Battery cell cover plate, battery, and electric device

Abstract

The application relates to a battery cell cover plate, a battery and an electric device, and belongs to the technical field of batteries. The application optimizes current distribution by differentiating the structures and positions of two pole columns. Two mounting holes are formed in a cover plate body and penetrate through a first pole column and a second pole column; the first pole column away from a center axis of the cover plate adopts a small-section column body, and the second pole column close to or coinciding with the center axis adopts a large-section column body; and the two pole columns are fixedly connected at the bottom of the cover plate through a connecting block. The application combines the current distribution characteristics of the battery internal cell pole group, cooperates the large-section column body with the small-section column body, makes the current distribution uniform, balances the pole column temperature rise, solves the local overheating problem caused by uneven current distribution of the traditional symmetrical pole column, and significantly improves the battery safety and service life.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to cell covers, batteries, and electrical devices. Background Technology

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing. The lithium battery cover is a key component in lithium-ion batteries, and its functions include welding with the shell to form a sealed cavity, leading out the positive and negative electrodes of the electrode group, and serving as an assembly carrier.

[0003] In related technologies, the cover plate riveting method involves a cover plate consisting of a riveting block, upper plastic, pole, aluminum sheet, lower plastic, sealing ring, etc. The pole is usually cylindrical, and the number depends on the current requirements, either a single pole or a double pole.

[0004] However, due to the welding layout of the battery pack bus, the center of the cell cover riveting block and the center axis of the cell are offset by a certain distance; the current of the cell electrode group is conducted to the outside of the terminal through the electrode tab; the current of the two terminals is inconsistent due to the current of the two terminals, while the two cylindrical terminals usually have the same structural size and the same current carrying capacity; this will result in the terminal near the center line of the electrode group having a relatively higher temperature, which will affect the safety of the cell. Summary of the Invention

[0005] Therefore, it is necessary to provide a cell cover plate, battery, and electrical equipment to address the above problems, which can solve the problem of uneven temperature of the cover plate terminals and high temperature rise of individual terminals during battery charging and discharging, resulting in reduced cell safety performance.

[0006] A battery cell cover plate, comprising:

[0007] The cover plate body is defined by the length direction, width direction, thickness direction and a first central axis in the thickness direction;

[0008] The cover plate body is provided with a first mounting hole and a second mounting hole that penetrate the cover plate body in the thickness direction at intervals along the length direction;

[0009] A first pole post includes a first plate part, a first column part and a first connecting part arranged sequentially along the thickness direction of the cover plate body. The first plate part is arranged on a first side in the thickness direction of the cover plate body, the first column part passes through a first mounting hole, and the first connecting part is located on a second side opposite to the first side in the thickness direction of the cover plate body.

[0010] A second pole post includes a second plate body, a second column body, and a second connecting part arranged sequentially along the thickness direction of the cover plate body. The second plate body is arranged on the first side in the thickness direction of the cover plate body, the second column body passes through the second mounting hole, and the second connecting part is located on the second side in the thickness direction of the cover plate body opposite to the first side.

[0011] A connecting block is located on the second side in the thickness direction of the cover plate body, and is fixed to the first pole post and the second pole post respectively through the first connecting part and the second connecting part;

[0012] The first columnar portion has a second central axis in the thickness direction, and the second columnar portion has a third central axis in the thickness direction. The distance between the second central axis and the first central axis is d1, and the distance between the third central axis and the first central axis is d2, where d1 > d2.

[0013] The cross-sectional area of ​​the first column portion perpendicular to the thickness direction is S1, and the cross-sectional area of ​​the second column portion perpendicular to the thickness direction is S2, where S1 < S2.

[0014] In one embodiment, the first column portion and the second column portion have the same dimensions in the width direction.

[0015] In one embodiment, the first column portion has a circular cross-section perpendicular to the thickness direction, and the second column portion has a racetrack-shaped cross-section perpendicular to the thickness direction.

[0016] In one embodiment, the third central axis coincides with the first central axis; or the second central axis and the third central axis are located on the same side of the first central axis in the length direction.

[0017] In one embodiment, it further includes:

[0018] A first insulating element is at least partially located between the cover plate body and the connecting block;

[0019] A second insulating element is at least partially located between the cover plate body and the first pole and between the cover plate body and the second pole;

[0020] A first sealing element is arranged around the first column portion and at least partially between the cover plate body and the annular gap of the first column portion;

[0021] A second seal is arranged around the second column portion and at least partially between the cover plate body and the annular gap of the second column portion.

