Battery cell and battery module

Abstract

The invention relates to the technical field of energy storage equipment, in particular to a battery cell and a battery module, and the battery cell comprises a pole group and an end plate. A first end face of the pole group is provided with a tab, the first end face is provided with a first part and a second part, the tab is located between the first part and the second part in the length direction of the first end face, and the size of the first part is smaller than that of the second part. The end plate covers the first end face, a first boss and a second boss are arranged on the side, facing the pole group, of the end plate, the first boss makes contact with the first part, and the second boss makes contact with the second part. In the length direction of the first end face, the maximum size of the first boss is W0, the maximum size of the second boss is W1, and the condition that W0 / W1 is larger than or equal to 0.4 and smaller than 1 is met. The battery module comprises a module shell and the battery cell, wherein the battery cell is arranged in the module shell. The battery cell pole group of the battery module is not easy to deflect when entering the shell, is not easy to damage and deform locally, and has higher quality stability.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage devices, and particularly to an electrode core and a battery module. Background Art

[0002] The pole group of the blade electrode core is relatively long, and the thrust for inserting the pole group into the shell is relatively large. If the force on the pole group during shell insertion is unbalanced, the pole group is likely to be deformed. An inner insulating film is coated on the pole group. Before inserting the pole group into the shell, the pole group and the end plate are first fixed by hot melting the inner insulating film, and then the whole is pushed into the shell. Along the length direction of the end plate, the pole tabs are not centered, so the supporting surface of the end plate for the pole group is not symmetrical, which is also likely to cause uneven forces at both ends of the pole group. When the pole group is inserted into the shell, it is likely to be skewed, easily causing corner pressing damage and deformation of the pole pieces on both sides and short circuit between the positive and negative pole pieces. Summary of the Invention

[0003] An object of the present invention is to provide an electrode core that can avoid situations such as skewing of the pole group during shell insertion and local pressing damage and deformation of the pole group, and has higher quality stability.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] Provide an electrode core, including:

[0006] A pole group, on the first end face of the pole group, there are pole tabs. The first end face has a first part and a second part. Along the length direction of the first end face, the pole tabs are located between the first part and the second part, and the size of the first part is smaller than that of the second part;

[0007] An end plate, the end plate covers the first end face. On the side of the end plate facing the pole group, there is a first boss and a second boss. The first boss contacts the first part, and the second boss contacts the second part. Along the length direction of the first end face, the maximum size of the first boss is W0, and the maximum size of the second boss is W1, satisfying 0.4 ≤ W0 / W1 < 1.

[0008] Optionally, along the length direction of the first end face, the maximum size W1 of the second boss satisfies 8 mm < W1 < 35 mm.

[0009] Optionally, the first boss includes a third boss and a fourth boss. The third boss is farther from the second boss than the fourth boss. The third boss extends along the width direction of the first end face, and the fourth boss is located at one end of the end plate along the width direction of the first end face.

[0010] Optionally, along the length direction of the first end face, the maximum size W01 of the third boss satisfies 8 mm < W01 < 25 mm.

[0011] Optionally, the end plate is provided with a receiving through hole, a part of the tab is located at the receiving through hole, the side wall of the receiving through hole is the side wall of the third boss, along the length direction of the first end face, the minimum dimension of the receiving through hole is K, the maximum dimension of the tab is H, and the maximum dimension of the fourth boss is W02, satisfying: 1.5 mm < K - W02 - H < 10 mm, and / or, K ≤ 110 mm, and / or, H ≤ 100 mm, and / or, W02 < 20 mm.

[0012] Optionally, the end plate is provided with a receiving through hole, a part of the tab is located at the receiving through hole, the end plate has an inclined plate, the inclined plate is located at the receiving through hole, and the inclined plate is adapted to the inclined surface formed by the convergence of the tabs.

[0013] Optionally, the second boss extends along the width direction of the first end face.

[0014] Optionally, along the length direction of the first end face, the first boss and the second boss are respectively located at both ends of the end plate.

[0015] Optionally, it further includes a housing and an explosion-proof valve. The electrode assembly is located inside the housing, the end plate is located at one end of the housing along its own length direction, and the explosion-proof valve is arranged on the side plate at one end of the housing along its own width direction.

[0016] Another object of the present invention is to provide a battery module, in which the electrode assembly of the battery cell is not easily deflected when entering the housing, is not easily locally crushed and deformed, and has higher quality stability.

