Battery cell shell and battery cell

Abstract

The invention relates to the technical field of power batteries, and particularly discloses a battery cell shell and a battery cell, the battery cell shell comprises a peripheral side plate and a bottom plate, and the bottom plate and the peripheral side plate jointly define an accommodating cavity for mounting a pole group. A groove is formed in the end face of the side, facing the containing cavity, of the bottom plate and surrounds the periphery of the bottom plate. The groove provides an avoiding space for the sharp corner of one end, which is arranged in the accommodating cavity, of the pole group, so that the sharp corner of one end, which is arranged in the accommodating cavity, of the pole group does not need to be cut off, the coating area of positive and negative electrode materials on the pole group is increased, the capacity of the battery cell is improved, and the battery cell shell is relatively high in compression strength and good in safety. The invention also provides a battery cell which comprises the battery cell shell.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and particularly to a cell housing and a cell. Background Art

[0002] The cell housing is an important part of a lithium-ion power battery. The cell housing and the cover plate are assembled and welded to jointly enclose a closed space for placing the electrode assembly. Since the spatial distribution of the battery pack in the whole vehicle is limited, the external dimensions of the cell are restricted. The wall thickness of the cell housing itself and the internal dimension design of the cell housing will directly affect the capacity of the cell. If the wall thickness of the cell housing is relatively thick, its pressure resistance is improved, but the capacity of the cell will become smaller, and the overall weight of the cell will also increase. If the wall thickness of the cell housing is relatively thin, although the capacity of the cell is improved, the pressure resistance of the cell housing will be reduced, and the safety performance is not good.

[0003] In addition, currently, the side wall and the bottom plate of the cell housing are usually naturally transitioned by an inner fillet, and the four sharp corners at the bottom of the electrode assembly will interfere with the inner fillet inside the cell housing. To avoid the above problems, generally, the four sharp corners at the bottom of the electrode assembly are chamfered to avoid the inner fillet inside the cell housing. However, chamfering the electrode assembly will result in a reduction in the coating area of the positive and negative materials on the electrode assembly, which will inevitably sacrifice the capacity of the cell. Summary of the Invention

[0004] The purpose of the present invention is to provide a cell housing and a cell, which improve the structural design of the cell housing, do not require chamfering the electrode assembly, improve the capacity of the cell, and have high pressure resistance and good safety performance.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a cell housing, which includes:

[0007] A peripheral side plate, the peripheral side plate enclosing a cylindrical structure;

[0008] A bottom plate, the bottom plate being connected to and sealing one end of the peripheral side plate, the bottom plate and the peripheral side plate enclosing a receiving cavity, a groove being provided on the end surface of the bottom plate facing the receiving cavity, the groove being arranged around the periphery of the bottom plate, the groove including a wall surface, the wall surface being located on the side close to the receiving cavity, and the end of the wall surface far from the bottom plate being transitionally connected to the end surface of the peripheral side plate facing the receiving cavity;

[0009] Wherein, along the length direction of the cell housing, the width of the open end of the groove is a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm;

[0010] Along the height direction of the battery cell housing, the depth of the groove is b, the thickness of the bottom plate is H3, and b and H3 satisfy: 0.1≤b / H3≤0.45;

[0011] The value range of H3 is: 0.7mm≤H3≤1.6mm.

[0012] Optionally, the peripheral side plate includes two first side plates and two second side plates, the two first side plates are arranged at both ends of the battery cell housing in the length direction, and the two second side plates are arranged at both ends of the battery cell housing in the width direction, and one end of the wall surface away from the bottom plate is transitionally connected to the end surfaces of the first side plate and the second side plate facing the accommodating cavity;

[0013] Wherein, along the length direction of the battery cell shell, the thickness of the first side plate is H1, b, H1 and H3 satisfy: (H3-b)≥H1, and the value range of H1 is: 0.4mm≤H1≤1.0mm;

[0014] And / or, along the width direction of the battery cell shell, the thickness of the second side plate is H2, b, H2 and H3 satisfy: (H3-b)≥H2, and the value range of H2 is: 0.3mm≤H2≤0.8mm.

[0015] Optionally, the end surface of the bottom plate facing away from the accommodating cavity is transitionally connected with the end surface of the first side plate facing away from the accommodating cavity through a first outer arc surface, and the distance between the end of the wall surface away from the bottom plate and the first outer arc surface is t1, t1≥H1.

[0016] Optionally, the end surface of the bottom plate facing away from the accommodating cavity is transitionally connected with the end surface of the second side plate facing away from the accommodating cavity through a second outer arc surface, and the distance between the end of the wall surface away from the bottom plate and the second outer arc surface is t2, t2≥H2.

[0017] Optionally, the cross section of the groove is a part of a circle, the radius of the circle where the wall surface of the groove is located is R, and the value range of R is: 2.0mm≤R≤20mm.

[0018] Optionally, the cross section of the groove is square or trapezoidal, the wall surface of the groove includes a first wall surface, a second wall surface and a bottom surface, and the bottom surface is transitionally connected to the first wall surface through a first transition surface;

[0019] And / or, the first wall surface and the end surface of the bottom plate facing the accommodating cavity are transitionally connected via a second transition surface;

[0020] And / or, the second wall surface and the end surface of the peripheral side plate facing the accommodating cavity are transitionally connected via a third transition surface;

[0021] And / or, the bottom surface and the second wall surface are transitionally connected via a fourth transition surface.

