Battery and electric device

Abstract

The invention relates to the technical field of new energy, and discloses a battery and a power utilization device, the battery comprises a battery cell, the battery cell comprises a battery cell body and a tab extending from one end face of the battery cell body along a first direction; the tabs are electrically connected with the pole columns through the switching sheets; the adapter plate and the pole are both positioned on one side, provided with the tab in the first direction, of the battery cell body; the tab at least partially covers the surface of one side, deviating from the battery cell body, of the adapter plate; at least partial area of the surface, close to the battery core, of the pole column is recessed towards the direction away from the battery core to form a concave part; the concave part is arranged at the circumferential end part of the pole column. According to the battery provided by the invention, the concave part can provide enough accommodating space for the tabs, ensure that the tabs are not in contact with the post terminals, and prevent the tabs from being inserted between the adapter plates and the post terminals, so that pseudo soldering is avoided, the overcurrent capacity between the adapter plates and the post terminals is effectively ensured, and excessive heat generated near the post terminals during charging and discharging of the battery is avoided.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and in particular to a battery and an electrical device. Background Art

[0002] When welding the tabs to the adapter in a battery, the tabs are typically welded to the bottom surface of the adapter. This results in a larger height gap between the adapter and the battery cell, resulting in low battery space utilization and affecting battery energy density. To further improve space utilization in the battery's height direction, the tabs can be connected so that they cover the top surface of the adapter and are welded to the tabs. However, this can cause the terminal to heat up significantly, making the battery susceptible to thermal runaway and posing a significant safety risk. Summary of the Invention

[0003] In view of this, the present invention provides a battery and an electrical device to solve the problem of severe heating of the electrode.

[0004] In a first aspect, the present invention provides a battery comprising:

[0005] A battery cell, the battery cell comprising a battery cell body and a tab extending from an end surface of the battery cell body along a first direction;

[0006] The adapter plate and the pole, and the tab is electrically connected to the pole via the adapter plate; the adapter plate and the pole are both located on the side of the battery body along the first direction where the tab is provided, and the surface of the pole close to the battery cell is welded to the adapter plate; the tab at least partially covers the side of the adapter plate away from the battery body to form a first area;

[0007] The surface of the pole close to the battery cell is at least partially recessed in a direction away from the battery cell to form a recessed portion, and the recessed portion is provided at a circumferential end portion of the pole;

[0008] The concave dimension of the concave portion along a plane perpendicular to the first direction is a, the concave dimension of the concave portion along the first direction is b, and the maximum thickness of the first region along the first direction is m, satisfying:

[0009] 0.03≤m / (a×b)≤10.

[0010] Beneficial Effects: This embodiment provides a recess on the pole. The recess provides sufficient space for the tab in a plane perpendicular to the first direction, ensuring that the tab and the pole are non-contacting and preventing the tab from being inserted between the adapter and the pole, thereby avoiding cold solder joints, improving welding quality, ensuring stable and reliable battery connections, and effectively ensuring the flow capacity between the adapter and the pole. This prevents excessive heat generation near the pole during battery charging and discharging, thereby reducing the risk of thermal runaway and potential safety hazards caused by poor connections during battery use, ensuring safe and stable battery operation. This not only effectively prevents direct overlap between the tab and the pole, but also ensures that the adapter's fusing structure can function normally when needed, thereby improving the safety performance of the battery.

[0011] In a second aspect, the present invention further provides an electrical device comprising the above-mentioned battery.

[0012] Since the electrical device includes a battery and has the same effect as the battery, it will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 is an exploded schematic diagram of a battery according to an embodiment of the present invention;

[0015] Figure 2 is a schematic cross-sectional view of a battery according to an embodiment of the present invention;

[0016] Figure 3 is an exploded schematic diagram of a battery in a cross-sectional state according to an embodiment of the present invention;

[0017] Figure 4 Schematic diagram of a pole according to an embodiment of the present invention Figure 1 ;

[0018] Figure 5 Schematic diagram of a pole according to an embodiment of the present invention Figure 2 ;

[0019] Figure 6 The cross section of a pole according to an embodiment of the present invention is shown in FIG. Figure 1 ;

[0020] Figure 7 The cross section of a pole according to an embodiment of the present invention is shown in FIG. Figure 2 ;

[0021] Figure 8The cross section of a pole according to an embodiment of the present invention is shown in FIG. Figure 3 ;

[0022] Figure 9 FIG. 1 is a schematic diagram of an adapter according to an embodiment of the present invention.

[0023] Description of reference numerals:

[0024] 1. Battery case; 11. Opening; 12. Case body;

[0025] 2. Shell cover; 21. Pole through hole; 22. Step portion; 23. Pole limit portion;

[0026] 3. Battery cell; 31. Battery cell body; 32. Tab; 321. First tab portion; 322. Bend portion; 323. Second tab portion; 324. Tab end;

[0027] 4. Adapter; 41. Pole lug connection; 42. Pole connection; 43. Transition portion;

[0028] 5. Pole; 51. Recess; 501. Bottom surface; 502. First groove surface; 503. Rounded corner. DETAILED DESCRIPTION

[0029] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] When welding the tabs to the adapter in a battery, the tabs are typically welded to the bottom surface of the adapter. This results in a larger height gap between the adapter and the battery cell, resulting in low battery space utilization and affecting battery energy density. To further improve space utilization in the battery height direction, the connection method can be set so that the tabs cover the top surface of the adapter, and the top surface of the adapter is welded to the tabs.

[0034] However, with this arrangement, the tab at least partially covers the upper surface of the adapter. If this portion of the tab is long, it can easily get inserted between the adapter and the terminal, creating a gap between them. This can lead to a cold weld when welding the adapter and the terminal, resulting in poor weld quality. This in turn leads to poor current flow between the adapter and the terminal, which can cause excessive heat generation near the terminal during battery charging and discharging, making the battery susceptible to thermal runaway.

