Battery pole piece and battery pack

Abstract

The utility model relates to a battery pole piece and a battery pack. The battery pole piece comprises a main body and a tab electrically connected with the main body, a chamfer part is arranged at the joint of the tab and the main body, and arc sections formed on the chamfer part comprise a main transition arc section and an auxiliary transition arc section which are connected with each other and have different radiuses. According to the invention, the problem of abrupt increase of stress at the corner part can be continuously improved and reduced, the occurrence of tearing at the position can be further reduced, and the product yield is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a battery pole piece and battery package. BACKGROUND

[0002] Lithium battery can be stacked by one or more groups of positive and negative pole pieces, the pole piece is usually provided with a tab, the positive tabs are gathered together to form a battery positive pole, and the negative tabs are intersected to form a battery negative pole, therefore the strength of the tab is crucial to the battery, and if tearing occurs, the battery performance will be reduced.

[0003] For this, the existing design scheme usually contains a main body and a tab, and can refer to Figure 1 The corner of the connection between the main body and the tab is provided with a fillet to disperse stress and reduce the risk of tearing to a certain extent, but it is found in actual application that the improvement of this structure on stress concentration is limited, the stress still sharply increases at the fillet, and tearing still occurs with a high probability, and can refer to Figure 2 There is room for improvement. SUMMARY

[0004] In order to overcome at least one of the defects of the prior art described above, according to one aspect of the utility model, a battery pole piece is provided, which comprises a main body and a tab electrically connected with the main body, a chamfer portion is arranged at the connection between the tab and the main body, and the arc segment formed on the chamfer portion comprises a main transition arc segment and a secondary transition arc segment which are connected with each other and have different radii.

[0005] In an embodiment of the present application, one end of the main transition arc segment is tangent to the tab, one end of the secondary transition arc segment is tangent to the main body, and the other end of the main transition arc segment is connected with the other end of the secondary transition arc segment.

[0006] The vertical distance from the tangent point of the main transition arc segment to the tab to the main body is H1, and the vertical distance from the intersection point of the extension line of the main transition arc segment and the main body to the tab is L1, wherein H1>L1.

[0007] In an embodiment of the present application, the relationship between H1 and L1 is 1.1*L1≤H1≤5*L1.

[0008] In an embodiment of the present application, H1=2*L1.

[0009] In an embodiment of the present application, the radius of the main transition arc segment is R1, and the radius of the secondary transition arc segment is R2, wherein R1>R2.

[0010] In an embodiment of the present application, the relationship between R1 and R2 is 0.05*R1≤R2≤0.9*R1.

[0011] In an embodiment of the present application, R2=0.2*R1.

[0012] In an embodiment of the present application, the height of the tab itself is H2, and the vertical distance from the tangent point where the main transition arc segment is tangent to the tab to the main body is H1, wherein H1≤H2.

[0013] In an embodiment of the present application, the relationship between H1 and H2 is: 0.1*H2≤H1≤H2.

[0014] In an embodiment of the present application, H1=0.8*H2.

[0015] According to another aspect of the present application, a battery pack is provided, characterized in comprising the battery tab described above, and the tab is arranged on one side of the long side of the main body.

[0016] In summary, the battery tab and battery pack provided by the present application have the following technical effects:

[0017] The present application can further reduce the occurrence of tearing at the position and improve product yield by continuously improving and reducing the steep increase of stress at the corner. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The stress distribution diagram of the existing tab design scheme;

[0019] Figure 2 The stress distribution diagram of the existing tab design scheme;

[0020] Figure 3 The current density model diagram of the existing tab design scheme;

[0021] Figure 4 The structure schematic diagram of the battery tab of the embodiment of the present application;

[0022] Figure 5 The stress distribution diagram of the battery tab of the embodiment of the present application; Figure 4 The local enlarged view of A in the middle;

[0023] Figure 6 The stress distribution diagram of the battery tab of the embodiment of the present application;

[0024] Figure 7 The current density model diagram of the battery tab of the embodiment of the present application;

[0025] Figure 8 The stress comparison diagram of the battery tab of the embodiment of the present application and the prior art scheme;

[0026] Figure 9The battery pole piece of the embodiment of the utility model and the current density model comparison chart of prior art scheme.