[0022] Optionally, the first transition surface is a curved surface, the radius of the first transition surface is r1, and the value range of r1 is: 1.0 mm ≤ r1 ≤ 5.0 mm;

[0023] And / or, the second transition surface is a cambered surface, the radius of the second transition surface is r2, and the value range of r2 is: 1.0 mm ≤ r2 ≤ 5.0 mm;

[0024] And / or, the third transition surface is a cambered surface, the radius of the second transition surface is r3, and the value range of r3 is: 3.0 mm ≤ r3 ≤ 10.0 mm;

[0025] And / or, the fourth transition surface is a curved surface, the radius of the fourth transition surface is r4, and the value range of r4 is: 1.0mm≤r4≤5.0mm.

[0026] Optionally, the compressive strength of the battery cell shell is greater than 1.2 MPa.

[0027] Optionally, a limiting step is provided on the end surface of the peripheral side plate facing the accommodating cavity, and the limiting step is located at an end of the peripheral side plate away from the bottom plate.

[0028] On the other hand, the present invention provides a battery cell, comprising a cover plate, a pole group, and a battery cell shell in any of the above schemes, wherein the pole group is arranged in a receiving cavity surrounded by a peripheral side plate and a bottom plate of the battery cell shell, and the cover plate is connected to one end of the peripheral side plate away from the bottom plate.

[0029] The beneficial effects of the present invention are:

[0030] The present invention provides a battery cell shell, comprising a peripheral side plate and a bottom plate, wherein the bottom plate and the peripheral side plate together enclose a receiving cavity for installing a pole group. A groove is provided on the end surface of the bottom plate facing the receiving cavity, and the groove is arranged around the four sides of the bottom plate. Through the arrangement of the groove, an escape space is provided for the sharp corner of one end of the pole group to be inserted into the receiving cavity, and there is no need to cut off the sharp corner of one end of the pole group to be inserted into the receiving cavity, so that the coating area of the positive and negative electrode materials on the pole group is increased, which is beneficial to improving the capacity of the battery cell, and the battery cell shell has a high pressure resistance and good safety.

[0031] The present invention also provides a battery cell, comprising a cover plate, an electrode group, and the above-mentioned battery cell shell, wherein the electrode group is arranged in a receiving cavity surrounded by a peripheral side plate and a bottom plate, and the cover plate is connected to an end of the peripheral side plate away from the bottom plate. By adopting the above-mentioned battery cell shell, the battery cell has a larger capacity, a higher pressure resistance, and good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings.

[0033] Figure 1 It is a cross-section of the battery cell housing provided in the first embodiment of the present invention Figure 1 ;

[0034] Figure 2 is Figure 1 a partial enlarged view of the position A in

[0035] Figure 3 is Figure 1 a partial enlarged view of the position B in

[0036] Figure 4 It is a cross-section of the battery cell housing provided in the first embodiment of the present invention Figure 2 ;

[0037] Figure 5 is Figure 4 a partial enlarged view of the position C in

[0038] Figure 6 It is a schematic diagram of the partial structure of the battery cell housing provided in the second embodiment of the present invention.

[0039] In the figure:

[0040] 100, peripheral side plate; 101, opening; 110, first side plate; 111, limiting step; 120, second side plate;

[0041] 200, bottom plate; 210, groove; 211, wall surface; 2111, first wall surface; 2112, second wall surface; 2113, bottom surface; 212, first outer arc surface; 213, second outer arc surface; 214, first transition surface; 215, second transition surface; 216, third transition surface; 217, fourth transition surface. Specific embodiments

[0042] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0044] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0046] Embodiment 1

[0047] As Figures 1 - 5 shown, this embodiment provides a battery cell housing, which includes a peripheral side plate 100 and a bottom plate 200. The peripheral side plate 100 encloses a cylindrical structure, and the bottom plate 200 is connected to and seals one end of the peripheral side plate 100. The bottom plate 200 and the peripheral side plate 100 jointly enclose a receiving cavity. An opening 101 is formed at one end of the peripheral side plate 100 away from the bottom plate 200, and the electrode group of the battery cell can be inserted into the receiving cavity through the opening 101. A groove 210 is provided on the end face of the bottom plate 200 facing the receiving cavity. The groove 210 is arranged around the periphery of the bottom plate 200. The groove 210 includes a wall surface 211, and the wall surface 211 is located on the side close to the receiving cavity. One end of the wall surface 211 away from the bottom plate 200 is transitionally connected to the end face of the peripheral side plate 100 facing the receiving cavity.

[0048] By providing the groove 210, a clearance space is provided for the sharp corner at one end of the pole group inserted into the accommodating cavity. Without cutting off the sharp corner at one end of the pole group inserted into the accommodating cavity, it is also possible to ensure that the sharp corner of the pole group does not interfere with the battery cell housing, avoiding the sharp corner of the pole group from piercing the battery cell housing, and the reliability of the battery cell housing is good. In addition, since there is no need to cut off the sharp corner at one end of the pole group inserted into the accommodating cavity, the coating area of the positive and negative electrode materials on the pole group is increased, which is beneficial to improving the capacity of the battery cell.

