation of the battery box 100 to further increase, resulting in an increased risk of vibration inside the battery box 100 and an increased risk of force on the battery cell output part 12. Therefore, further, the values ​​of a, b, and c are made to satisfy 0.005≤b / (a×c)≤0.04, thereby reducing the risk of fault in the battery cell output part 12, avoiding voltage jumps in the batteries 110 in the battery box 100, ensuring the consistency of the voltage of the batteries 110 in the battery box 100, and ensuring the cycle life and safety performance of the batteries 110.

[0174] Specifically, the battery 110 includes a lithium iron phosphate battery 110. This configuration can reduce heat generation during the battery 110 cycle and reduce gas generation inside the battery 110, thereby reducing stress on the cell output unit 12 and further reducing the risk of fracture of the cell output unit 12.

[0175] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0176] The preparation of the example battery and the comparative example battery includes the following steps: (1) Preparation of positive electrode: The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and the solvent NMP is added. The mixture is stirred in a vacuum mixer until the system is uniform to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheets are then cold pressed and slit. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies (92-98): (4-1): (4-1).

[0177] (2) Preparation of negative electrode sheet: The negative electrode active material graphite, the conductive agent acetylene black, the thickening agent CMC, and the binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred in a vacuum mixer until the system is uniform to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. The negative electrode sheets are then cold pressed and slit. The ratio of negative electrode graphite: conductive agent: thickening agent: binder is (90-96): (4-2): (2-1): (4-1).

[0178] (3) Preparation of electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0179] (4) Preparation of diaphragm: A polyethylene film was selected as the separator.

[0180] (5) Preparation of lithium-ion batteries: The positive electrode sheet, separator, and negative electrode sheet are stacked in order and wound or laminated to obtain a bare cell; the bare cell is placed in an outer packaging shell, dried, injected with electrolyte, and packaged, allowed to stand, formed, and constant capacity to obtain a lithium-ion battery.

[0181] The positive electrode active material can be selected from one or more of lithium-containing positive electrode active materials including lithium iron phosphate, a ternary material containing nickel, cobalt and manganese, and lithium iron manganese phosphate; The negative electrode active main material can be selected from one or more negative electrode active main materials such as artificial graphite, natural graphite, silicon carbon, silicon oxide, lithium titanate, etc.

[0182] In this application, the active main material of the positive electrode is selected from lithium iron phosphate as an example, with a mass ratio of positive electrode material: conductive agent: binder satisfying 96:2:2; and the main material of the negative electrode is selected from artificial graphite. Alternatively, in other embodiments, the main material of the positive electrode may be selected from one or more of a nickel-cobalt-manganese ternary material and lithium iron manganese phosphate; and the negative electrode may also include one or more of a silicon-carbon anode or natural graphite.

[0183] The difference between the batteries of each embodiment and the batteries of the comparative example lies in the values ​​of a, b, and c. Other characteristics of the batteries are the same, as shown in Table 1.

[0184] Battery pack preparation: Select battery cases and busbar assemblies from the same batch and with the same structural performance parameters, assemble the sample batteries into boxes according to the normal assembly process, and perform busbar welding.

[0185] The relevant performances of the batteries in the above examples and comparative examples were tested, and the test results are recorded in Table 1. The test method is as follows: 1. Battery pack pressure difference test after vibration The battery is vibration tested in accordance with the national standard GB 38031-2020, and the vibration parameters are tested in accordance with the requirements of GB 38031-8.2.1.

[0186] Afterwards, the battery pack was charged at 1C to 100% SOC and then adjusted to 50% SOC at 0.33C. 100 batteries in the battery pack were selected and the voltage of each battery was tested. The maximum and minimum battery voltages were taken and the maximum value minus the minimum value was calculated. When the maximum value minus the minimum value was greater than 30mV, the battery voltage consistency in the battery pack was poor and failed.

[0187] 2. Pole temperature rise test For each embodiment and comparative example, 10 batteries were taken respectively; the battery was discharged to 0% SOC at 0.33C, and after standing for 60 minutes, the temperature at this time was measured and recorded as t1. The battery was charged to 100% SOC at 1C, and the time was recorded as T. The temperature at this time was measured and recorded as t2. The temperature rise rate was calculated according to the formula temperature rise rate = (t2-t1) / T. If the temperature rise rate is greater than or equal to 0.9℃ / min, it is unqualified; if the temperature rise rate is less than 0.9℃ / min, it is qualified.

