Battery and battery module

Abstract

The invention relates to the field of batteries, and discloses a battery and a battery module. The battery comprises a shell and a battery cell arranged in the shell, one side plate of the shell is provided with a welding seam, and the welding seam is arranged in the length direction of the shell; a supporting plate is arranged between the battery cell and the side plate provided with the welding seam; the width W1 of the welding seam, the height H of the welding seam, the width W2 of the supporting plate and the thickness T of the supporting plate meet the condition that W1 * H / W2 * T is larger than or equal to 0.00083 and smaller than or equal to 0.075. The shell of the battery is more convenient for realizing uniform arrangement of the thickness, and the safety of the battery is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and particularly to a battery and a battery module. Background Art

[0002] For a rectangular blade battery, the structure of its housing is a cuboid tubular structure with openings at both ends. The housing of this structure usually undergoes processes such as stamping and stretching during the forming process. Since the housing is formed by an integral molding process, its surface has no joints. However, during the stamping and stretching processes, the bent parts of the housing usually have the problem of uneven thickness, which will reduce the safety performance of the housing.

[0003] There is an existing improvement method of using a metal plate with uniform thickness to form the housing through bending and welding. However, when bending and welding, there will be butt welds on the housing. If the welds are not properly treated, it may damage the battery cells during the assembly of the battery cells, increasing the safety hazards of the battery. Summary of the Invention

[0004] This application discloses a battery and a battery module for improving the safety of a battery with welds.

[0005] To achieve the above object, this application provides the following technical solutions: In a first aspect, this application provides a battery, which includes a housing and battery cells placed inside the housing; one side plate of the housing is provided with a weld, and the weld is arranged along the length direction of the housing; a support plate is provided between the battery cells and the side plate with the weld; the width W1 of the weld, the height H of the weld, the width W2 of the support plate, and the thickness T of the support plate satisfy: 0.00083 ≤ W1·H / W2·T ≤ 0.075; wherein, the width direction of the weld is the same as the width direction of the support plate, and the height direction of the weld is the same as the thickness direction of the support plate.

[0006] In the battery of this application, its housing can be formed by welding a plate with uniform thickness. Therefore, there is a weld on one side plate of the housing of this application. To prevent the burrs of the weld from damaging the battery cells, a support plate is provided between the side plate with the weld of the housing and the battery cells. The thickness and width of the support plate need to match the width and height of the weld, otherwise the problem of protection failure is likely to occur. In this application, the width W1 of the weld, the height H of the weld, the width W2 of the support plate, and the thickness T of the support plate satisfy: 0.00083 ≤ W1·H / W2·T ≤ 0.075. When W1, H, W2, and T satisfy the above relationship, it can not only avoid the problem that the weld scratches the support plate and then damages the battery cells, but also avoid the housing squeezing the battery cells when the battery cells are put into the housing, protecting the diaphragm and pole pieces of the battery cells from damage and avoiding the reduction of the safety of the battery.

[0007] In a second aspect, the present application provides a battery module, which includes a plurality of batteries of the present application. The plurality of batteries can be connected in series and parallel.

[0008] Since the battery module of the present application includes the batteries of the present application, the battery module of the present application has all the advantages of the batteries of the present application, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic structural diagram of a battery provided by an embodiment of the present application; Figure 2 is a schematic disassembled structural diagram of a battery of an embodiment; Figure 3 is a schematic structural diagram of a housing of an embodiment; Figure 4 is a schematic enlarged partial cross-sectional structure diagram at the weld of the first side plate; Figure 5 is a schematic structural diagram of a support plate of an embodiment; Figure 6 is a schematic enlarged end structure diagram of a support plate of an embodiment.

[0010] Reference Numerals in the Drawings: 01 - Battery; 10 - Housing; 11 - Side Plate; 12 - Weld; 111 - First Side Plate; 112 - Second Side Plate; 113 - Third Side Plate; 114 - Fourth Side Plate; 20 - Battery Cell; 30 - Support Plate; 31 - Rounded Corner; 40 - Cover Plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0011] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0012] Figure 1 is a schematic structural diagram of a battery of an embodiment of the present application. As Figure 1 shown, the battery 01 can be a blade battery, and its outer shape is a cuboid structure. The dimension of the battery 01 in the length direction (such as the x direction shown in Figure 1 ) is much larger than the dimension of the battery 01 in the thickness direction (such as the z direction shown in Figure 1 ) and the dimension of the battery 01 in the width direction (such as the y direction shown in Figure 1 ).

