Battery assembly and single battery

Abstract

The invention relates to the technical field of lithium batteries, in particular to a battery assembly and a single battery. The battery assembly comprises a pole group, a pole lug and a cover plate; the cover plate comprises a cover plate pole; the cover plate pole comprises a pole base arranged towards the pole group, and the pole base is attached to the pole group; the tab is led out from the pole group and is welded with the surface, far away from the pole group, of the pole base, a welding mark is formed on the tab, and an area formed by the welding mark is defined as a welding area; the battery assembly satisfies the following conditions: beta * S is greater than 1.5 F; wherein beta is the coefficient of tension which can be borne by the welding area and is not torn, S is the area of the welding area, and F is the thrust when the battery assembly is in thermal runaway. According to the battery assembly and the single battery provided by the invention, the problem that when thermal runaway occurs in an existing battery cell structure, the pole group randomly moves along with high-temperature and high-pressure airflow to shield the anti-explosion valve and further shield the exhaust channel is solved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and in particular to a battery assembly and a single battery. Background Art

[0002] Lithium-ion batteries have become the representative of modern high-performance batteries due to their advantages such as high operating voltage, large capacity, low self-discharge, good cycle performance, long service life, light weight and small size.

[0003] Long cell lithium-ion batteries such as Figure 9 and Figure 10 As shown, the design is usually designed with tabs on both sides. Its structure includes: a cover plate (integrated with the pole column, explosion-proof valve, injection hole, etc.), a shell, a pole group, and electrolyte. The cover plate and shell are welded together to form a sealed space with a certain mechanical strength to protect the pole group. The pole group is fixed to the pole base of the cover plate on both sides through the pole tabs on both sides through laser welding to achieve electrical connection. In addition, a second plastic cover part is designed at each side of the pole tab to protect the pole tab and provide bending space for the pole tab. The cover plate is integrated with an explosion-proof valve structure, which is mainly used for the directional discharge of high-temperature and high-pressure internal gases in the event of thermal runaway due to internal short circuit, thereby improving battery safety performance.

[0004] The pole ear of the above structure is welded to the bottom of the base of the cover pole column. There is a bending height space for the pole ear between the pole ear and the pole group. The pole ear is mainly insulated and fixed by the second plastic part of the cover plate. However, the insulating material of the second plastic part is generally made of PP material, and its strength and high temperature resistance are very limited, generally around 150 degrees. The temperature at which the battery cell undergoes thermal runaway is usually much higher than the melting point of these insulating materials. Once the insulating material of the second plastic part melts and fails, only the pole group is left inside the battery cell. This will cause the pole ear to lose its fixed support and increase in length along the length direction of the battery cell, resulting in an increase in the gap between the pole group and the cover plate and the shell. At this time, the pole group has a high degree of freedom inside the battery cell. When the high-temperature and high-pressure gas is exhausting in the direction of the explosion-proof valve, the pole group will move randomly with the high-temperature and high-pressure airflow to block the explosion-proof valve and the exhaust channel, greatly reducing the exhaust effect of the explosion-proof valve and reducing the safety performance of the battery cell.

[0005] In addition, the welding between the pole ear and the cover plate pole base in the above structure is not firm. When the high-temperature and high-pressure gas is exhausted in the direction of the explosion-proof valve, the welding point is prone to tearing. The pole group will also move randomly with the high-temperature and high-pressure airflow to block the explosion-proof valve and the exhaust channel, greatly reducing the exhaust effect of the explosion-proof valve and reducing the safety performance of the battery cell. Summary of the Invention

[0006] The purpose of this application is to provide a battery assembly and a single cell, thereby solving the problem that when thermal runaway occurs in the existing battery cell structure, the electrode group will randomly move with the high-temperature and high-pressure airflow to block the explosion-proof valve and then block the exhaust channel.

[0007] In a first aspect, the present application provides a battery assembly, comprising a pole group, a pole lug and a cover plate; the cover plate comprises a cover pole; the cover pole comprises a pole base arranged toward the pole group, the pole base being in contact with the pole group; the pole lug is led out from the pole group and welded to the surface of the pole base away from the pole group, a weld mark is formed on the pole lug, and the area where the weld mark is formed is defined as a welding area; the battery assembly satisfies: β×S>1.5F; wherein β is the tensile coefficient that the welding area can withstand without tearing, S is the area of ​​the welding area, and F is the thrust when the battery assembly undergoes thermal runaway.

