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; when F is greater than or equal to 180N and less than or equal to 300N, t is greater than or equal to 800 microns and less than or equal to 1200 microns, and S is greater than or equal to 90 mm < 2 > and less than or equal to 150 mm < 2 >; wherein S is the area of the welding area, F is the thrust when the battery assembly is subjected to thermal runaway, and t is the welding penetration of the welding area. 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 battery Fig. 9 and Fig.10 As shown, it is usually designed to have pole ears on both sides, and its structure includes: cover plate (with integrated pole column, explosion-proof valve, injection hole, etc.), shell, pole group, electrolyte, etc. After the cover plate and shell are welded, a closed space with certain mechanical strength is formed to protect the pole group; the pole group is fixed to the pole column base of the cover plate on both sides through laser welding through the pole ears on both sides to achieve electrical connection. In addition, the second plastic parts of the cover plate are designed at the pole ears on both sides to protect the pole ears and provide bending space for the pole ears; the cover plate is integrated with an explosion-proof valve structure, which is mainly used for the directional discharge of internal high-temperature and high-pressure gas when the battery has thermal runaway due to internal short circuit, so as to improve the safety performance of the battery.

[0004] The pole ear of the above structure is welded to the bottom of the base of the pole column of the cover plate. 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 thermal runaway occurs in the battery cell 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, for different material systems, cell capacities, voltages, etc., when thermal runaway occurs in the cell, the impact force on the pole group is different due to the different gas production temperatures / gas production volumes / gas production rates, which results in different requirements for the welding of the pole lugs: for the ternary system, the thermal runaway reaction is violent, the gas production temperature is high, the gas production volume is large, and the gas production rate is fast, so the impact force required to be resisted by the pole lug welding is high; for the ordinary iron-lithium system, the thermal runaway reaction is relatively mild, the gas production rate is slow, and the impact force required to be resisted by the pole lug welding is small. However, for the above structures, for different material systems, the welding between the pole lug and the base of the cover plate pole is not firm, the pole lug welding cannot meet the requirements of resisting impact force, the welding is prone to tearing, and it will also block the exhaust channel, greatly reducing the exhaust effect of the explosion-proof valve and the safety performance of the cell. Summary of the invention

[0006] The purpose of the present 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 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.

[0007] According to a first aspect of the present application, a battery assembly is provided, the battery assembly comprising a pole group, a pole ear and a cover plate; the cover plate comprises a cover plate pole; the cover plate pole comprises a pole base arranged toward the pole group, the pole base is in contact with the pole group; the pole ear 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 ear, and the area where the weld mark is formed is defined as a welding area; when 180N≤F≤300N, the battery assembly satisfies: 800μm≤t≤1200μm, and 90mm 2 ≤S≤150mm 2 ; Wherein, S is the area of ​​the welding zone, F is the thrust when the battery assembly undergoes thermal runaway, and t is the welding depth of the welding zone.

[0008] In any of the above technical solutions, further, when 130N≤F<180N, the battery assembly satisfies: 400μm≤t≤800μm, and 50mm 2 ≤S≤90mm 2 .

[0009] 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.

[0010] 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.

[0011] In any of the above technical solutions, further, the cover plate also includes a cover plate body, a rivet block and a first plastic part; the column portion sequentially passes through the pole base, the cover plate body, the first plastic part and the rivet block; the size of the rivet 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;

[0013] The insulating member includes a side portion and a bottom portion connected to each other, wherein the side portion is arranged between the cover plate body and the pole group, and the side portion is arranged around the pole ear and the cover plate pole; the bottom portion is attached between the pole base and the pole group.

[0014] In any of the above technical solutions, further, the insulating member also includes a top connected to the side; a portion of the top is arranged between the cover body and the pole ear, and a portion of the top is arranged between the cover body and the cover pole; a gap is provided between the pole ear and the second side of the pole base for the installation of the top.

[0015] 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 penetrating 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 holes of the cover plate body.

[0016] According to a second aspect of the present application, a single cell is provided, comprising the battery assembly as described above.

[0017] In any of the above technical solutions, further, the single cell includes a first cover plate and a second cover plate, 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, the second cover plate includes a second polarity pole; the first polarity pole is the cover plate pole.

[0018] In any of the above technical solutions, further, the single battery also includes an explosion-proof valve; the explosion-proof valve is arranged on the second cover plate.