[0017] To achieve this object, the present invention adopts the following technical solutions:

[0018] Provide a battery module, including a module housing and the above-mentioned battery cell, and the battery cell is arranged inside the module housing.

[0019] The beneficial effects of the present invention:

[0020] The present invention provides an electric core, which includes a pole group and an end plate. Among them, there are pole tabs on the first end face of the pole group. The first end face has a first part and a second part. Along the length direction of the first end face, the pole tabs are located between the first part and the second part. The size of the first part is smaller than that of the second part, that is, the pole tabs are not located in the middle but are offset to the side close to the first part. The end plate is covered at the first end face. The side of the end plate facing the pole group has a first boss and a second boss. The first boss contacts the first part, and the second boss contacts the second part. That is, during the process of inserting the pole group into the shell, there is a force between the first boss and the first part, and there is a force between the second boss and the second part. Along the length direction of the first end face, the maximum size of the first boss is W0, and the maximum size of the second boss is W1, satisfying 0.4 ≤ W0 / W1 < 1. The ratio of the maximum size of the first boss to the maximum size of the second boss being less than 1 can better adapt to the offset of the pole tabs to the side close to the first part, ensuring that, when the sizes of the pole tabs, the first boss, and the second boss remain unchanged, the distances between the pole tabs and the first boss and the second boss are as consistent as possible, thus preventing the pole tabs from being too close to a certain boss on one side, resulting in deformation or even tearing of the pole tabs. When the ratio of the maximum size of the first boss to the maximum size of the second boss is not less than 0.4, with a certain size of the second boss, it can ensure that the size of the first boss is not too small, and the difference between the two is not too large, so as to ensure that the stress areas of the first part and the second part do not differ too much, and the pole group is not subject to too small a stress area on one side, causing local deformation and even overall skew of the pole group, thus preventing the corners of the pole pieces on both sides of the pole group from being pressed and deformed during shell insertion, thereby preventing pole piece short circuit and ensuring that the electric core has high quality stability.

[0021] The present invention also provides a battery module, which includes a module housing and the above-mentioned electric core, and the electric core is arranged in the module housing. The pole group of the electric core in this battery module is not easily skewed during shell insertion, is not easily locally pressed and deformed, and has higher quality stability. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the electric core provided by an embodiment of the present invention from a first perspective;

[0023] Figure 2 is an exploded view of the electric core provided by an embodiment of the present invention;

[0024] Figure 3 is a schematic structural diagram of the end plate provided by an embodiment of the present invention from a first perspective;

[0025] Figure 4 is a schematic structural diagram of the end plate provided by an embodiment of the present invention from a second perspective;

[0026] Figure 5 is a schematic structural diagram of the electric core provided by an embodiment of the present invention from a second perspective;

[0027] Figure 6 is Figure 5 the sectional view taken along A-A in the middle;

[0028] Figure 7 is a partial sectional view of the battery cell provided by an embodiment of the present invention.

[0029] In the figure:

[0030] 1. Pole group; 11. First end face; 111. First part; 112. Second part; 12. Tab; 121. Inclined surface; 122. Middle section;

[0031] 2. End plate; 21. First boss; 211. Third boss; 212. Fourth boss; 22. Second boss; 23. Accommodating through hole; 231. First space; 232. Second space; 233. Communication hole; 24. Inclined plate;

[0032] 3. Housing; 4. Explosion-proof valve; 5. Cover plate; 6. Inner insulating film. Detailed implementation manners

[0033] Before explaining any implementation manners of the present application in detail, it should be understood that the present application is not limited to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0034] In the present application, the term "comprise", "include", "have" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device including such element.

[0035] In the present application, the term "and / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present application generally represents an "and / or" relationship between the front and rear associated objects.

[0036] In this application, the terms "connected", "combined", "coupled", and "installed" can be direct connections, combinations, couplings, or installations, or they can be indirect connections, combinations, couplings, or installations. Among them, by way of example, a direct connection means that two parts or components are connected together without the need for an intermediate member, and an indirect connection means that two parts or components are respectively connected to at least one intermediate member, and these two parts or components are connected through the intermediate member. In addition, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, and can include electrical connections or couplings.

