Battery and battery module

Abstract

The invention belongs to the technical field of batteries, and discloses a battery and a battery module, the battery comprises a pole group, a first cover plate module, a second cover plate module and a shell body with openings at two sides, the first cover plate module and the second cover plate module are respectively arranged at the openings of the shell body to form an accommodating cavity for accommodating the pole group, and the pole group is arranged in the accommodating cavity. The pole group comprises a pole lug and a pole group material area, the pole lug is formed by stacking and combining a plurality of layers of foils, and the width size of the joint of the pole lug and the pole group material area along the second direction is determined according to the following formula: # imgabs0 #, so that when the lower limit value of the width size of the joint of the pole lug and the pole group material area along the second direction is obtained, according to the technical scheme, only the space size of the battery containing cavity, the charging and discharging rate A of the battery, the capacity coefficient delta of the battery and the structural parameters forming the tabs need to be used, independent calculation for the capacity of the battery is not needed, and therefore the parameters needing to be calculated are reduced, the calculation difficulty is lowered, the calculation speed is increased, and the calculation period is shortened.

Description

Technical Field

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

[0002] Lithium-ion power batteries are a new type of high-energy battery based on the movement of lithium ions between the positive and negative electrodes. During charging, lithium ions are deintercalated from the positive electrode and embedded in the negative electrode through the electrolyte; during discharging, on the contrary, lithium ions are deintercalated from the negative electrode and return to the positive electrode to form a current for device use. Due to the advantages of high energy, high battery voltage, wide operating temperature range, long storage life, etc. of lithium-ion power batteries, they are widely used in various fields, including electric vehicles, energy storage systems, military equipment, etc. With continuous development, various different types of lithium-ion power batteries have emerged, such as blade batteries, square shell batteries, or large cylindrical batteries, etc.

[0003] Among them, the tab of the internal electrode group is connected to the terminal of the cover plate, which plays a role in leading out the internal circuit. The cross-sectional area of the tab needs to meet the overcurrent requirement of the battery cell, otherwise the current conduction efficiency of the tab will be reduced. The cross-sectional area of the tab is usually calculated from the number of foil layers constituting the tab, the thickness of the foil, and the width of the joint between the tab and the electrode group material area. Among them, the thickness and quantity of the foil usually depend on the specific material used for the foil.

[0004] However, when calculating the width of the joint between the tab and the electrode group material area in the battery, it is necessary to rely on the capacity of the battery for calculation. However, the capacity calculation of existing batteries is very cumbersome and requires calculating multiple parameters, such as the specific capacity of the material, the compaction density, the areal density, the proportion of active material, the coating area of the electrode sheet, etc., resulting in a large calculation difficulty and a long calculation cycle for the width of the joint between the tab and the electrode group material area. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery and a battery module with small calculation difficulty and fast calculation speed.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, a battery is provided. The battery includes an electrode group, a first cover plate module, a second cover plate module, and a housing body with double-sided openings. The first cover plate module and the second cover plate module are respectively arranged at the openings of the housing body to form an accommodation cavity for accommodating the electrode group. The electrode group includes a tab and an electrode group material area formed by stacking multiple layers of foil. The width dimension of the joint between the tab and the electrode group material area in the second direction is determined according to the following formula:

[0008] In the formula:

[0009] K is the width dimension of the junction of the tab and the tab group material area in the second direction, with the unit of mm;

[0010] U is the spatial dimension of the accommodation cavity in the first direction, with the unit of mm;

[0011] V is the spatial dimension of the accommodation cavity in the second direction, with the unit of mm;

[0012] W is the spatial dimension of the accommodation cavity in the third direction, with the unit of mm;

[0013] x is the gap coefficient of the tab group in the first direction, with the unit of mm;

[0014] y is the gap coefficient of the tab group in the second direction, with the unit of mm;

[0015] δ is the capacity coefficient of the battery, with the unit of Ah / mm 3 ;

[0016] R is the current-carrying coefficient of the tab, with the unit of Ah / mm 2 ;

[0017] A is the charge-discharge rate of the battery;

[0018] B is the number of foil layers constituting the tab;

[0019] T is the thickness of each layer of the foil, with the unit of mm.

