Battery cell and power battery

Abstract

The utility model relates to the technical field of batteries, and particularly discloses a battery cell and a power battery, and the battery cell comprises a shell, a first cover plate and a second cover plate, a first opening and a second opening are formed in the two ends, in the first direction, of the shell correspondingly, the first cover plate is connected to the shell and blocks the first opening, the second cover plate is connected to the shell and blocks the second opening, and a closed space is defined by the first cover plate, the second cover plate and the shell jointly. The first anti-explosion valve is arranged on the second cover plate, and the second anti-explosion valve is arranged on the shell. Through dual protection of the first anti-explosion valve and the second anti-explosion valve, when one of the first anti-explosion valve and the second anti-explosion valve fails, the other one can also play a pressure relief role, so that the explosion danger is avoided, and the safety of the battery cell is better. The utility model further provides a power battery which comprises the battery cell.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell and a power battery. Background Technology

[0002] With the increasing maturity of battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles. Currently, the cell structure of power batteries mainly includes traditional square cells with tabs on the same side and blade cells with tabs on opposite sides. The blade cell has its electrode assembly inside the housing, with a cover plate at each end of the housing along its length. Each cover plate has a terminal post, and the positive and negative tabs are led out from both sides of the electrode assembly and connected to the terminal post on one of the cover plates, respectively.

[0003] To ensure the safety of the battery cells, an explosion-proof valve is usually installed on one of the cover plates of the blade battery cell. However, if only one explosion-proof valve is installed on the blade battery cell, there is a possibility that the explosion-proof valve will fail and the blade battery cell will not be able to release pressure in time, which may cause an explosion hazard. Utility Model Content

[0004] The purpose of this utility model is to provide a battery cell and a power battery, wherein the battery cell is provided with two explosion-proof valves with opening pressure gradients, which play a dual protection role and avoid the risk of explosion caused by the failure of a single explosion-proof valve.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On the one hand, this utility model provides a battery cell, comprising:

[0007] The housing has a first opening and a second opening at its two ends along a first direction;

[0008] A first cover plate and a second cover plate, wherein the first cover plate is connected to the housing and seals the first opening, and the second cover plate is connected to the housing and seals the second opening;

[0009] The first explosion-proof valve is installed on the second cover plate;

[0010] The second explosion-proof valve is disposed on one of the side walls of the housing along the second direction;

[0011] Wherein, one of the first explosion-proof valve and the second explosion-proof valve is a main explosion-proof valve, and the other of the first explosion-proof valve and the second explosion-proof valve is an auxiliary explosion-proof valve. The opening pressure of the main explosion-proof valve is not greater than the opening pressure of the auxiliary explosion-proof valve, and the opening pressures of both the main explosion-proof valve and the auxiliary explosion-proof valve are less than the pressure resistance of the housing.

[0012] Optionally, the first explosion-proof valve is the main explosion-proof valve, the second explosion-proof valve is the auxiliary explosion-proof valve, the opening pressure of the first explosion-proof valve is c, the opening pressure of the second explosion-proof valve is b, and the pressure resistance of the housing is a, where c < b < a.

[0013] Where, c = A ± 0.2 MPa, b = c + 0.2 MPa, a ≥ 1.2 MPa;

[0014] The range of values ​​for A is: 0.6MPa≤A≤0.9MPa.

[0015] Optionally, the battery cell further includes an electrode assembly disposed within the housing. The electrode assembly includes a positive tab and a negative tab, which are led out from the same side of the electrode assembly. The positive tab is connected to a positive terminal provided on the first cover plate, and the negative tab is connected to a negative terminal provided on the first cover plate.

[0016] Optionally, the battery cell includes a first plastic component connected to the second cover plate, and the first plastic component is sandwiched between the second cover plate and the electrode assembly.

[0017] Optionally, the thickness of the first plastic part is d along the first direction;

[0018] The value of d is in the range of 0.1mm≤d≤2mm.

[0019] Optionally, the first plastic part is heat-fused and fixed to the end face of the second cover plate near the electrode assembly.

[0020] Optionally, the first plastic part is snap-fitted to the second cover plate.

[0021] Optionally, the first plastic part is provided with a vent hole, and along the first direction, the projection of the first explosion-proof valve on the second cover plate covers the projection of the vent hole on the second cover plate.

