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 with a positive pole lug and a negative pole lug, a cover plate module with a positive pole flow guide part and a negative pole flow guide part, and a shell body with a single side opening, the cover plate module is arranged at the opening of the shell body and is used for forming a containing cavity for containing the pole group, and the shell body is provided with a single side opening. The effective area S1 when the positive tab is welded with the positive current guide part and the effective area S2 when the negative tab is welded with the negative current guide part are determined according to a formula # imgabs0 # and a formula # imgabs1 #, so that the effective area lower limit values when the positive tab is welded with the positive current guide part and the negative tab is welded with the negative current guide part can be obtained only by virtue of the space size of the accommodating cavity; according to the method, the charge-discharge rate A of the battery and the capacity coefficient delta of the battery are combined, and calculation for the capacity of the battery is not needed, so that parameters needing to be calculated are reduced, the calculation difficulty is reduced, 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 particularly 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 electrode and the negative electrode. 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, their application fields are very wide, 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 effective area of the welding between the tab and the terminal needs to meet the overcurrent requirement of the battery. Otherwise, overheating will occur at the welding mark, affecting the cycle performance of the battery cell.

[0004] However, when calculating the effective area of the welding between the positive tab and the positive terminal and the negative tab and the negative terminal 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 multiple parameters need to be calculated, 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 effective area of the welding between the positive tab and the positive terminal and the negative tab and the negative terminal. 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 cover plate module, and a housing body with a single-sided opening. The electrode group includes a positive tab and a negative tab on the same side. The cover plate module includes a positive current collector and a negative current collector arranged at intervals. The cover plate module is arranged at the opening of the housing body to form a receiving cavity for accommodating the electrode group. The effective area of the welding between the positive tab and the positive current collector and the effective area of the welding between the negative tab and the negative current collector are determined according to the formula and the formula as follows:

[0008] In the formula:

[0009] S1 is the effective area when the positive electrode tab is welded to the positive electrode current collector, with the unit of mm 2 ;

[0010] S2 is the effective area when the negative electrode tab is welded to the negative electrode current collector, with the unit of mm 2 ;

[0011] U is the spatial dimension of the accommodation cavity along the first direction, with the unit of mm;

[0012] V is the spatial dimension of the accommodation cavity along the second direction, with the unit of mm;

[0013] W is the spatial dimension of the accommodation cavity along the third direction, with the unit of mm;

[0014] x is the gap coefficient of the electrode group along the second direction, with the unit of mm;

[0015] y is the gap coefficient of the electrode group along the first direction, with the unit of mm;

[0016] A is the charge and discharge rate of the battery;

[0017] δ is the capacity coefficient of the battery, with the unit of Ah / mm 3 ,

[0018] 8 is the current-carrying coefficient when the positive electrode tab is welded to the positive electrode current collector, with the unit of Ah / mm 2 ;

[0019] 12 is the current-carrying coefficient when the negative electrode tab is welded to the negative electrode current collector, with the unit of Ah / mm 2 .

[0020] Optionally, the cover module includes a first surface facing away from the electrode group and a second surface abutting against the electrode group, the housing body includes a first wall surface opposite to the open end, and the spatial dimension U of the accommodation cavity along the first direction is determined according to the following formula: U = H - J - a;

[0021] In the formula:

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

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

[0024] J is the thickness dimension of the first wall surface, with the unit of mm.

[0025] Optionally, the housing body includes two second wall surfaces 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 = L - I1 - I2;

[0026] In the formula:

[0027] L is the dimension of the housing body along the second direction, in mm;

[0028] I1 is the thickness dimension of one of the two second wall surfaces, in mm;

[0029] I2 is the thickness dimension of the other of the two second wall surfaces, in mm.

[0030] Optionally, the housing body includes two third wall surfaces 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 - M1 - M2;

[0031] In the formula:

[0032] T is the dimension of the housing body along the third direction, in mm;

[0033] M1 is the thickness dimension of one of the two third wall surfaces, in mm;

[0034] M2 is the thickness dimension of the other of the two third wall surfaces, in mm.