[0020] Optionally, the first cover module includes a first surface facing away from the tab group, a second surface in contact with the tab group, and a third surface in contact with the housing body. The second cover module includes a fourth surface facing away from the tab group, a fifth surface in contact with the tab group, and a sixth surface in contact with the housing body. The spatial dimension U of the accommodation cavity in the first direction is determined according to the following formula: U = L + b1 + b2 - a1 - a2;

[0021] In the formula:

[0022] L is the dimension of the housing body in the first direction, with the unit of mm;

[0023] a1 is the spacing dimension between the first surface and the second surface in the first direction, with the unit of mm;

[0024] b1 is the spacing dimension between the first surface and the third surface in the first direction, with the unit of mm;

[0025] a2 is the spacing dimension between the fourth surface and the fifth surface in the first direction, with the unit of mm;

[0026] b2 is the spacing dimension between the fourth surface and the sixth surface along the first direction, with the unit of mm.

[0027] Optionally, the housing body includes a first wall surface and a fourth wall surface that are oppositely arranged along the second direction, and the spatial dimension V of the accommodation cavity along the second direction is determined according to the following formula: V = H - t1 - t4;

[0028] In the formula;

[0029] H is the dimension of the housing body along the second direction, with the unit of mm;

[0030] t1 is the thickness dimension of the first wall surface, with the unit of mm;

[0031] t4 is the thickness dimension of the fourth wall surface, with the unit of mm.

[0032] Optionally, the housing body includes a second wall surface and a third wall surface that are oppositely arranged along the third direction, and the spatial dimension W of the accommodation cavity along the third direction is determined according to the following formula: W = T - t2 - t3;

[0033] In the formula;

[0034] T is the dimension of the housing body along the third direction, with the unit of mm;

[0035] t2 is the thickness dimension of the second wall surface, with the unit of mm;

[0036] t3 is the thickness dimension of the third wall surface, with the unit of mm.

[0037] Optionally, the gap coefficient x of the electrode group along the first direction satisfies 8 mm ≤ x ≤ 12 mm.

[0038] Optionally, the gap coefficient y of the electrode group along the second direction satisfies 6 mm ≤ y ≤ 9 mm.

[0039] Optionally, in the lithium iron phosphate system, the capacity coefficient δ of the battery satisfies 1.12×10 -4 Ah / mm 3 ≤ δ ≤ 2.47×10 -4 Ah / mm 3 .

[0040] Optionally, in the ternary system, the capacity coefficient δ of the battery satisfies 1.50×10 -4 Ah / mm 3 ≤ δ ≤ 3.35×10 -4 Ah / mm 3 .

[0041] Optionally, the distance dimension b1 between the first surface and the third surface in the first direction satisfies b1 ≥ 0.5 mm;

[0042] And / or, the distance dimension b2 between the fourth surface and the sixth surface in the first direction satisfies b2 ≥ 0.5 mm.

[0043] On the other hand, a battery module is provided, which includes a plurality of batteries as described in any one of the above, the plurality of batteries are arranged in sequence, and the plurality of batteries are connected in series and / or in parallel.

[0044] Advantages of the present invention:

[0045] The present invention provides a battery. When calculating the lower limit value of the width dimension of the junction between the tab and the tabbed material area in the second direction through the formula only the space dimensions of the battery accommodation cavity are required, that is, the space dimension U of the accommodation cavity in the first direction, the space dimension V of the accommodation cavity in the second direction, the space dimension W of the accommodation cavity in the third direction, the charge and discharge rate A of the battery, the capacity coefficient δ of the battery, and the structural parameters constituting the tab, that is, the number of foil layers constituting the tab and the thickness of each foil layer. There is no need to calculate the capacity of the battery separately, thereby reducing the parameters to be calculated, reducing the calculation difficulty, improving the calculation speed, and shortening the calculation cycle.

[0046] The present invention also provides a battery module. By applying the above battery, with the improvement of the calculation speed, the waiting time can be reduced during the production process of the battery module, thereby improving the overall production efficiency. Description of the drawings

[0047] Figure 1 is an exploded view of the structure of the battery provided by the present invention;

[0048] Figure 2 is a schematic structural view of the junction between the tab and the tabbed material area provided by the present invention;

[0049] Figure 3 A structural cross-sectional view of the battery provided by the present invention;

[0050] Figure 4 is Figure 3 an enlarged view of the structure of part Ⅰ in

[0051] Figure 5 is Figure 3 an enlarged view of the structure of part Ⅱ in

[0052] Figure 6 is a three-dimensional structural view of the housing body in the battery provided by the present invention;

[0053] Figure 7It is a plan view of the outer shell body of the battery provided by the present invention along the first direction.