[0008] In any of the above technical solutions, further, the cover plate pole also includes a column portion connected to the pole base; the pole group has a width direction, and the pole base extends along the width direction; the pole ear and the column portion are both welded to the pole base, and the pole ear and the column portion are spaced apart in the width direction.

[0009] In any of the above technical solutions, further, the pole group also has a thickness direction perpendicular to the width direction; the pole base includes a first side and a second side opposite to each other in the thickness direction, and the first side of the pole base is provided with a notch, and the notch divides the pole base into a first section and a second section connected to each other; the size of the second section in the thickness direction is larger than the size of the first section in the thickness direction, and the size of the second section in the width direction is smaller than the size of the first section in the width direction; the column portion is welded to the second section, and the pole ear is welded to the first section after being bent through the notch.

[0010] In any of the above technical solutions, further, the tab includes a bending section and a fitting section connected to each other, the welding area is arranged on the fitting section; the bending section is arranged on the defective portion, and the fitting section is fitted with the first section; in the thickness direction, the margins between the welding area and the fitting section on both sides are greater than 0.5 mm, and in the width direction, the margins between the welding area and the fitting section on both sides are greater than 0.5 mm.

[0011] In any of the above technical solutions, further, the cover plate also includes a cover plate body, a connecting block and a first plastic part; the column portion passes through the pole base, the cover plate body, the first plastic part and the connecting block in sequence; the size of the connecting block in the width direction is smaller than the size of the pole base in the width direction.

[0012] In any of the above technical solutions, further, the battery assembly also includes an insulating member; the insulating member includes a top, a side and a bottom; the side is arranged between the cover body and the pole group, and the side is arranged around the pole ear and the cover pole; the bottom is connected to the side, and the bottom is attached between the pole base and the pole group; the top is connected to the side, and part of the top is arranged between the cover body and the pole ear, and part of the top is arranged between the cover body and the cover pole, and the pole ear is provided with a gap from the second side of the pole base for the installation of the top.

[0013] In any of the above technical solutions, further, the battery assembly also includes a sealing plate; the cover plate body and the insulating member are both provided with through holes passing through themselves; the through holes of the cover plate body and the through holes of the insulating member both cover the pole ears, and the sealing plate is welded to the inner wall of the through hole of the cover plate body.

[0014] In any of the above technical solutions, further, β is 1.2N / mm 2 Up to 3.2N / mm 2 , S is 60mm 2 Up to 150mm 2 , F is 130N to 300N.

[0015] According to a second aspect of the present application, a single battery is provided, comprising the battery assembly described above.

[0016] In any of the above technical solutions, further, the single battery includes a first cover plate and a second cover plate, and the first cover plate and the second cover plate are respectively arranged at the two ends of the electrode group; the first cover plate includes a first polarity pole, and the second cover plate includes a second polarity pole; the first polarity pole is the cover plate pole.

[0017] In any of the above technical solutions, further, the single battery further includes an explosion-proof valve; and the explosion-proof valve is provided on the second cover plate.

[0018] The battery assembly of the present application includes a pole group, a tab, and a cover plate. The cover plate includes a cover plate pole, which includes a pole base disposed toward the pole group and in contact with the pole group. The tab extends from the pole group and is welded to the surface of the pole base facing away from the pole group, forming a weld mark on the tab. The area where the weld mark is formed is defined as the weld zone. The battery assembly satisfies the following conditions: β×S>1.5F; where β is the tensile force coefficient that the weld zone can withstand without tearing, S is the area of ​​the weld zone, and F is the thrust force when the battery assembly experiences thermal runaway.

[0019] According to the above technical features, the beneficial effects of this application are:

[0020] This application adjusts the tab welding position to be welded above the pole base. After welding, the tab is firmly fixed to the pole base, and the bottom surface of the pole base is in close contact with the pole group, with no gap between them. If a single cell experiences thermal runaway and the second plastic part of the cover fails due to melting, the pole group can still be prevented from shifting along the length of the pole group due to the strong welding of the tab and the pole base, thereby preventing the pole group from blocking the exhaust passage of the explosion-proof valve on the cover.