[0027] The drawing: 1 - main body, 2 - tab, 3 - chamfer part, 31 - main transition arc segment, 32 - secondary transition arc segment. DETAILED DESCRIPTION

[0028] In order to better understand and implement, the technical scheme in the embodiment of the utility model will be clearly and completely described below in combination with the drawings in the embodiment of the utility model.

[0029] In the description of the utility model, it needs to be explained that the orientation or position relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relationship shown based on the drawing, and is only for the convenience of describing the utility model and simplifying the description, and is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore can not be understood as a limitation on the utility model.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs. The terms used in the specification of the utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the utility model.

[0031] The embodiment of the utility model discloses a kind of battery pole piece.

[0032] The specific technical scheme of the present application will be described in detail below in conjunction with the drawings attached Figures 4-9 The specific technical scheme of the present application will be described in detail below in conjunction with the drawings attached

[0033] Specifically, the battery pole piece includes main body 1 and the tab 2 electrically connected with the main body 1, the connecting place between the tab 2 and the main body 1 is provided with chamfer part 3, the arc segment formed on the chamfer part 3 includes main transition arc segment 31 and secondary transition arc segment 32 that are connected and different in radius, to form asymmetric chamfer structure.

[0034] For this, the present application is provided with chamfer part 3 between tab 2 and main body 1, and the chamfer part 3 is specially designed, i.e. main transition arc segment 31 and secondary transition arc segment 32 that are connected and different in radius are designed, to form asymmetric chamfer structure. The purpose of thus setting is to improve the problem that stress is concentrated at the intersection of tab 2 and main body 1, and unlike the existing technology that stress increases sharply at the intersection chamfer, the stress of the structure of the application is more dispersed, and the transition is more gentle.

[0035] It should be noted that due to this particular position relationship, when stressed, stress will not be concentrated in a sharp corner as in a right angle or simple chamfer structure, but in the present application, due to the presence of the main transition arc segment 31 and the secondary transition arc segment 32, stress will be relatively more evenly distributed along the main transition arc segment 31 and the secondary transition arc segment 32. When an external force acts on the junction between the tab 2 and the main body 1, stress will be dispersed from the tab 2 along the main transition arc segment 31 and the secondary transition arc segment 32 to the main body 1, rather than sharply accumulated at a certain point, wherein the stress distribution of the present application can be seen in Figure 6 .

[0036] It can be seen that the present application can continue to improve and reduce the problem of sharp increase of stress at the corner, which can further reduce the occurrence of tearing at this position and improve product yield.

[0037] In addition to this, in addition to stress testing, the present application also conducts other tests, and finds that in addition to improving stress concentration, it also has other good effects.

[0038] Firstly, the present application also reduces the maximum stress under the same stress condition, and the stress at the intersection line of the tab 2 and the main body 1 is plotted, which can be seen in Figure 8 It can be seen that the maximum stress of the present application is much lower than that of the existing scheme, which not only can improve the bearing capacity of the tab 2, but also can effectively reduce the occurrence of tearing under the same condition, thereby improving product yield.

[0039] Secondly, through the structure of the present application, the problem of sharp increase of current density at the intersection of the tab 2 and the main body 1 is improved under the same current load condition, which is different from the sharp increase of stress at the intersection chamfer of the existing technology (see the stress distribution diagram of the existing structure in Figure 2 ), the current density of the structure of the present application is more dispersed and the transition is more gentle, which can be seen in the current density model diagram of the structure of the present application in Figure 7 .

[0040] Thirdly, in addition to improving the concentration of current density, the present application also reduces the maximum value of current density under the same current load condition, and the current density at the intersection line of the tab 2 and the main body 1 is plotted, which can be seen in Figure 9 It can be seen that the maximum value of the current density of the present application is much lower than that of the existing scheme (see the current density model diagram of the existing structure in Figure 3 ), which can effectively reduce the local heating loss of the tab 2, thereby improving the current conversion efficiency.

[0041] In this regard, the present application not only can continue to improve and reduce the problem of sharp increase of stress at the corner, which can further reduce the occurrence of tearing at this position and improve product yield, but also can improve the problem of large current density at the corner, which can further reduce current transmission loss and improve transmission efficiency.