[0037] In this application, those of ordinary skill in the art will understand that relative terms used in connection with a quantity or condition (e.g., "about", "approximately", "substantially", etc.) are intended to include the recited value and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances resulting from manufacturing, assembly, use in relation to a particular value, etc. Such terms should also be considered to disclose a range defined by the absolute values of two endpoints. A relative term may refer to a plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values without the use of relative terms should also be disclosed as having tolerances. In addition, "substantially" when expressing a relative angular positional relationship (e.g., substantially parallel, substantially perpendicular) may refer to a plus or minus a certain number of degrees (e.g., 1 degree, 5 degrees, 10 degrees or more) from the indicated angle.

[0038] In this application, those of ordinary skill in the art will understand that the functions performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0039] In this application, the orientation terms such as "upper", "lower", "left", "right", "front", "rear", etc. are described based on the orientation and positional relationship shown in the drawings, and should not be construed as a limitation on the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element. It should also be understood that orientation terms such as the upper side, lower side, left side, right side, front side, rear side, etc. not only represent the positive orientation, but can also be understood as the side orientation. For example, the lower side can include directly below, lower left, lower right, lower front, and lower rear, etc.

[0040] The pole group of the blade battery cell is relatively long, and the thrust for inserting the pole group into the shell is relatively large. If the force on the pole group during shell insertion is unbalanced, the pole group is likely to be deformed. An inner insulating film is coated on the pole group. Before inserting the pole group into the shell, the pole group and the end plate are fixed by heat melting the inner insulating film, and then the whole is pushed into the shell. Along the length direction of the end plate, the pole ear is not centered, so the supporting surface of the end plate for the pole group is not symmetrical, which is also likely to cause uneven forces at both ends of the pole group. When the pole group is inserted into the shell, it is prone to skew, which is likely to cause damage and deformation of the corners of the pole pieces on both sides and short circuit of the positive and negative pole pieces.

[0041] Therefore, this embodiment provides a battery cell to solve the above problems. This battery cell can avoid situations such as skew of the pole group 1 during shell insertion and local damage and deformation of the pole group 1, and has higher quality stability.

[0042] As Figures 1 - 7 shown, the battery cell of this embodiment includes a pole group 1 and an end plate 2. Among them, the pole ear 12 is provided on the first end face 11 of the pole group 1. The first end face 11 has a first part 111 and a second part 112. Along the length direction of the first end face 11, the pole ear 12 is located between the first part 111 and the second part 112. The size of the first part 111 is smaller than that of the second part 112, that is, the pole ear 12 is not located in the middle but is offset to the side close to the first part 111. The end plate 2 is covered at the first end face 11. The side of the end plate 2 facing the pole group 1 has a first boss 21 and a second boss 22. The first boss 21 contacts the first part 111, and the second boss 22 contacts the second part 112. That is, during the process of inserting the pole group 1 into the shell, there is a force between the first boss 21 and the first part 111, and there is a force between the second boss 22 and the second part 112.

[0043] In order to ensure that the first part 111 and the second part 112 are stressed as evenly as possible. Specifically, along the length direction of the first end face 11, the maximum dimension of the first boss 21 is W0, and the maximum dimension of the second boss 22 is W1, satisfying 0.4 ≤ W0 / W1 < 1. The ratio of the maximum dimension of the first boss 21 to the maximum dimension of the second boss 22 being less than 1 can better adapt to the offset of the tab 12 towards the side closer to the first part 111. Ensure that, with the dimensions of the tab 12, the first boss 21, and the second boss 22 unchanged, the distance between the edge of the tab 12 and the first boss 21, and the distance between the other edge of the tab 12 and the second boss 22 are as consistent as possible, which can prevent the tab 12 from being too close to a certain boss on one side, resulting in deformation or even tearing of the tab 12. When the ratio of the maximum dimension of the first boss 21 to the maximum dimension of the second boss 22 is not less than 0.4, with the dimension of the second boss 22 being certain, it can ensure that the dimension of the first boss 21 is not too small, and the difference between W0 and W1 is not too large, so as to ensure that the stress areas of the first part 111 and the second part 112 do not differ too much. The overall offset of the electrode group 1 can be prevented when the electrode group 1 is inserted into the shell without skewing, which can prevent the corners of the two-sided electrode sheets of the electrode group 1 from being crushed and deformed, thereby preventing short circuits between the electrode sheets and ensuring that the battery cell has high quality stability.