[0188] Table 1:

[0189] As can be seen from Table 1, in Examples 1 to 14, the values ​​of a, b, and c satisfy 0.003≤b / (a×c)≤0.4. Therefore, after the battery pack vibration test, the measured battery voltage differences of the sample batteries are all within the design requirements and meet the pressure difference conditions; moreover, the temperature rise at the pole during charging and discharging of the battery also meets the design requirements.

[0190] Furthermore, it can be seen from Table 1 that in Examples 10 to 14, the battery pack pressure difference test after vibration and the battery terminal temperature rise test all meet the test requirements, but the values ​​of some parameters have an impact on the relevant performance, among which: In Examples 10 and 13, the value of a is relatively small, resulting in a smaller connection area between the cell output portion and the electrode terminal assembly, insufficient welding strength, and the risk of breaking the tab layer, causing a voltage jump.

[0191] In Examples 11 and 14, a larger value for a results in a longer cell output portion, a longer current transmission path, an increased temperature rise in the electrode terminal assembly, and a larger welding area, making processing inconvenient. A larger value for b results in a longer current transmission path for the battery, resulting in more severe heat generation and affecting battery performance.

[0192] In Example 12 and Example 13, the value of b is small. When the battery is subjected to force vibration, the connection area is subjected to severe force and is easily torn, resulting in large fluctuations in the battery voltage.

[0193] In Example 12, the value of c is small, the process control is strict, and it is not easy to achieve in the process.

[0194] In Example 10 and Example 13, the value of c is relatively large, the tab layer is easily broken in the welding area, and the voltage jump is severe.

[0195] It can be seen from Table 1 that in Comparative Examples 1 and 2, the value of b / (a×c) is not in the range of 0.003 to 0.04 and is less than 0.003, which results in an increase in the tension on the first connection area, and the battery cell output part 12 is prone to tearing, resulting in an increased risk of battery voltage jumps, and further causing the battery pack pressure difference test to fail after vibration.

[0196] It can be seen from Table 1 that in Comparative Examples 3 and 4, the value of b / (a×c) is not in the range of 0.003 to 0.04 and is greater than 0.04, resulting in poor overcurrent capacity between the battery cell output part 12 and the electrode terminal assembly 2, which in turn causes the electrode terminal assembly to heat up too quickly and fail the pole temperature rise test.

[0197] 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: include: A battery cell (1) comprises a main body (11) and a battery cell output portion (12) extending from at least one end of the main body (11), wherein one end of the battery cell output portion (12) connected to the main body (11) is a root portion (121) of the battery cell output portion (12); An electrode terminal assembly (2) is welded to the cell output portion (12) to form a first connection area (3), wherein along a first direction, which is a lead-out direction of the cell output portion (12), the first connection area (3) has a first edge (31) close to the body portion (11) and a second edge (32) away from the body portion (11); Wherein, when the cell output portion (12) is flattened along the first direction, along the first direction, the distance between the root portion (121) and the second edge (32) is a, the distance between the root portion (121) and the first edge (31) is b, and the fault rate of the cell output portion (12) in the first connection area (3) is c, which satisfies 0.003≤b / (a×c)≤0.

04.

2. The battery according to claim 1, characterized in that A distance a between the root (121) and the second edge (32) and a distance b between the root (121) and the first edge (31) satisfy 0.17≤b / a≤0.

8.

3. The battery according to claim 1, characterized in that A second connection area (4) is also provided on the battery cell output portion (12), wherein the second connection area (4) is at least partially located between the main body portion (11) and the first connection area (3), and the second connection area (4) welds at least a portion of the battery cell output portion (12).

4. The battery according to claim 3, characterized in that The second connection area (4) includes a continuously arranged welding wire (41); or the second connection area (4) includes a plurality of welding wires (41), and the plurality of welding wires (41) are intermittently arranged.

5. The battery according to claim 3, characterized in that Along a second direction, which is parallel to the surface of the cell output portion (12) and perpendicular to the first direction, the width of the first connection area (3) is e, and the width of the second connection area (4) is f, satisfying f>e.