[0022] In addition, this application also provides a battery, comprising:

[0023] The battery casing has a receiving cavity and an open opening;

[0024] A battery cell electrode assembly is placed within the receiving cavity, and the battery cell electrode assembly has a length direction, a width direction, and a thickness direction consistent with the main body of the cover plate; and

[0025] As described above, a cell cover plate is arranged at the opening to seal the battery casing; wherein, both the first terminal and the second terminal are electrically connected to the cell electrode assembly.

[0026] In one embodiment, the connecting block has a fourth central axis in the thickness direction in a portion of the region between the first pole post and the second pole post.

[0027] The distance from the fourth central axis to the end face of the cell electrode group near the first electrode post along the length direction is A;

[0028] The distance from the fourth central axis to the end face of the cell electrode group away from the first electrode post along the length direction is B, and A < B;

[0029] Among them, distance A, distance B, area S1, and area S2 together satisfy:

[0030] 0.9≤(S1 / S2) / (A / B)≤1.1.

[0031] In one embodiment, the first plate portion of the first electrode post and the second plate portion of the second electrode post are both electrically connected to the tabs of the battery cell electrode assembly.

[0032] In one embodiment, the battery housing has two openings located at opposite ends of the battery housing.

[0033] In addition, this application also provides an electrical device including the battery described above.

[0034] In the aforementioned cell cover, battery, and electrical equipment, the second central axis of the first electrode post is far from the first central axis of the cover body, while the third central axis of the second electrode post is closer to or coincides with the first central axis. That is, the first electrode post is usually located on the edge side of the cell, and the second electrode post is located on the center side. At the same time, the first column is circular, and the second column is racetrack-shaped. The cross-sectional area S1 of the first column is smaller than the cross-sectional area S2 of the second column, thus optimizing the area of ​​the column within a limited space. The cross-sectional areas S1 and S2, as well as the distances A and B from the fourth central axis of the connecting block to the two ends of the cell electrode group, satisfy the formula: 0.8 ≤ (S1 / S2) / (A / B) ≤ 1.2. This ensures current density matching, makes the current distribution uniform, and reduces the temperature rise difference of the electrode posts after the current distribution is balanced, avoiding thermal runaway caused by local overheating.

[0035] This application also has the following advantages:

[0036] This application achieves uniform current distribution within a limited cover area by using racetrack-shaped poles in conjunction with circular poles. Furthermore, the columnar portions of the racetrack-shaped poles and the circular poles have the same dimensions in the width direction, which facilitates electrical connection. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the assembly of the battery cell cover plate of this application under an explosive state.

[0038] Figure 2 This is a top view of the battery cell cover plate of this application after assembly.

[0039] Figure 3 for Figure 2 AA section view in the image.

[0040] Figure 4 This is a schematic diagram of the structure of the first pole of this application.

[0041] Figure 5 This is a schematic diagram of the structure of the second pole of this application.

[0042] Figure 6 This is a schematic diagram of the internal connection structure of the battery in this application.

[0043] Wherein: 100, cover plate body; 200, first pole post; 300, second pole post; 400, connecting block; 500, first insulating component; 600, second insulating component; 700, first sealing component; 800, second sealing component; 900, cell electrode assembly; 1000, electrode tab;

[0044] 110. First mounting hole; 120. Second mounting hole;

[0045] 210. First plate portion; 220. First column portion; 230. First connecting portion;

[0046] 310. Second plate portion; 320. Second column portion; 330. Second connecting portion;

[0047] X1, First central axis; X2, Second central axis; X3, Third central axis; X4, Fourth central axis. Detailed Implementation

[0048] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0049] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0050] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0052] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0054] See Figures 1-3 The diagram shows a structural schematic of a cell cover plate according to an embodiment of this application.

[0055] This application provides a battery cell cover plate, comprising:

[0056] The cover plate body 100 defines the length direction, width direction, thickness direction and the first central axis X1 in the thickness direction, and at the same time, the first mounting hole 110 and the second mounting hole 120 are opened at intervals along the length direction, penetrating the thickness direction of the cover plate body 100.

[0057] Combination Figure 4 The diagram shows a schematic diagram of the structure of the first pole post in one embodiment of this application. In some embodiments, the first pole post 200 includes, along the thickness direction, a first plate portion 210 located on the first side of the cover plate body 100 in the thickness direction; a first column portion 220 passing through the first mounting hole 110 and having a circular cross-section, the first column portion 220 having a second central axis X2; and a first connecting portion 230 located on the second side of the cover plate body 100 in the thickness direction.