[0013] Figure 2Schematic diagram of the disassembly structure of a battery for an embodiment. As Figure 1 and Figure 2 shown, the battery 01 includes a housing 10, a battery cell 20, a support plate 30, and a cover plate 40. The battery cell 20 is disposed inside the housing 10. The cover plate 40 is disposed at the end of the battery 01.

[0014] Figure 3 Schematic diagram of the structure of a housing for an embodiment. As Figure 2 shown, the housing 10 may include four side plates 11. Two narrow side plates with relatively small areas and two wide side plates with relatively large areas. The four side plates 11 are sequentially connected to form a cube-shaped cylindrical structure with openings at both ends. Among them, the narrow side plates form the long and high surfaces of the housing. The wide side plates form the long and wide surfaces of the housing.

[0015] Among them, the four side plates 11 of the housing 10 may be respectively denoted as a first side plate 111, a second side plate 112, a third side plate 113, and a fourth side plate 114. Among them, the first side plate 111 and the third side plate 113 are opposite and spaced apart, and the second side plate 112 and the fourth side plate 114 are opposite and spaced apart. The first side plate 111, the second side plate 112, the third side plate 113, and the fourth side plate 114 are sequentially surrounded and connected. The first side plate 111 and the third side plate 113 may be the two narrow side plates of the housing 10. The second side plate 112 and the fourth side plate 114 may be the two wide side plates of the housing 10. That is, the areas of the first side plate 111 and the third side plate 113 are smaller than the areas of the second side plate 112 and the fourth side plate 114.

[0016] Refer to Figures 1 to 3 together. Along the length direction of the housing 10, both ends of the housing 10 are open ends. Cover plates 40 are respectively provided at the open ends on both sides of the housing 10. The two cover plates 40 are respectively hermetically connected to the housing 10. One of the cover plates 40 may be provided with a positive electrode post for connecting a positive electrode tab, and the other cover plate 40 may be provided with a negative electrode post for connecting a negative electrode tab. In addition, a positive electrode post and a negative electrode post may also be jointly provided on one cover plate 40. The battery cell is placed inside the housing 10, and the housing 10 is used to achieve the sealing and protection of the battery cell.

[0017] The housing of the embodiment of the present application can be formed by bending and welding a plate with a uniform thickness. Therefore, a weld seam 12 formed by welding may exist on the side plate 11 of the housing 10. The weld seam 12 is disposed along the length direction of the housing 10. Among them, the weld seam 12 may be disposed on the narrow side plate of the housing 10 or on the wide side plate of the housing 10. In one embodiment, the weld seam 12 is disposed on the narrow side plate of the housing 10, as Figure 3 shown in the first side plate 111 or the third side plate 113 in. When the weld seam 12 is located on the narrow side plate, when bending and seam welding, the two wide side plates can maintain a better deformation amount, which is more conducive to the welding of the narrow side plate.

[0018] The following takes the weld seam being arranged on the first side plate as an example for illustration.

[0019] Combined with Figure 2 and Figure 3 , the weld seam 12 formed by welding often has irregular surfaces such as welding slag or protrusions. To prevent the weld seam 12 from damaging the battery cell, a support plate 30 needs to be provided between the battery cell and the side plate 11 where the weld seam 12 is arranged, such as between the battery cell and the first side plate.

[0020] The support plate 30 is arranged between the battery cell 20 and the first side plate 111. The width of the support plate 30 is smaller than the width of the first side plate 111.

[0021] Figure 4 FIG. is a schematic enlarged view of a partial cross-section at the weld seam of the first side plate. Figure 5 FIG. is a schematic structural view of a support plate of an embodiment. As Figure 4 and Figure 5 shown, the width of the weld seam 12 is W1, the height of the weld seam 12 is H, the width of the support plate 30 is W2, and the thickness of the support plate 30 is T. Among them, the width direction of the weld seam 12 is the same as the width direction of the support plate 30, and the height direction of the weld seam 12 is the same as the thickness direction of the support plate 30.