[0035] Furthermore, under normal circumstances, the tab is connected to the adapter, which in turn connects to the terminal. A fuse structure can be placed on the adapter to provide fuse protection. However, if the tab covering the upper surface of the adapter is inserted between the adapter and the terminal, the end of the tab will directly overlap the terminal, affecting the fusing effect of the adapter's fuse structure. Furthermore, if excessive heat is generated near the terminal, the terminal and tab cannot be disconnected, resulting in a significant safety risk to the battery.

[0036] The following combination Figures 1 to 9 , describing embodiments of the present invention.

[0037] According to an embodiment of the present invention, on one hand, there is provided a battery, comprising:

[0038] The battery cell 3 includes a battery cell body 31 and a tab 32 extending from an end surface of the battery cell body 31 along a first direction;

[0039] The adapter plate 4 is electrically connected to the pole 5 and the tab 32 via the adapter plate 4. The adapter plate 4 and the pole 5 are both located on the side of the battery cell body 31 along the first direction where the tab 32 is provided. The surface of the pole 5 close to the battery cell 3 is welded to the adapter plate 4. The tab 32 at least partially covers the first area on the side of the adapter plate 4 facing away from the battery cell body 31.

[0040] The surface of the pole 5 close to the battery cell 3 is at least partially recessed in a direction away from the battery cell to form a recess 51, which is provided at a circumferential end of the pole 5;

[0041] The concave dimension of the concave portion 51 along a plane perpendicular to the first direction is a, the concave dimension of the concave portion 51 along the first direction is b, and the maximum thickness of the first region along the first direction is m, satisfying:

[0042] 0.03≤m / (a×b)≤10.

[0043] It should be noted that the battery cell 3 is composed of a positive electrode sheet, a negative electrode sheet and a separator disposed therebetween, which are wound or stacked to form a battery cell body.

[0044] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material. The positive electrode current collector can be made of metal materials such as aluminum foil, nickel foil, stainless steel, or a composite foil formed by a combination of metal and insulating materials. The positive electrode active material includes a positive electrode active main material, a conductive agent, an adhesive, etc. The positive electrode active main material includes one or more lithium-containing positive electrode active materials such as lithium iron phosphate, a ternary material containing nickel, cobalt and manganese, and lithium iron manganese phosphate;

[0045] Similarly, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material. The negative electrode current collector can be made of metal materials such as copper foil, aluminum foil, stainless steel, or a composite foil formed by a combination of metal and insulating materials; the negative electrode active material includes a negative electrode active main material, a conductive agent, an adhesive, etc. The negative electrode active main material includes one or more negative electrode active main materials such as artificial graphite, natural graphite, silicon carbon, silicon oxide, lithium titanate, etc.

[0046] The material of the adapter plate 4 can be aluminum, aluminum alloy, copper, copper alloy, stainless steel, nickel and the like.

[0047] The tab 32 is the current output end of the battery cell 3 , and the pole 5 is the current output end of the battery, which is fixedly mounted on the battery housing, and the housing is provided with a space for accommodating the battery cell.

[0048] The material of the battery case 1 includes at least one metal or alloy material such as aluminum, aluminum alloy, steel, nickel, copper, titanium, magnesium, etc.

[0049] The terminal 5 serves as the positive or negative connection point for the battery. By electrically connecting the tab 32 to the terminal 5, electrical energy can be input or output from the battery cell 3. Furthermore, the adapter 4 serves as a standardized connection intermediate between the tab 32 and the terminal 5, improving connection stability and ensuring the electrical connection between the tab 32 and the terminal 5. This ensures smooth current transfer from the battery cell 3 to the terminal 5, allowing the current to be further transferred to the outside of the battery or other parts of the battery system.

[0050] The pole 5 is connected to the adapter plate 4 by welding on the surface close to the battery cell 3 , and the welding method can be ultrasonic welding, resistance welding, laser welding, etc.

[0051] Since the pole tab 32 of this embodiment at least partially covers the surface of the side of the adapter plate 4 facing away from the battery cell body 31, when welding the adapter plate 4 and the pole 5, if the pole tab 32 is long, the pole tab 32 is easily inserted between the adapter plate 4 and the pole 5, resulting in a gap between the adapter plate 4 and the pole 5. When welding the adapter plate 4 and the pole 5, a cold weld will be formed, resulting in poor welding quality and loose welding.

[0052] To avoid this problem, this embodiment provides a recess 51 on the pole 5. In a plane perpendicular to the first direction, the recess 51 can provide sufficient space for the tab 32, ensuring that the tab 32 and the pole 5 are non-contacting and preventing the tab 32 from being inserted between the adapter 4 and the pole 5. This avoids cold solder joints, improves welding quality, ensures stable and reliable battery connections, effectively guarantees the flow capacity between the adapter 4 and the pole 5, and avoids excessive heat generation near the pole 5 during battery charging and discharging, thereby reducing the risk of thermal runaway of the battery and the safety hazards caused by poor connections during battery use, ensuring safe and stable operation of the battery. This not only effectively prevents direct overlap between the tab 32 and the pole 5, but also ensures that the fuse structure of the adapter 4 can function normally when needed, thereby improving the safety performance of the battery.

[0053] Specifically, the recess 51 is formed by recessing at least a portion of the surface of the pole 5 close to the battery cell 3 in a direction away from the battery cell, and the recess is provided at a circumferential end of the pole 5 .

[0054] The function of the recess 51 is to increase the distance between the end of the tab 32 and the pole 5, to prevent the end of the tab 32 from being inserted between the adapter 4 and the pole 5, causing a gap in the welding process between the pole 5 and the adapter 4, resulting in poor welding and the risk of cold welding. The current transmission rate during the battery charging and discharging process is slow and the resistance is large, leading to safety risks such as thermal runaway of the battery.