[0049] Continue to refer to Figure 1 and Figure 2 , along the length direction of the battery cell housing, the width of the open end of the groove 210 is a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm. Exemplarily, the value of a can be 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm or 5.0 mm. Among them, the length direction of the battery cell housing is Figure 1 the X-axis direction shown in

[0050] Continue to refer to Figure 4 and Figure 5 , along the width direction of the battery cell housing, the width of the open end of the groove 210 is also a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm. Among them, the width direction of the battery cell housing is Figure 4 the Y-axis direction shown in

[0051] It should be noted that the value of a should not be too large, otherwise the distribution area of the groove 210 on the bottom plate 200 is relatively large, resulting in a reduction in the contact area between the bottom plate 200 and the pole group, and the supporting effect of the bottom plate 200 on the pole group is poor, which is not conducive to ensuring the stability of the pole group fixed in the battery cell housing. When the vehicle encounters bumpy road conditions, the pole group may vibrate or collide with the battery cell housing in the battery cell housing. Of course, the value of a should not be too small, otherwise the clearance space formed at the groove 210 is relatively small, and the situation where the sharp corner of the pole group interferes with the battery cell housing will still occur, and it is necessary to chamfer the pole group, which is not conducive to improving the capacity of the battery cell.

[0052] Furthermore, along the height direction of the battery cell housing ( Figure 1 , Figure 4In the Z-axis direction shown in the figure, the depth of the groove 210 is b, and the thickness of the bottom plate 200 is H3. The relationship between b and H3 satisfies: 0.1 ≤ b / H3 ≤ 0.45. Among them, the value range of H3 is: 0.7 mm ≤ H3 ≤ 1.6 mm. Exemplarily, the value of H3 can be 0.7 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, etc. Correspondingly, the value of b / H3 can be 0.1, 0.2, 0.3, 0.4, 0.45, etc. For example, in some embodiments, the value of H3 is 1.0 mm, and the value of b can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.45 mm. Of course, H3 can also be other values within the above range, as long as the size limitation of 0.1 ≤ b / H3 ≤ 0.45 is satisfied between b and H3.

[0053] It should be noted that the position where the groove 210 is provided on the bottom plate 200 is the position where the bottom plate 200 is transitionally connected to the peripheral side plate 100. This position is most likely to be bumped, and the stress received is also relatively concentrated. Therefore, by restricting the depth b of the groove 210 to meet the above value range, it is to ensure that the bottom plate 200 can still maintain a high mechanical strength after the groove 210 is opened, and can meet the pressure resistance requirements of the battery cell housing. Otherwise, when the depth of the groove 210 is too large (i.e., b / H3 is too large), it may cause the battery cell housing to be easily cracked and deformed at the position where the groove 210 is provided, reducing the reliability of the battery cell housing and having poor safety. Of course, the depth of the groove 210 should not be too small (i.e., b / H3 is too small), otherwise the avoidance space formed by the groove 210 is insufficient, and the sharp corners of the electrode group are likely to interfere with the battery cell housing, and the electrode group needs to be chamfered, which is not conducive to improving the capacity of the battery cell.

[0054] Continue to refer to Figures 1 - 5 , the battery cell housing in this embodiment is square. The peripheral side plate 100 includes two first side plates 110 and two second side plates 120. The two first side plates 110 are arranged at both ends in the length direction of the battery cell housing, and the two second side plates 120 are arranged at both ends in the width direction of the battery cell housing. The groove 210 surrounds the periphery of the bottom plate 200 in a ring shape. Along the length direction of the battery cell housing ( Figure 1 in the X-axis direction shown in the figure), the end of the wall surface 211 of the groove 210 away from the bottom plate 200 is transitionally connected to the end surface of the first side plate 110 facing the accommodating cavity; along the width direction of the battery cell housing ( Figure 1 in the Y-axis direction shown in the figure), the end of the wall surface 211 of the groove 210 away from the bottom plate 200 is transitionally connected to the end surface of the second side plate 120 facing the accommodating cavity.

[0055] Along the length direction of the battery cell housing, the thickness of the first side plate 110 is H1, and the following relationship is satisfied among b, H1, and H3: (H3 - b) ≥ H1. The value range of H1 is: 0.4 mm ≤ H1 ≤ 1.0 mm. Wherein, the value of H3 - b is the remaining thickness at the position where the groove 210 is provided on the bottom plate 200. By ensuring (H3 - b) ≥ H1, the mechanical strength at the position where the bottom plate 200 and the first side plate 110 are transitionally connected is relatively high, and the pressure resistance of the battery cell housing meets the requirements. Exemplarily, the value of H1 can be 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, or 1.0 mm. For example, in some embodiments, when the value of H1 is 0.5 mm and the value of H3 is 1.0 mm, the value of b can be 0.15 mm, 0.2 mm, 0.3 mm, or 0.45 mm, etc. Of course, the values of H1, H3, and b can also take other values that meet the above size limitations, which are not listed one by one here.