[0054] In the figure:

[0055] 100, accommodation cavity;

[0056] 1, electrode group; 11, tab; 12, electrode group material area;

[0057] 2, first cover module; 21, first surface; 22, second surface; 23, third surface; 24, first cover body; 241, first closed part; 242, first insertion part; 25, first lower insulating part;

[0058] 3, second cover module; 31, fourth surface; 32, fifth surface; 33, sixth surface; 34, second cover body; 341, second closed part; 342, second insertion part; 35, second lower insulating part;

[0059] 4, outer shell body; 41, first wall surface; 42, second wall surface; 43, third wall surface; 44, fourth wall surface. Specific embodiments

[0060] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0061] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature can include the first and second features being in direct contact, or can also include the first and second features not being in direct contact but being in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under", and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0063] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "right", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0064] At present, when calculating the width of the joint between the inner tab and the tab group material area in the battery, it is necessary to rely on the capacity of the battery for calculation. However, the capacity calculation of the existing battery is very cumbersome and requires calculating multiple parameters, such as the gram capacity of the material, the compaction density, the surface density, the proportion of the active material, the coating area of the electrode sheet, etc. As a result, the calculation of the width of the joint between the tab and the tab group material area is difficult and the calculation period is long.

[0065] In order to reduce the calculation difficulty and improve the calculation speed, this embodiment provides a battery.

[0066] As Figures 1 to 7 shown, the battery includes a tab group 1, a first cover module 2, a second cover module 3, and a housing body 4 with double-sided openings. The first cover module 2 and the second cover module 3 are respectively arranged at the openings of the housing body 4 to form a receiving cavity 100 for accommodating the tab group 1. The tab group 1 includes a tab 11 and a tab group material area 12 formed by stacking multiple layers of foil materials. The width dimension of the joint between the tab 11 and the tab group material area 12 in the second direction is determined according to the following formula:

[0067] In the formula:

[0068] K is the width dimension of the joint between the tab 11 and the tab group material area 12 in the second direction, with the unit of mm;

[0069] U is the spatial dimension of the receiving cavity 100 in the first direction, with the unit of mm;

[0070] V is the spatial dimension of the receiving cavity 100 in the second direction, with the unit of mm;

[0071] W is the spatial dimension of the receiving cavity 100 in the third direction, with the unit of mm;

[0072] x is the gap coefficient of the tab group 1 in the first direction, with the unit of mm;

[0073] y is the gap coefficient of the tab group 1 in the second direction, with the unit of mm;

[0074] δ is the capacity coefficient of the battery, with the unit of Ah / mm 3 ;

[0075] R is the current-carrying coefficient of the tab 11, with the unit of Ah / mm 2 ;

[0076] A is the charge and discharge rate of the battery;

[0077] B is the number of foil layers forming the tab 11;

[0078] T is the thickness of each foil layer, with the unit of mm.

[0079] When calculating the lower limit value of the width dimension of the joint between the tab and the electrode group material area along the second direction through the formula only the space dimensions of the battery accommodation cavity are needed, that is, the space dimension U of the accommodation cavity along the first direction, the space dimension V of the accommodation cavity along the second direction, the space dimension W of the accommodation cavity along the third direction, the charge and discharge rate A of the battery, the capacity coefficient δ of the battery, and the structural parameters of the tab, that is, the number of foil layers forming the tab and the thickness of each foil layer. There is no need to calculate the battery capacity separately, thereby reducing the parameters to be calculated, reducing the calculation difficulty, improving the calculation speed, and shortening the calculation cycle.

[0080] In this embodiment, due to the difference in the polarity of the tab 11, the materials used to prepare the tab 11 are also different. When the tab 11 is the positive electrode, the tab 11 is composed of multiple layers of aluminum foil stacked together. At this time, the current-carrying coefficient of the tab 11 can be obtained as R = 10 according to the national standard. Therefore, the calculation formula for the width dimension K1 of the joint between the positive tab and the electrode group material area 12 along the second direction is: where B1 is the number of aluminum foil layers forming the positive tab, T1 is the thickness of each aluminum foil layer, and 12μm ≤ T1 ≤ 15μm; when the tab 11 is the negative electrode, the tab 11 is composed of multiple layers of copper foil stacked together. At this time, the current-carrying coefficient of the tab 11 can be obtained as R = 20 according to the national standard. Therefore, the calculation formula for the width dimension K2 of the joint between the negative tab and the electrode group material area 12 along the second direction is: where B2 is the number of copper foil layers forming the negative tab, and B2 - B1 = 1. Therefore, the calculation formula for the width dimension K2 of the joint between the negative tab and the electrode group material area 12 along the second direction can also be deformed into T2 is the thickness of each copper foil layer, and 5μm ≤ T2 ≤ 7μm.