[0035] Optionally, the gap coefficient x of the electrode group along the second direction satisfies 5 mm ≤ x ≤ 8 mm.

[0036] Optionally, the gap coefficient y of the electrode group along the first direction satisfies 5 mm ≤ y ≤ 10 mm.

[0037] 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 .

[0038] 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 .

[0039] Optionally, the second wall surface on the open side of the housing body is provided with a placement groove for accommodating the cover plate module.

[0040] 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.

[0041] Advantages of the present invention:

[0042] The present invention provides a battery. By using the formula and the formula to calculate the lower limit values of the effective areas when the positive electrode tab and the positive electrode current collector are welded and when the negative electrode tab and the negative electrode current collector are welded respectively, only the spatial dimensions of the battery accommodation cavity are required, that is, the spatial dimension U of the accommodation cavity in the first direction, the spatial dimension V of the accommodation cavity in the second direction, and the spatial dimension W of the accommodation cavity in the third direction, combined with the charge and discharge rate A of the battery and the capacity coefficient δ of the battery. There is no need to calculate the capacity of the battery separately, thereby reducing the parameters to be calculated, lowering the calculation difficulty, increasing the calculation speed, and shortening the calculation cycle.

[0043] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is an exploded view of the structure of the electrode group and the cover plate module provided by the present invention;

[0045] Figure 2 is a cross-sectional view of the structure of the battery provided by the present invention;

[0046] Figure 3 is Figure 2 an enlarged view of the structure of part I in

[0047] Figure 4 an isometric view of the outer shell body of the battery provided by the present invention;

[0048] Figure 5 is Figure 4 an enlarged view of the structure of part II in

[0049] Figure 6 a front cross-sectional view of the outer shell body of the battery provided by the present invention;

[0050] Figure 7 a side cross-sectional view of the outer shell body of the battery provided by the present invention.

[0051] In the figure:

[0052] 100, accommodation cavity;

[0053] 1. Electrode group; 11. Positive tab; 12. Negative tab;

[0054] 2. Cover plate module; 21. Positive current collector; 211. Positive column; 212. Positive connection piece; 22. Negative current collector; 221. Negative column; 222. Negative connection piece; 23. First surface; 24. Second surface; 25. Cover plate body; 26. Inner insulating part;

[0055] 3. Housing body; 31. First wall surface; 32. Second wall surface; 33. Placing groove; 34. Third wall surface. Detailed implementation mode

[0056] The present invention will be further described in detail below with reference to the 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. In addition, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0057] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected", 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 communication inside two elements or the interaction relationship between two elements. 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 situations.

[0058] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below", and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the horizontal height of the first feature is lower than that of the second feature.

[0059] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "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 understood 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.

[0060] When calculating the effective area during the welding of the positive tab and the positive terminal, as well as the negative tab and the negative terminal inside the battery currently, it is necessary to rely on the battery capacity for calculation. However, the existing battery capacity calculation is very cumbersome and requires calculating multiple parameters, such as the gram capacity of the material, the compaction density, the areal density, the proportion of the active material, the coating area of the electrode sheet, etc., which leads to a relatively large difficulty in calculating the effective area during the welding of the positive tab and the positive terminal, as well as the negative tab and the negative terminal, and a long calculation cycle.

[0061] In order to reduce the calculation difficulty and improve the calculation speed, this embodiment provides a battery.