[0056] Further, along the width direction of the battery cell housing, the thickness of the second side plate 120 is H2, and the following relationship is satisfied among b, H2, and H3: (H3 - b) ≥ H2. The value range of H2 is: 0.3 mm ≤ H2 ≤ 0.8 mm. The value of H3 - b is the remaining thickness at the position where the groove 210 is provided on the bottom plate 200. By ensuring (H3 - b) ≥ H2, the mechanical strength at the position where the bottom plate 200 and the second side plate 120 are transitionally connected is relatively high, and the pressure resistance of the battery cell housing meets the requirements. Exemplarily, the value of H2 can be 0.3 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm. For example, in some embodiments, when the value of H2 is 0.3 mm and the value of H3 is 1.0 mm, the value of b can be 0.15 mm, 0.2 mm, 0.3 mm, or 0.45 mm, etc. Of course, the values of H2, H3, and b can also take other values that meet the above size limitations, which are not listed one by one here.

[0057] Continue to refer to Figure 2 In this embodiment, the end face of the bottom plate 200 facing away from the accommodating cavity and the end face of the first side plate 110 facing away from the accommodating cavity are transitionally connected through a first outer arc surface 212. The distance between the end of the wall surface 211 of the groove 210 far from the bottom plate 200 and the first outer arc surface 212 is t1, that is, the wall thickness at the position where the bottom plate 200 and the first side plate 110 are transitionally connected is t1, and t1 ≥ H1. By ensuring that the value of t1 is greater than the value of H1, the mechanical strength at the connection between the bottom plate 200 and the first side plate 110 is relatively high. When the pressure inside the battery cell housing increases, the connection between the bottom plate 200 and the first side plate 110 will not crack, and the reliability of the battery cell housing is high.

[0058] Continue to refer to Figure 5, in this embodiment, the end surface of the bottom plate 200 facing away from the accommodation cavity and the end surface of the second side plate 120 facing away from the accommodation cavity are connected by a second outer arc surface 213. The distance between the end of the wall surface 211 of the groove 210 away from the bottom plate 200 and the second outer arc surface 213 is t2, that is, the wall thickness at the position where the bottom plate 200 and the second side plate 120 are connected by transition is t2, and t2≥H2. By ensuring that the value of t2 is greater than the value of H2, the mechanical strength at the connection between the bottom plate 200 and the second side plate 120 is relatively high. When the pressure inside the battery cell housing increases, the connection between the bottom plate 200 and the second side plate 120 will not break, and the reliability of the battery cell housing is high.

[0059] It should be noted that in this embodiment, the cross-section of the groove 210 is a part of a circle. The connections between the bottom plate 200 and the first side plate 110, and between the bottom plate 200 and the second side plate 120 are all transitioned by arcs. This kind of setting helps to reduce the stress at the connection between the bottom plate 200 and the peripheral side plate 100, and is also convenient for processing and forming. Optionally, the radius of the circle where the wall surface 211 of the groove 210 is located is R, and the value range of R is: 2.0mm≤R≤20mm. Exemplarily, the value of R can be 2.0mm, 3.0mm, 5.0mm, 10.0mm, 15.0mm or 20.0mm.

[0060] Continue to refer to Figure 1 and Figure 3 , a limiting step 111 is provided on the end surface of the peripheral side plate 100 facing the accommodation cavity, and the limiting step 111 is located at the end of the peripheral side plate 100 away from the bottom plate 200. The cover plate can be supported by the limiting step 111, so that the cover plate and the battery cell housing can be temporarily positioned, which is convenient for subsequent welding of the cover plate and the battery cell housing. Optionally, in this embodiment, the limiting step 111 is provided on the first side plate 110. In order to ensure that there is enough space for setting on the first side plate 110, and also to ensure that the mechanical strength of the first side plate 110 after processing the limiting step 111 meets the requirements, it is necessary to ensure that the thickness of the first side plate 110 is greater than the thickness of the second side plate 120, that is, H1>H2. The advantage of this kind of setting scheme is that the area of the first side plate 110 is relatively small, which is beneficial to reducing the weight of the battery cell housing.

[0061] This embodiment also provides a battery cell, including a cover plate, a pole group, and the above-mentioned battery cell housing. The pole group is arranged in the accommodation cavity surrounded by the peripheral side plate 100 and the bottom plate 200, and the cover plate is connected to the end of the peripheral side plate 100 away from the bottom plate 200, that is, the cover plate is connected to the end of the peripheral side plate 100 provided with the opening 101. By adopting the above-mentioned battery cell housing, it is ensured that the battery cell has a relatively large capacity, a relatively high pressure resistance, and good safety.

[0062] Embodiment Two

[0063] This embodiment provides a battery cell housing, which is different from the battery cell housing in the first embodiment in that: the structure of the groove 210 on the bottom plate 200 of the battery cell housing in this embodiment is slightly different.

[0064] See Figure 6 , in this embodiment, the cross-section of the groove 210 is trapezoidal. The wall surface 211 of the groove 210 includes a first wall surface 2111, a second wall surface 2112, and a bottom surface 2113. The first wall surface 2111 and the second wall surface 2112 are inclined with respect to the bottom surface 2113.