6. The battery according to claim 5, characterized in that Along the second direction, the first connection area (3) has a third edge (33) and a fourth edge (34) arranged opposite to each other, the second connection area (4) has a fifth edge (42) and a sixth edge (43) arranged opposite to each other, the battery cell output portion (12) has a seventh edge (122) and an eighth edge (123) arranged opposite to each other, the third edge (33) and the fifth edge (42) are arranged adjacent to the seventh edge (122), and the fourth edge (34) and the sixth edge (43) are arranged adjacent to the eighth edge (123); Along the second direction, the fifth edge (42) is arranged closer to the seventh edge (122) than the third edge (33), and the sixth edge (43) is arranged closer to the eighth edge (123) than the fourth edge (34).

7. The battery according to claim 6, characterized in that Along the second direction, the distance between the fifth edge (42) and the third edge (33) is g, and the distance between the sixth edge (43) and the fourth edge (34) is h, satisfying |gh|≤2mm.

8. The battery according to claim 6, characterized in that Along the second direction, the fifth edge (42) and the seventh edge (122) are spaced apart, and the sixth edge (43) and the eighth edge (123) are spaced apart.

9. The battery according to claim 8, characterized in that Along the second direction, the distance between the fifth edge (42) and the seventh edge (122) is i, and the distance between the sixth edge (43) and the eighth edge (123) is j, satisfying |ij|≤5mm.

10. The battery according to claim 5, characterized in that The width e of the first connection area (3) and the width f of the second connection area (4) satisfy 1.2≤f / e≤3.

11. The battery according to claim 3, characterized in that The second connection area (4) is welded to connect the cell output portion (12) and the electrode terminal assembly (2).

12. The battery according to claim 11, characterized in that Along the first direction, the distance d between the root portion (121) and the edge of one side of the second connection area (4) close to the main body portion (11) satisfies 5mm≤d≤15mm.

13. The battery according to claim 11, characterized in that Along the first direction, the first connection area (3) and the second connection area (4) are spaced apart, and the distance between the first connection area (3) and the second connection area (4) is k, which satisfies 1mm≤k≤15mm.

14. The battery according to claim 3, characterized in that The second connection area (4) is welded to the battery cell output portion (12), and the first connection area (3) is at least partially arranged in the second connection area (4).

15. The battery according to claim 14, characterized in that One of the first connection area (3) and the second connection area (4) is formed by laser welding, and the other of the first connection area (3) and the second connection area (4) is formed by ultrasonic welding.

16. The battery according to claim 14, characterized in that Along the first direction, the distance between the root portion (121) and the edge of one side of the second connection area (4) close to the main body portion (11) is L1, which satisfies 5mm≤L1≤20mm.

17. The battery according to claim 14, characterized in that The projection of the first connection area (3) on the battery cell output portion (12) along the third direction all falls within the projection of the second connection area (4) on the battery cell output portion (12) along the third direction, and the third direction is perpendicular to both the first direction and the second direction.

18. The battery according to any one of claims 1 to 17, characterized in that The cell output portion (12) between the first connection area (3) and the main body portion (11) forms a bending area (124).

19. The battery according to claim 18, characterized in that Along the first direction, the length of the bending area (124) is L2, satisfying 0.2≤L2 / b≤0.

8.

20. The battery according to claim 18, characterized in that The bending area (124) has a fold (1241) or a plurality of folds (1241) are arranged at intervals along the first direction.

21. The battery according to claim 20, characterized in that Along the first direction, the distance between a fold (1241) closest to the first connection area (3) and the first edge (31) is m, satisfying 2mm≤m≤5mm.

22. The battery according to claim 20, characterized in that Along the first direction, the distance between a fold (1241) closest to the main body (11) and the root (121) is n, satisfying 0.5 mm ≤ n ≤ 3 mm.

23. The battery according to any one of claims 1 to 22, characterized in that The battery cell output portion (12) comprises a plurality of tab layers (125) stacked along a third direction, and at least one of the tab layers (125) is provided with a protrusion (1253).

24. The battery according to claim 23, characterized in that Along the first direction, the distance between the protrusion (1253) and the root (121) is o, satisfying 0.5mm≤o≤2mm.