[0062] As Figures 1 to 7 shown, the battery includes a pole group 1, a cover plate module 2, and a housing body 3 with a single-sided opening. The pole group 1 includes a positive tab 11 and a negative tab 12 on the same side. The cover plate module 2 includes a positive current collector 21 and a negative current collector 22 arranged at intervals. The cover plate module 2 is disposed at the opening of the housing body 3 to form a receiving cavity 100 for accommodating the pole group 1. The effective area when the positive tab 11 is welded to the positive current collector 21 and the effective area when the negative tab 12 is welded to the negative current collector 22 are determined according to the following formula and formula as follows:

[0063] In the formula:

[0064] S1 is the effective area when the positive tab 11 is welded to the positive current collector 21, with the unit of mm 2 ;

[0065] S2 is the effective area when the negative tab 12 is welded to the negative current collector 22, with the unit of mm 2 ;

[0066] U is the spatial dimension of the receiving cavity 100 along the first direction, with the unit of mm;

[0067] V is the spatial dimension of the receiving cavity 100 along the second direction, with the unit of mm;

[0068] W is the spatial dimension of the receiving cavity 100 along the third direction, with the unit of mm;

[0069] x is the gap coefficient of the pole group 1 along the second direction, with the unit of mm;

[0070] y is the gap coefficient of the pole group 1 along the first direction, with the unit of mm;

[0071] δ is the capacity coefficient of the battery, with the unit of Ah / mm 3 ,

[0072] A is the charge-discharge rate of the battery;

[0073] 8 is the current-carrying coefficient of the welding between the positive electrode tab 11 and the positive electrode current collector 21, with the unit of Ah / mm 2 ;

[0074] 12 is the current-carrying coefficient of the welding between the negative electrode tab 12 and the negative electrode current collector 22, with the unit of Ah / mm 2 。

[0075] By using the formula and the formula to calculate the lower limit of the effective area of the positive electrode tab and the positive electrode current collector during welding and the lower limit of the effective area of the negative electrode tab and the negative electrode current collector during welding respectively, 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, and the space dimension W of the accommodation cavity along the third direction, combined with the charge-discharge rate A of the battery and the capacity coefficient δ of the battery. There is no need to calculate the battery capacity separately, thus reducing the parameters to be calculated, lowering the calculation difficulty, improving the calculation speed, and shortening the calculation cycle.

[0076] In this embodiment, since the charge-discharge rates A of batteries with different specifications and sizes are different, when calculating the charge-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-discharge rate A of the current battery.

[0077] Among them, since both the positive electrode tab 11 and the positive electrode current collector 21 are made of aluminum materials, and the welding of the tab and the current collector is located inside the battery. According to the national standard, the current-carrying coefficient in the formula for calculating the welding area of the positive electrode tab 11 is determined to be 8. Since both the negative electrode tab 12 and the negative electrode current collector 22 are made of copper materials, and the welding of the tab and the current collector is located inside the battery. According to the national standard, the current-carrying coefficient in the formula for calculating the welding area of the negative electrode tab 12 is determined to be 12.

[0078] Among them, in this embodiment, as Figure 2 shown, the positive electrode current collector 21 is composed of a positive electrode column 211 and a positive electrode connecting piece 212, the negative electrode current collector 22 is composed of a negative electrode column 221 and a negative electrode connecting piece 222. The positive electrode tab 11 is connected to the positive electrode column 211 through the positive electrode connecting piece 212, and the negative electrode tab 12 is connected to the negative electrode column 221 through the negative electrode connecting piece 222 to achieve current conduction; while in other embodiments, the positive electrode current collector 21 and the negative electrode current collector 22 are respectively the positive electrode column 211 and the negative electrode column 221. At this time, the positive electrode tab 11 is welded to the positive electrode column 211, and the negative electrode tab 12 is welded to the negative electrode column 221 to achieve current conduction.

[0079] Optionally, as Figure 3 and Figure 6As shown, the cover plate module 2 includes a first surface 23 facing away from the electrode group 1 and a second surface 24 in contact with the electrode group 1. The housing body 3 includes a first wall surface 31 opposite to the open end. The spatial dimension U of the accommodation cavity 100 in the first direction is determined according to the following formula: U = H - J - a;

[0080] In the formula:

[0081] H is the dimension of the housing body 3 in the first direction, in mm;

[0082] a is the spacing dimension between the first surface 23 and the second surface 24 in the first direction, in mm;

[0083] J is the thickness dimension of the first wall surface 31, in mm.