[0019] The battery assembly of the present application includes a pole group, a pole ear and a cover plate. The cover plate includes a pole column; the pole column includes a pole column base arranged toward the pole group, and the pole column base is attached to the pole group; the pole ear is led out from the pole group and welded to the surface of the pole column base away from the pole group, and a weld mark is formed on the pole ear, and the area where the weld mark is formed is defined as the welding area; when 180N≤F≤300N, the battery assembly meets the following requirements: 800μm≤t≤1200μm, and 90mm 2 ≤S≤150mm 2 ; Where S is the area of ​​the welding zone, F is the thrust when the battery assembly undergoes thermal runaway, and t is the welding depth of the welding zone.

[0020] According to the above technical features, the beneficial effects of this application are:

[0021] The present application adjusts the welding position of the pole ear to be welded above the pole base. The welded pole ear is firmly fixed on the pole base, and the bottom surface of the pole base is close to the pole group, with no gap between the pole group and the pole group. When a single cell has thermal runaway and the second plastic part of the cover fails due to melting, the pole group can still rely on the firm welding of the pole ear and the pole base without displacement along the length direction of the pole group, thereby preventing the pole group from blocking the exhaust channel of the explosion-proof valve on the cover.

[0022] On this basis, for the single cell of the ternary system, the thrust F (thrust is related to the gas production temperature / gas production volume / gas production rate) when thermal runaway occurs is generally between 180N and 300N. The battery assembly of this application meets the following conditions: when 180N≤F≤300N, 800μm≤t≤1200μm, and 90mm 2 ≤S≤150mm 2 .

[0023] When the battery component meets 800μm≤t≤1200μm and 90mm 2 ≤S≤150mm 2 All the thermal runaway safety tests of the battery components were passed. The welding strength of the pole lugs was able to withstand the impact of high-temperature and high-pressure gas on the pole group during thermal runaway of the single battery. After the test, the pole lugs were still firmly connected to the pole base and would not fall off.

[0024] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. 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 related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A partial structural schematic diagram of a battery assembly according to an embodiment of the present application is shown;

[0027] Figure 2 Show Figure 1 A structural diagram from another perspective;

[0028] Figure 3 Show Figure 1 Schematic diagram of the structure after installing the insulation and the top cover;

[0029] Figure 4 A front view showing one end of a single cell according to an embodiment of the present application;

[0030] Figure 5 Show Figure 4 AA cross-sectional structural diagram;

[0031] Figure 6 Show Figure 4 BB cross-sectional structure diagram;

[0032] Figure 7 A schematic diagram showing an exploded structure of one end of a single cell according to an embodiment of the present application;

[0033] Figure 8 A schematic diagram showing an exploded structure of the other end of a single cell according to an embodiment of the present application;

[0034] Fig. 9 A schematic diagram showing a cross-sectional structure of one end of a single cell in the prior art is shown;

[0035] Fig.10 A schematic cross-sectional structure diagram of the other end of a single cell in the prior art is shown.

[0036] Icons: 100-ear; 110-bending section; 120-fitting section; 121-welding area; 200-cover plate; 201-window; 211-pole base; 2111-first section; 2112-second section; 212-column; 220-first plastic part; 230-second plastic part; 240-riveting block; 250-top cover plate; 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

[0037] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0038] The components of the embodiments of the present application generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed, but merely represents the selected embodiments of the present application.

[0039] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0040] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application 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 therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] Prior to the present application, existing long-cell lithium-ion batteries such as Fig. 9 and Fig.10 As shown, the pole group 300 is fixed to the bottom of the cover plate pole base 211 on both sides by laser welding through the pole ears 100 on both sides to achieve electrical connection. In addition, a second cover plate plastic 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.

[0043] However, in the above structure, when thermal runaway occurs in the battery cell, 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 pole ear 100 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 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 to 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.

[0044] In addition, for different material systems, cell capacities, voltages, etc., when thermal runaway occurs in the cell, the impact force on the electrode group 300 is different due to the different gas production temperatures / gas production volumes / gas production rates, and thus different requirements are placed on the welding of the pole lug 100: for the ternary system, the thermal runaway reaction is violent, the gas production temperature is high, the gas production volume is large, and the gas production rate is fast, so the impact force required to be resisted by the welding of the pole lug 100 is large; for the ordinary iron-lithium system, the thermal runaway reaction is relatively mild, the gas production rate is slow, and the impact force required to be resisted by the welding of the pole lug 100 is small. However, for the above structures, for different material systems, the welding of the pole lug 100 and the cover plate pole base 211 is not firm, the pole lug welding cannot meet the requirements of resisting impact force, the welding is prone to tearing, and it will also block the exhaust channel, greatly reducing the exhaust effect of the explosion-proof valve and reducing the safety performance of the cell.