25. The battery according to any one of claims 1 to 24, characterized in that The battery cell (1) comprises a plurality of layers of pole pieces (13) stacked along a third direction, each of the pole pieces (13) comprising a sheet body (111) and a tab layer (125) extending from at least one end of the sheet body (111), a plurality of layers of the sheet body (111) forming the main body (11), a plurality of layers of the tab layer (125) forming the battery cell output portion (12), and a connection position between an edge of the sheet body (111) and an edge of the tab layer (125) having a chamfered structure (131).

26. The battery according to claim 25, characterized in that The radius of the chamfered structure (131) is R, satisfying 1mm≤R≤5mm.

27. The battery according to claim 25, characterized in that The battery core (1) further comprises an isolation layer (14), wherein the isolation layer (14) is provided between two adjacent layers of the pole pieces (13), and the isolation layer (14) extends from between adjacent sheets (111) to between adjacent tab layers (125).

28. The battery according to claim 27, characterized in that Along the first direction, the distance between one end of the isolation layer (14) close to the tab layer (125) and the connection end of the tab layer (125) and the sheet body (111) is p, satisfying 0.5 mm ≤ p ≤ 4 mm.

29. The battery according to any one of claims 1 to 28, characterized in that The cell output portion (12) comprises a plurality of tab layers (125) stacked along a third direction, and along the first direction, a distance between any two of the plurality of tab layers (125) away from one end of the main body portion (11) does not exceed 1 mm.

30. The battery according to any one of claims 1 to 28, characterized in that The cell output portion (12) comprises a plurality of tab layers (125) stacked along a third direction, and along the first direction, the plurality of tab layers (125) are staggered away from one end of the body portion (11).

31. The battery according to claim 29, characterized in that The cell output portion (12) is provided with a connection area, the connection area including the first connection area (3), and along a first direction, an edge of the connection area is arranged flush with an end of the cell output portion (12) away from the main body portion (11).

32. The battery according to claim 29 or 30, characterized in that The cell output portion (12) is provided with a connection area, the connection area including the first connection area (3), and along the first direction, an edge of the connection area is spaced apart from an end of the cell output portion (12) away from the main body portion (11).

33. The battery according to claim 32, characterized in that Along the first direction, the distance between the edge of the connection area and the end of the battery cell output portion (12) away from the main body portion (11) is L3, which satisfies 0.5mm≤L3≤3mm.

34. The battery according to any one of claims 1 to 33, characterized in that A third connection area (5) is provided on the battery cell output portion (12), and along the first direction, the third connection area (5) is located between the second edge (32) and an end of the battery cell output portion (12) away from the main body portion (11), and the third connection area (5) welds at least a portion of the battery cell output portion (12); and / or, the third connection area (5) is located on at least one side of the first connection area (3) in the second direction.

35. The battery according to claim 34, characterized in that The third connection area (5) is welded to the cell output portion (12) and the electrode terminal assembly (2).

36. The battery according to any one of claims 1 to 35, characterized in that Along the second direction, two side edges of the battery cell output portion (12) are arranged flush with two side edges of the main body portion (11).

37. The battery according to claim 36, characterized in that The values ​​of a, b, and c satisfy 0.005≤b / (a×c)≤0.

035.

38. The battery according to any one of claims 1 to 35, characterized in that Along the second direction, at least one side edge of the battery cell output portion (12) is spaced apart from the corresponding edge of the main body portion (11).

39. The battery according to claim 38, characterized in that Along the second direction, the distance between at least one side edge of the battery cell output portion (12) and the corresponding edge of the main body portion (11) is L4, and the width of the main body portion (11) is L5, satisfying 0.1≤L4 / L5≤0.

3.

40. The battery according to claim 39, characterized in that The values ​​of a, b, and c satisfy 0.008≤b / (a×c)≤0.

04.

41. The battery according to claim 38, characterized in that The center line of the battery cell output portion (12) in the second direction is collinearly arranged with the center line of the main body portion (11) in the second direction.

42. The battery according to claim 38, characterized in that The center line of the battery cell output portion (12) in the second direction is spaced apart from the center line of the main body portion (11) in the second direction.