[0065] Optionally, the angle between the first wall surface 2111 and the bottom surface 2113 is 120° - 160°. The angle between the second wall surface 2112 and the bottom surface 2113 is equal to the angle between the first wall surface 2111 and the bottom surface 2113, and is also 120° - 160°. The groove 210 is formed by enclosing the first wall surface 2111, the bottom surface 2113, and the second wall surface 2112. The opposite side of the bottom surface 2113 forms the open end of the groove 210. Along the length direction of the battery cell housing, the width of the open end of the groove 210 is a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm. Along the width direction of the battery cell housing, the width of the open end of the groove 210 is also a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm.

[0066] The bottom surface 2113 and the first wall surface 2111 are transitionally connected through a first transition surface 214. Through the setting of the first transition surface 214, the bottom surface 2113 and the first wall surface 2111 are smoothly transitioned. The first wall surface 2111 and the end surface of the bottom plate 200 facing the accommodating cavity are transitionally connected through a second transition surface 215. Through the setting of the second transition surface 215, the first wall surface 2111 and the end surface of the bottom plate 200 facing the accommodating cavity are smoothly transitioned. The second wall surface 2112 and the end surface of the peripheral side plate 100 facing the accommodating cavity are transitionally connected through a third transition surface 216. Through the setting of the third transition surface 216, the second wall surface 2112 and the end surface of the peripheral side plate 100 facing the accommodating cavity are smoothly transitioned. The bottom surface 2113 and the second wall surface 2112 are transitionally connected through a fourth transition surface 217. Through the setting of the fourth transition surface 217, the bottom surface 2113 and the second wall surface 2112 are smoothly transitioned. Thus, through the setting of the above transition surfaces, the stress at the connection between the bottom plate 200 and the peripheral side plate 100 is reduced, and the groove 210 is easy to process and form.

[0067] Optionally, both the first transition surface 214 and the fourth transition surface 217 in this embodiment are arc surfaces. The radius of the first transition surface 214 is r1, and the value range of r1 is: 1.0 mm ≤ r1 ≤ 5.0 mm. Exemplarily, the value of r1 can be 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm, or 5.0 mm. The radius of the fourth transition surface 217 is r4, and the value range of r4 is: 1.0 mm ≤ r4 ≤ 5.0 mm. Exemplarily, the value of r4 can be 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm, or 5.0 mm. Both the first transition surface 214 and the fourth transition surface 217 use arc surfaces for transition, making the wall surface 211 of the groove 210 relatively smooth as a whole, easy to process and manufacture, and avoiding stress concentration as much as possible, and the local strength of the battery cell housing is relatively high. More preferably, in some embodiments, the radius r1 of the first transition surface 214 is equal to the radius r4 of the fourth transition surface 217, making the shape of the groove 210 more regular and easier to process.

[0068] Furthermore, the second transition surface 215 is an arc surface, and the radius of the second transition surface 215 is r2. The value range of r2 is: 1.0 mm ≤ r2 ≤ 5.0 mm. Exemplarily, the value of r2 can be 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm, or 5.0 mm. The second transition surface 215 uses an arc surface for transition, making the transition between the first wall surface 2111 of the groove 210 and the end surface of the bottom plate 200 facing the accommodating cavity relatively smooth. On the one hand, it is easy to process and manufacture, avoids stress concentration, and can improve the local strength of the battery cell housing; on the other hand, it avoids the existence of sharp corners when the first wall surface 2111 and the end surface of the bottom plate 200 facing the accommodating cavity turn sharply here, which is likely to pierce the insulating layer (such as the separator) in the electrode group, resulting in poor insulation inside the electrode group.

[0069] The third transition surface 216 is also an arc surface, and the radius of the third transition surface 216 is r3. The value range of r3 is: 3.0 mm ≤ r3 ≤ 10.0 mm. Exemplarily, the value of r3 can be 3.0 mm, 5.0 mm, 7.0 mm, 9.0 mm, or 10.0 mm. The third transition surface 216 uses an arc surface for transition, making the transition between the second wall surface 2112 of the groove 210 and the end surface of the peripheral side plate 100 (including the first side plate 110 and the second side plate 120) facing the accommodating cavity relatively smooth. On the one hand, it is easy to process and manufacture, avoids stress concentration, and can improve the local strength of the battery cell housing; on the other hand, it avoids the existence of sharp corners when the second wall surface 2112 and the end surface of the peripheral side plate 100 facing the accommodating cavity turn sharply here, which is likely to pierce the insulating layer (such as the separator) in the electrode group, resulting in poor insulation inside the electrode group.

[0070] Of course, in other embodiments, the cross-section of the groove 210 can also be square. At this time, the wall surface 211 of the groove 210 still includes a first wall surface 2111, a second wall surface 2112, and a bottom surface 2113. Only the first wall surface 2111 and the second wall surface 2112 are perpendicular to the bottom surface 2113. The included angle between the first wall surface 2111 and the bottom surface 2113 is 90°, and the included angle between the second wall surface 2112 and the bottom surface 2113 is also 90°. The groove 210 is formed by enclosing the first wall surface 2111, the bottom surface 2113, and the second wall surface 2112. The opposite side of the bottom surface 2113 forms the open end of the groove 210. Along the length direction of the battery cell housing, the width of the open end of the groove 210 is a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm. Along the width direction of the battery cell housing, the width of the open end of the groove 210 is also a, and the value range of a is 1.0 mm ≤ a ≤ 5.0 mm.

