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

[0001] This application is a divisional application of the invention patent application with publication number CN2025112229221. The original application was filed on August 29, 2025; the application number is 2025112229221; and the invention title is "Battery, Battery Box and Electric Vehicle". Technical Field

[0002] This invention relates to the field of battery technology, specifically to batteries, battery boxes, and electric vehicles. Background Technology

[0003] A battery typically comprises an external structure and an internal structure. The external structure encloses a sealed space, while the internal structure includes the battery cells, which are housed within this sealed space. The battery cells' tabs are welded to the electrode terminal assemblies of the external structure, enabling current transmission. To ensure voltage stability within the battery pack, the voltages of multiple batteries within the same pack must be maintained within a certain range during design. However, in existing technologies, under certain operating conditions, factors such as vibration or manufacturing differences between batteries can lead to significant voltage differences among the batteries within the pack. This results in poor consistency between the batteries, and the possibility of overcharging or over-discharging during battery cycling, potentially causing a decrease in battery pack cycle life or even thermal runaway within the battery, posing safety risks. Summary of the Invention

[0004] In view of this, the present invention provides a battery, a battery box, and an electric vehicle to solve the problems in the prior art where the voltage difference between multiple batteries in a battery pack is large, resulting in poor consistency between the multiple batteries, and overcharging or over-discharging during battery cycling, which leads to battery pack cycle life degradation or thermal runaway and other safety risks.

[0005] In a first aspect, the present invention provides a battery comprising: A battery cell includes a body portion and a battery cell output portion extending from at least one end of the body portion, wherein the end of the battery cell output portion connected to the body portion is the root portion of the battery cell output portion; the battery cell includes a plurality of electrode layers stacked along a third direction, and the battery cell also includes an isolation layer, wherein the isolation layer is disposed between two adjacent electrode layers, and the isolation layer is a separator; An electrode terminal assembly is welded to the cell output portion to form a first connection area. A bending area is formed between the first connection area and the cell output portion between the cell output portion and the main body. Along a first direction, which is the lead-out direction of the cell output portion, the first connection area has a first edge close to the main body and a second edge away from the main body. The electrode terminal assembly includes a terminal body and an adapter piece. The adapter piece is welded to the cell output portion to form the first connection area, and the terminal body is connected to the adapter piece. The end face of the main body from which the cell output portion leads is disposed opposite to the side of the battery where the terminal body is located. Wherein, when the cell output section is flattened along the first direction, the distance between the root and the second edge along the first direction is a, the distance between the root and the first edge is b, and the tortuosity of the cell output section in the first connection area is c, satisfying 0.003≤b / (a×c)≤0.04.

[0006] Beneficial effects: The distance a between the root and the second edge, the distance b between the root and the first edge, and the discontinuity c of the cell output section in the first connection area satisfy 0.003≤b / (a×c)≤0.04. This ensures the overcurrent capacity between the electrode terminal assembly and the cell output section, avoids battery voltage jumps, and guarantees battery reliability. At the same time, it avoids safety problems such as battery thermal runaway, thus 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 tensile force from the main body when the battery vibrates. In particular, the cell output section is prone to tearing at the first edge of the first connection area, resulting in an excessively high failure rate of the cell output section, a large voltage difference between the cells, a decrease in the overall cycle life of the battery pack, and overcharging and over-discharging of the battery, affecting its use. 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 battery's internal resistance. It will also lead to a small welding area ratio in the first connection area, resulting in poor overcurrent capacity between the cell output section and the electrode terminal assembly. This will lead to an excessively fast heating rate of the electrode terminal assembly, increasing the risk of thermal runaway and affecting the battery's safety performance.

[0007] Secondly, the present invention also provides a battery box, including the battery described above, and further including a base plate and a frame. The base plate is disposed on the outer periphery of the frame and fixedly connected to the frame. The base plate and the frame enclose a receiving space. The battery is disposed in the receiving space and fixedly connected to the base plate. The batteries are connected in series or in parallel through conductive busbars.

[0008] Beneficial effects: When the battery box is subjected to vibration, it prevents voltage fluctuations in the batteries inside the battery box, thereby ensuring the overall consistency of the batteries during the charging and discharging process, thus ensuring the cycle life of the batteries, and avoiding battery thermal runaway caused by localized heat accumulation in the batteries, thereby ensuring the safety performance of the battery box.

[0009] Thirdly, the present invention also provides an electric vehicle, including the aforementioned battery box and chassis, wherein the side of the frame opposite to the base plate forms an opening, and the opening and the chassis are fixedly sealed together. Attached Figure Description

[0010] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of a welding method for the cell output section and 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 This is a schematic diagram of another welding method for the cell output section and electrode terminal assembly of the battery according to an embodiment of the present invention; Figure 4 for Figure 3 A top view of the battery shown; Figure 5 This is a schematic diagram of another welding method for the cell output section and electrode terminal assembly of the battery according to an embodiment of the present invention; Figure 6 for Figure 5 A top view of the battery shown; Figure 7 This is a top view of another welding method for the cell output section and electrode terminal assembly of the battery according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of a bonding wire in the second connection area according to an embodiment of the present invention; Figure 9 This is a schematic diagram of another type of bonding wire structure in the second connection area according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of a bending area of ​​the battery cell output section according to an embodiment of the present invention; Figure 11 This is a schematic diagram of another bending region of the battery cell output section according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the structure of the electrode sheet with protrusions according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the structure of the electrode sheet with a chamfered structure according to an embodiment of the present invention; Figure 14 This is a schematic diagram of the structure of the tab layer and the isolation layer in an embodiment of the present invention; Figure 15 This is a schematic diagram of the structure where the ends of the tab layer are flush, according to an embodiment of the present invention. Figure 16 This is a schematic diagram of the misaligned end of the tab layer according to an embodiment of the present invention; Figure 17 This is a schematic diagram of the structure in an embodiment of the present invention, showing that the end of the tab layer is flush with the second edge; Figure 18 This is a schematic diagram of the structure of the battery cell output section and electrode terminal assembly having a third connection area according to an embodiment of the present invention; Figure 19 This is a schematic diagram of the battery cell output section in the form of multiple tabs according to an embodiment of the present invention; Figure 20 This is a schematic diagram of the structure in which the main body and the battery cell output section are eccentrically arranged according to an embodiment of the present invention; Figure 21 This is a schematic diagram of the welding structure of the battery cell output section and the electrode body according to an embodiment of the present invention; Figure 22 This is a schematic diagram of the welding structure of the battery cell output section and the adapter plate according to an embodiment of the present invention; Figure 23 This is a schematic diagram of the structure of the first edge of the tabular layer in an embodiment of the present invention; Figure 24 This is a schematic diagram of a battery cell output section with a welding piece provided in an embodiment of the present invention; Figure 25 This is a schematic diagram of the structure of the battery cell output section when it is side-mounted according to an embodiment of the present invention; Figure 26 This is a schematic diagram of the structure when the battery cell output section is ejected according to an embodiment of the present invention; Figure 27 This is a schematic diagram of the structure of the electrode body when it is located on the large surface of the battery according to an embodiment of the present invention; Figure 28 This is a schematic diagram of the structure of the adapter piece with the first piece and the second piece before bending, according to an embodiment of the present invention. Figure 29 This is a schematic diagram of the structure of the adapter plate having a first piece and a second piece connecting the output part of the battery cell and the electrode body according to an embodiment of the present invention; Figure 30A schematic diagram of the structure of a battery according to an embodiment of the present invention, showing one side having an electrode body; Figure 31 A schematic diagram of the structure of a battery according to an embodiment of the present invention, wherein one side of the battery has two electrode bodies; Figure 32 This is a schematic diagram of the structure of the first projection of the present invention being a circle; Figure 33 This is a schematic diagram of the first projection of a square structure according to an embodiment of the present invention; Figure 34 This is a schematic diagram of the structure of the first projection of the present invention being elliptical; Figure 35 This is a schematic diagram of the structure of the first projection of an embodiment of the present invention, which is an elongated circle (racetrack shape); Figure 36 for Figure 35 The diagram shows the mating structure between the electrode body and the battery casing. Figure 37 This is a schematic diagram of the structure in which the protrusion and the cover plate are integrally formed according to an embodiment of the present invention; Figure 38 This is a schematic diagram of the structure of the protrusion and the cover plate being welded according to an embodiment of the present invention; Figure 39 This is a schematic diagram of a structure in which the folded edge is continuously arranged circumferentially according to an embodiment of the present invention; Figure 40 This is a schematic diagram of the structure of the folded edge segmented in the circumferential direction according to an embodiment of the present invention; Figure 41 This is a schematic diagram of the structure of the present invention, in which the electrode body is not inserted into the electrode hole and the electrode body is disposed on the cover plate. Figure 42 This is a schematic diagram of the structure of the present invention, in which the electrode body is not inserted into the electrode hole and the electrode body is disposed in the housing. Figure 43 This is a schematic diagram of the structure of the electrode body portion passing through the electrode hole in an embodiment of the present invention; Figure 44 This is a schematic diagram of the structure of the pole body completely inserted into the pole hole according to an embodiment of the present invention; Figure 45 This is a schematic diagram of the tab layer structure according to an embodiment of the present invention; Figure 46 This is a schematic diagram of the structure of the first type of battery according to an embodiment of the present invention; Figure 47 for Figure 46 The front view of the battery shown; Figure 48 for Figure 47 A cross-sectional view along the AA direction; Figure 49 for Figure 48 A magnified view of a portion of point B in the middle; Figure 50 This is a schematic diagram of the structure of a second type of battery (casing 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 A cross-sectional view along the CC direction; Figure 53 for Figure 52 A magnified view of a portion of point D in the middle; Figure 54 This is a schematic diagram of the structure of the third type of 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 along the EE direction; Figure 57 for Figure 56 A magnified view of a portion of point F in the middle; Figure 58 This is a schematic diagram of the structure of the fourth type of 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 along the GG direction; Figure 61 for Figure 60 A magnified view of a portion of point H in the middle; Figure 62 This is a schematic diagram of the structure of a battery with square electrode posts according to an embodiment of the present invention; Figure 63 This is a schematic diagram of the structure of the racetrack-shaped terminal block battery according to an embodiment of the present invention; Figure 64 This is a schematic diagram of the structure of a battery box according to an embodiment of the present invention; Figure 65 This is a schematic diagram of the structure of an electric vehicle according to an embodiment of the present invention; Figure 66 This is a CT scan showing the welded and unwelded areas of the battery cell output section and electrode terminal assembly.