[0022] Optionally, the length of the housing is L along the first direction;

[0023] The value range of L is: 250mm≤L≤600mm;

[0024] And / or, along the second direction, the width of the housing is H;

[0025] The value range of H is: 80mm≤H≤150mm;

[0026] And / or, along a third direction, the thickness of the shell is W;

[0027] The value range of W is: 13.5mm≤W≤30mm.

[0028] On the other hand, this utility model provides a power battery, including the battery cell of any of the above-mentioned solutions.

[0029] The beneficial effects of this utility model are as follows:

[0030] This utility model provides a battery cell, including a housing, a first cover plate, and a second cover plate. The housing has a first opening and a second opening at both ends along a first direction. The first cover plate is connected to the housing and seals the first opening, and the second cover plate is connected to the housing and seals the second opening. The first cover plate, the second cover plate, and the housing together form a closed space. A first explosion-proof valve is disposed on the second cover plate, and a second explosion-proof valve is disposed on the housing. Through the dual protection of the first and second explosion-proof valves, if one of the first and second explosion-proof valves fails, the other can still function to relieve pressure, avoiding the risk of explosion and improving the safety of the battery cell.

[0031] This invention also provides a power battery comprising the aforementioned battery cell. This power battery offers high safety, low risk of explosion, and high energy density. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the battery cell structure provided in the embodiments of this utility model;

[0034] Figure 2 This is an exploded view of the battery cell provided in the embodiments of this utility model;

[0035] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0036] Figure 4 for Figure 2 A magnified view of a section at point B in the middle;

[0037] Figure 5 This is a cross-sectional view of the battery cell provided in the embodiment of this utility model;

[0038] Figure 6 for Figure 5 A magnified view of a section at point C;

[0039] Figure 7 for Figure 5 A magnified view of a section at point D;

[0040] Figure 8 This is a schematic diagram of the structure of the first plastic part provided in the embodiment of this utility model.

[0041] In the picture:

[0042] 100. Housing; 110. First opening; 120. Second opening; 130. Second mounting hole; 200. First cover plate; 210. Positive electrode post; 211. Plate body; 212. Post body; 220. Negative electrode post; 230. Second plastic part; 231. Receiving groove; 240. Third plastic part; 250. Connecting block; 300. Second cover plate; 310. First mounting hole; 311. First recessed platform; 400. Electrode assembly; 410. Positive electrode tab; 420. Negative electrode tab; 500. First plastic part; 510. Vent hole; 600. First explosion-proof valve; 700. Second explosion-proof valve. Detailed Implementation

[0043] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0044] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for 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. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Moreover, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0047] like Figures 1-4 As shown, this embodiment provides a battery cell, which includes a housing 100, a first cover plate 200, and a second cover plate 300. The housing 100 is arranged along a first direction ( Figure 1 The housing 100 has a first opening 110 and a second opening 120 at both ends along the X-axis direction (i.e., the length direction of the housing 100). A first cover plate 200 is connected to the housing 100 and seals the first opening 110, and a second cover plate 300 is connected to the housing 100 and seals the second opening 120. The first cover plate 200, the second cover plate 300, and the housing 100 together form a closed space. A first explosion-proof valve 600 is disposed on the second cover plate 300, and a second explosion-proof valve 700 is disposed on the housing 100 along the second direction (i.e., the length direction of the housing 100). Figure 1 On one of the side walls (in the Y-axis direction shown, i.e., the width direction of the housing 100). By setting the first explosion-proof valve 600 and the second explosion-proof valve 700, the safety of the battery cell is improved. If one of the first explosion-proof valve 600 and the second explosion-proof valve 700 fails, the other can still play a pressure relief role to avoid the risk of explosion.

[0048] Furthermore, in this embodiment, one of the first explosion-proof valve 600 and the second explosion-proof valve 700 is a main explosion-proof valve, and the other is an auxiliary explosion-proof valve. The opening pressure of the main explosion-proof valve is less than that of the auxiliary explosion-proof valve, and both the opening pressures of the main and auxiliary explosion-proof valves are less than the pressure resistance of the housing 100. Therefore, when the pressure within the enclosed space formed by the first cover plate 200, the second cover plate 300, and the housing 100 increases, it will first reach the opening pressure of the main explosion-proof valve. If the main explosion-proof valve is functioning correctly, it will open first, releasing the pressure within the enclosed space. If the main explosion-proof valve fails, the pressure within the enclosed space will continue to increase until it reaches the opening pressure of the auxiliary explosion-proof valve. At this point, the auxiliary explosion-proof valve will open, releasing the pressure within the enclosed space and preventing the housing 100 from rupturing. In summary, the safety performance of the battery cell is greatly improved through the dual protection of the first explosion-proof valve 600 and the second explosion-proof valve 700. Of course, in some embodiments, the opening pressure of the main explosion-proof valve can also be equal to the opening pressure of the auxiliary explosion-proof valve.