[0084] By determining the dimension H of the housing body 3 in the first direction and the spacing dimension a between the first surface 23 and the second surface 24 of the cover plate module 2 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.

[0085] In this embodiment, the cover plate module 2 includes a cover plate body 25 and an inner insulating member 26. The inner insulating member 26 is connected to the side of the cover plate body 25 facing the open end of the housing body 3 and is in contact with the electrode group 1. The surface of the cover plate body 25 facing away from the electrode group 1 is the first surface 23, and the surface of the inner insulating member 26 in contact with the electrode group 1 is the second surface 24.

[0086] Optionally, as Figure 6 shown, the housing body 3 includes two second wall surfaces 32 oppositely arranged in the second direction. The spatial dimension V of the accommodation cavity 100 in the second direction is determined according to the following formula: V = L - I1 - I2;

[0087] In the formula:

[0088] L is the dimension of the housing body 3 in the second direction, in mm;

[0089] I1 is the thickness dimension of one of the two second wall surfaces 32, in mm;

[0090] I2 is the thickness dimension of the other of the two second wall surfaces 32, in mm.

[0091] By determining the dimension L of the housing body 3 in the second direction, and the thickness dimensions I1 and I2 of the two second wall surfaces 32 of the housing body 3 arranged oppositely in the second direction, the dimension V of the accommodation cavity 100 in 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 in the second direction.

[0092] Wherein, the thickness dimensions I1 and I2 of the two second wall surfaces 32 of the housing body 3 arranged oppositely in the second direction may be the same or different. In this embodiment, I1 = I2.

[0093] Furthermore, as Figure 5 shown, a placement groove 33 for accommodating the cover plate module 2 is provided on the second wall surface 32 located on the open side of the housing body 3. By providing the placement grooves 33 on the two second wall surfaces 32 of the housing body 3 arranged in the second direction, after the cover plate module 2 is assembled with the housing body 3, the cover plate module 2 can be smoothly inserted into the housing body 3. In this embodiment, the depth dimension of the placement groove 33 in the second direction is 0.05 mm. Therefore, when the length dimension of the cover plate module 2 in the second direction is set as P, it satisfies P = L - I1 - I2 + 0.1.

[0094] Optionally, as Figure 7 shown, the housing body 3 includes two third wall surfaces 34 arranged oppositely in the third direction, and the spatial dimension W of the accommodation cavity 100 in the third direction is determined according to the following formula: W = T - M1 - M2;

[0095] In the formula:

[0096] T is the dimension of the housing body 3 in the third direction, with the unit of mm;

[0097] M1 is the thickness dimension of one of the two third wall surfaces 34, with the unit of mm;

[0098] M2 is the thickness dimension of the other of the two third wall surfaces 34, with the unit of mm.

[0099] By determining the dimension T of the housing body 3 in the third direction, and the thickness dimensions M1 and M2 of the two third wall surfaces 34 of the housing body 3 arranged oppositely in the third direction, 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.

[0100] Wherein, the thickness dimensions M1 and M2 of the two third wall surfaces 34 of the housing body 3 arranged oppositely in the third direction may be the same or different. In this embodiment, M1 = M2.

[0101] For the housing body 3, the first wall surface 31 opposite to the open end needs to bear the electrode group 1, and a placement groove 33 for accommodating the cover plate module 2 needs to be opened on the second wall surface 32. Therefore, the thickness relationship between the wall surfaces of the housing body 3 satisfies J>I1 = I2>M1 = M2.