[0012] Explanation of reference numerals in the attached figures: 1. Battery cell; 11. Body section; 111. Sheet; 12. Battery cell output section; 121. Root; 122. Seventh edge; 123. Eighth edge; 124. Bending area; 1241. Crease; 125. Tab layer; 1251. Insulating layer; 1252. Metal layer; 1253. Protrusion; 13. Electrode sheet; 131. Chamfered structure; 14. Insulating layer; 2. Electrode terminal assembly; 21. Electrode post body; 211. First projection; 2111. Straight segment; 2112. Arc segment; 22. Adapter 221, First piece; 222, Second piece; 3, First connecting area; 31, First edge; 32, Second edge; 33, Third edge; 34, Fourth edge; 4, Second connecting area; 41, Welding wire; 42, Fifth edge; 43, Sixth edge; 5, Third connecting area; 6, Welded piece; 7, Outer shell; 71, Protrusion; 711, Folded edge; 712, Connecting edge; 72, Shell; 73, Cover plate; 731, Terminal hole; 100, Battery box; 110, Battery; 1000, Electric vehicle. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] The following is combined with Figures 1 to 66 The following describes embodiments of the present invention.

[0015] According to an embodiment of the present invention, a battery 110 is provided, comprising: a cell 1, including a body portion 11 and a cell output portion 12 extending from at least one end of the body portion 11, wherein the end of the cell output portion 12 connected to the body portion 11 is a root portion 121 of the cell output portion 12; an electrode terminal assembly 2, welded to the cell output portion 12 to form a first connection region 3, wherein the first connection region 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, the distance between the root portion 121 and the second edge 32 along the first direction is a, the distance between the root portion 121 and the first edge 31 is b, and the tortuosity of the cell output portion 12 in the first connection region 3 is c, satisfying 0.003≤b / (a×c)≤0.04.

[0016] Using 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 discontinuity c of the cell output section 12 in the first connection area 3 satisfy 0.003≤b / (a×c)≤0.04. This ensures the overcurrent capacity between the electrode terminal assembly 2 and the cell output section 12, avoids voltage jumps in the battery 110, and ensures the reliability of the battery 110. At the same time, it avoids safety problems such as thermal runaway of the battery 110, thus ensuring the safety performance of the battery 110.

[0017] Specifically, if the value of b / (a×c) is too small, the first connection area 3 will be easily subjected to tension from the body 11 when the battery 110 vibrates. In particular, the cell output section 12 is prone to tearing at the first edge 31 of the first connection area 3, resulting in an excessively high fault rate of the cell output section 12. This leads to a large voltage difference between the batteries 110, a decrease in the overall cycle life of the battery pack, and overcharging and over-discharging of the battery 110, affecting its use. If the value of b / (a×c) is too large, the current transmission path between the 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 lead to a small welding area ratio in the first connection area 3, resulting in poor overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2. This will lead to an excessively fast heating rate of the electrode terminal assembly 2, increasing the risk of thermal runaway of the battery 110 and affecting its safety performance.

[0018] Optionally, b / (a×c) can take any value from 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, 0.04, or a value between any two values.

[0019] It is worth noting that the welding reliability of the cell output section 12 and the electrode terminal assembly 2 is a key factor affecting the voltage of the battery 110. In related technologies, after the cell output section 12 and the electrode terminal assembly 2 are welded and a solder mark is formed, pores may form inside the solder mark, especially at the junction of the solder mark and the adjacent non-welded area (see [link to related technology]). Figure 66 Therefore, when the battery 110 is subjected to force, the cell output section 12 is easily subjected to tensile force, which can cause a break at the junction of the solder and non-soldering areas. This results in an increase in impedance between the cell output section 12 and the electrode terminal assembly 2, a decrease in the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, and a voltage drop in the battery 110, which causes a voltage jump in the battery 110.

[0020] 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 fracture rate c of the cell output section 12 in the first connection area 3, the tensile force from the body section 11 on the first connection area 3 is reduced, the risk of fracture of the cell output section 12 is reduced, and the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2 is not affected, thus avoiding the occurrence of voltage jump phenomenon of battery 110.

[0021] It is worth noting that during the production of battery 110, the cell output section 12 may need to be bent before being welded to the electrode terminal assembly 2. In this embodiment, when measuring the distance a between the root 121 and the second edge 32 and the distance b between the root 121 and the first edge 31, the cell output section 12 needs to be flattened along the first direction, that is, the cell output section 12 is extended along the first direction.

[0022] It should be further explained that, in this embodiment, the first direction (x-direction) is the length direction of the cell output section 12; correspondingly, the second direction (y-direction) is the width direction of the cell output section 12, and the third direction (z-direction) is the thickness direction of the cell output section 12. The root portion 121 is located at the connection point between one side edge of the body portion 11 and the cell output section 12.

[0023] It is understood that, in this embodiment, please refer to Figure 15 The cell output section 12 includes several tab layers 125 stacked along a third direction. The cell output section 12 and the electrode terminal assembly 2 are stacked along a third direction, and the cell output section 12 and the electrode terminal assembly 2 are welded together from the side of the cell output section 12 away from the electrode terminal assembly 2.

[0024] It should be noted that the layering rate refers to the ratio of the number of layers in the cell output section 12 not connected to the first connection area 3 at the first edge 31 to the total number of layers in the cell output section 12. For details, please refer to [link to relevant documentation]. Figure 23 The total number of layers in the cell output section 12 is 8. At the first edge 31, the number of layers in the cell output section 12 that are not connected to the first connection area 3 is 2, and the discontinuity rate c=2 / 8=0.25.

[0025] Furthermore, the fault rate testing method is as follows: 1. Remove the welded parts of the battery cell output section and electrode terminal assembly. Cut the sample in half after gel curing. The sample should be ground clearly without any visible scratches. First, use 800-grit sandpaper for rough grinding, and then use 2000-grit sandpaper for fine grinding. The grinding time is about 2 to 3 minutes. 2. Measure the number of fracture layers in the area where the weld pool meets the two tab layers. Black cracks and black pores indicate fracture. 3. The total number of fracture layers on the left side of the weld pool is C1, and the total number of fracture layers on the right side of the weld pool is C2. The fracture rate is calculated as (C1 + C2) / (total number of electrode layers × 2) × 100%.

[0026] In addition, the control of the delamination rate can be achieved by controlling and adjusting multiple factors such as oil stains and impurities on the surface of the tab foil, welding power, and material selection during the preparation of sample batteries through batch experiments. Batch testing can be conducted to calculate the relationship between the delamination rate and the above-mentioned influencing factors, thereby enabling the control of the delamination rate during the manufacturing process.

[0027] Specifically, in one embodiment, the distance 'a' between the root 121 and the second edge 32 and the distance 'b' between the root 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.

[0028] It is worth noting that if the value of b / a is too large, the transmission path of current 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 overcurrent capacity between the cell output part 12 and the electrode terminal assembly 2. This will lead to severe heat generation in the electrode terminal assembly 2, 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 body part 11 when the battery 110 vibrates. In particular, the cell output part 12 is prone to tearing at the first edge 31 of the first connection area 3, resulting in an excessively high fracture rate of the cell output part 12. This affects the overcurrent 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, thus 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, reducing the space utilization rate of the battery 110 and affecting the energy density of the battery 110.

[0029] Optionally, b / a can be any value from 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.

[0030] In one embodiment, such as Figures 3 to 9As shown, the cell output section 12 is further provided with a second connection area 4. The second connection area 4 is at least partially located between the main body section 11 and the first connection area 3. The second connection area 4 welds a portion of the cell output section 12 along at least a third direction. That is, at least a portion of the tab layer 125 can be gathered and welded through the second connection area 4. This arrangement can reduce the pulling force of the main body section 11 on the first connection area 3 through the cell output section 12, reduce the risk of breakage of the cell output section 12, and thus ensure the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, avoiding the occurrence of voltage jump phenomena in the battery 110.

[0031] It is worth noting that the first connection area 3 and the second connection area 4 are arranged along the first direction in the cell output section 12, and the second connection area 4 is located closer to the main body section 11 than the first connection area 3.

[0032] It should be further explained that the first connecting area 3 and the second connecting area 4 can be set at intervals or can overlap with each other. Specifically, the edges of the first connecting area 3 and the second connecting area 4 can overlap, or a portion of the area can overlap, or the first connecting area 3 can be completely located within the second connecting area 4.