[0021] On this basis, the battery assembly of this application meets the following requirements: β×S>1.5F. When the battery assembly meets β×S>1.5F, all thermal runaway safety tests of the battery assembly are passed. After the test, the terminal lugs and the terminal bases remain firmly connected without falling off, and there is no obvious movement of the terminal group.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A partial structural schematic diagram of a battery assembly according to an embodiment of the present application is shown;

[0025] Figure 2 Show Figure 1 A structural diagram from another perspective;

[0026] Figure 3 Show Figure 1 Schematic diagram of the structure after installing the insulation and top cover;

[0027] Figure 4 A front view showing one end of a single battery cell according to an embodiment of the present application;

[0028] Figure 5 Show Figure 4 AA cross-sectional structural diagram;

[0029] Figure 6 Show Figure 4 BB cross-sectional structure diagram;

[0030] Figure 7 A schematic diagram showing an exploded structure of one end of a single battery according to an embodiment of the present application is shown;

[0031] Figure 8 A schematic diagram showing the explosion structure of the other end of a single cell according to an embodiment of the present application;

[0032] Figure 9 A schematic diagram showing the cross-sectional structure of one end of a single cell in the prior art is shown;

[0033] Figure 10 A schematic diagram showing the cross-sectional structure of the other end of a single cell in the prior art is shown;

[0034] Figure 11 A schematic diagram showing the positional relationship between the welding area and the tab fitting section of an embodiment of the present application is shown.

[0035] Icons: 100-ear; 110-bending section; 120-fitting section; 121-welding area; 200-cover; 201-window; 211-pole base; 2111-first section; 2112-second section; 212-column; 220-first plastic part; 230-second plastic part; 240-connecting block; 250-top cover; 300-pole group; 400-insulating part; 410-top; 420-side; 430-bottom; 500-sealing plate; 600-explosion-proof valve; E-ear bending space; X-length direction; Y-width direction; Z-thickness direction. DETAILED DESCRIPTION

[0036] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent upon understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein. Rather, except for operations that must occur in a particular order, changes may be made that will be apparent upon understanding the disclosure of this application. Furthermore, descriptions of features known in the art may be omitted for clarity and brevity.

[0037] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways to implement the methods, devices, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0038] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, it may be directly “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on,” “directly connected to,” “directly coupled to,” “directly over,” or “directly covering” another element, there may be no other elements intervening therebetween.

[0039] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0040] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, a first member, component, region, layer, or portion in the examples described herein may also be referred to as a second member, component, region, layer, or portion without departing from the teachings of the examples.

[0041] For ease of description, spatial relational terms such as "above," "upper," "below," and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element would subsequently be "below" or "lower" relative to the other element. Thus, the term "above" includes both the orientations "above" and "below," depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0042] The terms used herein are intended only to describe various examples and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular is intended to include the plural. The terms "comprise," "include," and "have" list the presence of stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0043] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include changes in shapes that occur during manufacturing.

[0044] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0045] Before this application was proposed, existing long-cell lithium-ion batteries such as Figure 9 and Figure 10 As shown, the electrode group 300 is fixed to the bottom of the cover plate pole base 211 on both sides through the pole ears 100 on both sides by laser welding to achieve electrical connection. In addition, a second plastic cover part 230 is designed at the pole ears on both sides to protect the pole ears 100 and provide a bending space E for the pole ears.

[0046] However, in the above structure, when the battery cell experiences thermal runaway, once the insulating material such as the second plastic part 230 melts and fails, only the electrode group 300 will be left inside the battery cell. This will cause the electrode tab 100 to lose its fixed support and increase in length along the length of the battery cell, resulting in an increase in the gap between the electrode group 300 and the cover plate and the shell. At this time, the electrode group 300 has a high degree of freedom inside the battery cell. When the high-temperature and high-pressure gas is exhausting in the direction of the explosion-proof valve, the electrode group 300 will move randomly with the high-temperature and high-pressure airflow and block the explosion-proof valve and the exhaust channel, thereby greatly reducing the exhaust effect of the explosion-proof valve and reducing the safety performance of the battery cell.