[0102] 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 by the structural dimensions of the components in the housing body 3 and the cover plate module 2, the formula for calculating the effective area S1 when the positive electrode tab 11 is welded to the positive electrode current collector 21 can be transformed into The formula for the effective area S2 when the negative electrode tab 12 is welded to the negative electrode current collector 22 can be transformed into Compared with calculating using the spatial dimensions of each direction of the accommodation cavity 100, the calculation difficulty is lower and the calculation speed is faster.

[0103] Optionally, the gap coefficient x of the electrode group 1 in the second direction satisfies 5mm≤x≤8mm. By limiting the gap coefficient x of the electrode group 1 in the second direction to satisfy 5mm≤x≤8mm, on the one hand, to avoid being too small, which makes it difficult for the electrode group 1 to enter the housing and causes scratches on the electrode group 1, and on the other hand, to avoid being too large, which causes a gap between the electrode group 1 and the inner wall of the housing body 3 even after charging and expansion, resulting in the electrode group 1 moving and pulling the electrode tab.

[0104] The gap coefficient x of the electrode group 1 in the second direction is the sum of the gap when the electrode group 1 enters the housing, the length of the overhang of the separator from the negative electrode sheet, and the length of the overhang of the negative electrode sheet from the positive electrode sheet. Among them, the gap when the electrode group 1 enters the housing is the distance between the two side edges of the electrode group 1 in the second direction and the inner surface of the adjacent second wall surface 32; the length of the overhang of the separator from the negative electrode sheet refers to the distance of the part where the two sides of the separator exceed the two sides of the negative electrode sheet in the second direction; the length of the overhang of the negative electrode sheet from the positive electrode sheet refers to the distance of the part where the two sides of the negative electrode sheet exceed the two sides of the positive electrode sheet in the second direction.

[0105] To verify the influence of the gap coefficient x of the electrode group 1 in the second direction on the entry of the electrode group 1 into the housing, as shown in Table 1, three sets of examples and two sets of comparative examples are provided for verification.

[0106] Table 1

[0107]

[0108] As can be seen from the above table, when the gap coefficient x of the electrode group 1 in the second direction satisfies the range requirement of 5mm ≤ x ≤ 8mm, the insertion into the shell is smooth. When the gap coefficient x of the electrode group 1 in the second direction is less than the minimum value of the range 5mm ≤ x ≤ 8mm, the gap during the insertion of the electrode group 1 into the shell is too small, making it difficult to insert, resulting in scratches on the electrode group 1. When the gap coefficient x of the electrode group 1 in the second direction is greater than the maximum value of the range 5mm ≤ x ≤ 8mm, the electrode group 1 moves around, resulting in damage to the tab.

[0109] Optionally, the gap coefficient y of the electrode group 1 in the first direction satisfies 5mm ≤ y ≤ 10mm. By limiting the gap coefficient y of the electrode group 1 in the first direction to satisfy 5mm ≤ y ≤ 10mm, on the one hand, it avoids being too small, which may not provide enough space for the bending of the tab and cause the tab to be crushed. On the other hand, it avoids being too large, which may result in a gap between the electrode group 1 and the inner wall of the outer shell body 3 even after charging and expansion, causing the electrode group 1 to move around and damage the tab.

[0110] In this embodiment, the gap coefficient y of the electrode group 1 in the first direction is the length of the overhang of the separator and the negative electrode + the length of the overhang of the negative electrode and the positive electrode. The length of the overhang of the separator and the negative electrode refers to the distance of the parts on both sides of the separator exceeding the two sides of the negative electrode along the first direction. The length of the overhang of the negative electrode and the positive electrode refers to the distance of the parts on both sides of the negative electrode exceeding the two sides of the positive electrode along the first direction.

[0111] To verify the influence of the gap coefficient y of the electrode group 1 in the first 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.