[0033] In one embodiment, such as Figure 8 As shown, the second connection area 4 includes a continuously arranged welding line 41, that is, a continuous welding method is used when welding to form the second connection area 4. Or, as... Figure 9 As shown, the second connection area 4 includes multiple welding lines 41, which are intermittently arranged. That is, the second connection area 4 is formed by welding in segments.

[0034] It is worth noting that, during the welding process of the multilayer tab layer 125, segmented welding, compared to continuous welding, can reduce cracks and delamination caused by uneven thermal stress and excessively rapid cooling by effectively controlling heat input and cooling rate.

[0035] It should be noted that each solder wire 41 can form a solder mark. Therefore, the second connection area 4 can include only one complete solder mark, or it can be divided into multiple solder marks with intervals between them. Furthermore, the shape of the solder mark can be rectangular, circular, triangular, spiral, etc.

[0036] In the first embodiment of the second connection region 4, such as Figure 3 and Figure 4As shown, the second connection area 4 is welded to the cell output section 12 and the electrode terminal assembly 2. With this arrangement, when the battery 110 is subjected to force, the tensile force applied by the main body 11 to the cell output section 12 will first act on the second connection area 4. The second connection area 4 shares the force of the first connection area 3, thereby protecting the first connection area 3, increasing the tensile strength of the welded area between the cell output section 12 and the electrode terminal assembly 2 under vibration stress, reducing the risk of cell output section 12 fracture, and thus ensuring the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, preventing voltage jumps in the battery 110.

[0037] It is worth noting that by utilizing the first connection area 3 and the second connection area 4, the current-passing area between the cell output section 12 and the electrode terminal assembly 2 is increased, thereby improving the current-passing capacity of the cell output section 12.

[0038] In this embodiment, as Figure 3 As shown, along the first direction, the distance d between the root 121 and the edge of the second connection area 4 near the body 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 11 and the electrode terminal assembly 2.

[0039] It is worth noting that if the value of d 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. This leads to a poor overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, which in turn increases the heat generated by the battery 110 during use, increasing the risk of thermal runaway and affecting the safety performance of the battery 110. If the value of d is too small, the distance between the second connection area 4 and the main body 11 will be too close, causing 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 cell output section 12 is prone to tearing at the edge of the second connection area 4 near the main body 11, resulting in an excessively high fracture rate of the cell output section 12. This affects the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, thus affecting the use of the battery 110.

[0040] Optionally, d can be any value from 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, 15mm, or a value between any two of these values.

[0041] In this embodiment, as Figure 4As shown, along the second direction, which is parallel to the surface of the cell output section 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 configuration, when the battery 110 is subjected to force, the second connection area 4 can share more of the force, improving the protection effect on the first connection area 3.

[0042] Furthermore, in this embodiment, as 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 to each other, the second connection area 4 has a fifth edge 42 and a sixth edge 43 disposed opposite to each other, and the battery cell output section 12 has a seventh edge 122 and an eighth edge 123 disposed opposite to 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 sides of the second connection area 4 extend outward beyond the two sides of the first connection area 3. With this arrangement, the second connection area 4 can completely protect the first connection area 3, further improving the protection effect of the first connection area 3.

[0043] Furthermore, in this embodiment, as 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 sides of the second connecting area 4 extend outward beyond the two sides of the first connecting area 3 by approximately the same amount, and the center line of the second connecting area 4 along the second direction is collinear with the center line of the first connecting area 3 along the second direction. With this arrangement, the tensile force applied by the main body 11 to the cell output section 12 is distributed through the second connecting area 4, resulting in a more balanced tensile force transmitted to the first connecting area 3. This also makes the force on the first connecting area 3 more balanced, reducing the risk of breakage of the cell output section 12 at the first edge 31.

[0044] Optionally, |gh| can take any value from 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.

[0045] In this embodiment, as Figure 4As shown, 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. This arrangement utilizes 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, to buffer the force on the second connection area 4, preventing direct force on the edge of the second connection area 4 and thus reducing the risk of delamination. Furthermore, since the second connection area 4 is not welded to the edge of the cell output section 12, the welding yield of the second connection area 4 can be improved, avoiding the occurrence of cold solder joints and ensuring the overcurrent capacity of the cell output section 12.

[0046] Furthermore, in this embodiment, as 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|≤5mm. This setting can further improve the uniformity of force on the second connecting region 4 at the fifth edge 42 and the sixth edge 43, and avoid the increase in fault risk caused by the concentration of force at the edges of the second connecting region 4.

[0047] Optionally, |ij| can take any value from 0, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or a value between any two values.

[0048] Specifically, in this embodiment, the width e of the first connecting area 3 and the width f of the second connecting area 4 satisfy 1.2 ≤ f / e ≤ 3. This setting ensures the protective effect of the second connecting area 4 on the first connecting area 3 while preventing the second connecting area 4 from being torn.

[0049] It is worth noting that if the value of f / e is too large, the tensile force shared by the second connection area 4 will be too great, which may easily cause the cell output section 12 to tear at the edge of the second connection area 4 near the main body 11. This would result in an excessively high fracture rate of the cell output section 12, affecting the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, thus affecting the use of the battery 110. If the value of f / e is too small, the tensile force shared by the second connection area 4 will be limited, and the tensile force transmitted to the first connection area 3 will still be large. There is still a risk that the cell output section 12 will be torn at the first edge 31, resulting in insufficient protection for the first connection area 3.

[0050] Optionally, f / e can take any value from 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, or a value between any two values.

[0051] In this embodiment, as 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, satisfying 1mm≤k≤15mm. This arrangement ensures the welding quality between the cell output section 12 and the electrode terminal assembly 2 while preventing the second connection area 4 from being torn.

[0052] 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 prone to overlap, which can easily cause welding defects and affect the connection strength and current carrying capacity between the cell output section 12 and the electrode terminal assembly 2. If the value of k is too large, the distance between the second connection area 4 and the main body 11 may be too close, 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 cell output section 12 is prone to tearing at the edge of the second connection area 4 near the main body 11, resulting in an excessively high fracture rate of the cell output section 12. This affects the current carrying capacity between the cell output section 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use and affecting the use of the battery 110.

[0053] Optionally, k can be any value from 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, or a value between any two of these values.

[0054] In a second embodiment of the second connection region 4, such as Figure 5 As shown, the second connection area 4 is configured to weld the cell output section 12. That is, the entire tab layer 125 is welded through the second connection area 4, but the cell output section 12 and the electrode terminal assembly 2 do not need to be welded through the second connection area 4. This configuration, which reinforces the cell output section 12 through pre-welding, can improve the structural strength of the cell output section 12, reduce the pulling force of the body part 11 on the first connection area 3 through the cell output section 12, reduce the risk of cell output section 12 breakage, and thus ensure the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, preventing the occurrence of voltage jump phenomena in the battery 110.

[0055] 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.

[0056] Furthermore, in this embodiment, as Figure 5 and Figure 6As shown, the first connection area 3 is at least partially disposed within the second connection area 4. The cell output section 12 is pre-welded through the second connection area 4, and then the cell output section 12, which is integrally formed through the second connection area 4, is welded to the electrode terminal assembly 2 to improve the welding strength.

[0057] Furthermore, in this embodiment, as Figure 5 As shown, along the first direction, the distance between the root 121 and the edge of the second connection area 4 near the body 11 is L1, which satisfies 5mm≤L1≤20mm. This setting reduces the pulling force on the first connection area 3 while preventing wrinkling and deformation of the cell output section 12.

[0058] 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 will be too close, resulting in poor buffering effect of the cell output section 12 against tensile forces. This can easily cause the first connection area 3 to be directly subjected to force, increasing the risk of cell output section 12 breaking at the first edge 31. This will affect the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, thus affecting the use of the battery 110. If the value of L1 is too large, the cell output section 12 between the main body 11 and the second connection area 4 will be too long, resulting in increased material consumption and waste. It can also easily cause the cell output section 12 to wrinkle and deform, making it easy for the cell output section 12 to overlap with the main body 11 or other structural components, thus causing a short circuit risk.

[0059] Optionally, L1 can be any value from 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, or a value between any two of these values.

[0060] Of course, as alternative implementation methods, such as Figure 7 As shown, the projection of the first connection area 3 along the third direction onto the cell output section 12 falls entirely into the projection of the second connection area 4 along the third direction onto the cell output section 12. The third direction is perpendicular to both the first and second directions. This arrangement further ensures the welding quality between the cell output section 12 and the electrode terminal assembly 2, and improves the current-carrying capacity between the cell output section 12 and the electrode terminal assembly 2.

[0061] In one embodiment, such as Figure 10 and Figure 11 As shown, a bending region 124 is formed in the cell output section 12 between the first connection area 3 and the main body 11. By providing the bending region 124, the force on the first connection area 3 can be buffered, the force on the first edge 31 can be reduced, the risk of breakage of the cell output section 12 at the first edge 31 can be reduced, and the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2 can be guaranteed, thus avoiding the occurrence of voltage jump phenomenon in the battery 110.

[0062] Specifically, in one embodiment, the length of the bending area 124 along the first direction is L2, satisfying 0.2≤L2 / b≤0.8. This setting ensures the buffering effect of the bending area 124 while preventing excessive heat in the bending area 124 from causing safety risks.