[0022] Among them, in the embodiment of the present application, the width W1 of the weld seam 12 is defined as: within the cross-section of the weld seam 12, the width at the inner wall of the housing. The height H of the weld seam 12 is defined as: within the cross-section of the weld seam 12, along the thickness direction of the first side plate 111, the dimension from the bottom to the top of the weld seam 12. Among them, the cross-section of the weld seam 12 is a cross-section perpendicular to the length direction of the weld seam.

[0023] In the embodiment of the present application, W1, H, W2, and T satisfy: 0.00083 ≤ W1·H / W2·T ≤ 0.075. Exemplarily, the value of W1·H / W2·T can be, for example, 0.00083, 0.0005, 0.0001, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.075 or any value between any two of the above values.

[0024] The thickness and width of the support plate need to match the width and height of the weld seam, otherwise the problem of protection failure is likely to occur. In the present application, the width W1 of the weld seam, the height H of the weld seam, the width W2 of the support plate, and the thickness T of the support plate satisfy: 0.00083 ≤ W1·H / W2·T ≤ 0.075.

[0025] If the value of W1·H / W2·T is too large, the weld seam is likely to scratch the support plate, leaving scratches on the surface of the battery cell corresponding to the weld seam, which may easily cause damage to the separator or the electrode sheet, thereby affecting the battery performance. If the value of W1·H / W2·T is too small, it is difficult for the battery cell to be inserted into the case. When the battery cell is inserted into the case, it may be squeezed, and the separator of the battery cell is likely to be wrinkled and damaged, and the electrode sheet of the battery cell is likely to have problems such as material dropping, thereby affecting the battery performance. At the same time, if the value of W1·H / W2·T is too small, it is also not conducive to improving the energy density of the battery. Therefore, when W1, H, W2, and T satisfy the above relationship, it can protect the battery cell and avoid damage to the battery cell.

[0026] In one embodiment, the value range of the width W1 of the weld seam is 0.1~0.5 mm. Exemplarily, the value of the width W1 of the weld seam can be, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm or any value between any two of the above values. The width W1 of the weld seam cannot be too wide. If it is too wide, the proportion on the opposite surface is relatively large, and the resistance is large when the battery cell is inserted into the case, and it is easy to cause damage to the battery cell. At the same time, the width W1 of the weld seam cannot be too narrow. If it is too narrow, the welding strength is insufficient, affecting the safety performance of the battery in the later stage.

[0027] In one embodiment, the value range of the height H of the weld seam is 0.05~0.5 mm. Exemplarily, the value of the height H of the weld seam can be, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm or any value between any two of the above values. The height H of the weld seam cannot be too high. If it is too high, there is a risk of piercing the battery cell. At the same time, during the use of the battery, the weld seam abuts against the battery cell, and there will be lithium deposition. At the same time, the height H of the weld seam cannot be too low. If it is too low, there is a risk of incomplete welding.

[0028] In one embodiment, the value range of the width W2 of the support plate is 5~12 mm. Exemplarily, the value of the width W2 of the support plate can be, for example, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm or any value between any two of the above values. The width W2 of the support plate cannot be too wide. If it is too wide, during the liquid injection process, part of the electrolyte is located between the support and the case, and the time for infiltrating the battery cell is slow. At the same time, the width W2 of the support plate cannot be too narrow. If it is too narrow, there will be a deviation from the weld seam position, resulting in the weld seam contacting the surface of the battery cell.

[0029] In one embodiment, the thickness T of the support plate ranges from 0.2 to 0.5 mm. Exemplarily, the value of the thickness T of the support plate can be, for example, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, or any value between any two of the above values. The thickness T of the support plate cannot be too thick, as it will affect the internal space of the battery and reduce the energy density of the battery. At the same time, the thickness T of the support plate cannot be too thin, as it will not be able to effectively block the weld seam, and the weld seam will abut against the battery cell, causing lithium plating on the battery cell.

[0030] Wherein, when the weld seam is provided on the first side plate 111, along the width direction of the first side plate 111, the weld seam 12 is provided in the middle region of the first side plate 111. That is, the weld seam 12 is not provided at the edge of the first side plate 111 and is not connected to the adjacent second side plate 112 or fourth side plate 114.