[0081] In addition, since the charge and discharge rates A of batteries with different specifications and sizes are different, when calculating the charge and discharge rate A of the battery, first determine the time Z required for the current battery to be fully charged, with the unit of min; secondly, calculate according to the formula A = 60min / Z to obtain the charge and discharge rate A of the current battery.

[0082] Optionally, as Figures 4 to 6As shown, the first cover module 2 includes a first surface 21 facing away from the electrode group 1, a second surface 22 abutting against the electrode group 1, and a third surface 23 abutting against the housing body 4. The second cover module 3 includes a fourth surface 31 facing away from the electrode group 1, a fifth surface 32 abutting against the electrode group 1, and a sixth surface 33 abutting against the housing body 4. The spatial dimension U of the accommodation cavity 100 in the first direction is determined according to the following formula: U = L + b1 + b2 - a1 - a2;

[0083] In the formula:

[0084] L is the dimension of the housing body 4 in the first direction, with the unit of mm;

[0085] a1 is the spacing dimension between the first surface 21 and the second surface 22 in the first direction, with the unit of mm;

[0086] b1 is the spacing dimension between the first surface 21 and the third surface 23 in the first direction, with the unit of mm;

[0087] a2 is the spacing dimension between the fourth surface 31 and the fifth surface 32 in the first direction, with the unit of mm;

[0088] b2 is the spacing dimension between the fourth surface 31 and the sixth surface 33 in the first direction, with the unit of mm.

[0089] By determining the dimension L of the housing body 4 in the first direction, the spacing dimension a1 between the first surface 21 and the second surface 22 of the first cover module 2 in the first direction, the spacing dimension b1 between the first surface 21 and the third surface 23 of the first cover module 2 in the first direction, the spacing dimension a2 between the fourth surface 31 and the fifth surface 32 of the second cover module 3 in the first direction, and the spacing dimension b2 between the fourth surface 31 and the sixth surface 33 in the first direction, the spatial dimension U of the accommodation cavity 100 in the first direction can be more intuitively calculated through the above structural parameters, reducing the difficulty of obtaining the spatial dimension U of the accommodation cavity 100 in the first direction.

[0090] In this embodiment, the first cover module 2 includes a first cover body 24, and the first cover body 24 includes a first closed portion 241 and a first insertion portion 242. The surface of the first closed portion 241 facing the electrode group 1 protrudes in the direction close to the electrode group 1 to form the first insertion portion 242. The first insertion portion 242 is inserted inside the housing body 4. The first closed portion 241 is used to close the open end of the housing body 4. Among them, the first surface 21 is the surface of the first closed portion 241 facing away from the electrode group 1, the surface of the first closed portion 241 abutting against the housing body 4 is the third surface 23, and the first cover module 2 is further provided with a first lower insulating member 25 located inside the housing body 4 and used to abut against the electrode group 1. The surface of the first lower insulating member 25 abutting against the electrode group 1 is the second surface 22.

[0091] In this embodiment, the second cover plate module 3 includes a second cover plate body 34, and the second cover plate body 34 includes a second closing portion 341 and a second insertion portion 342. The surface of the second closing portion 341 facing the electrode group 1 protrudes in the direction close to the electrode group 1 to form the second insertion portion 342. The second insertion portion 342 is inserted into the inside of the housing body 4. The second closing portion 341 is used to close the opening of the housing body 4. Wherein the fourth surface 31 is the surface of the second closing portion 341 facing away from the electrode group 1, and the surface of the second closing portion 341 in contact with the housing body 4 is the sixth surface 33. The second cover plate module 3 further includes a second lower insulating member 35 located inside the housing body 4 and used to abut against the electrode group 1. The surface of the second lower insulating member 35 in contact with the electrode group 1 is the fifth surface 32.