[0063] It is worth noting that if the value of L2 / b is too small, resulting in a short length of the bending region 124, the buffering effect provided by the bending region 124 to the first connection region 3 will be insignificant, and the cell output section 12 will still have the risk of discontinuity. If the value of L2 / b is too large, resulting in a long length of the bending region 124, the overall length of the cell output section 12 will be too large, leading to excessive heat generation and poor heat dissipation in the cell output section 12, which may easily trigger the risk of thermal runaway of the battery 110.

[0064] Optionally, L2 / b can be any value from 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or a value between any two values.

[0065] Specifically, in one embodiment, the bending area 124 has a crease 1241 (see [link to documentation]). Figure 10 ) or it has several creases spaced apart along the first direction 1241 (see also) Figure 11 That is, the battery cell output section 12 between the main body 11 and the first connection area 3 can be bent once or multiple times. It is understood that each bend creates a crease 1241, for example, Figure 10 The bending area 124 shown has a crease 1241. Figure 11 The bending area 124 shown has three creases 1241.

[0066] Furthermore, in one embodiment, such as Figure 11 As shown, along the first direction, the distance between the crease 1241 closest to the first connection area 3 and the first edge 31 is m, satisfying 2mm≤m≤5mm. This setting provides a buffering effect for the first connection area 3 while ensuring the heat dissipation effect of the battery cell output section 12.

[0067] 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 from the bending area 124 and the heat from the first connection area 3 will be superimposed, resulting in poor heat dissipation of the cell output section 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 will be too far, and the buffering effect of the bending area 124 on the first connection area 3 will be insufficient. This will make it easy for the cell output section 12 to tear at the first edge 31, resulting in an excessively high fracture rate of the cell output section 12. This will affect the overcurrent capacity between the cell output section 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.

[0068] Optionally, m can be any value from 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 of these values.

[0069] Furthermore, in one embodiment, such as Figure 11 As shown, along the first direction, the distance between the crease 1241 closest to the main body 11 and the root 121 is n, which satisfies 0.5mm≤n≤3mm. This setting ensures the quality and safety performance of the battery 110 while preventing wrinkling and deformation of the cell output section 12.

[0070] It is worth noting that if the value of n is too large, the cell output section 12 between the main body 11 and the bending area 124 will be too long, resulting in increased material consumption and waste. Furthermore, the cell output section 12 is prone to wrinkling and deformation, which could lead to it easily overlapping with the main body 11 or other structural components, causing a short circuit risk. If the value of n is too small, the main body 11 and the bending area 124 will be too close. When bending the cell output section 12 to form the bending area 124, the sheet 111 of the main body 11 may be deformed under stress, posing a risk of the active layer of the sheet 111 shedding material. If this shed material falls into the battery 110, it could easily cause a safety accident in the battery 110.

[0071] Optionally, n can be any value from 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 of these values.

[0072] In one embodiment, such as Figure 12As shown, the cell output section 12 includes several layers of tabs 125 stacked along a third direction, and at least one tab layer 125 has a protrusion 1253. By providing the protrusion 1253 on the tab layer 125, the structural strength of the cell output section 12 can be improved, the pulling force of the body section 11 on the first connection area 3 through the cell output section 12 can be reduced, the risk of cell output section 12 breakage can be reduced, and the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2 can be guaranteed, thus avoiding the occurrence of voltage jump phenomenon in the battery 110.

[0073] Preferably, each tab layer 125 is provided with a protrusion 1253.

[0074] It is worth noting that, please refer to Figure 12 In one embodiment, the tab layer 125 is provided with a plurality of protrusions 1253 spaced apart along the second direction, and each protrusion 1253 extends along the first direction. Of course, in other alternative embodiments, the protrusions 1253 may also have other shapes and structures, such as wavy lines, serrated shapes, etc.

[0075] Furthermore, in one embodiment, such as Figure 12 As shown, along the first direction, the distance between the protrusion 1253 and the root 121 is 0, satisfying 0.5mm≤0≤2mm. This setting ensures the quality and safety performance of the battery 110 while preventing the cell output section 12 from tearing at the root 121.

[0076] It is worth noting that if the value of o is too large, the structural strength of the cell output section 12 near the root 121 will still be low, which may easily lead to tearing of the cell output section 12 at the root 121. If the value of o is too small, the protrusion 1253 connects to the root 121 near the cell output section 12, and the structural strength of the cell output section 12 near the root 121 will be too large, which may easily cause the active layer of the sheet 111 to fall off. If the fallen active layer falls into the battery 110, it may easily cause a safety accident of the battery 110.

[0077] Optionally, o can be any value from 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, or a value between any two of these values.

[0078] In one embodiment, such as 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 sheet bodies 111 form a body portion 11, and the several tab layers 125 form a battery cell output portion 12. The connection position between the edge of the sheet body 111 and the edge of the tab layer 125 has a chamfered structure 131. This arrangement can reduce the stress concentration of the battery cell 1 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.

[0079] Furthermore, in one embodiment, such as Figure 13 As shown, the radius of the chamfer structure 131 is R, which satisfies 1mm≤R≤5mm. This setting reduces the stress concentration at the root 121 of the cell 1 at the cell output section 12, while also facilitating the assembly of the battery 110.

[0080] 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 section 12 along the second direction will be too large, making it difficult to bend the cell output section 12 and causing the battery 110 to be assembled more difficultly. If the value of R is too small, there is still a risk of stress concentration at the root 121 of the cell output section 12, and the risk of the cell 1 tearing at the root 121 of the cell output section 12 is still relatively high.

[0081] Optionally, R can be any value from 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or a value between any two of these values.

[0082] Specifically, in one embodiment, such as Figure 14 As shown, the battery cell 1 also includes an isolation layer 14. An isolation layer 14 is disposed between two adjacent electrode layers 13, extending from between adjacent electrode layers 111 to between adjacent tab layers 125. The isolation layer 14 can limit the position of the battery cell output section 12 near the root 121, preventing the battery cell output section 12 from tearing, reducing the vibration of the battery cell output section 12, reducing the stress on the first connection area 3, thereby reducing the risk of breakage of the battery cell output section 12, and ensuring the overcurrent capacity between the battery cell output section 12 and the electrode terminal assembly 2, thus preventing voltage jump phenomena in the battery 110.

[0083] Furthermore, in one embodiment, such as Figure 14 As shown, along the first direction, the distance p between the end of the insulating layer 14 near the tab layer 125 and the connection end between the tab layer 125 and the sheet 111 satisfies 0.5mm≤p≤4mm. This setting avoids tearing of the root 121 of the cell output section 12 while also avoiding affecting the soldering of the cell output section 12.

[0084] It is worth noting that if the value of p is too small, the area of ​​the insulating layer 14 exerting a reaction force on the tab layer 125 when the cell output section 12 is under force will be small, increasing the risk of tearing of the tab layer 125. If the value of p is too large, the insulating layer 14 will occupy too much area of ​​the tab layer 125, affecting the welding of the cell output section 12 and the electrode terminal assembly 2.

[0085] Optionally, p can be any value from 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, or a value between any two of these values.

[0086] It should be noted that the electrode 13 includes a positive electrode and a negative electrode, which are stacked alternately in sequence, and the separator 14 is disposed between the positive electrode and the negative electrode. Specifically, the separator 14 is a membrane.

[0087] In one embodiment, such as Figure 15 As shown, the cell output section 12 includes several layers of tabs 125 stacked along a third direction. Along the first direction, the distance between the ends of any two tabs 125 furthest from the main body 11 does not exceed 1 mm. This arrangement facilitates the folding of the cell output section 12 during battery assembly and prevents the ends of the tabs 125 from being inserted backwards into the main body 11, thus ensuring the safety performance of the battery 110.

[0088] Furthermore, in one embodiment, such as Figure 17 As shown, the cell output section 12 is provided with a connection area, which includes a first connection area 3. Along the first direction, the edge of the connection area is flush with the end of the cell output section 12 away from the main body 11. That is, the connection area extends to the edge of the cell output section 12. This arrangement can close and fix the end of the cell output section 12, reducing the risk of short circuit caused by the cell output section 12 overlapping with other structural components of the battery 110, and improving the safety performance of the battery 110.

[0089] It is worth noting that if the connection area does not reach the edge of the cell output section 12, several layers of tabs 125 will still be in a loose state at the edge of the cell output section 12, which will cause the end of the cell output section 12 to be easily deformed. Therefore, it is easy to overlap with other structural components of the battery 110, causing a short circuit problem in the battery 110.

[0090] As an alternative implementation, in one embodiment, such as Figure 16As shown, the cell output section 12 includes several tab layers 125 stacked along a third direction. Along the first direction, the ends of the tab layers 125 away from the body section 11 are offset. This arrangement can improve the heat dissipation effect of the cell output section 12 at the ends and reduce the risk of thermal runaway of the battery 110.

[0091] Furthermore, in one embodiment, such as Figure 15 and Figure 16 As shown, the cell output section 12 is provided with a connection area, which includes a first connection area 3. Along the first direction, the edge of the connection area is spaced apart from the end of the cell output section 12 away from the body section 11. That is, the connection area does not reach the edge of the cell output section 12. This arrangement ensures the welding strength between the cell output section 12 and the electrode terminal assembly 2 while improving the heat dissipation effect of the connection area during current transmission.

[0092] It is worth noting that by maintaining a certain distance between the connection area and the end of the cell output section 12, it is possible to ensure that all the tab layers 125 can be welded to the electrode terminal assembly 2, thereby ensuring the welding strength between the cell output section 12 and the electrode terminal assembly 2, ensuring the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, and by utilizing the loose state of the cell output section 12, heat dissipation is more convenient, thus avoiding the risk of thermal runaway caused by excessive temperature of the cell output section 12.