[0055] The pole 5 may be cylindrical, racetrack-shaped, elliptical, quadrangular, or other polygonal in shape. In this embodiment, the cylindrical pole 5 is used as an example. The recess dimension a of the recess 51 along a plane perpendicular to the first direction may be the radial recess depth of the pole 5, while the recess dimension b of the recess 51 along the first direction may be the axial recess height of the pole 5.

[0056] The shape and size of the recess 51 can be designed according to the specific size and shape of the tab 32 to ensure that there is no overlap between the recess 51 and the tab 32. By precisely controlling the depth and height of the recess 51, it is possible to effectively prevent the tab 32 from being accidentally inserted between the adapter 4 and the terminal 5 during welding, thereby further improving the welding quality and ensuring the stability and safety of the battery connection.

[0057] In addition, considering the overcurrent requirements of the pole 5 , the depth and height of the recess 51 must also take into account the overcurrent capacity, ensuring that the conductive performance of the pole 5 is not reduced while not overlapping with the tab 32 .

[0058] In addition, considering the compactness of the overall structure of the battery, the depth and height of the recess 51 should be minimized without affecting the overall performance of the battery and ensuring that it does not overlap with the tab 32, so as to optimize space utilization, ensure the compactness of the internal structure of the battery, and avoid affecting the overall size and weight of the battery due to the recess 51 being too large.

[0059] The maximum thickness m of the first region of the tab 32 along the first direction actually represents the thickness of the overall structure formed by the tab sheets after being stacked and pressed together. This thickness directly affects the number of tab sheets contained in the tab. The thickness of the first region of the tab 32, that is, the tab 32 located on the upper part of the adapter, is the main factor affecting the overall length of the tab 32 after the entire tab 32 is extended. This is further explained as follows: When the number of tab sheets is greater, the thickness of the corresponding battery cell body 31 will inevitably be thicker. Figure 3 As shown, along the second direction, there is a certain distance between the lead-out position of the tab 32 located at the edge of the battery cell body 31 and the tab 32 located in the middle of the battery cell body 31. Increasing the thickness of the battery cell body 31 will further increase this distance, thereby increasing the length of the tab 32 to ensure that the multiple tabs overlap each other and meet welding requirements. The thicker the first area of ​​the tab 32 located on the upper part of the adapter after the tab 32 is folded, the longer the overall length of the tab 32 after extension, and thus the greater the risk of direct overlap between the tab 32 and the pole 5.

[0060] This embodiment controls the value of the formula m / (a×b) within the above range. On the one hand, it increases the distance between the bottom surface of the pole 5 and the pole ear 32, effectively preventing the pole ear 32 from being mistakenly inserted between the adapter plate 4 and the pole 5 during the welding process, avoiding the formation of cold welds between the pole 5 and the adapter plate 4, ensuring the flow capacity between the adapter plate 4 and the pole 5, and avoiding excessive heat generation near the pole 5 during battery charging and discharging, thereby reducing the risk of thermal runaway of the battery, reducing the safety hazards caused by poor connection during use of the battery, and ensuring safe and stable operation of the battery; on the other hand, it ensures the strength of the pole, avoids structural weakness caused by an excessively large recess, and affects the connection strength between the adapter plate and the bottom surface of the pole, thereby improving the overall safety and reliability of the battery.

[0061] In addition, the overcurrent difference caused by the small welding area between the pole 5 and the adapter 4 is avoided, ensuring the balance of overcurrent and conductive performance. By reasonably controlling the value of the formula m / (a×b), the internal space utilization of the battery can also be guaranteed, further improving the overall energy density of the battery.

[0062] Illustratively, in this embodiment, the value of m / (a×b) can be 0.03 or 0.08 or 0.1 or 0.25 or 0.43 or 0.91 or 1.2 or 2.3 or 4 or 5 or 6 or 7.8 or 8 or 10, etc., or it can be an interval range formed by any two of the above values.

[0063] If the value of the formula m / (a×b) is too small, the connection strength between the pole 5 and the adapter 4 is weak, and there is a risk of breakage at the connection between the pole 5 and the adapter 4 during battery vibration, affecting the reliable current transmission of the battery, and the flow area on the bottom of the pole 5 is small; if the value of the formula m / (a×b) is too large, the risk of welding failure between the pole 5 and the adapter 4 increases, a cold weld is formed between the pole 5 and the adapter 4, and the pole 5 generates a lot of heat, which can easily lead to safety risks such as thermal runaway inside the battery.

[0064] In some embodiments, a satisfies: 0.2 mm ≤ a ≤ 3 mm;

[0065] And / or, b satisfies: 0.2 mm ≤ b ≤ 2.5 mm;

[0066] And / or, m satisfies: 0.15mm≤m≤2mm.

[0067] The recessed dimension of the recess 51 along a plane perpendicular to the first direction is a. By controlling a within the above range, the recess 51 can effectively accommodate the tab 32, avoiding interference between the tab 32 and the adapter 4 and the pole 5, reducing the risk of overlap between the pole and the end of the tab, avoiding the formation of a cold weld between the pole 5 and the adapter 4, ensuring the flow capacity between the adapter 4 and the pole 5, and avoiding excessive heat generation near the pole 5 during battery charging and discharging, thereby reducing the risk of thermal runaway of the battery. At the same time, the strength of the pole 5 is guaranteed, avoiding structural weakness caused by an excessively large dimension a, and avoiding poor flow due to a small welding area between the pole 5 and the adapter 4, ensuring a balance between flow and conductivity, and improving the overall safety and reliability of the battery.