[0071] Further, continue to refer to Figure 6 , along the height direction of the battery cell housing, the depth of the groove 210 is b, and the thickness of the bottom plate 200 is H3. The relationship between b and H3 satisfies: 0.1 ≤ b / H3 ≤ 0.45. The value range of H3 is: 0.7 mm ≤ H3 ≤ 1.6 mm.

[0072] The relationship between b, H1, and H3 satisfies: (H3 - b) ≥ H1; the value range of H1 is: 0.4 mm ≤ H1 ≤ 1.0 mm.

[0073] The relationship between b, H2, and H3 satisfies: (H3 - b) ≥ H2; the value range of H2 is: 0.3 mm ≤ H2 ≤ 0.8 mm.

[0074] This embodiment also provides a battery cell, including a cover plate, a pole group, and the above-mentioned battery cell housing. The pole group is arranged in the accommodation cavity surrounded by the peripheral side plate 100 and the bottom plate 200, and the cover plate is connected to one end of the peripheral side plate 100 provided with an opening 101. By adopting the above-mentioned battery cell housing, the capacity of the battery cell is relatively large, the voltage withstand strength is relatively high, and the safety performance is good. Optionally, the battery cell housing in this embodiment can be formed by stamping and stretching.

[0075] Next, four battery cells with different capacities are assembled. Verify the influence of the relevant parameters of the groove 210 on the capacity of the battery cell and the voltage withstand strength of the battery cell housing. Table 1 specifically gives the structural dimensions of the battery cell housing in some specific implementation schemes.

[0076] Table 1

[0077]

[0078] Referring to Embodiment 1 and Embodiment 2, taking the capacity of the battery cell as 5.2 Ah as an example, the relevant dimensional parameters H1, H2, H3, a, b, H3 - b, and b / H3 of the battery cell housing all satisfy their corresponding dimensional ranges. The measured capacity of the battery cell is increased by 2.9% - 4.2% compared with the designed capacity, the capacity of the battery cell is significantly improved, and the pressure resistance of the battery cell housing is greater than 1.2 MPa, meeting the strength requirements of the battery cell for the battery cell housing, and the reliability is relatively high.

[0079] It should be noted that the designed capacity of the battery cell is the capacity of the battery cell after chamfering the electrode group using the traditional technical solution, and the measured capacity is the capacity of the battery cell when the electrode group is not chamfered or the chamfer is small using the technical solution in this embodiment.

[0080] On the contrary, in Comparative Example 1, the parameter H3 in the battery cell housing is less than the minimum value of its value range 0.7 mm ≤ H3 ≤ 1.6 mm, the values of H1, H2, a, and b / H3 are the same as those of the battery cell housing in Embodiment 1, and the value of H3 - b is lower than that of H3 - b in Embodiment 1. At this time, the measured capacity of the battery cell is increased by 2.1% compared with the designed capacity, and the capacity of the battery cell is slightly improved. However, due to the small values of H3 and H3 - b, the thickness of the bottom plate 200 is too thin, and the transition connection between the bottom plate 200 and the peripheral side plate 100 (i.e., the position where the groove 210 is located) is prone to breakage. The pressure resistance of the battery cell housing is ≤ 1.2 MPa, and the pressure resistance test fails. The reliability of the battery cell housing is poor and cannot meet the product requirements of the battery cell.

[0081] In Comparative Example 2, the parameter H1 in the battery cell housing is less than the minimum value of its value range 0.4 mm ≤ H1 ≤ 1.0 mm, the parameter H2 is less than the minimum value of its value range 0.3 mm ≤ H2 ≤ 0.8 mm, and the values of H3, a, and b / H3 are the same as those of the battery cell housing in Embodiment 2. At this time, the measured capacity of the battery cell is increased by 4.0% compared with the designed capacity, and the capacity of the battery cell is improved. However, due to the small values of H1 and H2, the thicknesses of the first side plate 110 and the second side plate 120 are too thin, resulting in problems of deformation and rupture during the stretch forming of the battery cell housing. The pressure resistance of the completed battery cell housing is ≤ 1.2 MPa, and the pressure resistance test fails. The mechanical strength of the battery cell housing is insufficient and cannot meet the product requirements of the battery cell.

[0082] Referring to Embodiment 3 and Embodiment 4, taking the capacity of the battery cell as 117 Ah as an example, the relevant dimensional parameters H1, H2, H3, a, b, H3 - b, and b / H3 of the battery cell housing all satisfy their corresponding dimensional ranges. The measured capacity of the battery cell is increased by 1.0% - 2.0% compared with the designed capacity, the capacity of the battery cell is significantly improved, and the pressure resistance of the battery cell housing is greater than 1.2 MPa, meeting the strength requirements of the battery cell for the battery cell housing, and the reliability is relatively high.