[0093] Specifically, in this embodiment, along the first direction, the distance between the edge of the connection area and the end of the cell output section 12 away from the body section 11 is L3, satisfying 0.5mm≤L3≤3mm. This setting improves the welding quality of the cell output section 12 and the electrode terminal assembly 2 while reducing the risk of delamination in the cell output section 12.

[0094] It is worth noting that if the value of L3 is too small, the edge of the connection area will be too close to the other end of the cell output section 12 and the root 121, which may affect the welding quality of the connection area and the heat dissipation performance of the cell output section 12. If the value of L3 is too large, the connection area may be too close to the root 121 of the cell output section 12, which may increase the risk of the cell output section 12 breaking in the connection area.

[0095] Optional, optional, the value of L3 can be any value among 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value between two of them.

[0096] It should be noted that the connection area refers to all the soldering areas on the cell output section 12. That is, it may not only be the first connection area 3, but may also include other soldering areas, such as the pre-soldering area (which refers to the solder mark that pre-solders several layers of tab layers 125 together).

[0097] In one embodiment, such as Figure 18 As shown, a third connection area 5 is provided on the cell output section 12. Along the first direction, the third connection area 5 is located between the second edge 32 and the end of the cell output section 12 away from the main body 11. The third connection area 5 welds a portion of the cell output section 12 along at least the third direction. This arrangement can further improve the structural strength of the cell output section 12.

[0098] As an alternative implementation, the third connection region 5 may also be located on at least one side of the first connection region 3 in the second direction.

[0099] Furthermore, in one embodiment, such as Figure 18 As shown, the third connection area 5 is welded to the cell output section 12 and the electrode terminal assembly 2. This arrangement improves the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2.

[0100] In one embodiment, such as Figure 2 and Figure 20 As shown, along the second direction, at least one edge of the cell output section 12 is spaced apart from the edge of the corresponding body section 11. That is, the battery 110 adopts a multi-tab form, which is beneficial to improving the energy density of the battery 110.

[0101] Specifically, along the second direction, the distance between at least one edge of the cell output section 12 and the corresponding edge of the body section 11 is L4, and the width of the body section 11 is L5, satisfying 0.1≤L4 / L5≤0.3. This arrangement ensures the connection strength between the cell output section 12 and the body section 11 while avoiding any impact on the energy density of the battery 110.

[0102] It is worth noting that if the values ​​of L4 / L5 are too large, the width of the cell output section 12 will be too small, resulting in a weak connection between the cell output section 12 and the main body 11, which will affect the overcurrent capacity of the cell output section 12. If the values ​​of L4 / L5 are too small, the width of the cell output section 12 will be too large, resulting in the cell output section 12 occupying too much space, which will affect the energy density of the battery 110. At the same time, excessive redundancy in the cell output section 12 may easily cause insulation risks such as reverse insertion.

[0103] Optionally, L4 / L5 can be any value from 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.

[0104] Furthermore, at this time, the connection strength between the cell output section 12 and the main body section 11 is relatively small, and the force on the cell output section 12 is relatively concentrated, resulting in a relatively concentrated stress in the first connection area 3. Therefore, the values ​​of a, b, and c are made to satisfy 0.008≤b / (a×c)≤0.04, reducing the risk of cell output section 12 failure, thereby ensuring the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, and avoiding the occurrence of voltage jump phenomenon in the battery 110.

[0105] Furthermore, in one embodiment, such as Figure 2 As shown, the center line of the cell output section 12 in the second direction is collinear with the center line of the body section 11 in the second direction. This arrangement positions the cell output section 12 in the middle of the body section 11, which is more conducive to the transmission of current in the body section 11. Furthermore, the tension on the cell output section 12 from the body section 11 is more uniform, preventing excessive stress on local parts of the cell output section 12 and thus reducing the risk of breakage. This, in turn, ensures the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, and prevents voltage jumps in the battery 110.

[0106] Of course, as alternative implementation methods, such as Figure 20 As shown, the center line of the cell output section 12 in the second direction is spaced apart from the center line of the body section 11 in the second direction. That is, the cell output section 12 is positioned off-center from the body section 11, which facilitates the welding and assembly of the cell output section 12.

[0107] Furthermore, in one embodiment, such as 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 setting reduces the risk of breakage in the cell output section 12 while avoiding an excessively long current transmission path.

[0108] It is worth noting that if the value of q is too small, the pulling force from the body 11 on the cell output section 12 will be large, and the cell output section 12 is prone to tearing at the first edge 31, resulting in an excessively high fracture rate of the cell output section 12. This affects the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, causing the output voltage of the battery 110 to jump during use, thus affecting the use of the battery 110. If the value of q is too large, the current transmission path between the 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 overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2. This will further increase the heat generated by the battery 110 during use, increasing the risk of thermal runaway of the battery 110 and affecting the safety performance of the battery 110.

[0109] Optionally, q can be any value among 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, and 35mm, or a value between any two of these values.

[0110] In addition, in other alternative implementations, such as Figure 19 As shown, along the second direction, the two side edges of the cell output section 12 are flush with the two side edges of the body section 11. That is, the battery 110 adopts a full tab form, which can enhance the structural strength of the cell output section 12. It is worth noting that along the second direction, the cell output section 12 occupies the entire width direction of the body section 11. At this time, the connection strength between the cell output section 12 and the body section 11 is relatively large, the force-bearing area of ​​the cell output section 12 is increased, and the stress concentration problem in the first connection area 3 is reduced. Therefore, further, the values ​​of a, b, and c are made to satisfy 0.005≤b / (a×c)≤0.035, which reduces the risk of fracture of the cell output section 12 and improves the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2.

[0111] In one embodiment, such as Figure 21 As shown, the electrode terminal assembly 2 includes an electrode post body 21, which is directly welded to the cell output section 12 to form a first connection area 3. That is, the cell output section 12 is directly connected to the electrode post body 21 without the need for an adapter piece 22, thereby reducing the resistance during current transmission and increasing overcurrent.

[0112] Of course, as alternative implementation methods, such as Figure 22 As shown, the electrode terminal assembly 2 includes an electrode post body 21 and an adapter plate 22. The adapter plate 22 is welded to the cell output section 12 to form a first connection area 3, and the electrode post body 21 is connected to the adapter plate 22. That is, the electrical connection between the cell output section 12 and the electrode post body 21 is achieved through the adapter plate 22. Welding several layers of tabs 125 to the adapter plate 22 results in better welding effect and improved welding strength.

[0113] In one embodiment, such as Figure 23 As shown, the breakage rate c of the cell output section 12 in the first connection area 3 satisfies 15%≤c≤75%. This setting simplifies the welding process while ensuring the overcurrent capacity between the electrode terminal assembly 2 and the cell output section 12, further reducing the risk of voltage jumps in the battery 110.

[0114] It is worth noting that if the value of c is too large, the impedance during current transmission will be too high, affecting the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2. Furthermore, the risk of tearing of the cell output section 12 when the battery 110 is under stress will increase, leading to a further increase in the fracture rate of the cell output section 12. This, in turn, will cause voltage fluctuations in the battery 110 during use, affecting its performance. If the value of c is too small, the requirements for welding processes will be too high, increasing processing difficulty and affecting production efficiency.

[0115] Optionally, c can take any value from 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or a value between any two values.

[0116] In one embodiment, the distance 'a' between the root 121 and the second edge 32 satisfies 5mm ≤ a ≤ 20mm. This setting ensures the safety performance of the battery 110 while avoiding any impact on its energy density.

[0117] It is worth noting that if the value of 'a' is too large, the length of the cell output section 12 will be too large, occupying too much space within the battery 110, which may affect the energy density of the battery 110. Furthermore, excessive redundancy in the cell output section 12 may lead to insulation risks such as overlap. If the value of 'a' is too small, the welding area of ​​the first connection region 3 may be too small, resulting in poor overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2. This, in turn, leads to an excessively rapid temperature rise rate in the electrode terminal assembly 2, increasing the risk of thermal runaway in the battery 110 and affecting its safety performance.

[0118] Optionally, the value of 'a' can be any value among 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, and 20mm, or a value between any two of these values.

[0119] In one embodiment, the distance b between the root 121 and the first edge 31 satisfies 3mm ≤ b ≤ 10mm. This configuration ensures the overcurrent capability between the electrode terminal assembly 2 and the cell output section 12, preventing voltage jumps in the battery 110 while reducing the internal resistance of the battery 110.

[0120] 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 will be 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 easily subjected to tension from the main body 11 when the battery 110 vibrates. In particular, at the first edge 31 of the first connection area 3, the cell output section 12 is prone to tearing, resulting in an excessively high fault rate of the cell output section 12. This leads to a large voltage difference between the batteries 110, a decrease in the overall cycle life of the battery pack, and overcharging and over-discharging of the battery 110, affecting the use of the battery 110.

[0121] Optionally, the value of b can be any value among 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, and 10mm, or a value between any two of these values.

[0122] In one embodiment, such as Figure 24 As shown, a welding tab 6 is provided on the side of the cell output section 12 facing away from the electrode terminal assembly 2. By providing the welding tab 6, the welding effect during the welding of the cell output section 12 and the electrode terminal assembly 2 can be improved, the welding strength between the cell output section 12 and the electrode terminal assembly 2 can be increased, the risk of tearing of the cell output section 12 when the battery 110 is subjected to force can be reduced, the risk of delamination of the cell output section 12 can be reduced, and thus the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2 can be guaranteed, avoiding the occurrence of voltage jump phenomena in the battery 110.