[0068] Illustratively, in this embodiment, the value of a may be 0.2 mm, 0.3 mm, 0.8 mm, 1 mm, 1.5 mm, 2.3 mm, 2.8 mm, or 3 mm, etc., or may be an interval formed by any two of the above values.

[0069] The recessed dimension b of the recess 51 along the first direction is controlled within the above range to ensure that the recess 51 can effectively accommodate the tab 32, avoid interference between the tab 32 and the adapter plate 4 and the pole 5, reduce the risk of overlap between the pole and the end of the tab, avoid the formation of a cold weld between the pole 5 and the adapter plate 4, ensure the flow capacity between the adapter plate 4 and the pole 5, and avoid excessive heat generation near the pole 5 during battery charging and discharging, thereby reducing the risk of thermal runaway of the battery. At the same time, the strength of the pole 5 is avoided, the deformation of the pole 5 is reduced, the structural stability of the pole 5 is improved, and the failure of the assembly of the pole 5 and the housing is avoided.

[0070] Illustratively, in this embodiment, the value of b may be 0.2 mm, 0.3 mm, 0.8 mm, 1 mm, 1.5 mm, 1.7 mm, 2.3 mm, 2.5 mm, etc., or may be an interval formed by any two of the above values.

[0071] The maximum thickness of the tab 32 along the first direction is m. When m is larger, the tab 32 is more likely to be staggered, so that the end of the tab after staggering is pointed, closer to the pole post 5, and easier to overlap. By controlling m within the above range, the staggered phenomenon of the tab 32 can be effectively avoided, the risk of contact between the pointed end and the pole post 5 is reduced, and the welding quality of the pole post 5 and the adapter 4 is ensured. In addition, the matching degree between the tab 32 and the recess 51 can be ensured, and interference caused by the excessive thickness of the tab 32 can be avoided, and the overlap of the tab 32 and the pole post 5 can be avoided. In addition, the value of m affects the overcurrent capacity of the tab 32. By accurately controlling the value of m, the conductive performance of the tab 32 can be guaranteed, the insufficient overcurrent capacity of the tab 32 can be avoided, and the increased difficulty of welding due to excessive thickness can be avoided.

[0072] Illustratively, in this embodiment, the value of m may be 0.15 mm, 0.3 mm, 0.8 mm, 1 mm, 1.5 mm, 1.7 mm, 2 mm, etc., or may be an interval formed by any two of the above values.

[0073] In conjunction with Table 1 below, through several examples and comparative examples, the provided batteries were tested for battery overcurrent capacity and performance testing to measure the connection strength between the pole and the adapter to verify whether they were qualified.

[0074] Table 1

[0075]

[0076] Regarding Table 1 above, the following are explained:

[0077] Performance 1. The battery overcurrent capacity test method is as follows:

[0078] For each example and comparative example, 10 batteries were taken from each test. At room temperature (25°C), the batteries were discharged at 0.33C to 0% SOC. After standing for 60 minutes, the temperature at this time was measured and recorded as t1. The batteries were then charged at 1C to 100% SOC, the time 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", and the average value was taken as the temperature rise rate of the battery under this parameter. If the temperature rise rate is greater than or equal to 0.9°C / min, it is unqualified; if the temperature rise rate is less than 0.9°C / min, it is qualified.

[0079] Performance 2. The performance test method for measuring the connection strength between the pole and the adapter is as follows:

[0080] The test object is a battery pack. For each embodiment and comparative example, 200 square shell batteries are taken respectively. The square shell batteries are grouped and fixed to the bottom plate of the battery box, and the conductive bar is welded on the battery pole. After the installation is completed, the box cover is covered and fixed. In accordance with the requirements of GB / T2423.43, the test object is installed on the vibration table. The test process is carried out in accordance with the provisions of GB / T2423.56. Random and fixed-frequency vibration loads are applied in each direction respectively, and the loading order should be z-axis random, z-axis fixed frequency, y-axis random, y-axis fixed frequency, x-axis random, x-axis fixed frequency (the connection direction of the front and rear parts of the battery pack is the x-axis direction, and the other horizontal direction perpendicular to the x-axis direction is the y-axis direction). The vibration frequency, power spectrum density PSD, vibration time, etc. are shown in Table 2 below.

[0081] After the test, remove the battery and check whether there are any weld marks or fractures on the poles and the bottom of the adapter. If the total number of weld marks or fractures exceeds 10%, it is unqualified.

[0082] Table 2

[0083]

[0084] Regarding the test results, combined with Table 1 above, the following is explained:

[0085] From Examples 1-7, it can be seen that when the formula value satisfies 0.03≤m / (a×b)≤10, the temperature rise rate is less than 0.9°C / min, which is qualified; the total number of weld fractures does not exceed 10%, which is qualified; and the performance requirements are met.

[0086] It can be seen from Example 8 that although the formula value satisfies 0.03≤m / (a×b)≤10, when a does not satisfy the range of 0.2mm≤a≤3mm, after the performance 1 test, the temperature rise rate is slightly greater than 0.9℃ / min, which is unqualified and also cannot meet the performance requirements.

[0087] As can be seen from Example 9, although the formula value satisfies 0.03≤m / (a×b)≤10, when m does not satisfy the range of 0.15mm≤m≤2mm, after Performance 2 test, the weld marks of the pole and the adapter are broken and the total number of weld mark breaks exceeds 10%, which is unqualified and also cannot meet the performance requirements.

[0088] In Comparative Example 1, the formula value exceeded the upper limit, and the temperature rise rate was greater than 0.9°C / min, which was unqualified and failed to meet the performance requirements. In Comparative Example 2, the formula value exceeded the lower limit, and the total number of weld mark fractures exceeded 10%, which was unqualified and failed to meet the performance requirements.