[0044] Optionally, along the length direction of the first end face 11, the first boss 21 and the second boss 22 are respectively located at both ends of the end plate 2. That is, when the length of the end plate 2 is certain, it can provide sufficient accommodation space for the tab 12 between the first boss 21 and the second boss 22 to the greatest extent. On the basis of ensuring that the contact surface between the first end face 11 and the end plate 2 is large enough, it can ensure that both sides of the tab 12 are not compressed and deformed.

[0045] Optionally, along the length direction of the first end face 11, the maximum dimension W1 of the second boss 22 satisfies 8 mm < W1 < 35 mm. W1 being greater than 8 mm can ensure that the contact area between the second part 112 and the second boss 22 is sufficient, and the pressure is not too large, which can prevent adverse situations such as excessive local stress and deformation of the second part 112. When the length of the end plate 2 is certain, W1 being less than 35 mm can reserve sufficient accommodation space for the tab 12 and ensure that both sides of the tab 12 are not compressed and deformed.

[0046] Optionally, the second boss 22 is provided to extend along the width direction of the first end surface 11. Optionally, in this embodiment, both ends of the second boss 22 extend to both ends of the width direction of the first end surface 11. When the maximum dimension W1 of the second boss 22 along the length direction of the first end surface 11 remains unchanged and the width of the first end surface 11 remains unchanged, the second boss 22 extending along the width direction of the first end surface 11 can further increase the contact area between the second portion 112 and the second boss 22, and will not cause the problem of unbalanced force between the end plate 2 and the first end surface 11 due to the second boss 22 being close to one side of the end plate 2 in the width direction.

[0047] Optionally, the first boss 21 includes a third boss 211 and a fourth boss 212, the third boss 211 is farther away from the second boss 22 than the fourth boss 212, and the third boss 211 is extended along the width direction of the first end face 11. Optionally, in this embodiment, both ends of the third boss 211 extend to both ends of the width direction of the first end face 11 respectively. Along the width direction of the first end face 11, the fourth boss 212 is located at one end of the end plate 2. The third boss 211 is extended near the edge of one side of the end plate 2, and the contact area between the first part 111 and the third boss 211 can be maximized under the condition that the maximum dimension W01 of the third boss 211 along the length direction of the first end face 11 remains unchanged and the width of the first end face 11 remains unchanged, thereby reducing the pressure at the first part 111 and avoiding deformation of the first part 111 caused by excessive local force. The fourth boss 212 is located at one end of the end plate 2 along the width direction of the first end face 11, and because the tab 12 is bent and arranged between the third boss 211 and the second boss 22, the tab 12 formed by the multiple layers of bending will form an inclined surface 121. The distance between the inclined surface 121 of the tab 12 and the first end face 11 is larger in the middle and smaller on both sides. Therefore, the fourth boss 212 is arranged on one side to reduce the position interference that may be caused to the tab 12. According to the original size design, the fourth boss 212 does not contact the tab 12, but due to the limited overall length of the end plate 2, the reserved gap between the tab 12 and the fourth boss 212 is small. Therefore, when the fourth boss 212 contacts the tab 12 due to assembly or processing errors, the fourth boss 212 is arranged at one end in the width direction to reduce the pressure on the tab 12, thereby reducing the impact and damage to the tab 12. That is, providing the fourth boss 212 on one side of the end plate 2 can maximize the contact area between the end plate 2 and the first end face 11 while minimizing damage to the tab 12 caused by assembly or processing errors.

[0048] Optionally, along the length direction of the first end face 11, the maximum dimension W01 of the third boss 211 satisfies 8 mm < W01 < 25 mm. That W01 is greater than 8 mm can ensure that the contact area between the first part 111 and the third boss 211 is sufficient, and the pressure will not be too large, preventing adverse situations such as excessive local stress and deformation of the first part 111. That W01 is less than 25 mm can ensure that, with a certain length of the end plate 2, the tab 12 has sufficient accommodation space, and both sides of the tab 12 will not be deformed by pressure.