[0123] In one embodiment, such as Figure 25 and Figure 26 As shown, the end face of the main body 11 from which the cell output section 12 is led out is positioned opposite to the side of the battery 110 where the terminal body 21 is provided.

[0124] Specifically, such as Figure 26 As shown, the cell output section 12 is top-out, and the side of the battery 110 with the terminal body 21 is the top surface of the battery 110; or, as... Figure 25 As shown, the cell output section 12 is side-mounted, and the side of the battery 110 with the terminal body 21 is the side of the battery 110. For example, cylindrical battery 110, prismatic battery 110, and short-blade battery 110.

[0125] It is worth noting that the cell output section 12 and the electrode body 21 are located on the same side. The force on the electrode body 21 is directly transmitted to the cell output section 12, which causes the cell output section 12 to be subjected to greater force, thus increasing the risk of tearing of the cell output section 12 and consequently increasing the risk of fracture of the cell output section 12.

[0126] As an alternative implementation method, such as Figures 27 to 29 as well as Figures 46 to 53As shown, the end face of the main body 11 from which the cell output section 12 is led out is adjacent to the side of the battery 110 where the terminal body 21 is provided.

[0127] Specifically, such as Figure 27 and Figure 49 As shown, when the cell output section 12 is flattened along the first direction, its surface 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 large surface of the battery 110, and the cell output section 12 is parallel to the large surface of the battery 110 and connected to the terminal body 21. In this case, the force on the terminal body 21 is directly transmitted to the cell output section 12, causing the cell output section 12 to experience greater force, which increases the risk of tearing of the cell output section 12, and further increases the risk of fracture of the cell output section 12.

[0128] Or, such as Figure 28 , Figure 29 and Figure 53 As shown, the adapter 22 includes a first piece 221 and a second piece 222 connected at a predetermined angle. The cell output section 12 is bent to connect with the first piece 221. The second piece 222 is positioned opposite the side of the battery 110 where the terminal body 21 is located, and is connected to the terminal body 21. That is, the cell output section 12 and the terminal body 21 are located on opposite sides, and are connected by the L-shaped adapter 22. In this case, the force on the terminal body 21 will not be directly applied to the cell output section 12, which can reduce the force on the cell output section 12 and reduce the risk of tearing of the cell output section 12.

[0129] It is worth noting that the surface of the cell output section 12 refers to the large surface of the cell output section 12, that is, the surface of the cell output section 12 perpendicular to the third direction, which is the surface formed by the enclosing of the first direction and the second direction.

[0130] In one embodiment, such as Figure 30 As shown, the side of the battery 110 that is provided with the terminal body 21 has one terminal body 21. For example, a short-blade battery 110 or a cylindrical battery 110.

[0131] Of course, in other alternative implementations, such as Figure 31As shown, the battery 110 has two electrode bodies 21 on one side. For example, a prismatic battery 110. At this time, the heat generated by the cell output section 12 is concentrated, and the gas inside the battery 110 is concentrated and impacts the same side of the battery 110, resulting in a large force on the cell output section 12. Therefore, further, the values ​​of a, b, and c are made to satisfy 0.006≤b / (a×c)≤0.032 to reduce the risk of breakage of the cell output section 12, thereby ensuring the overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2 and avoiding the occurrence of voltage jump phenomenon in the battery 110.

[0132] In one embodiment, such as Figure 32 and Figure 54 As shown, the battery 110 also includes a housing 7, which has a first surface. A terminal body 21 is disposed on the first surface, and at least a portion of the terminal body 21 is located on the side of the housing 7 opposite to 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. That is, the terminal body 21 is a cylindrical terminal. The cylindrical terminal experiences more uniform force, thus the force transmitted to the cell output section 12 is also more uniform, avoiding localized stress concentration in the cell output section 12 and reducing the risk of tearing of the cell output section 12.

[0133] As an alternative implementation, in one embodiment, such as Figure 33 and Figure 62 As shown, the first projection 211 is square. That is, the electrode body 21 is a square electrode. The square electrode has higher assembly stability with the battery 110 casing 7, avoiding the electrode body 21 from being twisted under force and causing the cell output part 12 to twist and deform, thus reducing the risk of tearing of the cell output part 12.

[0134] As an alternative implementation, in one embodiment, such as Figure 34 and Figure 35 As shown, the first projection 211 is elongated. This design allows for an increase in the area of ​​the first projection 211, thereby improving the current-carrying capacity of the pole body 21.

[0135] Specifically, in one embodiment, such as Figure 34 As shown, the first projection 211 is an ellipse.

[0136] Or, in one embodiment, such as Figure 35 and Figure 63 As shown, the outer contour of the first projection 211 includes two straight segments 2111 and two circular arc segments 2112. The two straight segments 2111 are arranged at intervals relative to each other, and the two circular arc segments 2112 are respectively connected to the two ends of the two straight segments 2111 on the same side. That is, the first projection 211 is an elongated oval (also known as a racetrack shape).

[0137] Furthermore, such as Figure 36 As shown, the straight segment 2111 is parallel to the long side of the side of the battery 110 where the electrode body 21 is located. This improves the deformation resistance of the electrode body 21 and reduces the risk of deformation.

[0138] Furthermore, the elliptical and racetrack-shaped terminals increase the current output rate of the battery 110, increase the current-carrying 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 body 11 and the electrode terminal assembly 2.

[0139] In one embodiment, such as Figures 37 to 44 as well as Figures 54 to 61 As shown, the battery 110 also includes a housing 7, which has a first surface. The terminal body 21 is disposed on the first surface. The housing 7 includes a protrusion 71 disposed on the first surface. The protrusion 71 forms a folded edge 711 that fastens to the side of the terminal body 21 away from the cell output section 12. This arrangement, by pressing and limiting the terminal body 21 with the folded edge 711, reduces the impact of vibration on the terminal body 21, thereby reducing the force transmitted to the cell output section 12 and reducing the risk of tearing of the cell output section 12.

[0140] Specifically, in one embodiment, such as Figure 37 and Figure 57 As shown, the outer casing 7 also includes a main body, with the protrusion 71 integrally formed with the main body. This arrangement increases the connection strength between the protrusion 71 and the main body, and improves the limiting effect of the protrusion 71 on the electrode body 21. This further reduces the vibration of the electrode body 21, thereby further reducing the force transmitted to the cell output section 12 and further reducing the risk of tearing of the cell output section 12.

[0141] Of course, in other alternative implementations, such as Figure 38 and Figure 61 As shown, the outer casing 7 also includes a main body, with a protrusion 71 welded to the main body. In this case, the connection strength between the protrusion 71 and the main body is relatively low, resulting in a relatively poor limiting effect of the protrusion 71 on the electrode body 21. This leads to increased vibration of the electrode body 21, increasing the stress on the cell output section 12 and relatively increasing the risk of tearing of the cell output section 12. Furthermore, the values ​​of a, b, and c satisfy 0.009 ≤ b / (a×c) ≤ 0.04.

[0142] It is worth noting that, such as 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 closest to the cell output section 12 is fixedly connected to the main body, and the side of the connecting edge 712 furthest from the cell output section 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 electrode body 21 furthest from the cell output section 12.

[0143] Furthermore, in one embodiment, such as Figure 39 As shown, the folded edge 711 is continuously arranged circumferentially along the side of the electrode body 21 away from the cell output section 12. That is, the protrusion 71 has a ring structure; specifically, both the connecting edge 712 and the folded edge 711 have a ring structure. With this arrangement, the folded edge 711 can completely limit the electrode body 21 circumferentially, and the protrusion 71 has a better limiting effect on the electrode body 21, which can further reduce the vibration of the electrode body 21, thereby further reducing the force transmitted to the cell output section 12 and further reducing the risk of tearing of the cell output section 12.

[0144] Or, in one embodiment, such as Figure 40 As shown, the folded edge 711 is segmented along the circumference of the side of the electrode body 21 away from the cell output section 12. That is, the connecting edge 712 has a ring structure, while the folded edge 711 has a segmented structure, meaning the folded edge 711 is discontinuous along the circumference. In this case, the heat dissipation effect of the electrode body 21 is better. However, the folded edge 711 limits part of the electrode body 21, making the limiting effect of the protrusion 71 on the electrode body 21 relatively poor. This will increase the vibration of the electrode body 21, causing the cell output section 12 to be subjected to increased force, and relatively increasing the risk of tearing of the cell output section 12.

[0145] In one embodiment, such as Figures 41 to 44 As shown, the battery 110 also includes a housing 7, which includes a housing 72 and a cover plate 73. At least one end of the housing 72 has an opening, and the cover plate 73 is connected to the housing 72 and seals the opening.

[0146] It is worth noting that the aforementioned main body can be either a housing 72 or a cover plate 73. That is, the protrusion 71 can be provided on the housing 72 (see [link to documentation]). Figure 42 ), or it can be set in cover plate 73 (see Figure 41 ).

[0147] Furthermore, in one embodiment, such as Figure 41As shown, the electrode body 21 is disposed on the cover plate 73. It is worth noting that the cover plate 73 and the housing 72 are welded together. The housing 72 has a poor restraining effect on the cover plate 73, and the cover plate 73 and the electrode body 21 are at risk of deformation. Therefore, the cell output section 12 is easily subjected to stress, and the risk of tearing of the cell output section 12 is relatively increased.