[0089] The preparation of the battery includes the following steps:

[0090] (1) Preparation of positive electrode sheet:

[0091] The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF were mixed, and the solvent NMP was added. The mixture was stirred in a vacuum mixer until the mixture was homogeneous to obtain a positive electrode slurry. The positive electrode slurry was evenly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheets were then cold pressed and slit. Specifically, the mass ratio of positive electrode material: conductive agent: binder was 96:2:2.

[0092] (2) Preparation of negative electrode sheet:

[0093] The negative electrode active material graphite, the conductive agent acetylene black, the thickener CMC, and the binder SBR are mixed, deionized water is added as a solvent, and the mixture is stirred in a vacuum mixer until the mixture is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on both surfaces of the negative electrode current collector copper foil. After drying at room temperature, the mixture is transferred to an oven for further drying. The negative electrode sheets are then cold pressed and slit. The ratio of negative electrode graphite: conductive agent: thickener: binder is 96:1.5:1.5:1.

[0094] (3) Preparation of electrolyte:

[0095] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0096] (4) Preparation of diaphragm:

[0097] A polyethylene film was selected as the separator.

[0098] (5) Preparation of lithium-ion batteries:

[0099] The above-mentioned positive electrode sheet, separator, and negative electrode sheet are prepared in sequence through the lamination process, so that the separator is placed between the positive and negative electrode sheets to play an isolating role. After the battery cell is prepared, the battery cell is placed in the shell, the battery cover is welded, and the battery is subjected to processes such as liquid injection, formation, and constant capacity.

[0100] It should be noted that the embodiments listed above are only some possible implementation forms that may be used in the battery preparation process, and are not an exhaustive list of all implementation forms. Those skilled in the art can understand that the preparation of batteries is not limited to the selection of positive and negative electrode materials, electrolyte formulation, and diaphragm selection listed above.

[0101] In some embodiments, m≤b is satisfied.

[0102] By limiting m≤b, it is ensured that the recess 51 on the pole 5 does not overlap with the tab 32, further ensuring that the tab 32 will not be mistakenly inserted between the adapter 4 and the pole 5 during the welding process, and the size of the recess 51 is kept reasonable, which not only meets the requirement that the recess 51 and the tab 32 do not overlap, but also does not affect the structural strength and conductive performance of the pole 5.

[0103] In some embodiments, combined Figure 4 As shown, the recess 51 is arranged at a position on the pole 5 such that it corresponds to the pole lug 32 .

[0104] By providing the recess 51 only in a partial circumferential area of ​​the pole 5 rather than in the entire circumferential area of ​​the pole 5, the strength and current carrying capacity of the pole 5 can be better guaranteed, and the influence of the recess 51 on the overall structure of the pole 5 can be effectively reduced. At the same time, the precise correspondence between the tab 32 and the recess 51 is ensured, thereby further optimizing the utilization rate of the internal space of the battery.

[0105] In some embodiments, a plurality of recesses 51 are provided at intervals in the circumferential direction around the pole 5 .

[0106] It should be noted that a plurality specifically refers to at least two.

[0107] Combine Figure 1 、 Figure 4 As shown, the tab 32 is formed into two parts along the second direction. When two battery cells share a common terminal, the two battery cells can be folded toward each other and share the same adapter 4. Alternatively, when the capacity of a single battery cell is large, resulting in a thicker tab 32, the tabs 32 can be stacked in two groups. This grouped stacking effectively reduces the thickness of a single tab group, reduces the risk of breakage, and ensures the effective welding area of ​​the tab 32.

[0108] At this time, the two sets of tabs correspond to different circumferential areas of the pole 5. By providing multiple recesses 51 spaced apart circumferentially around the pole 5, the two sets of tabs correspond to the recesses 51 on either side of the pole, ensuring that the pole 5 can be spaced apart for tabs 32 extending at different positions, ensuring that each set of tabs is reliably welded to the pole and adapter, further improving the welding quality of the pole assembly and the overall structural stability of the battery. At the same time, it avoids the small flow area on the bottom surface of the pole affecting the overall flow transmission rate of the tabs. At the same time, it optimizes the spatial layout of the pole 5, maximizes the use of the internal space of the battery, and further improves the energy density and safety of the battery.

[0109] In other embodiments, combined Figure 5 As shown, the recess 51 is continuously arranged around the circumference of the pole 5 and satisfies the following condition: 0.1≤m / (a×b)≤4.5.

[0110] By continuously setting the recess 51 around the circumference of the pole 5, the recess 51 can provide sufficient space for the tab 32, ensuring that the tab 32 is non-contacting with the pole 5, preventing the tab 32 from being inserted between the adapter 4 and the pole 5, thereby avoiding cold soldering, effectively ensuring the flow capacity between the adapter 4 and the pole 5, and avoiding excessive heat generation near the pole 5 during battery charging and discharging, thereby reducing the risk of thermal runaway of the battery. At the same time, the continuous setting of the recess 51 around the circumference of the pole 5 can ensure that the tab 32 does not overlap with the pole 5 at any angle, reducing the difficulty of assembling the pole 5 and eliminating the need to install the pole 5 at a specific angle, thereby simplifying the assembly process and improving production efficiency. At the same time, the continuous setting of the recess 51 further enhances the versatility of the pole 5 and adapts to a wider variety of tab 32 layouts. At this time, the range of the value of the formula m / (a×b) is further limited to avoid the continuous arrangement of the recesses 51 resulting in a smaller flow area on the bottom surface of the pole, which affects the overall flow on the bottom surface of the pole. At the same time, the continuous arrangement of the recesses 51 can effectively increase the distance between the pole 5 and the tab 32, and prevent the end of the tab from being inserted into the bottom surface of the pole.

[0111] In some embodiments, combined Figure 6 As shown, along the first direction, the pole 5 forms at least two pole step portions corresponding to the recess 51 , and the following condition is satisfied: 0.15≤m / (a×b)≤4.1.