[0045] In view of this, the first aspect of the present application provides a battery assembly, thereby solving the problem that when thermal runaway occurs in the existing battery cell, 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. Figures 1 to 8 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.

[0046] In addition, for the convenience of description, the pole tab 100 , pole base 211 and pole group 300 of the present application and the pole tab 100 , pole base 211 and pole group 300 of the prior art use the same reference numerals.

[0047] like Figure 1 and Figure 2As shown, the battery assembly of the present application includes a pole group 300, a pole ear 100 and a cover plate 200. Among them, the cover plate 200 includes a cover plate pole; the cover plate pole includes a pole base 211 arranged toward the pole group, and the pole base 211 is attached to the pole group 300; the pole ear 100 is led out from the pole group 300 and welded to the surface of the pole base 211 away from the pole group, and a weld mark is formed on the pole ear, and the area where the weld mark is formed is defined as the welding area; when 180N≤F≤300N, the battery assembly meets: 800μm≤t≤1200μm, and 90mm 2 ≤S≤150mm 2 ; Wherein, S is the area of ​​the welding area 121, F is the thrust when the battery assembly undergoes thermal runaway, and t is the welding depth of the welding area 121.

[0048] That is to say, the present application adjusts the welding position of the pole tab 100 to be welded above the pole base 211, and the welded pole tab is firmly fixed on the pole base 211, and the bottom surface of the pole base 211 is in close contact with the pole group 300, with no gap between the pole group 300. When a single cell has thermal runaway and the second plastic part of the cover fails due to melting, the pole group 300 can still rely on the firm welding of the pole tab 100 and the pole base 211 without displacement along the length direction of the pole group, thereby preventing the pole group from blocking the exhaust channel of the explosion-proof valve on the cover.

[0049] On this basis, for the single cell of the ternary system, the thrust F (thrust is related to the gas production temperature / gas production volume / gas production rate) when thermal runaway occurs is generally between 180N and 300N. The battery assembly of this application meets the following conditions: when 180N≤F≤300N, 800μm≤t≤1200μm, and 90mm 2 ≤S≤150mm 2 .

[0050] When the battery component meets 800μm≤t≤1200μm and 90mm 2 ≤S≤150mm 2 All the thermal runaway safety tests of the battery components were passed. The welding strength of the pole lugs was able to withstand the impact of high-temperature and high-pressure gas on the pole group during thermal runaway of the single battery. After the test, the pole lugs were still firmly connected to the pole base without falling off, and there was no obvious movement of the pole group 300.

[0051] In the embodiment of the present application, it should be noted that the pole tab 100 and the pole base 211 are laser welded, and a weld mark penetrating the pole tab 100 is formed, and the area where the weld mark is formed is the welding area 121. Preferably, during laser welding, the welding penetration of the pole base 211 can be 0, so that the welding penetration t of the pole tab welding area is the thickness of the pole tab.

[0052] In order to verify the design effect, different single cells were arranged for actual measurement and verification, and the results are as follows.

[0053] Example 1, ternary NCM system, single cell capacity 115Ah, voltage 3.5V:

[0054] t / μm <![CDATA[S / mm 2 ]]> Verify the effect 1 1200 70 The proportion of side spray in single battery is 1 / 5, the pole ear falls off from the pole base, and the pole group moves to block the explosion-proof valve. 2 1100 80 The proportion of single battery fires is 2 / 5, the pole ear falls off from the pole base, and the pole group moves to block the explosion-proof valve 3 1000 85 The proportion of single battery fires is 1 / 5, the pole ear falls off from the pole base, and the pole group moves to block the explosion-proof valve 4 900 90 The safety test passed and the explosion-proof valve opened normally 5 800 90 The safety test passed and the explosion-proof valve opened normally 6 800 95 The safety test passed and the explosion-proof valve opened normally 7 750 100 The safety test passed the rate of 1 / 5, there are single battery explosion-proof valve exhaust is not smooth, shell rupture, fire problems 8 700 110 The safety test passed the rate of 2 / 5, there are single battery explosion-proof valve exhaust is not smooth, shell cracking, fire problems 9 650 120 The safety test passed the rate of 1 / 5, there are single battery explosion-proof valve exhaust is not smooth, shell cracking problem