[0148] Of course, as alternative implementation methods, such as Figure 42 As shown, the electrode body 21 is disposed on the housing 72. It is worth noting that the electrode body 21 is disposed on at least one side wall of the housing 72. This side wall of the housing 72 is usually integrally formed with other adjacent walls. Therefore, the overall structural strength of the housing 72 is high and it is not easy to deform. As a result, the force on the electrode body 21 is relatively small, which in turn reduces the force on the cell output section 12 and lowers the risk of tearing of the cell output section 12.

[0149] Specifically, in one embodiment, the cover plate 73 has an electrode post hole 731, and the electrode post body 21 is correspondingly disposed with respect to the electrode post hole 731. For example... Figure 41 As shown, the pole body 21 is located on the side of the cover plate 73 away from the pole tab; or, as... Figure 43 As shown, the electrode body 21 passes through the electrode hole 731, with one end of the electrode body 21 near the cell output section 12 located inside the electrode hole 731. That is, the electrode body 21 does not penetrate the electrode hole 731, and the electrode body 21 does not occupy the internal space of the casing 72, thereby improving the space utilization of the battery 110 and thus improving the energy density of the battery 110.

[0150] Furthermore, in one embodiment, such as Figures 41 to 43 As shown, part of the cell output section 12 is located inside the terminal hole 731. This arrangement reduces the risk of the cell output section 12 being inserted backwards into the body section 11.

[0151] Of course, in other alternative implementations, such as Figure 44 As shown, the cover plate 73 has a terminal hole 731, and the terminal body 21 is correspondingly arranged in the terminal hole 731. The terminal body 21 passes through the terminal hole 731, and the end of the terminal body 21 near the cell output section 12 extends out of the terminal hole 731. This arrangement facilitates the connection and assembly of the cell output section 12 and the terminal body 21.

[0152] In one embodiment, such as Figure 45As shown, the battery cell output section 12 includes several tab layers 125 stacked along a third direction. Each tab layer 125 includes an insulating layer 1251 and two metal layers 1252, which are disposed on opposite sides of the insulating layer 1251 along the third direction. Specifically, the battery cell 1 includes several electrode sheets 13 stacked along a third direction. Each electrode sheet 13 includes 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 tab layers 125. The several sheet layers 111 form a body section 11, and the several tab layers 125 form the battery cell output section 12. The current collector includes an insulating layer 1251 and two metal layers 1252 to form a composite current collector. This improves the flexibility of the current collector, reduces the risk of cell output section 12 failure, and ensures the overcurrent capacity between cell output section 12 and electrode terminal assembly 2, thus preventing voltage jump phenomena in battery 110.

[0153] Specifically, in one embodiment, such as 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 configuration improves the flexibility of the current collector while ensuring its conductivity.

[0154] It is worth noting that if t1 / t2 is too large, the thickness of the metal layer 1252 will be small, which is not conducive to electron transmission, and the impedance of the battery 110 will increase, and the voltage drop of the battery 110 will increase. If t1 / t2 is too small, the thickness of the insulating layer 1251 will be small, and the effect of improving the flexibility of the current collector will not be obvious, and there will still be a risk of breakage of the cell output section 12.

[0155] Optionally, t1 / t2 can take any value from 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.

[0156] Furthermore, in one embodiment, the metal layer 1252 comprises either copper or aluminum.

[0157] It is worth noting that the cell output section is the area on the cell electrode that is not covered with active material. As the current output terminal of the cell, it is formed by multiple single-layer current collectors. The multiple current collectors can be connected by welding, and can be connected by at least one welding method such as resistance welding, ultrasonic welding, or laser welding.

[0158] It should be further explained that the root 121 of the cell output section 12 is the end of the area on the electrode 13 that is not coated with active material.

[0159] It is understandable that the battery cell 1 is formed by winding or stacking a positive electrode plate, a negative electrode plate and a separator (i.e., the separator layer 14) disposed between the two.

[0160] The positive electrode sheet includes a positive current collector and a positive active material. The positive current collector can be made of metal materials such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metals and insulating materials. The positive active material includes the main positive active material, conductive agent, binder, etc. The main positive active material includes one or more lithium-containing positive active materials such as lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0161] Similarly, the negative electrode sheet includes the negative electrode current collector and the negative electrode active material. The negative electrode current collector can be made of metals such as copper foil, aluminum foil, and stainless steel, or it can be a composite foil formed by combining metals and insulating materials. The negative electrode active material includes the negative electrode active material, conductive agent, binder, etc. The negative electrode active material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0162] The separator (i.e., the separator layer 14) is used to achieve insulation between adjacent positive and negative electrode plates and to allow ions to shuttle back and forth for conduction. It can be lithium ions or sodium ions. The material of the separator layer 14 includes a base film layer of PP or PE. A ceramic layer and / or an adhesive layer can also be provided on at least one surface of the base film layer. The ceramic layer plays a role in improving the high temperature resistance of the separator layer 14, and the adhesive layer is used to improve the bonding strength between the base film layer and the electrode plate 13.

[0163] The battery 110 in this embodiment can be applied to many technical fields such as power tools, electric bicycles, electric motorcycles, electric cars, military equipment, and aerospace.

[0164] In addition, the battery 110 can be cylindrical, square prism, hexagonal prism, pouch, etc., and the battery casing 7 is cylindrical or hexagonal prism. The battery casing 7 is subjected to uniform stress, and the stress between the cell output section 12 and the electrode terminal assembly 2 is dispersed. Correspondingly, the distance from the root 121 of the cell output section 12 to the connection area can be reduced, further improving the current transmission rate of the cell 1, reducing the internal heat generation of the battery 110, ensuring the thermal safety of the battery pack, and shortening the charging and discharging time. When the battery 110 is a prismatic battery, the vibration risk of the cell output section 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 cell output section 12 to the connection area and / or reducing the discontinuity of the cell output section 12 at the connection area, the risk of electrode tab deformation can be reduced, thereby reducing the risk of tearing of the cell output section 12 and avoiding the occurrence of voltage jump problems in the battery 110.

[0165] As the size of the battery 110 increases, especially in the length direction, the vibration of the connection area formed by the cell output section 12 and the electrode terminal assembly 2 increases. In particular, the size of the battery 110 has a more significant impact on the connection strength of the connection area along the lead-out direction of the cell output section 12. Therefore, the range of values ​​for b / (a×c) needs to be reasonably adjusted.

[0166] Furthermore, the length of the battery 110 ranges from 200mm to 1000mm, with a preferred length of 300mm to 700mm. This ensures the overall energy density of a single battery 110 while avoiding an excessively long current transmission path that could affect the overall rate performance of the battery 110.

[0167] Regarding the dimensions of the battery 110 in the direction perpendicular to the large surface of the electrode 13, i.e. 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 cell output section 12. On the other hand, the smaller the thickness of the battery 110, the weaker the structural strength of the cell output section 12 and the greater the risk of deformation of the cell output section 12 under stress. Therefore, it is also necessary to reasonably adjust the range of values ​​for b / (a×c).

[0168] Furthermore, in the direction of the vertical electrode 13 (i.e., the third direction), the size (thickness) of the battery 110 ranges from 20mm to 90mm, preferably from 30mm to 80mm.

[0169] It is worth noting that the battery casing 7 can be made of metals or alloys such as aluminum, aluminum alloy, steel, titanium, magnesium, and nickel, and the casing 7 can be used to provide structural protection for the battery cell 1.

[0170] According to an embodiment of the present invention, in another aspect, a battery box 100 is also provided, such as... Figure 64 As shown, the device includes the battery 110 described above, as well as a base plate and a frame. The base plate is disposed on the outer periphery of the frame and fixedly connected to the frame. The base plate and the frame enclose a receiving space. The battery 110 is disposed in the receiving space and fixedly connected to the base plate. The batteries 110 are connected in series or in parallel through conductive busbars.

[0171] It is worth noting that in the relevant technology, when the battery box 100 is subjected to vibration, the voltage of some batteries 110 in the battery box 100 jumps, causing an excessive voltage difference between batteries 110 in the battery box 100. This results in poor overall consistency of batteries 110 during the charging and discharging process of the battery box 100, affecting the cycle life of batteries 110. Severe voltage jumps in batteries 110 can also cause local heat accumulation in batteries 110, leading to safety risks such as thermal runaway of batteries 110.

[0172] When the battery box 100 of this embodiment is subjected to vibration, it can prevent the voltage of the battery 110 inside the battery box 100 from jumping, thereby ensuring the overall consistency of the battery 110 during the charging and discharging process of the battery box 100, thus ensuring the cycle life of the battery 110, and avoiding the problem of thermal runaway of the battery 110 caused by the local heat accumulation of the battery 110, thereby ensuring the safety performance of the battery box 100.

[0173] According to an embodiment of the present invention, in another aspect, an electric vehicle 1000 is also provided, such as... Figure 65 As shown, the battery box 100 and chassis mentioned above are included. The side of the frame opposite to the base plate forms an opening, and the opening and chassis are fixedly sealed.