[0049] As an optional solution, in this embodiment, the first explosion-proof valve 600 is the main explosion-proof valve, and the second explosion-proof valve 700 is the auxiliary explosion-proof valve. That is, the opening pressure of the first explosion-proof valve 600 is less than the opening pressure of the second explosion-proof valve 700. In this case, let the opening pressure of the first explosion-proof valve 600 be denoted as c, the opening pressure of the second explosion-proof valve 700 as b, and the pressure resistance of the housing 100 as a, where c < b < a. By ensuring c < b < a, the first explosion-proof valve 600 will open first before the housing 100 ruptures to relieve pressure and minimize the risk of explosion. If the first explosion-proof valve 600 fails or its venting capacity cannot meet the venting requirements, the second explosion-proof valve 700 will open before the housing 100 ruptures to quickly relieve pressure and minimize the risk of explosion. In this embodiment, the shell 100, the first cover plate 200, and the second cover plate 300 can all be made of aluminum, and the shell 100 can be connected to the first cover plate 200 and the second cover plate 300 by welding. The compressive strength α of the shell 100 satisfies: a≥1.2MPa.

[0050] Furthermore, the opening pressure c of the first explosion-proof valve 600 satisfies: c = A ± 0.2 MPa, and the opening pressure b of the second explosion-proof valve 700 satisfies: b = c + 0.2 MPa. The value range of A is: 0.6 MPa ≤ A ≤ 0.9 MPa. For example, when the battery cell is a ternary lithium battery system, the opening pressure of the first explosion-proof valve 600 is 0.9 MPa ± 0.2 MPa, and the opening pressure of the second explosion-proof valve 700 is 1.1 MPa. When the battery cell is a lithium iron phosphate battery system, the opening pressure of the first explosion-proof valve 600 is 0.6 MPa ± 0.2 MPa, and the opening pressure of the second explosion-proof valve 700 is 0.8 MPa.

[0051] Of course, in other embodiments, the second explosion-proof valve 700 can be used as the main explosion-proof valve, and the first explosion-proof valve 600 can be used as the auxiliary explosion-proof valve. In this case, the opening pressure of the second explosion-proof valve 700 is c, and the opening pressure of the first explosion-proof valve 600 is b. The value of c still satisfies the above: c = A ± 0.2 MPa; the value of b still satisfies the above: b = c + 0.2 MPa.

[0052] See Figure 3 , Figure 5 and Figure 6 In this embodiment, the battery cell also includes an electrode assembly 400, which is disposed within a closed space formed by the first cover plate 200, the second cover plate 300, and the housing 100. The electrode assembly 400 includes a positive electrode tab 410 and a negative electrode tab 420, which are led out from the same side of the electrode assembly 400. The positive electrode tab 410 is connected to the positive terminal 210 disposed on the first cover plate 200, and the negative electrode tab 420 is connected to the negative terminal 220 disposed on the first cover plate 200. Since the positive tab 410 and the negative tab 420 are located on the same side of the electrode group 400, only one side of the housing 100 needs to be reserved for the positive tab 410 and the negative tab 420 to be bent. This saves the space occupied by the positive tab 410 and the negative tab 420 in the housing 100, increases the arrangement space of the electrode group 400, thereby improving the volume utilization rate of the electrode group 400 in the housing 100 and resulting in a higher energy density of the battery cell.

[0053] See Figure 4 , Figure 5 and Figure 7 The battery cell includes a first plastic component 500, which is connected to a second cover plate 300 and sandwiched between the second cover plate 300 and the electrode group 400. The first plastic component 500 insulates the second cover plate 300 from the electrode group 400, preventing short circuits or other electrical risks caused by contact between the electrode group 400 and the second cover plate 300. For example, the first plastic component 500 can be made of PP or ceramic materials, providing good insulation and ensuring electrical safety.