[0112] Table 2

[0113]

[0114] As can be seen from the above table, when the gap coefficient y of the electrode group 1 in the first direction satisfies the range requirement of 5mm ≤ y ≤ 10mm, the insertion into the shell is smooth. When the gap coefficient y of the electrode group 1 in the first direction is less than the minimum value of the range 5mm ≤ y ≤ 10mm, it cannot provide enough space for the bending of the tab, resulting in the tab being crushed. When the gap coefficient y of the electrode group 1 in the first direction is greater than the maximum value of the range 5mm ≤ y ≤ 10mm, the electrode group 1 moves around, resulting in damage to the tab.

[0115] 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 system to satisfy 1.12×10 -4 Ah / mm 3 ≤δ≤2.47×10 -4 Ah / mm 3 , the effective area calculated for the welding of the tab and the terminal post is highly targeted and accurate.

[0116] 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 the welding of the tab and the terminal post is highly targeted and accurate.

[0117] 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 = the length of the positive electrode sheet material area × the height of the positive electrode sheet material area × the positive electrode surface density × the active material content × 2 × the positive electrode specific capacity × the number of positive electrode sheet layers. 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, the active material content is %, and further, the length of the positive electrode sheet material area = L - I1 - I2 - x, and the height of the positive electrode sheet material area = H - J - a - y. Among them, the assembly ratio is 89% - 91%, so it can be obtained that Denote the in the formula as δ, so as to obtain the capacity coefficient δ of the battery. Among them, the units of each parameter in the formula are converted, that is, mm 2 is converted to cm 2 , mg is converted to g, and mAh is converted to Ah. Among them, the parameter "2" represents the coating on both sides of the foil.

[0118] 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 = 135 mAh / g - 155 mAh / g, the specific capacity of the positive electrode in the ternary system = 180 mAh / g - 210 mAh / g, the thickness of the positive electrode sheet = 155 μm - 215 μm, the thickness of the negative electrode sheet 105 μm - 167 μm, the thickness of the separator = 10 μm - 12 μm. Substituting the above data, the capacity coefficient δ of the battery in the lithium iron phosphate system is obtained, that is, 1.12×10 -4 Ah / mm 3 ≤δ≤2.47×10 -4 Ah / mm 3 , the capacity coefficient δ of the battery in the ternary system is obtained, that is, 1.50×10 -4 Ah / mm 3 ≤δ≤3.35×10 -4 Ah / mm 3 .

[0119] Table 3

[0120]

[0121] Limiting the above parameters according to the values in Table 3, the lower limit value of the effective area S1 when the positive electrode current collector 21 is welded to the positive electrode tab 11 and the lower limit value of the effective area S2 when the negative electrode current collector 22 is welded to the negative electrode tab 12 in different systems under the current size specification are obtained. That is, in the ternary system, the effective area S1 when the positive electrode tab 11 is welded to the positive electrode current collector 21 satisfies S1 ≮ 21 mm 2 , the effective area S2 when the negative electrode tab 12 is welded to the negative electrode current collector 22 satisfies S2 ≮ 14 mm 2 ; in the lithium iron phosphate system, the effective area S1 when the positive electrode tab 11 is welded to the positive electrode current collector 21 satisfies S ≮ 15.7 mm 2 , the effective area S2 when the negative electrode tab 12 is welded to the negative electrode current collector 22 satisfies S2 ≮ 10.45 mm 2 .

[0122] In order to verify the rationality of the effective area S1 when the positive electrode tab 11 is welded to the positive electrode current collector 21 calculated by 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 welding area of the positive electrode tab 11 and the positive electrode current collector 21 under different lower weld mark areas.

[0123] Table 4

[0124]

[0125] As shown in Table 4, in the ternary system, when the effective area S1 of the positive electrode tab 11 and the positive electrode current collector 21 during welding is greater than the lower limit value of the effective area S1 of the positive electrode tab 11 and the positive electrode current collector 21 during welding calculated through the above various parameters, the temperature of the welding mark area is less than 55°C and the performance is good. When the effective area S1 of the positive electrode tab 11 and the positive electrode current collector 21 during welding is less than the lower limit value of the effective area S1 of the positive electrode tab 11 and the positive electrode current collector 21 during welding calculated through the above various parameters, the temperature of the welding mark area exceeds 55°C and the cycle performance of the battery decreases.