[0031] As an exemplary illustration, along the width direction of the first side plate 111, the weld seam 12 is provided in the middle region of the first side plate, and the distance from the edge of the weld seam 12 to the edge of the first side plate 111 is 1 / 5 - 1 / 3 of the width of the first side plate. Exemplarily, the distance from the edge of the weld seam 12 to the edge of the first side plate is 1 / 5, 1 / 4.8, 1 / 4.5, 1 / 4.2, 1 / 4, 1 / 3.8, 1 / 3.5, 1 / 3.2, 1 / 3, or any value between any two of the above values. The weld seam is provided in the middle region of the first side plate, which is convenient for welding, can improve the welding strength, disperse the welding stress, and avoid welding stress concentration.

[0032] Wherein, the length L1 of the support plate is less than the length L2 of the battery cell. When injecting the electrolyte, part of the electrolyte will flow into the gap between the support plate and the housing. The length of the support plate is less than the length of the battery cell, which can leave a part of the space between the support plate and the battery cell, so that the electrolyte enters the battery cell from this space, shortening the flow path of the electrolyte.

[0033] In one embodiment, along the length direction of the support plate, the ends on both sides of the support plate do not extend beyond the ends of the battery cell. Exemplarily, the length of the battery cell is greater than the length of the support plate.

[0034] Figure 6 It is a schematic diagram of the enlarged structure of the end of the support plate in one embodiment. As Figure 6 shown, along the length direction of the support plate 30, at least one end of the support plate 30 is provided with a rounded corner 31. In one embodiment, rounded corners 31 are provided at both ends of the support plate 30. By providing the rounded corners 31, it is convenient to install the support plate into the interior of the housing.

[0035] In the battery according to the embodiment of the present application, an insulating film is coated on the surface of the battery cell. Among them, the length of the support plate is less than the length of the insulating film. In one embodiment, the support plate can be disposed between the insulating film and the housing. In this mounting structure, the support plate is disposed between the insulating film and the housing, which can facilitate the coating of the battery cell.

[0036] In another embodiment, the support plate can be disposed between the battery cell and the insulating film to prevent the support plate from warping when entering the housing.

[0037] Based on the same technical purpose, the present application also provides a battery module. The battery module includes a plurality of batteries according to the present application. The plurality of batteries can be connected in series or in parallel.

[0038] The effects of the battery according to the present application will be described below in conjunction with specific embodiments.

[0039] Examples 1-45 and Comparative Examples 1-12 are each a battery. The parameters and performances of the batteries in different examples and comparative examples are listed in Table 1. For the sample batteries in each example and comparative example, the material composition and structural dimensions of the selected electricity are the same. The structural material of the housing is the same. The weld of the housing exists on the first side plate of the housing, that is, the narrow side plate.

[0040] Among them, in each sample battery, different sizes are selected for the thickness and width of the support plate, and different sizes are selected for the width and internal height of the housing weld. The sizes of each sample battery are listed in Table 1.

[0041] During the process of assembling into the housing, observe whether the battery cell is easy to enter the housing and whether the battery cell is damaged. After the assembly is completed, disassemble the battery after assembling into the housing, and observe whether the battery cell and the support plate are damaged. The results are listed in Table 1.

[0042] Table 1:

[0043] In Examples 1 to 45, the battery cell was assembled into the housing normally, without resistance, the battery cell was not squeezed, and there were no problems such as diaphragm damage and electrode sheet dropping of the battery cell. When the battery was disassembled, the support plate did not show scratches, the surface of the battery cell was normal, and the diaphragm was not damaged.

[0044] Among them, in Examples 32 to 45, although the battery cell was normal during the assembly and disassembly into the housing, the related structural dimensions were likely to cause other process problems in the battery assembly. For example, in Examples 32 to 38, the weld was too narrow, the welding strength was insufficient, and there were welding defect problems, which affected the safety performance of the battery in the later stage. In Examples 39 to 45, the weld was too wide and the proportion on the relative surface was large, the resistance was large when the battery cell entered the housing, and it was easy to cause damage to the battery cell.

[0045] In Examples 34, 35, 38, 40, 41, 43 and Example 45, the support plate is too wide. During the liquid injection process, part of the electrolyte is located between the support and the housing, and the time to infiltrate the battery core is slow. In Examples 32, 33, 36, 37, 39, 42 and Example 44, if the support plate is too narrow, there will be a deviation from the weld position, resulting in the weld touching the surface of the battery core and not being able to fully protect the battery core.