[0054] Further, see Figure 5 and Figure 8 In this embodiment, the first plastic part 500 is generally flat, along the first direction ( Figure 5 , Figure 8 In the X-axis direction (i.e., the length direction of the housing 100), the thickness of the first plastic part 500 is d, and the value of d ranges from 0.1mm to 2mm. For example, the value of d can be 0.1mm, 0.3mm, 0.5mm, 0.8mm, 1.0mm, 2.0mm, or 3.0mm. In order to ensure the mechanical strength of the first plastic part 500 while taking into account its space occupation within the housing 100, the thickness d of the first plastic part 500 in this embodiment is preferably 0.3mm. At this time, it can ensure that the mechanical strength of the first plastic part 500 is relatively high, which can provide a certain support for the second cover plate 300, while occupying less space, which is conducive to improving the space utilization rate of the electrode assembly 400 within the housing 100.

[0055] As an optional solution, in this embodiment, the first plastic part 500 can be connected to the end face of the second cover plate 300 near the electrode assembly 400 by heat fusion. Exemplarily, a heat fusion column can be provided on the end face of the first plastic part 500 facing the second cover plate 300, and a fixing groove can be provided on the side of the second cover plate 300 facing the first plastic part 500. The heat fusion column is inserted into the fixing groove, and through ultrasonic heat fusion, the end of the heat fusion column inserted into the fixing groove is melted and fixed in the fixing groove, thereby achieving a connection and fixation between the first plastic part 500 and the second cover plate 300, and ensuring accurate positioning between them. Of course, multiple heat fusion columns and fixing grooves can also be provided, with multiple heat fusion columns evenly spaced on the first plastic part 500, and correspondingly multiple fixing grooves evenly spaced on the second cover plate 300. The fixing grooves and heat fusion columns correspond one-to-one, with each heat fusion column inserted into a corresponding fixing groove. The force between the first plastic part 500 and the second cover plate 300 is uniform, resulting in high connection strength.

[0056] In other implementations, the first plastic part 500 can also be snap-fitted to the second cover plate 300. For example, a slot can be provided on the end face of the second cover plate 300 facing the electrode assembly 400, and a protrusion can be provided on the end face of the first plastic part 500 facing the second cover plate 300. The protrusion engages within the slot, thereby achieving a fixed connection between the first plastic part 500 and the second cover plate 300, ensuring accurate positioning. Of course, multiple slots and protrusions can be provided, with multiple protrusions evenly spaced on the first plastic part 500 and correspondingly multiple slots evenly spaced on the second cover plate 300. The protrusions and slots correspond one-to-one, with each protrusion engaging within a slot. This ensures uniform force distribution between the first plastic part 500 and the second cover plate 300, resulting in high connection strength. Of course, in some embodiments, the hot melt pillar and the snap protrusion on the first plastic part 500 can also be provided at the same time. Correspondingly, the fixing groove and the snap groove on the second cover plate 300 are also provided at the same time, further improving the connection strength between the first plastic part 500 and the second cover plate 300.

[0057] Furthermore, in this embodiment, the first explosion-proof valve 600 can be separately disposed from the second cover plate 300. The second cover plate 300 is provided with a first mounting hole 310, and a first recessed platform 311 is provided on the side of the first mounting hole 310 facing the electrode assembly 400. The first explosion-proof valve 600 is installed in the first mounting hole 310, and the circumferential edge of the first explosion-proof valve 600 overlaps with the bottom wall of the first recessed platform 311. The circumferential edge of the first explosion-proof valve 600 is welded to the side wall of the first recessed platform 311 to realize the connection and fixation between the first explosion-proof valve 600 and the second cover plate 300. The first plastic part 500 is provided with a vent hole 510. Along the first direction (the length direction of the housing 100), the projection of the first explosion-proof valve 600 on the second cover plate 300 covers the projection of the vent hole 510 on the second cover plate 300. Therefore, when the pressure inside the housing 100 exceeds the opening pressure of the first explosion-proof valve 600, the high-temperature and high-pressure gas can be discharged outside the housing 100 through the vent 510 and the first explosion-proof valve 600 after opening, avoiding the risk of explosion. Furthermore, since the first explosion-proof valve 600, the positive terminal 210, and the negative terminal 220 are respectively located at both ends of the length of the housing 100, thermoelectric separation can be ensured, improving the safety performance of the battery cell.