[0092] Optionally, as Figures 6 to 7 shown, the housing body 4 includes a first wall surface 41 and a fourth wall surface 44 oppositely arranged along the second direction. The spatial dimension V of the accommodation cavity 100 along the second direction is determined according to the following formula: V = H - t1 - t4;

[0093] In the formula;

[0094] H is the dimension of the housing body 4 along the second direction, with the unit of mm;

[0095] t1 is the thickness dimension of the first wall surface 41, with the unit of mm;

[0096] t4 is the thickness dimension of the fourth wall surface 44, with the unit of mm.

[0097] By determining the dimension H of the housing body 4 along the second direction, the thickness dimension t1 of the first wall surface 41 of the housing body 4, and the thickness dimension t4 of the fourth wall surface 44 of the housing body 4, the dimension V of the accommodation cavity 100 along the second direction can be more intuitively calculated through the above structural parameters, reducing the difficulty of obtaining the spatial dimension V of the accommodation cavity 100 along the second direction.

[0098] Optionally, as Figures 6 to 7 shown, the housing body 4 includes a second wall surface 42 and a third wall surface 43 oppositely arranged along the third direction. The spatial dimension W of the accommodation cavity 100 along the third direction is determined according to the following formula: W = T - t2 - t3;

[0099] In the formula;

[0100] T is the dimension of the housing body 4 along the third direction, with the unit of mm;

[0101] t2 is the thickness dimension of the second wall surface 42, with the unit of mm;

[0102] t3 is the thickness dimension of the third wall surface 43, with the unit of mm.

[0103] By determining the dimension T of the housing body 4 in the third direction, the wall thickness dimension t2 of the second wall surface 42 of the housing body 4, and the wall thickness dimension t3 of the third wall surface 43 of the housing body 4, the dimension W of the accommodation cavity 100 in the third direction can be more intuitively calculated through the above structural parameters, reducing the difficulty of obtaining the spatial dimension W of the accommodation cavity 100 in the third direction.

[0104] Among them, the thicknesses of the first wall surface 41, the second wall surface 42, the third wall surface 43, and the fourth wall surface 44 that make up the housing body 4 can be the same or different. The forming of the housing body 4 generally includes two processes: bending and welding of aluminum plates and extrusion of aluminum rods. The housing body 4 with equal wall thickness generally adopts the process of bending and laser welding of aluminum plates, and the housing body 4 with unequal wall thickness generally adopts the extrusion process. In this embodiment, the housing body 4 with equal wall thickness of bending laser welding is preferably selected, that is, t1 = t2 = t3 = t4.

[0105] Since the spatial dimension U of the accommodation cavity 100 in the first direction, the spatial dimension V of the accommodation cavity 100 in the second direction, and the spatial dimension W of the accommodation cavity 100 in the third direction can be calculated through the structural dimensions of the components in the housing body 4, the first cover module 2, and the second cover module 3, the formula for calculating the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 in the second direction can be deformed into The formula for calculating the width dimension K2 of the joint between the negative electrode tab and the electrode group material area 12 in the second direction can be deformed into Compared with calculating using the spatial dimensions of each direction of the accommodation cavity 100, its calculation difficulty is lower and the calculation speed is faster.

[0106] Optionally, the gap coefficient x of the electrode group 1 in the first direction satisfies 8mm ≤ x ≤ 12mm. By limiting the gap coefficient x of the electrode group 1 in the first direction to satisfy 8mm ≤ x ≤ 12mm, on the one hand, it avoids being too small, resulting in insufficient space for the bending of the electrode tab 11 and causing the electrode tab 11 to be crushed, and on the other hand, it avoids being too large, resulting in a gap between the electrode group 1 and the inner wall of the housing body 4 even after charging and expansion, causing the electrode group 1 to move and strain the electrode tab 11.

[0107] In this embodiment, the gap coefficient x of the electrode group 1 in the first direction is the length of the Overhang between the separator and the negative electrode sheet + the length of the Overhang between the negative electrode sheet and the positive electrode sheet. The length of the Overhang between the separator and the negative electrode sheet refers to the distance of the parts on both sides of the separator exceeding the two sides of the negative electrode sheet along the first direction, and the length of the Overhang between the negative electrode sheet and the positive electrode sheet refers to the distance of the parts on both sides of the negative electrode sheet exceeding the two sides of the positive electrode sheet along the first direction.

[0108] To verify the influence of the clearance coefficient x of the electrode group 1 in the first direction on the insertion of the electrode group 1 into the shell, as shown in Table 1, three sets of examples and two sets of comparative examples are provided for verification.