[0112] By constructing recess 51 into at least two stepped steps, a reliable connection area at the bottom of the pole is ensured while avoiding local bottlenecks in the current transmission process. The multiple steps buffer current transmission and prevent severe heating of the pole bottom, thereby ensuring a reliable electrical connection between the pole and the adapter plate and improving the current transmission rate. This ensures that recess 51 and tab 32 do not overlap, providing space for tab 32, ensuring non-contact between tab 32 and pole 5 and preventing tab 32 from being inserted between adapter plate 4 and pole 5. The stepped structure also enhances the mechanical strength of pole 5, avoiding structural weakness caused by an overly large recess and ensuring the overall strength of the pole.

[0113] In some embodiments, along the first direction, the pole step portion on the side of the pole 5 close to the battery cell 3 is a first step portion, and the pole step portion adjacent to the first step portion and away from the battery cell 3 is a second step portion; the size of the second step portion along the first direction and / or the second direction is larger than the size of the first step portion, wherein the second direction is perpendicular to the first direction.

[0114] This prevents the concave portion on the surface of the pole bottom connection from being too large, which would affect the connection strength between the pole and the adapter. By providing two-level pole steps, buffering is achieved to avoid excessive differences and large forces that would affect the connection strength between the two.

[0115] In some embodiments, combined Figure 7 As shown, the pole 5 includes a bottom surface 501 facing the side of the battery body 31, and the recess 51 includes a first groove surface 502 continuously arranged with the bottom surface 501. The first groove surface 502 is inclined relative to the bottom surface 501, and the angle between the first groove surface 502 and the bottom surface 501 is β, which satisfies: 110°≤β≤170°.

[0116] By tilting the first slot surface 502 relative to the bottom surface 501, the probability of contact between the tab 32 and the pole 5 can be reduced. Furthermore, the tilting of the first slot surface 502 relative to the bottom surface 501 can ensure the strength of the pole 5. When the pole 5 is subjected to external force, the bottom surface 501 and the first slot surface 502 are jointly subjected to the force, dispersing the stress and enhancing the structural stability of the pole 5.

[0117] Illustratively, in this embodiment, the value of β may be 110°, 120°, 135°, 150°, 170°, etc., or may be an interval formed by any two of the above values.

[0118] In some embodiments, combined Figure 8 As shown, the pole 5 includes a bottom surface 501 facing the side of the battery cell body 31, and the recess 51 includes a first groove surface 502 provided continuously with the bottom surface 501;

[0119] The first groove surface 502 transitions with the bottom surface 501 at a right angle;

[0120] Alternatively, the first groove surface 502 and the bottom surface 501 are transitioned via a rounded corner portion 503 .

[0121] By making the first groove surface 502 and the bottom surface 501 transition through the rounded corner portion 503 , it is ensured that the recess 51 does not contact the end of the pole lug, and stress concentration is avoided, thereby improving the overall durability of the pole 5 .

[0122] As a variation, when the first slot surface 502 transitions to the bottom surface 501 at a right angle, the structure is simpler and easier to manufacture. At the same time, the right-angle design can also effectively disperse local stress and ensure the strength of the pole 5 .

[0123] In some embodiments, combined Figure 3 、 Figure 9 As shown, the adapter plate 4 includes a tab connection portion 41 and a post connection portion 42. The post connection portion 42 is adapted to form a protrusion relative to the tab connection portion 41 along a first direction toward a side away from the cell body 31. By adapting the post connection portion 42 to form a protrusion relative to the tab connection portion 41 along the first direction toward a side away from the cell body 31, the distance between the tab and the top surface of the adapter plate can be further increased, facilitating the confinement of the tab 32 within the area corresponding to the tab connection portion 41. This ensures that the tab 32 does not interfere with the post 5 during insertion, further reducing the risk of poor soldering and improving the reliability of the overall structure. This also ensures efficient utilization of the battery's internal space.

[0124] In some embodiments, the pole connecting portion 42 and the tab connecting portion 41 are connected via a transition portion 43 ;

[0125] The transition portion 43 is arranged to be inclined in a direction away from the tab end 324 of the tab 32 .

[0126] By tilting the transition portion 43 away from the tab end 324 of the tab 32 , the distance between the tab 32 and the adapter 4 can be increased, thereby preventing the welding between the pole 5 and the adapter 4 from being affected.

[0127] In some embodiments, the transition portion 43 has an inclination angle C that satisfies: 10°≤C≤50°.

[0128] If the tilt angle C is too large, the flow area of ​​the adapter plate 4 is small and the battery current transmission rate is slow; if the tilt angle C is too small, the tab 32 is easily inserted into the upper part of the adapter plate 4, which can easily affect the welding of the tab 32 and the adapter plate 4.

[0129] In some embodiments, the pole connecting portion 42 is disposed beyond the pole tab 32 along the first direction.

[0130] By arranging the pole connecting portion 42 beyond the pole tab 32 along the first direction, it is more advantageous to prevent the pole tab 32 from being inserted between the pole 5 and the adapter 4 , thereby ensuring the welding yield.

[0131] In some embodiments, a height difference between the pole connecting portion 42 and the tab connecting portion 41 along the first direction is h, which satisfies: 0.1 mm≤h≤3 mm.

[0132] Illustratively, in this embodiment, the value of h may be 0.1 mm, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, or 3 mm, etc., or may be an interval formed by any two of the above values.

[0133] In some embodiments, the tab connection portions 41 are provided on both sides of the pole connection portion 42 along the second direction, and the tab connection portions 41 on both sides are suitable for connecting to the tabs 32 respectively; wherein the second direction is perpendicular to the first direction.

[0134] It should be noted that, in this embodiment, the second direction may specifically be a direction perpendicular to the large surface of the battery.