[0058] Of course, in other embodiments, the first explosion-proof valve 600 can also be integrally formed with the second cover plate 300. In this case, the weak part on the first explosion-proof valve 600 can be directly formed on the second cover plate 300 by mechanical stamping. Alternatively, the weak part on the first explosion-proof valve 600 can be directly processed on the second cover plate 300 by a laser engraving machine. The specific processing method can be achieved using common processes in the art, which will not be described in detail here. It should be noted that the aforementioned weak part is the position that is first broken when the first explosion-proof valve 600 is opened.

[0059] Optionally, in this embodiment, the second explosion-proof valve 700 can be separately installed from the housing 100. A second mounting hole 130 is provided on one side wall of the housing 100 along the second direction. A second recessed platform is provided on the side of the second mounting hole 130 facing the electrode group 400. The second explosion-proof valve 700 is installed in the second mounting hole 130, and the circumferential edge of the second explosion-proof valve 700 overlaps with the bottom wall of the second recessed platform. The circumferential edge of the second explosion-proof valve 700 is welded to the side wall of the second recessed platform, thus achieving a fixed connection between the second explosion-proof valve 700 and the housing 100. When the pressure inside the housing 100 exceeds the opening pressure of the second explosion-proof valve 700, high-temperature and high-pressure gas can be discharged outside the housing 100 through the opened second explosion-proof valve 700, avoiding the risk of explosion. Furthermore, since the second explosion-proof valve 700, the positive electrode post 210, and the negative electrode post 220 are not located on the same side of the housing 100, thermoelectric separation can also be ensured, improving the safety performance of the battery cell.

[0060] Of course, in other embodiments, the second explosion-proof valve 700 can also be integrally formed with the housing 100. In this case, the weak point on the second explosion-proof valve 700 can be directly formed on the housing 100 by mechanical stamping. Alternatively, the weak point on the second explosion-proof valve 700 can be directly machined on the housing 100 by a laser engraving machine. The specific processing method can be achieved using common processes in the art, which will not be detailed here. It should be noted that the aforementioned weak point is the location that is first broken when the second explosion-proof valve 700 is opened.

[0061] See also Figure 3 and Figure 6 In this embodiment, the battery cell also includes two second plastic parts 230, two connecting blocks 250, and one third plastic part 240. The second plastic parts 230 and the third plastic parts 240 are made of the same material as the first plastic part 500, and the connecting blocks 250 are made of the same material as the housing 100. The two second plastic parts 230 are disposed on the side of the first cover plate 200 away from the electrode group 400, and the two second plastic parts 230 are along a second direction (…). Figure 3 , Figure 5The Y-axis direction (i.e., the width direction of the housing 100) is shown in the diagram, with the connecting blocks 250 arranged at intervals. Each connecting block 250 is disposed on the side of a second plastic part 230 facing away from the first cover plate 200, and a third plastic part 240 is disposed on the side of the first cover plate 200 near the pole group 400. The positive electrode post 210 includes a plate portion 211 and a column portion 212. The column portion 212 passes through a third plastic component 240, a first cover plate 200, one of the second plastic components 230, and one of the connecting blocks 250. The column portion 212 is then riveted to the connecting block 250. At this point, the column portion 212 expands outwards to form a protrusion, which abuts against the connecting block 250 to press the connecting block 250 and the second plastic component 230 against the side of the first cover plate 200 away from the electrode assembly 400. The plate portion 211 of the positive electrode post 210 presses the third plastic component 240 against the side of the first cover plate 200 near the electrode assembly 400. The second plastic component 230 insulates the connecting block 250 from the first cover plate 200, and the third plastic component 240 insulates the positive electrode post 210 from the first cover plate 200. The structure of the negative terminal 220 is the same as that of the positive terminal 210, and the mounting structure of the negative terminal 220 on the first cover plate 200 is the same as that of the positive terminal 210 on the first cover plate 200, which will not be described in detail here.

[0062] More preferably, a receiving groove 231 is provided on the side of the second plastic part 230 away from the first cover plate 200, and part of the connecting block 250 is embedded in the receiving groove 231, thereby reducing the space occupied by the cell in the first direction. When they are assembled into a power battery, it is beneficial to improve the energy density of the power battery.

[0063] See also Figure 1 Along the first direction ( Figure 1 The X-axis direction shown is the length direction of the housing 100. The length of the housing 100 is L, and the value of L ranges from 250mm to 600mm. For example, the value of L can be 250mm, 300mm, 350mm, 400mm, 500mm, or 600mm, etc. Along the second direction ( Figure 1 The Y-axis direction shown is the width direction of the housing 100. The width of the housing 100 is H, and the value of H ranges from 80mm to 150mm. For example, the value of H can be 80mm, 100mm, 120mm, or 150mm, etc. Along the third direction ( Figure 1 The Y-axis direction shown is the thickness direction of the housing 100. The thickness of the housing 100 is W, and the value of W ranges from 13.5mm to 30mm. For example, the value of W can be 13.5mm, 15.0mm, 20.0mm, 25.0mm, or 30.0mm, etc.