[0083] On the contrary, in Comparative Example 3, the value of the parameter b / H3 in the cell housing is small and does not meet the dimensional limit of 0.1 ≤ b / H3 ≤ 0.45. The values of H1, H2, H3, and a are the same as those of the cell housing in Example 3. At this time, although the pressure resistance of the cell housing > 1.2 MPa and the pressure resistance test passes, the measured capacity of the cell only increases by 0.18% compared with the designed capacity, and the improvement effect on the cell capacity is not obvious, which cannot meet the product requirements of the cell.

[0084] In Comparative Example 4, the value of the parameter b / H3 in the cell housing is large and does not meet the dimensional limit of 0.1 ≤ b / H3 ≤ 0.45. At the same time, the dimensional limit of H3 - b ≥ H1 is not met between b, H1, and H3; the dimensional limit of H3 - b ≥ H2 is also not met between b, H2, and H3. The values of H1, H2, H3, and a are the same as those of the cell housing in Example 4. At this time, the measured capacity of the cell increases by 2.0% compared with the designed capacity, and the capacity of the cell has increased. However, the wall thickness at the position where the groove 210 is provided on the bottom plate 200 is small, and the local strength is insufficient. The pressure resistance of the completed cell housing ≤ 1.2 MPa, and the pressure resistance test fails, which cannot meet the product requirements of the cell.

[0085] Referring to Example 5 and Example 6, taking the cell capacity of 350 Ah as an example, the values of the relevant dimensional parameters H1, H2, H3, a, b, H3 - b, and b / H3 of the cell housing all meet their corresponding dimensional ranges. The measured capacity of the cell increases by 1.0% - 1.4% compared with the designed capacity, and the capacity of the cell is significantly improved. Moreover, the pressure resistance of the cell housing is greater than 1.2 MPa, meeting the strength requirements of the cell for the cell housing, and the reliability is relatively high.

[0086] On the contrary, in Comparative Example 5, the parameter H1 in the cell housing is less than the minimum value of its value range of 0.4 mm ≤ H1 ≤ 1.0 mm, and the parameter H2 is less than the minimum value of its value range of 0.3 mm ≤ H2 ≤ 0.8 mm. The values of H3 and a are the same as those of the cell housing in Example 5. At this time, the measured capacity of the cell increases by 0.8% compared with the designed capacity, and the capacity of the cell has increased. However, due to the small values of H1 and H2, the thicknesses of the first side plate 110 and the second side plate 120 are too thin, resulting in problems of deformation and cracking of the cell housing during stretch forming. The pressure resistance of the completed cell housing ≤ 1.2 MPa, the pressure resistance test fails, and the mechanical strength of the cell housing is insufficient, which cannot meet the product requirements of the cell.

[0087] In Comparative Example 6, the parameter H3 in the cell housing is greater than the maximum value of its value range 0.7 mm ≤ H3 ≤ 1.6 mm. The values of H1, H2, a, and b are the same as those of the cell housing in Example 6. At this time, the measured capacity of the cell is 1.3% higher than the designed capacity, and the capacity of the cell has increased. However, the value of H3 is large, and the thickness of the bottom plate 200 is large. Although its pressure resistance strength is greater than 1.2 MPa and the pressure resistance test passes, the weight of the cell housing is large, and the energy density of the cell does not meet the standard and cannot meet the product requirements of the cell.

[0088] Referring to Example 7 and Example 8, taking the capacity of the cell as 625 Ah as an example, the relevant dimensional parameters H1, H2, H3, a, b, H3 - b, and b / H3 of the cell housing all meet their corresponding dimensional ranges. The measured capacity of the cell is 0.8% - 1.1% higher than the designed capacity, and the capacity of the cell has increased significantly. Moreover, the pressure resistance strength of the cell housing is greater than 1.2 MPa, meeting the strength requirements of the cell for the cell housing, and the reliability is relatively high.

[0089] On the contrary, in Comparative Example 7, the parameter H1 in the cell housing is greater than the maximum value of its value range 0.4 mm ≤ H1 ≤ 1.0 mm, and the parameter H2 is greater than the maximum value of its value range 0.3 mm ≤ H2 ≤ 0.8 mm. The values of H3, a, and b are the same as those of the cell housing in Example 7. At this time, the measured capacity of the cell is 0.7% higher than the designed capacity, and the capacity of the cell has increased. However, the values of H1 and H2 are large, and the thicknesses of the first side plate 110 and the second side plate 120 are too large. Although the pressure resistance strength of the completed cell housing is greater than 1.2 MPa and the pressure resistance test passes, the weight of the cell housing is large, and the energy density of the cell does not meet the standard and cannot meet the product requirements of the cell.

[0090] In Comparative Example 8, the value of the parameter b / H3 in the cell housing is large, not meeting the dimensional limit of 0.1 ≤ b / H3 ≤ 0.45. At the same time, b, H1, and H3 do not meet the dimensional limit of H3 - b ≥ H1; b, H2, and H3 also do not meet the dimensional limit of H3 - b ≥ H2. The values of H1, H2, H3, and a are the same as those of the cell housing in Example 8. At this time, the measured capacity of the cell is only 1.4% higher than the designed capacity, and the improvement effect on the cell capacity is obvious. However, the wall thickness at the position where the groove 210 is provided on the bottom plate 200 is small, the local strength of the cell housing is insufficient, the pressure resistance strength of the cell housing is ≤ 1.2 MPa, and the pressure resistance test fails and cannot meet the product requirements of the cell.