[0042] Specifically, the main body 1 can be rectangular in shape, and the tab 2 can also be rectangular in shape. When both the main body 1 and the tab 2 are rectangular, such a shape is easier to achieve through conventional processing techniques such as cutting and stamping during the manufacturing process of the battery tab. For example, in a stamping process, a rectangular die can more accurately process the material to produce a main body 1 and a tab 2 with regular shapes. Compared with complex shapes, the rectangular profile is simple, and the design and manufacture of the die are less difficult, which can effectively reduce production costs and improve production efficiency.

[0043] Specifically, one end of the main transition arc segment 31 is tangent to the tab 2, one end of the secondary transition arc segment 32 is tangent to the main body 1, and the other end of the main transition arc segment 31 is connected to the other end of the secondary transition arc segment 32. In this way, the one end of the main transition arc segment 31 is tangent to the side of the tab 2, the one end of the secondary transition arc segment 32 is tangent to the side of the main body 1, and the other ends of the two are connected, thus forming a continuous stress transition channel; when the battery tab is subjected to external force, the stress will not suddenly change during the process of being transmitted from the tab 2 to the main body 1. For example, in actual use, the battery can be subjected to external forces such as vibration and extrusion. This continuous arc segment structure can make the stress smoothly transition from the tab 2 to the main body 1 along the arc segment, thereby effectively avoiding the concentration of stress at the connection, reducing the possibility of damage to the tab 2 or the main body 1 caused by stress concentration.

[0044] Of course, in some other embodiments, the positions of the main transition arc segment 31 and the secondary transition arc segment 32 can be interchanged, that is, one end of the main transition arc segment 31 is tangent to the main body 1, and one end of the secondary transition arc segment 32 is tangent to the tab 2. In this way, the above-mentioned effects can also be achieved.

[0045] Specifically, the perpendicular distance from the tangent point where the main transition arc segment 31 is tangent to the tab 2 to the main body 1 is H1, and the perpendicular distance from the intersection point where the extension line of the main transition arc segment 31 intersects the main body 1 to the tab 2 is L1, where H1>L1. In this way, when the battery tab is subjected to external force, the stress will be transmitted from the tab 2 to the main body 1. Due to H1>L1, the position relationship of the main transition arc segment 31 makes the stress more inclined to diffuse along the main transition arc segment 31 to the inside of the main body 1 during the process of being transmitted from the tab 2 to the main body 1. For example, when external pressure is applied to the tab 2, the stress will not directly rush to the edge of the main body 1, but will be guided to a wider area inside the main body 1 along the direction of the main transition arc segment 31, thereby avoiding excessive concentration of stress at the edge of the tab 2 and the main body 1.

[0046] Moreover, for current conduction, this structure helps to make the change in current density more gradual. Since the position of the main transition arc segment 31 is determined by the relationship between H1 and L1, the sharp increase in current density at the junction is reduced, and the risk of local overheating is reduced.

[0047] More importantly, from the perspective of structure, the position relationship of the main transition arc segment 31 enhances the stability of the connection between the tab 2 and the main body 1. Because the stress can be effectively dispersed, the current conduction is also more smooth, and the connection structure between the tab 2 and the main body 1 is not easy to be damaged due to stress concentration or local overheating in the long-term use process. For example, in the repeated charging and discharging process of the battery, the electrode material will change in volume and other conditions, and this structure can better withstand the influence brought by these changes, maintain the good connection between the tab 2 and the main body 1, and improve the service life and reliability of the battery.

[0048] Specifically, the ratio relationship between H1 and L1 is: 1.1*L1≤H1≤5*L1. For the ratio relationship between H1 and L1, after many experiments, when it is in the range of 1.1*L1≤H1≤5*L1, this range ensures that the main transition arc segment 31 has a suitable position to guide stress dispersion, and can avoid excessive stress concentration. Within this range, the stress can be guided along the main transition arc segment 31 to a more suitable position in the main body 1, avoiding excessive accumulation of stress at the edge of the tab 2, effectively reducing the possibility of damage to the tab 2 or the main body 1 caused by stress concentration.

[0049] And in terms of current conduction, this range helps to balance the change of current density at the junction of the tab 2 and the main body 1. If H1 exceeds this range, the current may not be able to spread well on the main transition arc segment 31, resulting in an unreasonable sharp increase or decrease in current density at the junction of the tab 2 and the main body 1. Within the range of 1.1L1≤H1≤5L1, the situation of excessively high or low local current density can be avoided, reducing local overheating and energy loss.