[0049] As Figure 3 and Figure 4 shown, optionally, the end plate 2 is provided with an accommodation through-hole 23, and part of the tab 12 is located at the accommodation through-hole 23, that is, the tab 12 is electrically connected to the output end on the cover plate 5 through the accommodation through-hole 23. The side wall of the accommodation through-hole 23 is the side wall of the third boss 211, that is, the area where the accommodation through-hole 23 does not correspond to the fourth boss 212 is the accommodating area for the tab 12. Along the length direction of the first end face 11, the minimum dimension of the accommodation through-hole 23 is K, the maximum dimension of the tab 12 is H, and the maximum dimension of the fourth boss 212 is W02, satisfying 1.5 mm < K - W02 - H < 10 mm. Optionally, in this embodiment, along the length direction of the first end face 11, the width of the accommodation through-hole 23 is the same everywhere, the width of the tab 12 is the same everywhere, and the width of the fourth boss 212 is the same everywhere, which is a rectangular structure. Therefore, the above-mentioned limiting condition is equivalent to that after subtracting the width of the fourth boss 212 from the width of the accommodation through-hole 23, the remaining width is more than 1.5 mm larger than the width of the tab 12, which can prevent the assembly error of the electrode group 1 entering the shell, the slight skew of the electrode group 1, or the processing error of the end plate 2 and the tab 12, resulting in the edge of the tab 12 contacting the edge of the accommodation through-hole 23, deformation or even tearing of the edge of the tab 12, and reducing the process yield of the battery cell. And after subtracting the width of the fourth boss 212 and the width of the tab 12 from the width of the accommodation through-hole 23, the width of the remaining space is less than 10 mm. Without changing the overall width of the end plate 2, too large remaining space will cause insufficient contact area between the end plate 2 and the electrode group 1, or the problem that the tab 12 is not wide enough and the current flux is limited.

[0050] Optionally, in this embodiment, along the length direction of the first end face 11, the minimum dimension K of the accommodation through-hole 23 satisfies K ≤ 110 mm, that is, the width of the accommodation through-hole 23 cannot exceed 110 mm, so as to avoid too small contact area between the end plate 2 and the electrode group 1.

[0051] Optionally, along the length direction of the first end face 11, the maximum dimension H of the tab 12 satisfies H ≤ 100 mm, that is, the width of the tab 12 cannot exceed 100 mm. On the premise of ensuring the current flux, if the tab 12 is too wide, it is easy to interfere with the side walls of the accommodation through-hole 23 on both sides.

[0052] Optionally, along the length direction of the first end surface 11 , the maximum dimension W02 of the fourth boss 212 satisfies W02<20 mm, that is, the width of the fourth boss 212 is less than 20 mm, so as not to occupy the accommodation space of the tab 12 .

[0053] like Figure 3 、 Figure 4 and Figure 7 As shown, optionally, the end plate 2 has an inclined plate 24, which is located at the accommodating through-hole 23 to divide the accommodating through-hole 23 into a first space 231 and a second space 232. The first space 231 and the second space 232 are connected through the connecting hole 233. The root of the pole tab 12 is located in the first space 231, and the inclined plate 24 is adapted to the inclined surface 121 formed by the folding of the pole tab 12. The portion of the pole tab 12 close to the cover plate 5 extends into the second space 232, and the pole tab 12 is bent in the second space 232, partially resting on the inclined plate 24. The middle section 122 of the pole tab 12 can be supported by the inclined plate 24 of the end plate 2, which is conducive to ensuring that the end of the pole tab 12 is firmly connected to the connecting piece or the output end.

[0054] It can be seen that the two sides of the accommodating through hole 23 along the length direction of the end plate 2 are the third boss 211 and the second boss 22 , so as to maximize the use of the length space of the end plate 2 .

[0055] like Figure 2 As shown, the battery cell optionally further includes a housing 3, a cover plate 5, and an explosion-proof valve 4. The electrode assembly 1 is positioned within the housing 3, the end plate 2 is positioned at one end of the housing 3 along its length, and the cover plate 5 is positioned outside the end plate 2. The cover plate 5 is sealed to the housing 3 to form the battery cell housing. The explosion-proof valve 4 is positioned on a side plate at one end of the housing 3 along its width. Without the explosion-proof valve 4 on the cover plate 5, the end plate 2 does not need to reserve space for explosion protection. This maximizes the space for the tabs 12 to ensure current flow. It also ensures a sufficient contact area between the first end face 11 and the end plate 2, preventing problems such as localized deformation of the electrode assembly 1 due to excessive force, or uneven force on the electrode assembly 1 causing it to tilt into the housing. Furthermore, positioning the explosion-proof valve 4 at one end of the housing 3 along its width can shorten the exhaust path and improve the safety of the battery cell. Furthermore, since the cover plate 5 is provided with a lower plastic, removing the explosion-proof valve 4 from the cover plate 5 prevents thermal deformation of the lower plastic due to laser welding, further improving the safety of the battery cell.