[0047] In addition, the welding between the pole ear 100 and the cover plate pole base 211 of the above structure is not firm. When the high-temperature and high-pressure gas is exhausted in the direction of the explosion-proof valve, the welding point is prone to tearing. The pole group will also move randomly with the high-temperature and high-pressure airflow to block the explosion-proof valve and the exhaust channel, greatly reducing the exhaust effect of the explosion-proof valve and reducing the safety performance of the battery cell.

[0048] In view of this, the first aspect of the present application provides a battery assembly, which solves the problem that when thermal runaway occurs in the existing battery cell, the pole group will randomly move with the high-temperature and high-pressure airflow to block the explosion-proof valve and then block the exhaust channel. Figures 1 to 8 ,as well as Figure 11 The battery assembly according to some embodiments of the present application is described. For ease of description, the following description will be based on an example in which the length direction X, thickness direction Z, and width direction Y of the cover plate pole are perpendicular to each other.

[0049] In addition, for the convenience of description, the electrode tab 100 , the electrode base 211 and the electrode group 300 of the present application and the electrode tab 100 , the electrode base 211 and the electrode group 300 of the prior art use the same reference numerals.

[0050] like Figure 1 and Figure 2 As shown, the battery assembly of the present application includes an electrode group 300, a tab 100 and a cover plate 200. The cover plate 200 includes a cover plate pole, which includes a pole base 211 disposed toward the electrode group 300. The pole base 211 is in contact with the electrode group 300. The tab 100 is led out from the electrode group 300 and welded to the surface of the pole base 211 away from the electrode group 300. Figure 1 As shown, a weld mark is formed on the tab 100, and the area where the weld mark is formed is defined as the welding area 121. The battery assembly satisfies: β×S>1.5F; wherein β is the tensile coefficient that the welding area 121 can withstand without tearing, S is the total area of ​​the welding area 121, and F is the thrust (pulling force) when the battery assembly undergoes thermal runaway.

[0051] In other words, the present application adjusts the welding position of the tab 100 to be welded above the pole base 211. After welding, the tab 100 is firmly fixed to the pole base 211, and the bottom surface of the pole base 211 is in close contact with the pole assembly 300, with no gap between the pole assembly 300 and the pole assembly 300. When a single cell experiences thermal runaway and the second plastic part of the cover plate fails due to melting, the pole assembly 300 can still be prevented from displacing along the length direction X of the pole assembly 300 due to the firm welding of the tab 100 and the pole base 211, thereby preventing the pole assembly 300 from blocking the exhaust passage of the explosion-proof valve on the cover plate.

[0052] On this basis, the battery assembly of the present application satisfies: β×S>1.5F. When the battery assembly satisfies β×S>1.5F, the battery assembly passes all thermal runaway safety tests, and after the test, the tab 100 and the pole base 211 remain firmly connected without falling off, and the pole group 300 has no obvious movement.

[0053] In the embodiment of the present application, it should be noted that the tab 100 and the pole base 211 are laser welded, and a weld mark is formed on the tab 100 that penetrates the tab 100 . The area where the weld mark is formed is the welding area 121 .

[0054] Among them, β is closely related to factors such as the number of tab layers, foil type, and effective welding penetration, and is generally around 1.2N / mm 2Up to 3.2N / mm 2 S can be designed based on the space layout of the cover and the overcurrent requirements of the single battery, and is generally between 60mm 2 Up to 150mm 2 F is the thrust (pulling force) exerted on the electrode assembly 300 along the length direction X of the single cell under the action of high-pressure airflow when the single cell experiences thermal runaway. F is generally between 130N and 300N.

[0055] In order to verify the design effect, different single cells were arranged for welding area verification, and the results are as follows.

[0056]

[0057] It can be seen that when β×S>1.5F, all the thermal runaway safety tests of the single battery cells are passed. After the test, the tab 100 and the pole base 211 are still firmly connected, and there is no obvious movement of the pole group.