[0050] More importantly, the battery will face various complex working conditions in actual use, such as different temperatures, humidities, vibrations and other conditions. The range of 1.1L1≤H1≤5L1 enables the connection structure of the tab 2 and the main body 1 to better adapt to these changes. For example, in a high-temperature environment, the expansion of the electrode material and other conditions may affect the connection between the tab 2 and the main body 1, and this reasonable structure range can to some extent alleviate the problems of stress concentration and uneven current distribution, and improve the performance and reliability of the battery in harsh environments.

[0051] Specifically, H1 can be specifically 1.1*L1, 1.5*L1, 1.9*L1, 2.3*L1, 2.7*L1, 3.1*L1, 3.5*L1, 3.9*L1, 4.3*L1, 4.7*L1 or 5*L1, etc. Of course, in other embodiments, H1 can also be other values within the range of 1.1*L1≤H1≤5*L1, which can be selected according to actual conditions, and will not be described here.

[0052] Further specifically, H1 is 2*L1 optimal. When H1 = 2*L1, the position of the main transition arc segment 31 can provide the most ideal stress guiding path. In the process of stress transmission from the tab 2 to the main body 1 when the battery tab is subjected to external force, the stress can be dispersed in an optimal manner along the main transition arc segment 31. This position relationship enables the stress to form a balanced distribution state between the tab 2 and the main body 1, neither allowing the stress to concentrate too early at the edge of the tab 2 nor making the stress too dispersed to be out of control within the main body 1. At the same time, compared with other H1 and L1 ratio relationships, H1 = 2*L1 can minimize the stress concentration area, and the stress can spread from the tab 2 to the inside of the main body 1 along the main transition arc segment 31 uniformly, so that the stress concentration at the connection between the tab 2 and the main body 1 is minimized. This is very important for the long-term stability of the battery tab, because stress concentration is one of the main reasons for the damage of the tab 2 and the main body 1, and minimizing the stress concentration area can effectively prolong the service life of the battery tab.

[0053] And in terms of current conduction, H1 = 2*L1 can achieve the optimal current density distribution, and the position of the main transition arc segment 31 enables the current to spread between the tab 2 and the main body 1 in the most uniform manner. Compared with other ratio relationships, the current density changes most gently at the junction of the tab 2 and the main body 1 at this time, avoiding the sharp increase or decrease of the current density, thereby reducing the risk of local overheating.

[0054] Further specifically, the radius of the main transition arc segment 31 is R1, and the radius of the auxiliary transition arc segment 32 is R2, where R1 > R2. This design enables the stress to be gradually buffered in the process of transmission from the tab 2 to the main body 1. When the stress is transmitted from the tab 2 along the main transition arc segment 31, the larger radius R1 provides a relatively gentle transition, and then the stress is transmitted to the auxiliary transition arc segment 32 with a smaller radius, and the stress is further adjusted and dispersed in this process. This transition from large radius to small radius can effectively avoid stress concentration, so that the stress is gradually dispersed to the main body 1 part in the whole transmission process.

[0055] At the same time, due to the difference between R1 and R2, the stress distribution between the tab 2 and the main body 1 is more reasonable. The main transition arc segment 31 with a large radius guides the stress to be widely dispersed in the initial stage, and the auxiliary transition arc segment 32 with a small radius can guide the stress more accurately to the edge part of the main body 1, so that the stress distribution is more uniform. For example, when the battery is subjected to external extrusion, this structure can enable the stress to be uniformly distributed to all corners of the main body 1 from the tab 2, rather than accumulated in a local area, thereby improving the ability of the battery tab structure to withstand external force.

[0056] And, in the process of current conduction, the structure of R1>R2 helps to improve the distribution of current density. Because the radius of the main transition arc segment 31 is larger, the current has enough space to be initially dispersed, which can effectively avoid the sharp change of current density at the connection between the tab 2 and the main body 1, and reduce the risk of local overheating.

[0057] Among them, specifically, the relationship between R1 and R2 is: 0.05*R1≤R2≤0.9*R1. For the proportional relationship between R1 and R2, after many experiments, when in the range of 0.05R1≤R2≤0.9R1, this range ensures that the radius ratio between the main transition arc segment 31 and the auxiliary transition arc segment 32 is in a reasonable interval. Within this range, the dispersion degree of stress from the main transition arc segment 31 to the auxiliary transition arc segment 32 can be effectively controlled, so that the stress can be gradually and smoothly transmitted from the tab 2 to the main body 1.