[0064] Furthermore, the length of the electrode assembly 400 along the first direction is L1, and the relationship between L1 and L satisfies: 10mm ≤ L - L1 ≤ 15mm. That is, the difference between the length L of the housing 100 along the first direction and the dimension L1 of the electrode assembly 400 along the first direction is within the range of 10mm-15mm. L - L1 is the dimension of the space occupied by the electrode tabs of the electrode assembly 400 along the length direction of the housing 100. This results in high space utilization of the electrode assembly 400 within the housing 100 and high energy density of the battery cell. For example, the value of L - L1 can be 10.0mm, 11.5mm, 12.0mm, 13.0mm, or 15.0mm, etc. The width of the electrode assembly 400 along the second direction is H1, and the relationship between H1 and H satisfies: 1mm ≤ H - H1 ≤ 3mm. By controlling H-H1 within the aforementioned range, interference between the electrode assembly 400 and the sidewalls of the housing 100 in the width direction can be avoided, and a small space is left between the electrode assembly 400 and the sidewalls of the housing 100 in the width direction for easy assembly. For example, the value of H-H1 can be 1.0mm, 1.2mm, 1.5mm, 2.0mm, or 3.0mm, etc. The thickness of the electrode assembly 400 along a third direction is W1, and the relationship between W1 and W satisfies: 0.5mm ≤ W - W1 ≤ 2mm. By controlling W-W1 within the aforementioned range, interference between the electrode assembly 400 and the sidewalls of the housing 100 in the thickness direction can be avoided, and a small space is left between the electrode assembly 400 and the sidewalls of the housing 100 in the thickness direction for easy assembly. For example, the value of W-W1 can be 0.5mm, 0.9mm, 1.2mm, 1.5mm, or 2.0mm, etc.

[0065] The values ​​of L-L1, H-H1, and W-W1 should not exceed the upper limit of their respective size constraints; otherwise, the arrangement space within the housing 100 will be wasted, reducing the space utilization of the electrode group 400 within the housing 100 and hindering the improvement of the cell's energy density. Conversely, the values ​​of L-L1, H-H1, and W-W1 should not exceed the lower limit of their respective size constraints; otherwise, insufficient arrangement space for the electrode group 400 will easily lead to interference with the housing 100, affecting assembly.

[0066] Table 1 below provides specific implementation examples comparing the positive electrode tab 410 and negative electrode tab 420 of the electrode group 400 within several sets of housings 100 of the same size when they are led out on the same side (in this embodiment) and led out on opposite sides (in the conventional technical solution).

[0067] Table 1

[0068]

[0069] Taking Comparative Example 1 and Embodiment 1 as examples, under the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 With the increase in the size of the X-axis direction shown, the space utilization rate of the pole group 400 within the housing 100 is increased by 1.838%, and the energy density of the cell is improved.

[0070] In Comparative Example 2 and Example 2, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 With the increase in the size of the X-axis direction shown, the space utilization rate of the pole group 400 within the housing 100 is increased by 1.891%, and the energy density of the cell is improved.

[0071] In Comparative Example 3 and Example 3, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 With the increase in the size of the X-axis direction shown, the space utilization rate of the pole group 400 within the housing 100 is increased by 1.925%, and the energy density of the cell is improved.

[0072] In Comparative Example 4 and Embodiment 4, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 With the increase in the size of the X-axis direction shown, the space utilization rate of the pole group 400 within the housing 100 is increased by 1.149%, and the energy density of the cell is improved.

[0073] In Comparative Example 5 and Embodiment 5, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 With the increase in the size of the X-axis direction shown, the space utilization rate of the pole group 400 within the housing 100 is increased by 1.182%, and the energy density of the cell is improved.

[0074] In Comparative Example 6 and Example 6, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 As the size of the electrode group 400 (in the X-axis direction shown in the figure) increases, the space utilization rate of the electrode group 400 within the housing 100 increases by 1.203%, and the energy density of the cell is improved.