[0109] Table 1

[0110]

[0111] As can be seen from the above table, when the clearance coefficient x of the electrode group 1 in the first direction meets the range requirement of 8 mm ≤ x ≤ 12 mm, the insertion into the shell is smooth. When the clearance coefficient x of the electrode group 1 in the first direction is less than the minimum value of the range of 8 mm ≤ x ≤ 12 mm, there is not enough space for the bending of the tab 11, resulting in the tab 11 being crushed. When the clearance coefficient x of the electrode group 1 in the first direction is greater than the maximum value of the range of 8 mm ≤ x ≤ 12 mm, the electrode group 1 moves around, resulting in the tab 11 being strained.

[0112] Optionally, the clearance coefficient y of the electrode group 1 in the second direction satisfies 6 mm ≤ y ≤ 9 mm. By limiting the clearance coefficient y of the electrode group 1 in the second direction to satisfy 6 mm ≤ y ≤ 9 mm, on the one hand, it avoids being too small, which may cause difficulties in inserting the electrode group 1 into the shell and result in scratching of the electrode group 1. On the other hand, it avoids being too large, which may cause a gap between the electrode group 1 and the inner wall of the outer shell body 4 even after charging and expansion, resulting in the electrode group 1 moving around and straining the tab 11.

[0113] In this embodiment, the clearance coefficient y of the electrode group 1 in the second direction is the sum of the insertion clearance of the electrode group 1, the height of the overhang of the separator from the negative electrode sheet, and the height of the overhang of the negative electrode sheet from the positive electrode sheet. The insertion clearance of the electrode group 1 is the distance between the two side edges of the electrode group 1 in the second direction and the inner surfaces of the opposite first wall surface 41 and the fourth wall surface 44. The height of the overhang of the separator from the negative electrode sheet refers to the distance of the parts where the two sides of the separator extend beyond the two sides of the negative electrode sheet in the second direction. The height of the overhang of the negative electrode sheet from the positive electrode sheet refers to the distance of the parts where the two sides of the negative electrode sheet extend beyond the two sides of the positive electrode sheet in the second direction.

[0114] To verify the influence of the clearance coefficient y of the electrode group 1 in the second direction on the insertion of the electrode group 1 into the shell, as shown in Table 2, three sets of examples and two sets of comparative examples are provided for verification.

[0115] Table 2

[0116]

[0117] As can be seen from the above table, when the gap coefficient y of the electrode group 1 in the second direction meets the range requirement of 6 mm ≤ y ≤ 9 mm, the shell insertion is smooth. When the gap coefficient y of the electrode group 1 in the second direction is less than the minimum value of the range of 6 mm ≤ y ≤ 9 mm, the gap during the shell insertion of the electrode group 1 is too small, resulting in scratches on the electrode group 1. When the gap coefficient y of the electrode group 1 in the second direction is greater than the maximum value of the range of 6 mm ≤ y ≤ 9 mm, the electrode group 1 moves around, resulting in strain on the tab 11.

[0118] Optionally, in the lithium iron phosphate system, the capacity coefficient δ of the battery satisfies 1.12×10 -4 Ah / mm 3 ≤δ≤2.47×10 - 4 Ah / mm 3 . By limiting the capacity coefficient δ of the battery in the lithium iron phosphate system to satisfy 1.12×10 -4 Ah / mm 3 ≤δ≤2.47×10 -4 Ah / mm 3 , the effective area calculated for welding the tab 11 and the terminal post is highly targeted and accurate.

[0119] Optionally, in the ternary system, the capacity coefficient δ of the battery satisfies 1.50×10 -4 Ah / mm 3 ≤δ≤3.35×10 - 4 Ah / mm 3 . By limiting the capacity coefficient δ of the battery in the ternary system to satisfy 1.50×10 -4 Ah / mm 3 ≤δ≤3.35×10 -4 Ah / mm 3 , the effective area calculated for welding the tab 11 and the terminal post is highly targeted and accurate.

[0120] In this embodiment, the capacity coefficient of the battery is derived from the battery capacity calculation. The battery capacity is defined as C, and the battery capacity C = length of the positive electrode sheet material area × height of the positive electrode sheet material area × surface density of the positive electrode × active material content × 2 × specific capacity of the positive electrode × number of positive electrode sheets. Among them, the units of the length and height of the positive electrode sheet material area are mm, the unit of the surface density is mg / cm 2 , the unit of the specific capacity is mAh / g, and the active material content is %. Further, the length of the positive electrode sheet material area = L + b1 + b2 - a1 - a2 - x, and the height of the positive electrode sheet material area = H - t1 - t4 - y, where the assembly ratio is 89% - 91%, so it can be obtained that Substitute the formula Denoted as δ, thus obtaining the capacity coefficient δ of the battery, where the units of each parameter in the formula are converted, i.e., mm 2 Converted to cm 2 , mg is converted to g, mAh is converted to Ah, and the parameter "2" represents coating on both sides of the foil.