[0058] And, in terms of current conduction, this range helps to balance the change of current density at the connection between the tab 2 and the main body 1. Within the range of 0.05R1≤R2≤0.9R1, the current can be relatively stably conducted between the main transition arc segment 31 and the auxiliary transition arc segment 32, avoiding the situation of too high or too low local current density, reducing the risk of energy loss and local overheating.

[0059] Among them, specifically, R2 can be specifically 0.05*R1, 0.1*R1, 0.2*R1, 0.3*R1, 0.4*R1, 0.5*R1, 0.6*R1, 0.7*R1, 0.8*R1 or 0.9*R1, etc. Of course, in other embodiments, R2 can also be other numerical values within the range of 0.05*R1≤R2≤0.9*R1, which can be selected according to actual conditions, and will not be described here.

[0060] Among them, specifically, R2 is best at 0.2*R1. When R2 is 0.2R1, an ideal stress buffer path is formed between the main transition arc segment 31 and the auxiliary transition arc segment 32. The stress transmitted from the tab 2 is initially dispersed after passing through the main transition arc segment 31 (radius R1), and enters the auxiliary transition arc segment 32 (radius 0.2R1). At this time, the smaller radius of the auxiliary transition arc segment 32 can more accurately guide the stress to diffuse to the edge part of the main body 1, so that the stress can be more concentratedly distributed in the area near the edge of the main body 1 that needs to be strengthened. Stress bearing, while avoiding the concentration of stress in this process.

[0061] At the same time, this optimal proportion relationship can minimize the degree of stress concentration. Compared with other ratios of R2 and R1, the radius of the sub-transition arc segment 32 of 0.2*R1 can most effectively and evenly guide the stress into the main body 1 after dispersing the stress of the main transition arc segment 31. This helps to achieve the optimal distribution of stress between the tab 2 and the main body 1, maximally reduces the possibility of damage to the tab 2 or the main body 1 caused by stress concentration, and thus improves the structural stability of the battery tab when subjected to external force.

[0062] In terms of current conduction, the optimal distribution of current density can be achieved when R2 is 0.2R1. This can make the change in current density at the connection between the tab 2 and the main body 1 most gentle, avoiding sharp increase or decrease in current density, thus effectively reducing the risk of local overheating and improving the electrical performance of the battery.

[0063] In particular, the height of the tab 2 is H2, and the vertical distance from the tangent point where the main transition arc segment 31 is tangent to the tab 2 to the main body 1 is H1, where H1≤H2. When H1≤H2, there is enough space for stress to disperse during transmission from the tab 2 to the main body 1, i.e. under the condition of H1≤H2, the stress can be reasonably dispersed from the tab 2 to the main body 1 within the height range of the tab 2, effectively avoiding damage to the top of the tab 2 caused by stress concentration. At the same time, this height relationship makes the transmission path of stress within the tab 2 more reasonable. Since H1 does not exceed H2, when stress is dispersed from the edge of the tab 2 (near the tangent point) along the main transition arc segment 31 to the main body 1, it can make full use of the height space of the tab 2, making it more evenly distributed in the connection area between the tab 2 and the main body 1, improving the structural stability of the tab 2, and thus enhancing the ability of the entire battery tab structure to withstand external stress.

[0064] In terms of current conduction, the condition of H1≤H2 is conducive to the uniform distribution of current within the tab 2. When current enters the main body 1 from the tab 2, the height H2 of the tab 2 provides enough space for the distribution of current within the tab 2. When the vertical distance H1 from the tangent point of the main transition arc segment 31 to the main body 1 satisfies H1≤H2, it avoids local aggregation of current within the tab 2, thus optimizing the conduction process of current between the tab 2 and the main body 1.

[0065] wherein specifically, the relationship between H1 and H2 is: 0.1*H2≤H1≤H2. For the proportional relationship between H1 and H2, after multiple tests, when in the range of 0.1*H2≤H1≤H2, this range ensures that the tangent point position of the main transition arc segment 31 tangent to the tab 2 is in a reasonable interval in the height direction, that is, when H1 is in this range, the stress can start to disperse from the tab 2 to the main body 1 through the main transition arc segment 31 at a suitable part of the height of the tab 2, avoiding excessive accumulation of stress in local areas such as the bottom or top of the tab 2, thereby effectively preventing the formation of stress concentration areas.