[0091] In summary, as can be seen from the above results, when the values of the relevant dimensional parameters H1, H2, H3, a, b, H3 - b, and b / H3 of the battery cell housing all meet their corresponding dimensional ranges, the capacity of the battery cell can be improved, and the mechanical strength of the battery cell housing can be ensured to be relatively high. The pressure resistance of the battery cell housing is greater than 1.2 MPa, meeting the strength requirements of the battery cell for the battery cell housing.

[0092] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting 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 enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A battery cell housing, characterized in that, include: A peripheral side plate, wherein the peripheral side plate forms a cylindrical structure; A bottom plate, the bottom plate is connected to and blocked at one end of the peripheral side plate, the bottom plate and the peripheral side plate are arranged to form a receiving cavity, a groove is arranged on the end surface of the bottom plate facing the receiving cavity, the groove is arranged around the bottom plate, the groove includes a wall surface, the wall surface is located on a side close to the receiving cavity, and an end of the wall surface away from the bottom plate is transitionally connected to the end surface of the peripheral side plate facing the receiving cavity; Wherein, along the length direction of the battery cell shell, the width of the open end of the groove is a, and the value range of a is 1.0mm≤a≤5.0mm; Along the height direction of the battery cell housing, the depth of the groove is b, the thickness of the bottom plate is H3, and b and H3 satisfy: 0.1≤b / H3≤0.45; The value range of H3 is: 0.7mm≤H3≤1.6mm.

2. The cell housing according to claim 1, characterized in that, The peripheral side plate includes two first side plates and two second side plates, the two first side plates are arranged at both ends of the battery cell shell in the length direction, and the two second side plates are arranged at both ends of the battery cell shell in the width direction, and the end of the wall surface away from the bottom plate is transitionally connected to the end surfaces of the first side plate and the second side plate facing the accommodating cavity; Wherein, along the length direction of the battery cell shell, the thickness of the first side plate is H1, b, H1 and H3 satisfy: (H3-b)≥H1, and the value range of H1 is: 0.4mm≤H1≤1.0mm; And / or, along the width direction of the battery cell shell, the thickness of the second side plate is H2, b, H2 and H3 satisfy: (H3-b)≥H2, and the value range of H2 is: 0.3mm≤H2≤0.8mm.

3. The cell housing according to claim 2, wherein, The end surface of the bottom plate facing away from the accommodating cavity and the end surface of the first side plate facing away from the accommodating cavity are transitionally connected through a first outer arc surface, and the distance between the end of the wall surface away from the bottom plate and the first outer arc surface is t1; t1 and H1 satisfy: t1 ≥ H1.

4. The cell housing according to claim 2, wherein, The end surface of the bottom plate facing away from the accommodating cavity and the end surface of the second side plate facing away from the accommodating cavity are transitionally connected through a second outer arc surface, and the distance between the end of the wall surface away from the bottom plate and the second outer arc surface is t2; t2 and H2 satisfy: t2≥H2.

5. The cell housing according to claim 1, characterized in that, The cross section of the groove is a part of a circle, and the radius of the circle where the wall surface of the groove lies is R; The value range of R is: 2.0mm≤R≤20mm.

6. The cell housing according to claim 1, characterized in that, The cross section of the groove is square or trapezoidal, the wall surface of the groove includes a first wall surface, a second wall surface and a bottom surface, and the bottom surface is transitionally connected to the first wall surface through a first transition surface; And / or, the first wall surface and the end surface of the bottom plate facing the accommodating cavity are transitionally connected via a second transition surface; And / or, the second wall surface and the end surface of the peripheral side plate facing the accommodating cavity are transitionally connected via a third transition surface; And / or, the bottom surface and the second wall surface are transitionally connected via a fourth transition surface.

7. The cell housing according to claim 6, characterized in that, The first transition surface is an arc surface, the radius of the first transition surface is r1, and the value range of r1 is: 1.0 mm ≤ r1 ≤ 5.0 mm; and / or, the second transition surface is an arc surface, the radius of the second transition surface is r2, and the value range of r2 is: 1.0 mm ≤ r2 ≤ 5.0 mm; and / or, the third transition surface is an arc surface, the radius of the second transition surface is r3, and the value range of r3 is: 3.0 mm ≤ r3 ≤ 10.0 mm; and / or, the fourth transition surface is an arc surface, the radius of the fourth transition surface is r4, and the value range of r4 is: 1.0 mm ≤ r4 ≤ 5.0 mm.

8. The cell housing according to claim 1, characterized in that, The voltage withstand strength of the battery cell housing is greater than 1.2 MPa.

9. The cell housing according to claim 1, wherein A limiting step is provided on the end surface of the peripheral side plate facing the accommodating cavity, and the limiting step is located at one end of the peripheral side plate far from the bottom plate.

10. A battery cell, characterized in that, It includes a cover plate, a pole group, and the battery cell housing according to any one of claims 1-9. The pole group is arranged in the accommodating cavity surrounded by the peripheral side plate and the bottom plate of the battery cell housing, and the cover plate is connected to one end of the peripheral side plate far from the bottom plate.

Images