[0121] Among them, in this formula, the positive electrode surface density = 20mg / cm 2 ~25mg / cm 2 , the active material content = 95% - 98%, the specific capacity of the positive electrode in the lithium iron phosphate system = 135mAh / g - 155mAh / g, the specific capacity of the positive electrode in the ternary system = 180mAh / g - 210mAh / g, the thickness of the positive electrode sheet = 155um - 215um, the thickness of the negative electrode sheet 105um - 167um, the thickness of the separator = 10um - 12um. Substituting the above data, the capacity coefficient δ of the battery under the lithium iron phosphate system is obtained, i.e., 1.12×10 -4 Ah / mm 3 ≤δ≤2.47×10 -4 Ah / mm 3 , the capacity coefficient δ of the battery under the ternary system is obtained, i.e., 1.50×10 -4 Ah / mm 3 ≤δ≤3.35×10 -4 Ah / mm 3 .

[0122] Optionally, the spacing dimension b1 of the first surface 21 and the third surface 23 along the first direction satisfies b1≥0.5mm, preferably 0.75mm; by limiting the spacing dimension b1 of the first surface 21 and the third surface 23 along the first direction, it is avoided that the size is too small, resulting in too low structural strength and easy deformation.

[0123] The spacing dimension b2 of the fourth surface 31 and the sixth surface 33 along the first direction satisfies b2≥0.5mm, preferably 0.75mm. By limiting the spacing dimension b2 of the fourth surface 31 and the sixth surface 33 along the first direction, it is avoided that the size is too small, resulting in too low structural strength and easy deformation.

[0124] Table 3

[0125]

[0126] Limit the above parameters according to the values in Table 3 to obtain the lower limit of the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 of the battery in different systems in the current size specification along the second direction, and the width dimension K2 of the joint between the negative electrode tab and the electrode group material area 12 along the second direction, that is, in the ternary system, the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 along the second direction is not less than 34.17 mm, and the width dimension K2 of the joint between the negative electrode tab and the electrode group material area 12 along the second direction is not less than 40 mm; in the lithium iron phosphate system, the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 along the second direction is not less than 25.42 mm, and the width dimension K2 of the joint between the negative electrode tab and the electrode group material area 12 along the second direction is not less than 29.76 mm.

[0127] In order to verify the rationality of the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 calculated through the above various parameters, as shown in Table 4, four groups of examples and four groups of comparative examples are selected to verify the calculation results in the ternary system and observe the temperature conditions of the positive electrode tab at different widths.

[0128] Table 4

[0129]

[0130] As known from Table 4, in the ternary system, when the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 along the second direction is greater than the lower limit of the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 calculated through the above various parameters, the temperature of the electrode tab 11 is less than 55 °C and the performance is good. When the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 along the second direction is less than the lower limit of the width dimension K1 of the joint between the positive electrode tab and the electrode group material area 12 calculated through the above various parameters, the temperature of the electrode tab 11 exceeds 55 °C and the cycle performance of the battery decreases.

[0131] In order to verify the rationality of the width dimension K2 of the joint between the negative electrode tab and the electrode group material area 12 calculated through the above various parameters, as shown in Table 5, four groups of examples and four groups of comparative examples are selected to verify the calculation results in the ternary system and observe the temperature conditions of the negative electrode tab at different widths.

[0132] Table 5

[0133]

[0134] As shown in Table 5, in the ternary system, when the width dimension K2 of the negative electrode tab at the joint with the electrode group material area 12 along the second direction is greater than the lower limit value of the width dimension K2 of the negative electrode tab at the joint with the electrode group material area 12 along the second direction calculated through the above various parameters, the temperature of the tab 11 is less than 55 °C and the performance is good. When the width dimension K2 of the negative electrode tab at the joint with the electrode group material area 12 along the second direction is less than the lower limit value of the width dimension K2 of the negative electrode tab at the joint with the electrode group material area 12 along the second direction calculated through the above various parameters, the temperature of the tab 11 exceeds 55 °C and the cycle performance of the battery deteriorates.