43. The battery according to claim 38, characterized in that Along the second direction, the distance between one side edge of the first connection area (3) and the corresponding edge of the main body (11) is q, satisfying 5mm≤q≤35mm.

44. The battery according to any one of claims 1 to 43, characterized in that The electrode terminal assembly (2) comprises a pole body (21), and the pole body (21) is directly welded to the cell output portion (12) to form the first connection area (3).

45. The battery according to any one of claims 1 to 43, characterized in that The electrode terminal assembly (2) comprises a pole body (21) and a transfer plate (22), wherein the transfer plate (22) is welded to the cell output portion (12) to form the first connection area (3), and the pole body (21) and the transfer plate (22) are connected.

46. ​​The battery according to any one of claims 1 to 45, characterized in that The fault rate c of the battery cell output portion (12) in the first connection area (3) satisfies 15%≤c≤75%; and / or, The distance a between the root (121) and the second edge (32) satisfies 5mm≤a≤20mm; and / or, The distance b between the root (121) and the first edge (31) satisfies 3mm≤b≤10mm.

47. The battery according to claim 44 or 45, characterized in that A welding piece (6) is provided on a side of the cell output portion (12) facing away from the electrode terminal assembly (2).

48. The battery according to claim 44 or 45, characterized in that The end surface of the main body (11) leading out of the battery cell output portion (12) is arranged opposite to a surface of the battery (110) on which the pole body (21) is provided.

49. The battery according to claim 44, characterized in that The end surface of the main body (11) leading out of the battery cell output portion (12) is arranged adjacent to a surface of the battery (110) on which the pole body (21) is arranged.

50. The battery according to claim 49, characterized in that When the cell output portion (12) is flattened along a first direction, the surface of the cell output portion (12) is arranged parallel to a surface of the battery (110) on which the pole body (21) is provided; or, The adapter plate (22) comprises a first plate (221) and a second plate (222) connected at a predetermined angle, the cell output portion (12) being connected to the first plate (221), the second plate (222) being arranged opposite to a side of the battery (110) on which the pole body (21) is provided, and the second plate (222) being connected to the pole body (21).

51. The battery according to claim 44 or 45, characterized in that The battery (110) has one pole body (21) on one side where the pole body (21) is provided.

52. The battery according to claim 44 or 45, characterized in that The battery (110) has two pole bodies (21) on one side where the pole body (21) is provided.

53. The battery according to claim 52, characterized in that The values ​​of a, b, and c satisfy 0.006≤b / (a×c)≤0.

032.

54. The battery according to claim 44 or 45, characterized in that The battery (110) further comprises a housing (7), the housing (7) having a first surface, the pole body (21) being arranged on the first surface, the pole body (21) being at least partially located on a side of the housing (7) facing away from the main body (11), and an orthographic projection of at least a portion of the pole body (21) on the first surface forming a first projection (211), the first projection (211) being circular.

55. The battery according to claim 44 or 45, characterized in that The battery (110) further comprises a housing (7), the housing (7) having a first surface, the pole body (21) being arranged on the first surface, the pole body (21) being at least partially located on a side of the housing (7) facing away from the main body (11), and an orthographic projection of at least a portion of the pole body (21) on the first surface forming a first projection (211), the first projection (211) being square.

56. The battery according to claim 44 or 45, characterized in that The battery (110) further comprises a housing (7), the housing (7) having a first surface, the pole body (21) being arranged on the first surface, the pole body (21) being at least partially located on a side of the housing (7) facing away from the main body (11), and an orthographic projection of at least a portion of the pole body (21) on the first surface forming a first projection (211), the first projection (211) being in the shape of an elongated strip.

57. The battery according to claim 56, characterized in that The first projection (211) is elliptical.

58. The battery according to claim 56, characterized in that The outer contour of the first projection (211) comprises two straight line segments (2111) and two arc segments (2112), the two straight line segments (2111) are arranged at intervals relative to each other, and the two arc segments (2112) are respectively connected to two ends of the two straight line segments (2111) on the same side.

59. The battery according to claim 58, characterized in that The straight line segment (2111) is arranged parallel to the long side of a side of the battery (110) on which the pole body (21) is arranged.