[0058] In the embodiment of the present application, in order to facilitate the welding of the tab 100 and ensure the flow area of ​​the tab 100 and the cover plate pole. Figure 2 As shown, the cover plate pole of the present application also includes a column portion 212 connected to the pole base 211, the pole base 211 extends along the width direction Y, the pole tab 100 and the column portion 212 are both welded to the pole base 211, and the pole tab 100 and the column portion 212 are spaced apart in the width direction Y.

[0059] In addition, in order to further facilitate the bending and welding of the tab 100 and the welding of the column 212, Figure 2 As shown, the pole base 211 of the present application includes a first side and a second side that are opposite to each other in the thickness direction Z. The first side of the pole base 211 is provided with a notch, which divides the pole base 211 into a first section 2111 and a second section 2112 that are connected to each other. The second section 2112 has a larger dimension in the thickness direction Z than the first section 2111. As such, the space left by the notch allows the tab 100 to be bent, meaning that the tab 100 can be bent through the notch and then welded to the first section 2111. The second section 2112 has a larger dimension in the thickness direction Z, allowing for welding of the bottom end of the pole portion 212.

[0060] In addition, in this embodiment, Figure 2 As shown, the size of the second section 2112 in the width direction Y is smaller than the size of the first section 2111 in the width direction Y. In this way, the first section 2111 has a larger size in the width direction Y, which can leave enough space for the tab 100 to be welded, thereby improving the welding strength of the tab 100 and ensuring the flow area.

[0061] Specifically, if Figure 1As shown, the tab 100 includes a bending section 110 and a bonding section 120 connected to each other, wherein the bending section 110 is arranged in the defective portion, the bonding section 120 is bonded to the first section 2111 , and the welding area 121 is arranged in the middle of the bonding section 120 .

[0062] The dimension A of the fitting section 120 of the tab 100 in the width direction Y and the dimension B of the fitting section 120 of the tab 100 in the thickness direction Z can be calculated based on the overcurrent requirements of the single battery. Figure 11 As shown, in the thickness direction Z, the margins L1 on both sides of the welding area 121 and the bonding section 120 are both greater than 0.5 mm; in the width direction Y, the margins L2 on both sides of the welding area 121 and the bonding section 120 are both greater than 0.5 mm, which can facilitate welding with an external welding gun and leave a welding position for the welding gun.

[0063] In order to verify the design effect, the results are as follows.

[0064] L1 / mm L2 / mm 1 0.3 0.5 L1＜0.5 L1 is too small, and the tab welding mark has problems with extending outside the tab 2 0.4 0.5 L1＜0.5 L1 is too small, and the tab welding mark has problems with extending outside the tab 3 0.5 0.5 / No abnormality in welding 4 0.5 0.4 L2＜0.5 L2 is too small, and the tab welding mark has problems with extending outside the tab 5 0.5 0.3 L2＜0.5 L2 is too small, and the tab welding mark has problems with extending outside the tab 6 0.5 0.6 / No abnormality in welding 7 0.6 0.7 / No abnormality in welding

[0065] In the embodiments of the present application, Figure 3 and Figure 6 As shown, the cover plate 200 further includes a cover plate body (e.g., a top cover plate 250), a connecting block 240, and a first plastic part 220. The post portion 212 sequentially passes through the pole base 211, the cover plate body, the first plastic part 220, and the connecting block 240. The dimension of the connecting block 240 in the width direction Y is smaller than the dimension of the pole base 211 in the width direction Y.

[0066] In summary, compared to the prior art, the present application lengthens the pole base 211 of the cover plate pole and adjusts the welding position of the pole tab 100 to be welded above the pole base 211. After welding, the pole tab 100 is firmly fixed to the pole base 211, and the bottom surface of the pole base 211 is in close contact with the pole group, with no gap between it and the pole group 300. If a single cell experiences thermal runaway and the second plastic part of the cover plate fails due to melting, the pole group 300 can still be prevented from shifting along the length direction X of the pole group 300 due to the firm welding of the pole tab 100 and the pole base 211, thereby preventing the pole group 300 from blocking the exhaust passage of the explosion-proof valve on the cover plate.