[0066] At the same time, during current conduction, this range helps to optimize the distribution range of current density at the junction of the tab 2 and the main body 1. That is, within the range of 0.1*H2≤H1≤H2, the current can be evenly distributed in the tab 2 and conducted to the main body 1 through the main transition arc segment 31 in a suitable path, avoiding the situation of excessively high or low local current density, reducing the risk of local overheating and energy loss.

[0067] wherein specifically, H1=0.8*H2 is optimal. When H1=0.8*H2, during the process of stress transmission from the tab 2 to the main body 1, the tangent point of the main transition arc segment 31 tangent to the tab 2 is at a nearly perfect height position. At this time, the stress can be dispersed along the main transition arc segment 31, fully and evenly utilizing most of the height space of the tab 2 to achieve smooth and uniform transition of stress from the tab 2 to the main body 1. At the same time, compared with other proportional relationships of H1 and H2, H1=0.8*H2 can most effectively avoid the formation of stress concentration points at the junction of the tab 2 and the main body 1, making the stress distribution between the tab 2 and the main body 1 more reasonable and uniform, greatly reducing the possibility of damage to the tab 2 or the main body 1 structure caused by stress concentration, thereby effectively guaranteeing the stability of the battery tab structure when subjected to external forces.

[0068] And in terms of current conduction, the setting of H1=0.8*H2 can achieve the optimal distribution of current density. Under this size relationship, the change of current density at the junction of the tab 2 and the main body 1 is the most gentle, avoiding both the sharp increase of current density in local areas leading to overheating and the excessively sparse distribution affecting overall conduction efficiency, allowing the current to be conducted in the most ideal state throughout the battery tab.

[0069] Specifically, the tab 2 is arranged on one side of the long side of the main body 1. In this way, when assembling the battery module, this layout is conducive to the close arrangement of the batteries. The shape of the battery main body 1 is usually rectangular, and placing the tab 2 on one side of the long side can be arranged neatly together. For example, in a cuboid-shaped battery module shell, this arrangement can make full use of the space and reduce the internal gap of the module, thereby placing more batteries in a limited space and improving the energy density of the battery module.

[0070] In addition, the tab 2 on one side of the long side of the main body 1 can shorten the transmission path of the current between the inside and outside of the battery. For the charging and discharging process of the battery, the current enters or flows out of the main body 1 from the tab 2. The tab 2 layout on one side of the long side allows the current to be distributed more evenly within the battery main body 1 (when discharging) or collected more efficiently (when charging), reducing energy loss and resistance heating due to a long transmission path, and more effectively reducing internal resistance and improving the charging and discharging efficiency of the battery.

[0071] In addition, this layout helps to improve the uniformity of current distribution within the battery main body 1. Since the tab 2 is on one side of the long side, the current entering the main body 1 can spread more evenly to each part of the main body 1 along the long side direction, and this uniform current distribution can avoid excessive local current density and reduce the risk of battery performance degradation and safety hazards due to local overheating.

[0072] Specifically, the overall material of the battery tab is copper, aluminum or other conductive metal materials. In this way, since copper and aluminum are commonly used conductive materials, they have good electrical conductivity. Taking copper as an example, it has high electrical conductivity and can efficiently pass current in the battery tab, reducing energy loss. During the charging and discharging process of the battery, good electrical conductivity can ensure that the current is quickly transmitted within the tab, for example, in high-power batteries for electric vehicles, such efficient current conduction helps to achieve fast charging and powerful power output.

[0073] Specifically, other conductive metal materials can also be silver, gold, nickel, zinc, etc. Silver has excellent electrical conductivity and can be used in some special battery application scenarios that require extremely high electrical conductivity (such as high-precision electronic instrument batteries), but due to the high cost, the application range is relatively narrow. Gold has extremely high chemical stability and can be used in some batteries that need to work in harsh chemical environments (such as some deep-sea probe batteries). Nickel is commonly used in some nickel-hydrogen batteries, etc., which can provide good electrochemical performance. Zinc is commonly used in zinc-manganese dry batteries, etc., and plays an important role in some disposable batteries.