[0056] Optionally, the electrode group 1 is coated with an inner insulating film 6 to ensure insulation between the electrode group 1 and the housing 3. Optionally, a cover plate 5 is provided at one end opening along the length of the housing 3, with one output terminal provided on the cover plate 5 and another output terminal provided on the bottom surface of the other end of the housing 3. In this embodiment, an end plate 2 is provided on the cover plate 5, while no end plate 2 is provided on the bottom surface of the other end of the housing 3. In this embodiment, the injection port is provided on the bottom surface of the housing 3.

[0057] In order to verify that the battery cell can avoid situations such as the pole group 1 being skewed when inserted into the case and local crushing and deformation of the pole group 1, and has higher quality stability, as shown in Table 1 and Table 2 below, this embodiment provides six groups of example battery cells and five groups of comparative example battery cells, and inspections are carried out after the pole group 1 is inserted into the case. The similarities between the six groups of example battery cells and the five groups of comparative example battery cells are as follows: the length H of the pole ear 12 is 58 mm for all, and the overall length of the end plate 2, that is, W1 + K + WO1, is 109 mm for all. The structural features of the end plate 2 and the connection relationships between the structures of the six groups of example battery cells and the five groups of comparative example battery cells are the same. The only difference lies in the dimensional arrangements of the second boss 22, the third boss 211, the fourth boss 212, and the receiving through-hole 23, that is, along the length direction of the first end face 11, the maximum dimension W1 of the second boss 22, the maximum dimension W01 of the third boss 211, the maximum dimension W02 of the fourth boss 212, and the minimum dimension K of the receiving through-hole 23.

[0058] Specifically, Table 1 below shows the dimensional parameters of each structure of the end plate 2 of the six groups of example battery cells, and the dimensional parameters all meet the above-mentioned more optimal value ranges. For example: 0.4 ≤ W0 / W1 < 1, W1 > 8 mm, W01 > 8 mm, and K - W02 - H > 1.5 mm. After inspection, the pole group 1 of these six groups of example battery cells is inserted into the case smoothly, the pole group 1 has no obvious skew, the corners of the pole ear 12 are not deformed, and the pole ear 12 does not show phenomena such as tearing, and the battery cells can all be used normally.

[0059] Table 1

[0060]

[0061]

[0062] Table 2

[0063] Category Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 W1 + K + W01 (mm) 109 109 109 109 109 H (mm) 58.0 58.0 58.0 58.0 58.0 W1 (mm) 25.0 25.0 25.0 25.0 15 W01 (mm) 6 8 7 10 11 W02 (mm) 0 0 2.6 16 10 K (mm) 78 76 77 74 83 (W01 + W02) / W1 0.24 0.32 0.38 1.04 1.4 K - W02 (mm) 78.00 76.00 74.40 58.00 73.00

[0064] As shown in Table 2, the maximum dimension W01 of the third boss 211 of the end plate 2 of the battery cell of Comparative Example 1 along its own length direction is 6 mm, which does not meet the more preferable value range greater than 8 mm. The fourth boss 212 is not provided on the end plate 2, and the ratio of W0 to W1, that is, the value of (W01 + W02) / W1 is 0.24, which is less than the minimum value 0.4 of the more preferable value range. That is, compared with the maximum width of the second boss 22, the maximum width of the third boss 211 is too small, and the stress area of the first part 111 of the first end face 11 is too small. Deformation is likely to occur at the first part 111, and the electrode group 1 is likely to be skewed when entering the case. After testing, it is found that the electrode group 1 of this group of battery cells is indeed significantly skewed and the corner of the electrode tab 12 is deformed when the electrode group 1 enters the case. However, since the minimum width K of the receiving through hole 23 has a large value, the gap between the two sides of the receiving through hole 23 and the two side edges of the electrode tab 12 is large, and the electrode tab 12 is not torn, which does not affect the use.