[0075] In Comparative Example 7 and Example 7, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 As the size of the electrode group 400 (in the X-axis direction shown in the diagram) increases, the space utilization rate of the electrode group 400 within the housing 100 increases by 0.766%, and the energy density of the battery cell is improved.

[0076] In Comparative Example 8 and Embodiment 8, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 As the size of the electrode group 400 (in the X-axis direction shown in the diagram) increases, the space utilization rate of the electrode group 400 within the housing 100 increases by 0.788%, and the energy density of the battery cell is improved.

[0077] In Comparative Example 9 and Embodiment 9, with the same housing 100 size, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, when the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from the same side of the electrode assembly 400, space is saved within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 With the increase in the size of the X-axis direction shown, the space utilization rate of the pole group 400 within the housing 100 increased by 0.802%, and the energy density of the cell was improved.

[0078] The results above show that, under the same housing 100 dimensions, compared to the technical solution where the positive electrode tab 410 and negative electrode tab 420 of the electrode assembly 400 are led out from opposite sides of the electrode assembly 400, leading out from the same side of the electrode assembly 400 saves space within the housing 100 on the side opposite to the positive electrode tab 410 and negative electrode tab 420. The electrode assembly 400 along the first direction ( Figure 1 The increased size of the X-axis direction (as shown in the diagram) improves the space utilization of the electrode group 400 within the housing 100, which is beneficial for increasing the energy density of the battery cell.

[0079] This embodiment also provides a power battery, which includes the aforementioned battery cells. This power battery has high safety, low explosion risk, and high energy density.

[0080] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A battery cell, characterized in that, include: The housing has a first opening and a second opening at its two ends along a first direction; A first cover plate and a second cover plate, wherein the first cover plate is connected to the housing and seals the first opening, and the second cover plate is connected to the housing and seals the second opening; The first explosion-proof valve is installed on the second cover plate; The second explosion-proof valve is disposed on one of the side walls of the housing along the second direction; Wherein, one of the first explosion-proof valve and the second explosion-proof valve is a main explosion-proof valve, and the other of the first explosion-proof valve and the second explosion-proof valve is an auxiliary explosion-proof valve. The opening pressure of the main explosion-proof valve is not greater than the opening pressure of the auxiliary explosion-proof valve, and the opening pressures of both the main explosion-proof valve and the auxiliary explosion-proof valve are less than the pressure resistance of the housing.

2. The battery cell according to claim 1, characterized in that, The first explosion-proof valve is the main explosion-proof valve, the second explosion-proof valve is the auxiliary explosion-proof valve, the opening pressure of the first explosion-proof valve is c, the opening pressure of the second explosion-proof valve is b, and the pressure resistance of the housing (100) is a, where c < b < a. Where, c = A ± 0.2 MPa, b = c + 0.2 MPa, a ≥ 1.2 MPa; The range of values ​​for A is: 0.6MPa≤A≤0.9MPa.

3. The battery cell according to claim 1, characterized in that, The battery cell also includes an electrode assembly disposed within the housing. The electrode assembly includes a positive tab and a negative tab, which are led out from the same side of the electrode assembly. The positive tab is connected to a positive terminal provided on the first cover plate, and the negative tab is connected to a negative terminal provided on the first cover plate.

4. The battery cell according to claim 3, characterized in that, The battery cell includes a first plastic component, which is connected to the second cover plate and is sandwiched between the second cover plate and the electrode assembly.

5. The battery cell according to claim 4, characterized in that, Along the first direction, the thickness of the first plastic part is d, and the value of d ranges from 0.1mm to 2mm.

6. The battery cell according to claim 4, characterized in that, The first plastic part is heat-fused and fixed to the end face of the second cover plate near the electrode assembly.

7. The battery cell according to claim 4, characterized in that, The first plastic part is snapped onto the second cover plate.

8. The battery cell according to claim 4, characterized in that, The first plastic part is provided with a vent hole, and along the first direction, the projection of the first explosion-proof valve on the second cover plate covers the projection of the vent hole on the second cover plate.

9. The battery cell according to claim 1, characterized in that, Along the first direction, the length of the shell is L, and the value of L is in the range of 250mm≤L≤600mm; And / or, along the second direction, the width of the housing is H, and the value of H is in the range of 80mm≤H≤150mm; And / or, along a third direction, the thickness of the shell is W; The value range of W is: 13.5mm≤W≤30mm.

10. A power battery, characterized in that, The battery cell includes any one of claims 1-9.

Images