[0067] On this basis, the welding area and welding tension coefficient between the tab 100 and the pole base 211 are reasonably limited to ensure that β×S>1.5F. In this way, it can be ensured that when a single battery cell experiences thermal runaway, the tab 100 and the pole base 211 are firmly welded and will not fall off.

[0068] Furthermore, in an embodiment of the present application, the battery assembly further includes an insulating member 400. Figure 3 、 Figure 5 and Figure 6 As shown, the insulator includes a top portion 410 , side portions 420 , and a bottom portion 430 .

[0069] The top portion 410 is connected to the side portion 420, and a portion of the top portion 410 is disposed between the cover body and the tab 100, and a portion of the top portion 410 is disposed between the cover body and the cover pole. Furthermore, a gap is provided between the tab 100 and the second side of the pole base 211 for the top portion 410 to be installed. Thus, the top portion 410 is disposed between the tab 100 / cover pole and the cover body (e.g., including the top cover sheet 250), providing insulation.

[0070] The side portion 420 is connected to the top portion 410 and is disposed between the cover plate body and the electrode group 300. The side portion 420 surrounds the electrode tab 100 and the cover plate electrode column. The side portion 420 is disposed in such a manner as to be in contact with the electrode group 300 and surround the electrode tab 100 and the cover plate electrode column, thereby protecting the cover plate electrode column and the electrode tab 100 while also providing installation space.

[0071] The bottom 430 is connected to the side 420 and is fitted between the pole base 211 and the pole group 300 . The bottom 430 not only acts as an insulator but also provides support for the pole base 211 , thereby facilitating welding of the tab 100 .

[0072] It is also worth mentioning that Figure 3 and Figure 7 As shown, the battery assembly of the present application also includes a sealing plate 500. The cover plate body (e.g., including the top cover sheet 250) and the insulating member 400 are both provided with through-holes (windows 201) extending therethrough. The through-holes of the cover plate body and the insulating member 400 both cover the tabs 100, and the sealing plate 500 is welded to the inner wall of the through-holes of the cover plate body. In this way, when the single battery is assembled, the tabs 100 can be bent and welded through the through-holes of the cover plate body (e.g., including the top cover sheet 250) and the insulating member 400, and then sealed with the sealing plate 500.

[0073] The specific process is as follows:

[0074] The assembly process of single battery cells is as follows: lamination - pre-welding and cutting of tabs - assembly of pole group and cover plate - bending and welding of tabs to pole base of cover plate - welding of cover plate sealing plate - pole group into shell - welding and sealing of opposite cover plate.

[0075] According to a second aspect of the present application, a single battery is provided, comprising the battery assembly described above.

[0076] Furthermore, if Figure 7 and Figure 8As shown, the single battery includes a first cover plate and a second cover plate, which are respectively arranged at the two ends of the electrode group. The first cover plate includes a first polarity pole, the second cover plate includes a second polarity pole, and the first polarity pole is a cover plate pole.

[0077] That is to say, among the cover plates at both ends of the single battery of the present application (the two cover plates at both ends in the longitudinal direction X), the pole column and the pole ear 100 of one of the cover plates can be designed as above, because the pole ear 100 and the pole column at one end are firmly fixed to limit the displacement of the pole group 300 along the longitudinal direction X, thereby preventing the pole group 300 from blocking the exhaust channel of the explosion-proof valve 600 on the cover plate.

[0078] Furthermore, considering the effective space of the cover plate, the explosion-proof valve 600 can be arranged on the second cover plate, that is, the explosion-proof valve 600 is arranged on the cover plate that does not adopt the above design.

[0079] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the aforementioned embodiments within the technical scope disclosed in the present application, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be covered by the scope of protection of the present application.

Claims

1. A battery assembly, characterized in that: The battery assembly comprises a pole group (300), a pole ear (100) and a cover plate (200); the cover plate (200) comprises a cover plate pole; The cover plate pole comprises a pole base (211) arranged toward the pole group (300), and the pole base (211) is in contact with the pole group (300); The pole lug (100) is led out from the pole group (300) and welded to a surface of the pole base (211) away from the pole group (300), a weld mark is formed on the pole lug (100), and an area where the weld mark is formed is defined as a welding area (121); The battery assembly satisfies: β×S>1.5F; Wherein, β is the tensile force coefficient that the welding area (121) can withstand without tearing, S is the area of ​​the welding area (121), and F is the thrust when thermal runaway occurs in the battery assembly.