[0065] As shown in Table 2, the maximum dimension W01 of the third boss 211 of the end plate 2 of the battery cell of Comparative Example 2 along its own length direction is 8 mm, which still does not meet the more preferable value range greater than 8 mm. The fourth boss 212 is not provided on the end plate 2 either, and the ratio of W0 to W1, that is, the value of (W01 + W02) / W1 is 0.32, which is still less than the minimum value 0.4 of the more preferable value range. That is, compared with the maximum width of the second boss 22, the maximum width of the third boss 211 is still too small, and the stress area of the first part 111 of the first end face 11 is too small. Deformation is likely to occur at the first part 111, and the electrode group 1 is likely to be skewed when entering the case. After testing, it is found that the electrode group 1 of this group of battery cells is indeed significantly skewed and the corner of the electrode tab 12 is deformed when the electrode group 1 enters the case. However, since the minimum width K of the receiving through hole 23 still has a large value, the gap between the two sides of the receiving through hole 23 and the two side edges of the electrode tab 12 is large, and the electrode tab 12 is not torn, which does not affect the use.

[0066] As shown in Table 2, the maximum dimension W01 of the third boss 211 of the end plate 2 of the battery cell of Comparative Example 3 along its own length direction is 7 mm, which still does not meet the more preferable value range greater than 8 mm. The end plate 2 is provided with a fourth boss 212. The ratio of W0 to W1, that is, the value of (W01 + W02) / W1 is 0.38, which is still slightly less than the minimum value 0.4 of the more preferable value range. That is, compared with the maximum width of the second boss 22, the maximum width of the third boss 211 is still too small, and the stress area of the first part 111 of the first end face 11 is too small. Deformation is likely to occur at the first part 111, and the electrode group 1 is likely to be skewed when entering the housing. After detection, it is found that the electrode group 1 of this group of battery cells is significantly skewed when the electrode group 1 enters the housing, and the corner of the electrode tab 12 is deformed. However, since the minimum width K of the accommodating through hole 23 still has a large value, the gap between both sides of the accommodating through hole 23 and the two side edges of the electrode tab 12 is large, and the electrode tab 12 is not torn, which does not affect the use. However, compared with the battery cells of Comparative Example 1 and Comparative Example 2, the skewing degree of the electrode group 1 of the battery cell of Comparative Example 3 is slightly reduced.

[0067] As shown in Table 2, the maximum dimension W01 of the third boss 211 of the end plate 2 of the battery cell of Comparative Example 4 along its own length direction is 10 mm, which meets the more preferable value range greater than 8 mm. The end plate 2 is also provided with a fourth boss 212. The maximum dimension W02 of the fourth boss 212 along the length direction of the end plate 2 is 16 mm. The ratio of W0 to W1, that is, the value of (W01 + W02) / W1 is 1.04, which does not meet the more preferable value range less than 1. And the value of K - W02 - H is 0, which does not meet the more preferable value range greater than 1.5. That is, the overlapping area between the electrode tab 12 and the fourth boss 212 of this group of battery cells is too large. After detection, the electrode group 1 of this group of battery cells is significantly skewed when the electrode group 1 enters the housing, and the corner of the electrode tab 12 is deformed. And because the overlapping area between the electrode tab 12 and the fourth boss 212 is too large, the fourth boss 212 abuts against the electrode tab 12, resulting in excessive local stress on the electrode tab 12, deformation and tearing of the electrode tab 12, and reduction of the current-carrying area, which will directly affect the safety of the battery cell.

[0068] As shown in Table 2, the ratio of W0 to W1 of the battery cell of Comparative Example 5, that is, the value of (W01 + W02) / W1 is 1.4, which does not meet the more preferable value range less than 1. That is, the stress area of the first part 111 of the first end face 11 of the electrode group 1 of this group of battery cells is large, and the stress area of the second part 112 is too small. The second part 112 is prone to local deformation, and the electrode group 1 is prone to skew. After detection, the electrode group 1 of this group of battery cells is significantly skewed when entering the housing, the electrode tab 12 deflects to one side of the first boss 21, the stress at the corner of the electrode tab 12 is large, and the electrode plate is deformed and damaged, resulting in a low manufacturing yield of the battery cell.

[0069] It can be seen that when the ratio of W0 to W1 of the end plate 2, that is, the value of (W01 + W02) / W1, meets the better value range, the situation that the electrode group 1 is skewed when entering the shell and the electrode tab corner is crushed and deformed can be better avoided, so that the short circuit of the electrode tab can be prevented, and the high quality stability of the battery cell can be ensured.