[0126] In order to verify the rationality of the effective area S2 of the negative electrode tab 12 and the negative electrode current collector 22 during welding 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 welding mark area of the negative electrode tab 12 and the negative electrode current collector 22 under different welding mark areas.

[0127] Table 5

[0128]

[0129] As shown in Table 5, in the ternary system, when the effective area S2 of the negative electrode tab 12 and the negative electrode current collector 22 during welding is greater than the lower limit value of the effective area S2 of the negative electrode tab 12 and the negative electrode current collector 22 during welding calculated through the above various parameters, the temperature of the welding mark area is less than 55°C and the performance is good. When the effective area S2 of the negative electrode tab 12 and the negative electrode current collector 22 during welding is less than the lower limit value of the effective area S2 of the negative electrode tab 12 and the negative electrode current collector 22 during welding calculated through the above various parameters, the temperature of the welding mark area exceeds 55°C and the cycle performance of the battery decreases.

[0130] 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.

[0131] Obviously, the above 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 cover plate module and a shell body with a single-side opening, wherein the electrode group comprises a positive electrode ear and a negative electrode ear located on the same side, the cover plate module comprises a positive electrode current guide and a negative electrode current guide arranged at intervals, the cover plate module is arranged at the opening of the shell body to form a receiving cavity for accommodating the electrode group, and the effective area of ​​the positive electrode ear when welded to the positive electrode current guide and the effective area of ​​the negative electrode ear when welded to the negative electrode guide are calculated according to the formula and formula To confirm: Where: S1 is the effective area when the positive electrode ear and the positive electrode current guide are welded, in mm 2 ; S2 is the effective area when the negative electrode ear and the negative electrode current guide are welded, in mm 2 ; 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 second direction, in mm; y is the gap coefficient of the pole group along the first direction, in mm; δ is the capacity coefficient of the battery, in Ah / mm 3 , A is the charge and discharge rate of the battery; 8 is the flow coefficient of the welding between the positive electrode ear and the positive electrode current guide, in Ah / mm 2 ; 12 is the flow coefficient of the welding between the negative electrode ear and the negative electrode current guide, in Ah / mm 2 .

2. The battery according to claim 1, characterized in that The cover plate module includes a first surface facing away from the pole group and a second surface abutting against the pole group, the shell body includes a first wall surface opposite to the opening, and the spatial dimension U of the accommodating cavity along the first direction is determined according to the following formula: U=HJa; Where: H is the dimension of the housing body along the first direction, in mm; a is the distance between the first surface and the second surface along the first direction, in mm; J is the thickness of the first wall, in mm.

3. The battery according to claim 1, characterized in that The shell body includes two second walls arranged opposite to each other along the second direction, and the spatial dimension V of the accommodating cavity along the second direction is determined according to the following formula: V=L-I1-I2; Where: L is the size of the housing body along the second direction, in mm; I1 is the thickness of one of the two second walls, in mm; I2 is the thickness dimension of the other one of the two second walls, in mm.

4. The battery according to claim 1, characterized in that The shell body includes two third walls arranged opposite to each other along the third direction, and the spatial dimension W of the accommodating cavity along the third direction is determined according to the following formula: W=T-M1-M2; Where: T is the dimension of the housing body along the third direction, in mm; M1 is the thickness of one of the two third walls, in mm; M2 is the thickness dimension of the other one of the two third walls, in mm.

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

6. The battery according to claim 1, characterized in that The gap coefficient y of the pole group along the first direction satisfies 5mm≤y≤10mm.

7. The battery according to claim 1, characterized in that In the iron-lithium system, the capacity coefficient δ of the battery satisfies 1.12×1 0-4 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 3, characterized in that The second wall surface is located on one side of the opening of the shell body and is provided with a placement groove for accommodating the cover module.

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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