[0058] Combination Figure 5 The diagram shows a schematic diagram of the structure of the second pole post in one embodiment of this application. In some embodiments, the second pole post 300 includes, along the thickness direction, a second plate portion 310 located on the first side of the cover plate body 100 in the thickness direction, a second column portion 320 passing through the second mounting hole 120 and having a racetrack-shaped cross-section, and the second column portion 320 having a third central axis X3; it also includes a second connecting portion 330 located on the second side of the cover plate body 100 in the thickness direction.

[0059] Please continue reading. Figure 3 The distance between the second central axis X2 and the first central axis X1 is d1, and the distance between the third central axis X3 and the first central axis X1 is d2, satisfying d1 > d2.

[0060] In some embodiments, the circular first column portion 220 has a cross-sectional area S1, and the racetrack-shaped second column portion 320 has a cross-sectional area S2, satisfying S1 < S2; and the first column portion 220 and the second column portion 320 have the same dimensions in the width direction.

[0061] In some embodiments, the connecting block 400 is located above the cover plate body 100 and is fixed to the first connecting portion 230 and the second connecting portion 330 by welding or riveting.

[0062] In some embodiments, the first insulating member 500 is located between the lower surface of the cover plate body 100 and the connecting block 400 to prevent short circuits; the second insulating member 600 covers the upper surface of the cover plate body 100 and the inner wall of the mounting hole; the first sealing member 700 fills the annular gap between the first column portion 220 and the first mounting hole 110; the second sealing member 800 fills the annular gap between the second column portion 320 and the second mounting hole 120, and airtightness is ensured by the first sealing member 700 and the second sealing member 800.

[0063] Please continue reading. Figure 6 This application also provides a battery, comprising:

[0064] The battery casing has a receiving cavity and at least one opening, preferably two openings at opposite ends;

[0065] The cell electrode assembly 900 is located in the receiving cavity and has the same length, width and thickness as the cover plate body 100.

[0066] The cell cover plate closes the opening of the housing. The first plate part 210 and the second plate part 310 are respectively welded to the tabs 1000 of the cell electrode group 900.

[0067] In some embodiments, the connecting block 400 defines a fourth central axis X4 in the region between the first pole post 200 and the second pole post 300, and the distance from the fourth central axis X4 to the end face of the cell electrode group 900 adjacent to the first pole post 200 is A; the distance from the fourth central axis X4 to the end face of the cell electrode group 900 away from the first pole post 200 is B, and A < B.

[0068] The relationships between the cross-sectional areas S1 and S2 and the distances A and B satisfy:

[0069] 0.9 ≤ (S1 / S2) / (A / B) ≤ 1.1

[0070] The above mathematical model ensures uniform current density and avoids localized overheating.

[0071] Example 1

[0072] The radius of the circular pole and the semicircular radius of the runway pole are r=2.8mm, and the center distance of the arcs of the runway pole is d;

[0073] The distances from the center of the rivet block to the two ends of the battery cell terminal are A=35mm and B=70mm respectively; adjust the center distance of the semicircle of the raceway terminal and measure whether the highest temperature of the raceway terminal under the same charging and discharging conditions meets the requirements (≤55℃).

[0074] The experimental results of this embodiment are shown in Table 1.

[0075] Table 1

[0076]

[0077] Example 2

[0078] The radius of the circular pole and the radius of the semicircle of the runway pole are r=3mm, and the center distance of the arc of the runway pole is d;

[0079] The distances from the center of the rivet block to the two ends of the battery cell terminal are A=40mm and B=75mm respectively; adjust the center distance of the semicircle of the raceway terminal and measure whether the highest temperature of the charge and discharge terminal under the same conditions meets the requirements (≤55℃).

[0080] The experimental results of this embodiment are shown in Table 2.

[0081] Table 2

[0082]

[0083] Example 3

[0084] The radius of the circular pole and the semicircular radius of the runway pole are r=3.5mm, and the center distance of the arcs of the runway pole is d;

[0085] The distances from the center of the rivet block to the two ends of the cell electrode are A=35mm and B=65mm respectively; adjust the center distance of the semicircle of the raceway electrode and measure whether the highest temperature of the charge and discharge electrode under the same conditions meets the requirements (≤55℃).

[0086] The experimental results of this embodiment are shown in Table 3.

[0087] Table 3

[0088]

[0089] The data from Examples 1 to 3 above show that when (S1 / S2) / (A / B) > 1.1, the runway pole temperature is higher than the standard.