[0070] Moreover, the cover plate 5 of this battery cell adopts a structure without an explosion-proof valve 4. The explosion-proof valve 4 is arranged on the small-side side wall of the shell 3 of the battery cell, which can shorten the exhaust passage and improve the safety of the battery cell. And because there is a lower plastic at the cover plate 5, not setting the explosion-proof valve 4 at the cover plate 5 can avoid thermal deformation caused by laser welding of the lower plastic, and can further improve the safety of the battery cell. And this battery cell can reduce the battery cell performance problems such as electrode tab damage or short circuit caused by poor fixation and support of the electrode group 1 by optimizing the size of the end plate 2, and improve the manufacturing yield of the battery cell. In addition, by reasonably defining the size relationship between the electrode tab 12 and the end plate 2, the tearing of the electrode tab 12 during assembly can also be avoided, and the battery cell has defects. It can be seen that the battery cell provided in this embodiment has a higher manufacturing yield and higher safety performance.

[0071] This embodiment also provides a battery module, including a module housing and the above-mentioned battery cell, and the battery cell is arranged in the module housing. Optionally, this battery module has multiple battery cells, and the multiple battery cells are arranged in sequence along their own thickness directions.

[0072] The electrode group 1 of the battery cell of this battery module is not easy to be skewed when entering the shell and is not easy to be locally crushed and deformed, so both the single battery cell and the battery module have higher quality stability.

[0073] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, and are not limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A battery cell, characterized in that, Comprising: A pole group (1), on the first end face (11) of the pole group (1) there is a pole tab (12), the first end face (11) has a first part (111) and a second part (112), along the length direction of the first end face (11), the pole tab (12) is located between the first part (111) and the second part (112), and the size of the first part (111) is smaller than the size of the second part (112); An end plate (2), the end plate (2) is covered at the first end face (11), on the side of the end plate (2) facing the pole group (1) there are a first boss (21) and a second boss (22), the first boss (21) contacts the first part (111), the second boss (22) contacts the second part (112), along the length direction of the first end face (11), the maximum size of the first boss (21) is W0, the maximum size of the second boss (22) is W1, and 0.4 ≤ W0 / W1 < 1 is satisfied.

2. The battery cell according to claim 1, wherein, Along the length direction of the first end face (11), the maximum size W1 of the second boss (22) satisfies 8 mm < W1 < 35 mm.

3. The battery cell according to claim 1, wherein, The first boss (21) includes a third boss (211) and a fourth boss (212), the third boss (211) is farther from the second boss (22) than the fourth boss (212), the third boss (211) extends along the width direction of the first end face (11), and the fourth boss (212) is located at one end of the end plate (2) along the width direction of the first end face (11).

4. The cell according to claim 3, wherein Along the length direction of the first end face (11), the maximum size W01 of the third boss (211) satisfies 8 mm < W01 < 25 mm.

5. The battery cell according to claim 3, characterized in that, The end plate (2) is provided with a receiving through hole (23), a part of the pole tab (12) is located at the receiving through hole (23), the side wall of the receiving through hole (23) is the side wall of the third boss (211), along the length direction of the first end face (11), the minimum size of the receiving through hole (23) is K, the maximum size of the pole tab (12) is H, and the maximum size of the fourth boss (212) is W02, and 1.5 mm < K - W02 - H < 10 mm, and / or, K ≤ 110 mm, and / or, H ≤ 100 mm, and / or, W02 < 20 mm are satisfied.

6. The battery cell according to any one of claims 1-5, characterized in that, The end plate (2) is provided with a receiving through hole (23), a part of the pole tab (12) is located at the receiving through hole (23), the end plate (2) has an inclined plate (24), the inclined plate (24) is located at the receiving through hole (23), and the inclined plate (24) is adapted to the inclined surface (121) formed by converging with the pole tab (12).

7. The battery cell according to any one of claims 1-5, characterized in that, The second boss (22) extends along the width direction of the first end face (11).

8. The battery cell according to any one of claims 1-5, characterized in that, Along the length direction of the first end face (11), the first boss (21) and the second boss (22) are respectively located at both ends of the end plate (2).

9. The battery cell according to any one of claims 1-5, characterized in that, It further includes a housing (3) and an explosion-proof valve (4). The electrode group (1) is located inside the housing (3), the end plate (2) is located at one end of the housing (3) along its own length direction, and the explosion-proof valve (4) is arranged on the side plate at one end of the housing (3) along its own width direction.

10. Battery module, characterized in that, It includes a module housing and the battery cell according to any one of claims 1-9, and the battery cell is arranged inside the module housing.

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