[0174] At this time, the chassis, acting as the cover of the battery box 100, further increases the deformation of the battery box 100, leading to an increased risk of internal vibration and a greater risk of stress on the cell output section 12. Therefore, the values ​​of a, b, and c are further optimized to satisfy 0.005 ≤ b / (a×c) ≤ 0.04, reducing the risk of cell breakage in the cell output section 12, preventing voltage jumps in the battery 110 within the battery box 100, ensuring the consistency of the battery 110 voltage within the battery box 100, and guaranteeing the cycle life and safety performance of the battery 110.

[0175] Specifically, the battery 110 includes a lithium iron phosphate battery 110. This configuration can reduce the heat generation during the battery 110 cycle, reduce the gas generation inside the battery 110, thereby reducing the stress on the cell output section 12 and thus reducing the risk of cell output section 12 failure.

[0176] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0177] The preparation of the example battery and the comparative battery includes the following steps: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it is cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0178] (2) Preparation of negative electrode: The negative electrode active material graphite, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly 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. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode graphite: conductive agent: thickener: binder is (90~96): (4~2): (2~1): (4~1).

[0179] (3) Preparation of electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0180] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0181] (5) Preparation of lithium-ion batteries: The above-mentioned positive electrode sheet, separator, and negative electrode sheet are stacked in sequence, and then wound or stacked to obtain a bare cell. The bare cell is placed in an outer packaging shell, dried, injected with electrolyte, and then packaged, left to stand, formed, and calibrated to obtain a lithium-ion battery.

[0182] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate. The negative electrode active material can be selected from one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0183] In this application, the positive electrode active material is selected from lithium iron phosphate as an example, and the mass ratio of positive electrode material: conductive agent: binder satisfies 96:2:2; the negative electrode material is selected from artificial graphite. Optionally, in other embodiments, the positive electrode material can be selected from one or more of nickel-cobalt-manganese ternary materials and lithium manganese iron phosphate; the negative electrode can also include one or more of silicon-carbon negative electrode or natural graphite.

[0184] The difference between the batteries in each embodiment and the comparative battery lies in the values ​​of a, b, and c. Apart from these, all other characteristics of the batteries are the same, as shown in Table 1.

[0185] Battery pack preparation: Select battery boxes and busbar assemblies from the same batch with the same structural performance parameters, assemble the sample batteries into the box according to the normal assembly process, and weld the busbars.

[0186] The relevant performance of the batteries in the above embodiments and comparative examples was tested, and the test results are recorded in Table 1. The test methods are as follows: 1. Battery pack differential pressure test after vibration Vibration tests were conducted on the battery in accordance with the national standard GB 38031-2020, and the vibration parameters were tested according to the requirements of GB 38031-8.2.1.

[0187] Next, 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 recorded, and the difference between the maximum and minimum values ​​was calculated. When the difference between the maximum and minimum values ​​was greater than 30mV, the battery voltage consistency in the battery pack was poor and the pack was unqualified.

[0188] 2. Column temperature rise test For each embodiment and comparative example, 10 batteries were taken. The batteries were discharged at 0.33C to 0% SOC, left to stand for 60 minutes, and the temperature at this time was measured and recorded as t1. The batteries were charged at 1C to 100% SOC, the time was recorded as T, and 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.

[0189] Table 1:

[0190] 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 differential pressure of the sample battery is within the design requirement range and meets the differential pressure condition. Furthermore, the temperature rise at the terminal during battery charging and discharging also meets the design requirements.

[0191] Furthermore, as shown in Table 1, in Examples 10 to 14, the battery pack differential pressure test and battery terminal temperature rise test after vibration all met the test requirements, but the values ​​of some parameters had some impact on the relevant performance, including: In Examples 10 and 13, the value of a is small, which results in a smaller connection area between the cell output section and the electrode terminal assembly, insufficient welding strength, and a risk of tab layer breakage, causing voltage jumps.

[0192] In Examples 11 and 14, a larger value for 'a' results in a longer cell output section, a longer current transmission path, increased temperature rise of the electrode terminal assembly, and a larger welding area, making processing inconvenient. A larger value for 'b' results in a longer current transmission path in the battery, more severe heat generation, and affects battery performance.

[0193] In Examples 12 and 13, the value of b is small. When the battery is subjected to force and vibration, the connection area is subjected to severe stress and is prone to tearing, resulting in large fluctuations in battery voltage.

[0194] In Example 12, the value of c is relatively small, the process control is more stringent, and it is not easy to achieve in the manufacturing process.

[0195] In Examples 10 and 13, when the value of c is large, the tab layer is prone to breakage at the welding area, and the voltage jump is severe.

[0196] As can be seen from Table 1, in Comparative Example 1 and Comparative Example 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 leads to an increase in the tensile force on the first connection area, making the cell output part 12 prone to tearing, increasing the risk of battery voltage jump, and thus causing the battery pack differential voltage test to fail after vibration.

[0197] As can be seen from Table 1, 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, which results in poor overcurrent capacity between the cell output section 12 and the electrode terminal assembly 2, which in turn leads to an excessively fast heating rate of the electrode terminal assembly and failure of the electrode temperature rise test.

[0198] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized by, include: The battery cell (1) includes a body portion (11) and a battery cell output portion (12) extending from at least one end of the body portion (11), wherein the end of the battery cell output portion (12) connected to the body portion (11) is the root portion (121) of the battery cell output portion (12); the battery cell (1) includes a plurality of electrode sheets (13) stacked along a third direction, and the battery cell (1) also includes an isolation layer (14), wherein the isolation layer (14) is disposed between two adjacent electrode sheets (13), and the isolation layer (14) is a separator; The electrode terminal assembly (2) is welded to the cell output section (12) to form a first connection area (3). A bending area (124) is formed between the first connection area (3) and the cell output section (12) between the cell output section (11) and the body section (11). Along a first direction, the first direction is the lead-out direction of the cell output section (12). The first connection area (3) has a first edge (31) close to the body section (11) and a second edge (32) away from the body section (11). The electrode terminal assembly (2) includes a terminal body (21) and an adapter piece (22). The adapter piece (22) is welded to the cell output section (12) to form the first connection area (3). The terminal body (21) is connected to the adapter piece (22). The end face of the body section (11) from which the cell output section (12) is led out is disposed opposite to the side of the battery (110) on which the terminal body (21) is disposed. In the state where the cell output section (12) is flattened along the first direction, the distance between the root (121) and the second edge (32) along the first direction is a, the distance between the root (121) and the first edge (31) is b, and the fault rate of the cell output section (12) in the first connection area (3) is c, which satisfies 0.003≤b / (a×c)≤0.

04.

2. The battery of claim 1, wherein, Along the first direction, the length of the bending region (124) is L2, which satisfies 0.2≤L2 / b≤0.

8.

3. The battery of claim 1, wherein, The bending area (124) has a single crease (1241) or a number of creases (1241) spaced apart along the first direction.

4. The battery of claim 3, wherein, Along the first direction, the distance between the crease (1241) closest to the first connecting area (3) and the first edge (31) is m, which satisfies 2mm≤m≤5mm.

5. The battery of claim 3, wherein, Along the first direction, the distance between the crease (1241) closest to the body part (11) and the root part (121) is n, which satisfies 0.5mm≤n≤3mm.

6. The battery according to any one of claims 1 to 5, characterized in that, The fault rate c of the cell output section (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.

7. The battery according to claim 1, characterized in that, The cell output section (12) has a welding piece (6) on the side facing away from the electrode terminal assembly (2).

8. The battery according to any one of claims 1 to 5, characterized in that, The battery (110) also includes a housing (7) having a first surface, the electrode body (21) being disposed on the first surface, the housing (7) including a protrusion (71) disposed on the first surface, the protrusion (71) forming a folded edge (711) that engages with the electrode body (21) on the side away from the cell output portion (12).

9. The battery according to claim 8, characterized in that, The outer shell (7) also includes a main body, and the protrusion (71) is integrally formed with the main body.

10. The battery according to claim 8, characterized in that, The outer shell (7) also includes a main body, and the protrusion (71) is welded to the main body.

11. The battery according to claim 8, characterized in that, The folded edge (711) is segmented along the circumference of the side of the electrode body (21) away from the cell output section (12).

12. The battery according to claim 8, characterized in that, The folded edge (711) is continuously arranged circumferentially along the side of the electrode body (21) away from the cell output section (12).

13. The battery according to any one of claims 1 to 5, characterized in that, The battery cell output section (12) includes several electrode layers (125) stacked along a third direction. Each electrode layer (125) includes an insulating layer (1251) and two metal layers (1252). The two metal layers (1252) are respectively disposed on opposite sides of the insulating layer (1251) along a third direction.

14. The battery according to claim 13, 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.

15. The battery according to claim 13, characterized in that, The metal layer (1252) includes either copper or aluminum.

16. A battery box, characterized in that, The battery (110) according to any one of claims 1 to 15 further includes a base plate and a frame. The base plate is disposed on the outer periphery of the frame and fixedly connected to the frame. The base plate and the frame enclose a receiving space. The battery (110) is disposed in the receiving space and fixedly connected to the base plate. The batteries (110) are connected in series or in parallel through conductive busbars.

17. An electric vehicle, characterized in that, Includes the battery box (100) and chassis as described in claim 16, wherein the side of the frame opposite to the base plate forms an opening, and the opening and the chassis are fixedly sealed together.

18. The electric vehicle according to claim 17, characterized in that, The values ​​of a, b, and c satisfy 0.005 ≤ b / (a×c) ≤ 0.

04.

19. The electric vehicle according to claim 18, characterized in that, The battery (110) includes a lithium iron phosphate battery (110).

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