[0090] When (S1 / S2) / (A / B) < 0.9, the pole temperature no longer decreases, and as the value of (S1 / S2) / (A / B) decreases, the arc center distance d of the runway pole will continue to increase (causing material waste).

[0091] Therefore, based on the maximum temperature requirement of the charge and discharge electrode posts, and considering cost and lightweight design, when 0.9 ≤ (S1 / S2) / (A / B) ≤ 1.1, the current density can be ensured to be uniform, local overheating can be avoided, and material waste can also be avoided.

[0092] In other embodiments, this application also provides an electrical device including the battery described above.

[0093] In summary, this application solves the problem of temperature difference in the terminals caused by uneven current distribution in the cell electrode group 900 by using an asymmetrical terminal design with a position offset d1 > d2 and a cross-sectional area S1 < S2, combined with the current distribution optimization of the connecting block 400. The racetrack-shaped second column 320 improves the current carrying capacity in a limited space, thereby improving the overall battery safety and lifespan.

[0094] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell cover plate, characterized in that, include: The cover plate body is defined by the length direction, width direction, thickness direction and a first central axis in the thickness direction; The cover plate body is provided with a first mounting hole and a second mounting hole that penetrate the cover plate body in the thickness direction at intervals along the length direction. A first pole post includes a first plate portion, a first column portion and a first connecting portion arranged sequentially along the thickness direction of the cover plate body. The first plate portion is arranged on a first side of the thickness direction, the first column portion passes through a first mounting hole, and the first connecting portion is located on a second side of the cover plate body opposite to the first side of the thickness direction. A second pole post includes a second plate portion, a second column portion and a second connecting portion arranged sequentially along the thickness direction. The second plate portion is arranged on a first side of the thickness direction, the second column portion passes through a second mounting hole, and the second connecting portion is located on a second side of the thickness direction opposite to the first side. A connecting block is located on the second side in the thickness direction and is fixed to the first pole post and the second pole post respectively through the first connecting part and the second connecting part; The first columnar portion has a second central axis in the thickness direction, and the second columnar portion has a third central axis in the thickness direction. The distance between the second central axis and the first central axis is d1, and the distance between the third central axis and the first central axis is d2, where d1 > d2. The cross-sectional area of ​​the first column portion perpendicular to the thickness direction is S1, and the cross-sectional area of ​​the second column portion perpendicular to the thickness direction is S2, where S1 < S2.

2. The cell cover plate according to claim 1, characterized in that, The first column portion and the second column portion have the same dimensions in the width direction.

3. The cell cover plate according to claim 2, characterized in that, The first column portion has a circular cross-section perpendicular to the thickness direction, and the second column portion has a racetrack-shaped cross-section perpendicular to the thickness direction.

4. The cell cover plate according to any one of claims 1-3, characterized in that, The third central axis coincides with the first central axis; or The second central axis and the third central axis are located on the same side of the first central axis in the length direction.

5. The cell cover plate according to any one of claims 1-3, characterized in that, Also includes: A first insulating element is at least partially located between the cover plate body and the connecting block; A second insulating element, at least partially located between the cover plate body and the first pole and between the cover plate body and the second pole; A first sealing element is arranged around the first column portion and at least partially between the cover plate body and the annular gap of the first column portion; A second seal is arranged around the second column portion and at least partially between the cover plate body and the annular gap of the second column portion.

6. A battery, characterized in that, include: The battery casing has a receiving cavity and an open opening; A battery cell electrode assembly is placed within the receiving cavity, and the battery cell electrode assembly has a length direction, a width direction, and a thickness direction consistent with the main body of the cover plate; and The cell cover plate as described in any one of claims 1-5 is arranged in the opening to close the battery casing; wherein the first terminal and the second terminal are both electrically connected to the cell electrode assembly.

7. The battery according to claim 6, characterized in that, The connecting block has a fourth central axis in the thickness direction in a portion of the area between the first pole post and the second pole post. The distance from the fourth central axis to the end face of the cell electrode group near the first electrode post along the length direction is A; The distance from the fourth central axis to the end face of the cell electrode group away from the first electrode post along the length direction is B, and A < B; Wherein, A, B, S1, and S2 together satisfy: 0.9≤(S1 / S2) / (A / B)≤1.

1.

8. The battery according to claim 6, characterized in that, The first plate portion of the first electrode post and the second plate portion of the second electrode post are both electrically connected to the tabs of the battery cell electrode assembly.

9. The battery according to claim 6, characterized in that, The battery casing has two openings located at opposite ends of the battery casing.

10. An electrical appliance, characterized in that, Includes the battery as described in any one of claims 6-9.

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