[0135] In this embodiment, a battery module is further provided. The battery module includes a plurality of the above-mentioned batteries, and the plurality of batteries are arranged in sequence and are connected in series and / or in parallel. By applying the above-mentioned battery, with the improvement of the calculation speed, the waiting time can be reduced during the production process of the battery module, thereby improving the overall production efficiency.

[0136] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly explaining the present invention and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A battery, characterized in that The battery comprises an electrode group, a first cover plate module, a second cover plate module and a shell body with double-sided openings, wherein the first cover plate module and the second cover plate module are respectively arranged at the openings of the shell body to form a receiving cavity for accommodating the electrode group, and the electrode group comprises an electrode ear and an electrode group material area formed by stacking and combining multiple layers of foil materials, and the width dimension of the junction of the electrode ear and the electrode group material area along the second direction is determined according to the following formula: Where: K is the width of the junction between the electrode tab and the electrode assembly area along the second direction, in mm; U is the spatial dimension of the accommodating cavity along the first direction, in mm; V is the spatial dimension of the accommodating cavity along the second direction, in mm; W is the spatial dimension of the accommodating cavity along the third direction, in mm; x is the gap coefficient of the pole group along the first direction, in mm; y is the gap coefficient of the pole group along the second direction, in mm; δ is the capacity coefficient of the battery, in Ah / mm 3 ; R is the current coefficient of the lug, in Ah / mm 2 ; A is the charge and discharge rate of the battery; B is the number of foil layers constituting the tab; T is the thickness of each layer of the foil, in mm.

2. The battery according to claim 1, characterized in that The first cover plate module includes a first surface away from the pole group, a second surface abutting the pole group, and a third surface abutting the shell body, the second cover plate module includes a fourth surface away from the pole group, a fifth surface abutting the pole group, and a sixth surface abutting the shell body, and the spatial dimension U of the accommodating cavity along the first direction is determined according to the following formula: U=L+b1+b2-a1-a2; Where: L is the size of the housing body along the first direction, in mm; a1 is the distance between the first surface and the second surface along the first direction, in mm; b1 is the distance between the first surface and the third surface along the first direction, in mm; a2 is the distance between the fourth surface and the fifth surface along the first direction, in mm; b2 is the distance between the fourth surface and the sixth surface along the first direction, and the unit is mm.

3. The battery according to claim 1, characterized in that The housing body comprises a first wall surface and a fourth wall surface which are arranged opposite to each other along the second direction, and a spatial dimension V of the accommodating cavity along the second direction is determined according to the following formula: V=H-t1-t4; Where: H is the dimension of the housing body along the second direction, in mm; t1 is the thickness of the first wall, in mm; t4 is the thickness of the fourth wall, in mm.

4. The battery according to claim 1, characterized in that The housing body comprises a second wall surface and a third wall surface which are arranged opposite to each other along the third direction, and a spatial dimension W of the accommodation cavity along the third direction is determined according to the following formula: W=T-t2-t3; Where: T is the dimension of the housing body along the third direction, in mm; t2 is the thickness of the second wall, in mm; t3 is the thickness of the third wall, in mm.

5. The battery according to claim 1, characterized in that The gap coefficient x of the pole group along the first direction satisfies 8mm≤x≤12mm.

6. The battery according to claim 1, characterized in that The gap coefficient y of the pole group along the second direction satisfies 6mm≤y≤9mm.

7. The battery according to claim 1, characterized in that In the iron-lithium system, the capacity coefficient δ of the battery satisfies 1.12×10 -4 Ah / mm 3 ≤δ≤2.47×10 -4 Ah / mm 3 .

8. The battery according to claim 1, characterized in that In the ternary system, the capacity coefficient δ of the battery satisfies 1.50×10 -4 Ah / mm 3 ≤δ≤3.35×10 -4 Ah / mm 3 .

9. The battery according to claim 2, characterized in that A spacing dimension b1 between the first surface and the third surface along the first direction satisfies b1≥0.5 mm; And / or, a spacing dimension b2 between the fourth surface and the sixth surface along the first direction satisfies b2 ≥ 0.5 mm.

10. A battery module, characterized in that: The battery module comprises a plurality of batteries as described in any one of claims 1 to 9, the plurality of batteries are arranged in sequence, and the plurality of batteries are connected in series and / or in parallel.

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