[0135] The pole connecting portion 42 is provided with a pole lug connecting portion 41 on both sides along the second direction, and the pole lug connecting portions 41 on both sides are suitable for connecting the pole lugs 32 respectively; thereby facilitating the pole lugs 32 of at least two battery cells 3 to be respectively arranged on both sides of the pole connecting portion 42, thereby improving the connection strength between the pole lugs 32 and the adapter 4, and avoiding the situation where one end is subjected to excessive force, which affects the connection strength between the pole 5 and the adapter 4.

[0136] The battery shell 1 includes a first wall. As one implementation form, the first wall can be one of the wall surfaces of the main part of the battery shell 1. As another implementation form, at least one end of the battery shell 1 has an opening 11, and the shell cover 2 is installed at the opening 11. At this time, the first wall can specifically refer to the shell cover 2 installed at the opening 11.

[0137] In some embodiments, combined Figure 1 As shown, the battery also includes:

[0138] A battery case 1, in which the battery cell 3 is disposed, comprises a case body 12 and a case cover 2, wherein the case body 12 has an opening 11 at at least one end thereof;

[0139] The shell cover 2 is disposed on the opening 11 ; the pole 5 is disposed on the first surface of the battery shell 1 , the first surface is provided with a through hole, and the pole 5 and the through hole are disposed opposite to each other.

[0140] It should be noted that the pole 5 can be provided on the housing cover 2 or on the housing body 12 .

[0141] A pole or an adapter plate may be provided in the through hole to achieve electrical connection between the pole and the adapter plate.

[0142] In some embodiments, a step portion 22 is provided on the side of the shell cover 2 facing the battery cell 3 and surrounding at least a portion of the through hole. By providing the step portion 22 on the side of the shell cover 2 facing the battery cell 3 and surrounding at least a portion of the through hole, the step portion 22 is suitable for accommodating the tab 32, thereby increasing the accommodation space at the end of the tab, ensuring that the tab 32 does not contact the terminal post 5, and preventing the tab 32 from being inserted between the adapter plate 4 and the terminal post 5, thereby avoiding cold solder joints.

[0143] In some embodiments, the battery shell 1 is provided with a pole limiting portion 23 , which protrudes from the battery shell 1 and is provided on the upper portion of the pole 5 , and satisfies: 0.15≤m / (a×b)≤3.9.

[0144] The pole limiting portion 23 and the battery shell 1 can be connected as one piece or as a separate piece. The limiting portion connected as one piece has higher strength, thereby limiting the vibration of the pole 5 and ensuring the connection strength between the pole 5 and the adapter 4.

[0145] The pole limiting portion 23 protrudes from the battery shell 1 and is arranged on the upper part of the pole 5, thereby improving the connection strength between the pole 5 and the adapter 4 and avoiding the risk of welding failure between the pole 5 and the adapter 4.

[0146] Combine Figure 3 As shown, the pole ear 32 of this embodiment includes a first pole ear portion 321 connected to the battery cell body 31 and a second pole ear portion 323 away from the battery cell body 31, the first pole ear portion 321 and the second pole ear portion 323 are respectively located on both sides of the adapter plate 4 along the first direction, and the first pole ear portion 321 and the second pole ear portion 323 are connected via the bending portion 322; by welding the upper surface of the adapter plate 4 to the first pole ear portion 321, a stable connection between the pole ear 32 and the adapter plate 4 is achieved.

[0147] In order to better distinguish the boundary position of the first pole ear portion 321, the bending portion 322 and the second pole ear portion 323, Figure 5 As shown, extension lines are respectively drawn on the upper surface and the lower surface of the adapter plate 4 along the second direction, wherein the area where the pole ear 32 is located between the extension line of the upper surface and the extension line of the lower surface of the adapter plate 4 is the bending portion 322; the area where the pole ear 32 is located above the extension line of the upper surface of the adapter plate 4 is the second pole ear portion 323; and the area where the pole ear 32 is located below the extension line of the lower surface of the adapter plate 4 is the first pole ear portion 321.

[0148] In some embodiments, combined Figure 2 As shown, along the second direction, the distance from the tab end 324 of the tab 32 to the side wall of the recess 51 of the pole post 5 is j, which satisfies: 0.5 mm ≤ j ≤ 5 mm; wherein the second direction is perpendicular to the first direction.

[0149] By restricting the distance between the end 324 of the tab 32 and the side wall of the recess 51 formed by the pole 5, the tab 32 and the pole 5 can be prevented from overlapping. At the same time, by limiting the upper limit of the distance j, the tab 32 can be prevented from being too short, thereby preventing the tab 32 from having insufficient current capacity.

[0150] In some embodiments, combined Figure 2 As shown, the tab 32 and the adapter plate 4 are spaced apart from each other along the side of the second direction, with a spacing distance k satisfying: 0.2 mm ≤ k ≤ 5 mm; wherein the second direction is perpendicular to the first direction.

[0151] By setting the side spacing between the pole ear 32 and the adapter plate 4 along the second direction, the distance between the pole ear end 324 and the pole post 5 is increased, while preventing the side of the adapter plate 4 from scratching the pole ear 32 and affecting the overcurrent of the pole ear 32; but if the distance is too large, the pole ear 32 is likely to overlap with the metal shell, posing a safety risk of internal short circuit in the battery.

[0152] According to another aspect of an embodiment of the present invention, there is provided an electrical device comprising the above-mentioned battery.

[0153] Electrical devices include: energy storage equipment, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and many other technical fields.

[0154] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the present invention.