2. The battery assembly according to claim 1, characterized in that: The cover plate pole also includes a pole portion (212) connected to the pole base (211); The pole group (300) has a width direction (Y), and the pole base (211) extends along the width direction (Y); The pole tab (100) and the column portion (212) are both welded to the pole base (211), and the pole tab (100) and the column portion (212) are spaced apart in the width direction (Y).

3. The battery assembly according to claim 2, characterized in that: The pole group (300) also has a thickness direction (Z) perpendicular to the width direction (Y); The pole base (211) comprises a first side and a second side opposite to each other in the thickness direction (Z), the first side of the pole base (211) being provided with a notch, the notch dividing the pole base (211) into a first section (2111) and a second section (2112) connected to each other; The dimension of the second section (2112) in the thickness direction (Z) is greater than the dimension of the first section (2111) in the thickness direction (Z), and the dimension of the second section (2112) in the width direction (Y) is smaller than the dimension of the first section (2111) in the width direction (Y); The column portion (212) is welded to the second section (2112), and the electrode tab (100) is bent through the notch portion and then welded to the first section (2111).

4. The battery assembly according to claim 3, characterized in that: The electrode tab (100) comprises a bending section (110) and a bonding section (120) connected to each other, and the welding area (121) is arranged on the bonding section (120); The bending section (110) is arranged at the defective portion, and the fitting section (120) fits with the first section (2111); In the thickness direction (Z), the margins between the welding area (121) and the bonding section (120) on both sides are greater than 0.5 mm, and in the width direction (Y), the margins between the welding area (121) and the bonding section (120) on both sides are greater than 0.5 mm.

5. The battery assembly according to claim 3, characterized in that: The cover plate (200) further comprises a cover plate body, a connecting block (240) and a first plastic part (220); The column portion (212) sequentially passes through the pole base (211), the cover plate body, the first plastic part (220) and the connection block (240); The dimension of the connection block (240) in the width direction (Y) is smaller than the dimension of the pole base (211) in the width direction (Y).

6. The battery assembly according to claim 5, characterized in that: The battery assembly further includes an insulating member (400); The insulating member (400) comprises a top portion (410), a side portion (420) and a bottom portion (430); The side portion (420) is arranged between the cover plate body and the pole group (300), and the side portion (420) is arranged around the pole ear (100) and the cover plate pole; The bottom portion (430) is connected to the side portion (420), and the bottom portion (430) is attached between the pole base (211) and the pole group (300); The top (410) is connected to the side (420), and part of the top (410) is arranged between the cover body and the pole ear (100), and part of the top (410) is arranged between the cover body and the cover pole, and the pole ear (100) is provided with a gap for installing the top (410) from the second side of the pole base (211).

7. The battery assembly according to claim 6, characterized in that: The battery assembly also includes a sealing plate (500); The cover plate body and the insulating member (400) are both provided with through holes penetrating through the cover plate body; The through hole of the cover plate body and the through hole of the insulating member (400) both cover the pole lug (100), and the sealing plate (500) is welded to the inner wall of the through hole of the cover plate body.

8. The battery assembly according to any one of claims 1 to 7, characterized in that: β is 1.2N / mm 2 Up to 3.2N / mm 2 , S is 60mm 2 Up to 150mm 2 , F is 130N to 300N.

9. A single cell battery, characterized in that: A battery assembly as claimed in any one of claims 1 to 8; The single cell comprises a first cover plate and a second cover plate, wherein the first cover plate and the second cover plate are respectively arranged at two ends of the electrode group (300); The first cover plate includes a first polarity pole, and the second cover plate includes a second polarity pole; The first polarity pole is the cover plate pole.

10. The single cell according to claim 9, characterized in that: The single cell further comprises an explosion-proof valve (600); The explosion-proof valve (600) is arranged on the second cover plate.

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