60. The battery according to claim 57 or 58, characterized in that The values ​​of a, b, and c satisfy 0.003≤b / (a×c)≤0.

036.

61. The battery according to any one of claims 54 to 59, characterized in that The housing (7) comprises a protrusion (71) provided on the first surface, wherein the protrusion (71) forms a folded edge (711) that is buckled onto a side of the pole body (21) away from the battery cell output portion (12).

62. The battery according to claim 61, characterized in that The housing (7) further comprises a main body, and the protruding portion (71) is integrally provided with the main body.

63. The battery according to claim 61, characterized in that The housing (7) further comprises a main body, and the protruding portion (71) is welded to the main body.

64. The battery according to claim 63, characterized in that The values ​​of a, b, and c satisfy 0.009≤b / (a×c)≤0.

04.

65. The battery according to claim 61, characterized in that The folded edge (711) is arranged in sections along the circumference of a side of the pole body (21) away from the battery cell output portion (12).

66. The battery according to claim 61, characterized in that The folded edge (711) is continuously arranged along the circumference of a side of the pole body (21) away from the battery cell output portion (12).

67. The battery according to any one of claims 44 to 66, characterized in that The battery (110) further comprises a housing (7), wherein the housing (7) comprises a shell (72) and a cover plate (73), wherein at least one end of the shell (72) has an opening, the cover plate (73) is connected to the shell (72) and blocks the opening, and the pole body (21) is arranged on the cover plate (73).

68. The battery according to claim 67, characterized in that A pole hole (731) is provided on the cover plate (73), the pole body (21) is arranged corresponding to the pole hole (731), and the pole body (21) is located on a side of the cover plate (73) away from the battery cell output portion (12).

69. The battery according to claim 67, characterized in that The cover plate (73) is provided with a pole hole (731), the pole body (21) is arranged corresponding to the pole hole (731), the pole body (21) is passed through the pole hole (731), and one end of the pole body (21) close to the battery cell output portion (12) extends out of the pole hole (731).

70. The battery according to claim 67, characterized in that The cover plate (73) is provided with a pole hole (731), the pole body (21) is arranged corresponding to the pole hole (731), the pole body (21) is passed through the pole hole (731), and one end of the pole body (21) close to the battery cell output portion (12) is located in the pole hole (731).

71. The battery according to claim 68 or 70, characterized in that Part of the battery cell output portion (12) is located in the pole hole (731).

72. The battery according to any one of claims 44 to 66, characterized in that The battery (110) further comprises a housing (7), the housing (7) comprising a shell (72) and a cover plate (73), at least one end of the shell (72) having an opening, the cover plate (73) being connected to the shell (72) and sealing the opening, and the pole body (21) being arranged on the shell (72).

73. The battery according to any one of claims 1 to 72, characterized in that The cell output portion (12) comprises a plurality of tab layers (125) stacked along a third direction, the tab layer (125) comprising an insulating layer (1251) and two metal layers (1252), the two metal layers (1252) being arranged on two opposite sides of the insulating layer (1251) along the third direction.

74. The battery according to claim 73, characterized in that Along the third direction, the thickness of the insulating layer (1251) is t1, and the thickness of the metal layer (1252) is t2, satisfying 0.2≤t1 / t2≤0.

5.

75. The battery according to claim 73, characterized in that The metal layer (1252) includes copper elements or aluminum elements.

76. A battery box, characterized in that: The invention comprises a battery (110) according to any one of claims 1 to 75, further comprising a base plate and a frame, wherein the base plate is arranged on the periphery of the frame and is fixedly connected to the frame, wherein the base plate and the frame enclose a receiving space, wherein the battery (110) is arranged in the receiving space and is fixedly connected to the base plate, and wherein the batteries (110) are connected in series or in parallel via conductive bars.

77. An electric vehicle, characterized in that: It comprises the battery box (100) as claimed in claim 76 and a chassis, wherein a side of the frame opposite to the bottom plate forms an opening surface, and the opening surface and the chassis are fixedly sealed.

78. The electric vehicle according to claim 77, characterized in that The values ​​of a, b, and c satisfy 0.005≤b / (a×c)≤0.

04.

79. The electric vehicle according to claim 78, characterized in that The battery (110) comprises a lithium iron phosphate battery (110).

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