[0046] In Examples 33, 35, 36, 38, 43, 44, and Example 45, if the weld is too high, there is a risk of piercing the battery core. At the same time, during the use of the battery, when the weld abuts against the battery core, there will be lithium deposition. In Examples 32, 34, 37, 39, 40, 41 and Example 42, if the weld is too low, there is a risk of incomplete welding, resulting in welding quality problems and affecting the safety of battery use.

[0047] In Examples 36, 37, 38, 39, 41, 44, and Example 45, if the support plate is too thick, it will affect the internal space of the battery and reduce the energy density of the battery. In Examples 32, 33, 34, 35, 40, 42 and Example 43, if the support plate is too thin, it is easy to fold during the process of entering the housing. At the same time, the weld will abut against the battery core, causing lithium deposition.

[0048] In Comparative Examples 1-6, it is difficult to assemble the battery core into the housing. During the process of entering the housing, the battery core is extruded, and there is a situation of diaphragm wrinkling. After the battery is disassembled, the diaphragm is damaged by wrinkling, and the battery electrode sheet drops material.

[0049] In Comparative Examples 7-12, when the battery core enters the housing, the weld is easy to scratch the support plate. After the battery is disassembled, there are scratches on the bottom surface of the support plate, and there are indentations and scratches on the battery core diaphragm.

[0050] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A battery, characterized in that: It comprises a shell and a battery cell placed in the shell; A side plate of the shell is provided with a weld, and the weld is arranged along the length direction of the shell; A support plate is provided between the battery core and the side plate provided with the welding seam; The width W1 of the weld, the height H of the weld, the width W2 of the support plate, and the thickness T of the support plate satisfy: 0.00083≤W1·H / W2·T≤0.075; wherein the width direction of the weld is the same as the width direction of the support plate, and the height direction of the weld is the same as the thickness direction of the support plate.

2. The battery according to claim 1, characterized in that The width W1 of the weld is in the range of 0.1 to 0.5 mm.

3. The battery according to claim 1, characterized in that The height H of the weld is in the range of 0.05 to 0.5 mm.

4. The battery according to claim 1, characterized in that The width W2 of the support plate ranges from 5 to 12 mm.

5. The battery according to claim 1, characterized in that The thickness T of the support plate ranges from 0.2 to 0.5 mm.

6. The battery according to any one of claims 1 to 5, characterized in that: The housing is a rectangular parallelepiped structure, including a first side plate, a second side plate, a third side plate and a fourth side plate which are sequentially connected and surrounded; the first side plate and the third side plate are opposite to each other and spaced apart, and the second side plate and the fourth side plate are opposite to each other and spaced apart; The areas of the first side plate and the third side plate are smaller than those of the second side plate and the fourth side plate, and the welding seam is provided on the first side plate.

7. The battery according to claim 6, characterized in that Along the length direction of the rectangular parallelepiped structure, two ends of the shell are open ends.

8. The battery according to claim 6, characterized in that Along the width direction of the first side plate, the welding seam is arranged in the middle area of ​​the first side plate.

9. The battery according to claim 8, characterized in that Along the width direction of the first side plate, the distance between the edge of the weld and the edge of the first side plate is 1 / 5-1 / 3 of the width of the first side plate.

10. The battery according to any one of claims 1 to 5, characterized in that: The length of the support plate is smaller than the length of the battery core.

11. The battery according to claim 10, characterized in that Along the length direction of the support plate, ends of both sides of the support plate do not exceed ends of the battery core.

12. The battery according to claim 11, characterized in that The length of the battery core is greater than the length of the support plate.

13. The battery according to any one of claims 1 to 5, characterized in that: Along the length direction of the support plate, at least one end portion of the support plate is provided with a rounded corner.

14. The battery according to any one of claims 1 to 5, characterized in that: The surface of the battery core is covered with an insulating film, and the length of the support plate is smaller than the length of the insulating film.

15. The battery according to claim 14, characterized in that The support plate is arranged between the insulating film and the shell.

16. The battery according to claim 14, characterized in that The support plate is arranged between the battery core and the insulating film.

17. A battery module, characterized in that: The battery module comprises a plurality of batteries as described in any one of claims 1-16.

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