[0074] The embodiments of the utility model further disclose a battery pack, the battery pack specifically comprises the above-mentioned battery pole piece. Because the battery pole piece has the optimized structure, can effectively improve the current density distribution and reduce the energy loss in the current transmission process, using this battery pole piece in the battery pack can significantly improve the charge-discharge efficiency of the whole battery pack. For example, in the battery pack of the electric vehicle, the efficient charge-discharge efficiency means shortening the charging time, and at the same time, can better output electric energy during the vehicle driving, prolongs the cruising range of the vehicle. At the same time, the special structure of the battery pole piece helps to disperse stress, reduces the possibility of damage of the tab 2 and the main body 1 due to stress concentration in the repeated charge-discharge process. When this battery pole piece is applied to the battery pack, the battery in the battery pack can still maintain good performance after multiple charge-discharge cycles. For example, in the battery pack of the energy storage system, better cycle life can reduce the battery replacement frequency and reduce the maintenance cost.

[0075] And, the battery pole piece can make the current density more dispersed and gentle at the intersection of the tab 2 and the pole body 1, effectively reduces the maximum value of the current density, thereby reducing the local heating loss of the battery. In the environment of the battery pack combined by multiple batteries, local overheating can cause a series of safety problems, such as thermal runaway. Using this battery pole piece can reduce the safety hazards caused by local overheating inside the battery pack.

[0076] In addition, the battery pack further comprises the battery pole piece provided by any one of the technical solutions of the embodiments of the utility model. Therefore, the battery pack provided by the utility model has all the beneficial effects of the battery pole piece of any one of the technical solutions of the embodiments of the utility model, which will not be repeated here.

[0077] The technical means disclosed in the utility model scheme is not only limited to the technical means disclosed in the above-mentioned embodiments, but also includes the technical solution composed of any combination of the above technical features. It should be pointed out that, for ordinary skilled persons in the technical field, on the premise of not departing from the principle of the utility model, a number of improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the utility model.

Claims

1. A battery pole piece, characterized by, The battery tab includes a main body (1) and a tab (2) electrically connected to the main body (1), a chamfer (3) is arranged at the connection between the tab (2) and the main body (1), and the arc segment formed on the chamfer (3) includes a main transition arc segment (31) and a secondary transition arc segment (32) that are connected and have different radii.

2. The battery pole piece of claim 1, wherein, One end of the main transition arc segment (31) is tangent to the tab (2), one end of the secondary transition arc segment (32) is tangent to the main body (1), and the other end of the main transition arc segment (31) is connected to the other end of the secondary transition arc segment (32). The vertical distance from the tangent point of the main transition arc segment (31) to the tab (2) to the main body (1) is H1, and the vertical distance from the intersection point of the extension line of the main transition arc segment (31) and the main body (1) to the tab (2) is L1, wherein H1>L1.

3. The battery electrode of claim 2, wherein, The relationship between H1 and L1 is 1.1*L1≤H1≤5*L1.

4. The battery electrode of claim 2, wherein the binder is present in an amount of 0.1 to 10 wt% based on the total weight of the electrode. H1=2*L1.

5. The battery electrode of any one of claims 1-4, wherein the binder is present in an amount of 0.1 to 10 wt. % based on the total weight of the electrode. The radius of the main transition arc segment (31) is R1, and the radius of the secondary transition arc segment (32) is R2, wherein R1>R2.

6. The battery electrode of claim 5, wherein, The relationship between R1 and R2 is 0.05*R1≤R2≤0.9*R1.

7. The battery electrode of claim 2, wherein, R2=0.2*R1.

8. The battery pole piece of any one of claims 1-4, wherein, The height of the tab (2) itself is H2, and the vertical distance from the tangent point of the main transition arc segment (31) to the tab (2) to the main body (1) is H1, wherein H1≤H2.

9. The battery electrode of claim 8, wherein, The relationship between H1 and H2 is 0.1*H2≤H1≤H2.

10. The battery electrode of claim 8, wherein, H1=0.8*H2.

11. A battery pack, characterized by The battery tab includes a main body (1) and a tab (2) electrically connected to the main body (1), a chamfer (3) is arranged at the connection between the tab (2) and the main body (1), and the arc segment formed on the chamfer (3) includes a main transition arc segment (31) and a secondary transition arc segment (32) that are connected and have different radii.

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