Claims

1. A battery, characterized in that: include: A battery cell (3), the battery cell (3) comprising a battery cell body (31) and a tab (32) extending from an end surface of the battery cell body (31) along a first direction; A transfer plate (4) and a pole (5), wherein the pole lug (32) is electrically connected to the pole (5) via the transfer plate (4); the transfer plate (4) and the pole (5) are both located on a side of the battery cell body (31) along the first direction where the pole lug (32) is provided, and the pole (5) is welded to the transfer plate (4) on a surface close to the battery cell (3); the pole lug (32) at least partially covers a first area formed on a surface of the transfer plate (4) on a side facing away from the battery cell body (31); The surface of the pole (5) close to the battery cell (3) is at least partially recessed in a direction away from the battery cell to form a recess (51), and the recess is provided at a circumferential end of the pole (5); The concave dimension of the concave portion (51) along a plane perpendicular to the first direction is a, the concave dimension of the concave portion (51) along the first direction is b, and the maximum thickness of the first region along the first direction is m, satisfying: 0.03≤m / (a×b)≤10.

2. The battery according to claim 1, characterized in that Satisfies: m≤b.

3. The battery according to claim 1, characterized in that The recess (51) is arranged at a position on the pole (5) suitable for corresponding to the pole lug (32).

4. The battery according to claim 3, characterized in that A plurality of recesses (51) are arranged at circumferential intervals around the pole (5).

5. The battery according to claim 1, characterized in that The recess (51) is continuously arranged around the circumference of the pole (5) and satisfies the following relationship: 0.1≤m / (a×b)≤4.

5.

6. The battery according to claim 1, characterized in that Along the first direction, the pole (5) forms at least two pole step portions corresponding to the recess (51), and the following condition is satisfied: 0.15≤m / (a×b)≤4.

1.

7. The battery according to claim 6, characterized in that Along the first direction, the pole step portion on the side of the pole (5) close to the battery cell (3) is a first step portion, and the pole step portion adjacent to the first step portion and away from the battery cell (3) is a second step portion; the size of the second step portion along the first direction and / or the second direction is larger than the size of the first step portion, wherein the second direction is perpendicular to the first direction.

8. The battery according to claim 1, characterized in that The pole (5) includes a bottom surface (501) facing the side of the battery cell body (31); the recess (51) includes a first groove surface (502) continuously arranged with the bottom surface (501); the first groove surface (502) is inclined relative to the bottom surface (501); the angle between the first groove surface (502) and the bottom surface (501) is β, which satisfies: 110°≤β≤170°.

9. The battery according to claim 1, characterized in that The pole (5) includes a bottom surface (501) facing the side of the battery cell body (31), and the recess (51) includes a first groove surface (502) continuously provided with the bottom surface (501); The first groove surface (502) transitions to the bottom surface (501) at a right angle; Alternatively, the first groove surface (502) and the bottom surface (501) transition via a rounded corner portion (503).

10. The battery according to any one of claims 1 to 9, characterized in that The adapter plate (4) comprises a tab connection portion (41) and a pole connection portion (42), wherein the pole connection portion (42) is adapted to form a protrusion relative to the tab connection portion (41) along the first direction toward a side away from the battery cell body (31).

11. The battery according to claim 10, characterized in that The pole connecting portion (42) and the tab connecting portion (41) are connected via a transition portion (43); The transition portion (43) is arranged to be inclined in a direction away from the tab end (324) of the tab (32).

12. The battery according to claim 11, characterized in that The inclination angle of the transition portion (43) is C, which satisfies: 10°≤C≤50°.

13. The battery according to claim 10, characterized in that The pole connecting portion (42) is arranged beyond the pole lug (32) along the first direction.

14. The battery according to claim 10, characterized in that A height difference between the pole connecting portion (42) and the tab connecting portion (41) along the first direction is h, which satisfies the following conditions: 0.1 mm ≤ h ≤ 3 mm.

15. The battery according to claim 10, characterized in that The tab connection portion (41) is provided on both sides of the pole connection portion (42) along a second direction, and the tab connection portions (41) on both sides are suitable for respectively connecting to the tabs (32); wherein the second direction is perpendicular to the first direction.

16. The battery according to any one of claims 1 to 9, characterized in that The battery further comprises: A battery shell (1), wherein the battery core (3) is arranged in the battery shell (1), the battery shell (1) comprises a shell body (12) and a shell cover (2), and an opening (11) is formed at at least one end of the shell body (12); The shell cover (2) is arranged on the opening portion (11); the pole (5) is arranged on the first surface of the battery shell (1); the first surface is provided with a through hole, and the pole (5) and the through hole are arranged opposite to each other.

17. The battery according to claim 16, characterized in that A step portion (22) is provided on one side of the shell cover (2) facing the battery core (3) and surrounding at least a portion of the through hole.

18. The battery according to claim 16, characterized in that The battery shell (1) is provided with a pole limiting portion (23), the pole limiting portion (23) protrudes from the battery shell (1), is arranged on the upper part of the pole (5), and satisfies the following conditions: 0.15≤m / (a×b)≤3.

9.

19. The battery according to any one of claims 1 to 9, characterized in that The a satisfies: 0.2mm≤a≤3mm; And / or, b satisfies: 0.2 mm ≤ b ≤ 2.5 mm; And / or, m satisfies: 0.15mm≤m≤2mm.

20. The battery according to any one of claims 1 to 9, characterized in that Along the second direction, the distance from the end (324) of the tab (32) to the side wall of the recess (51) formed by the pole (5) is j, satisfying: 0.5mm≤j≤5mm; wherein the second direction is perpendicular to the first direction.

21. The battery according to any one of claims 1 to 9, characterized in that The tab (32) and the adapter plate (4) are spaced apart along the side of the second direction, with a spacing distance k satisfying: 0.2 mm ≤ k ≤ 5 mm; wherein the second direction is perpendicular to the first direction.

22. An electrical device, characterized in that: A battery according to any one of claims 1 to 21.

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