[0055] It can be seen that for the ternary system, the welding depth t must be between 800μm and 1200μm, and the effective welding area S of the welder must be between 90mm 2 Up to 150mm 2 The welding strength of the pole ear is sufficient to resist the impact of high-temperature and high-pressure gas on the pole group during thermal runaway, and keep it firmly welded to the pole base without falling off.

[0056] In addition, for single cells of the iron-lithium system, the thrust F (thrust is related to gas production temperature / gas production volume / gas production rate) when thermal runaway occurs is generally between 130N and 180N. The battery assembly of this application meets the following requirements: 400μm≤t≤800μm, and 50mm 2 ≤S≤90mm 2 .

[0057] When the battery assembly meets 130N≤F≤180N, 400μm≤t≤800μm, and 50mm 2 ≤S≤90mm 2 All the thermal runaway safety tests of the battery components were passed. The welding strength of the pole lugs was able to withstand the impact of high-temperature and high-pressure gas on the pole group during thermal runaway of the single battery. After the test, the pole lugs were still firmly connected to the pole base without falling off, and there was no obvious movement of the pole group 300.

[0058] Example 2, iron-lithium system, capacity 120Ah, voltage 3.2V:

[0059]

[0060] It can be seen that for the iron-lithium system, the welding depth t must be between 400μm and 800μm, and the effective welding area of ​​the welder must be 50mm 2 Up to 90mm 2 The welding strength of the pole ear is sufficient to resist the impact of high-temperature and high-pressure gas on the pole group when the battery cell is thermally runaway, and keep it firmly welded to the pole base without falling off.

[0061] 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 2As 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 ear 100 and the column portion 212 are both welded to the pole base 211, and the pole ear 100 and the column portion 212 are spaced apart in the width direction Y.

[0062] In addition, the bending and welding of the tab 100 and the welding of the column 212 are further facilitated. Figure 2 As shown, the pole base 211 of the present application includes a first side and a second side opposite to each other in the thickness direction Z, and a notch is provided on the first side of the pole base 211. The notch divides the pole base 211 into a first section 2111 and a second section 2112 connected to each other, wherein the size of the second section 2112 in the thickness direction Z is greater than the size of the first section 2111 in the thickness direction Z. In this way, the space left by the notch can be bent by the tab 100, that is, the tab 100 can be welded to the first section 2111 after being bent through the notch. The second section 2112 has a large size in the thickness direction Z, and can be welded to the bottom end of the column 212.

[0063] 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 size of the first section 2111 in the width direction Y is large, and sufficient space can be reserved for welding the tab 100, which can not only improve the welding strength of the tab 100, but also ensure the flow area.

[0064] Specifically, Figure 1 As 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 at 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 .

[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 (for example, a top cover sheet 250), a riveting 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 riveting block 240, and the size of the riveting block 240 in the width direction Y is smaller than the size of the pole base 211 in the width direction Y.

[0066] In summary, compared with the prior art, the present application lengthens the pole base 211 of the pole of the cover plate, and adjusts the welding position of the pole ear 100 to be welded above the pole base 211. The pole ear 100 after welding is firmly fixed on the pole base 211, and the bottom surface of the pole base 211 is close to the pole group, and there is no gap between the pole group 300. When thermal runaway occurs in the single cell and the second plastic part of the cover plate fails due to melting, the pole group 300 can still rely on the firm welding of the pole ear 100 and the pole base 211 without displacement along the length direction X of the pole group 300, thereby preventing the pole group 300 from blocking the exhaust channel of the explosion-proof valve on the cover plate.

[0067] In addition, for different single-cell battery systems, the effective melting depth and effective area of ​​the pole ear welding are reasonably designed to meet the overcurrent requirements of the single-cell battery while ensuring that the pole ear welding is firm. When the single-cell battery has thermal runaway, the welding force between the pole ear and the pole base is sufficient to resist the impact force of the internal gas of the single-cell battery on the pole group along the length direction, thereby ensuring that the pole group will not be displaced along the length direction and block the explosion-proof valve on the opposite cover plate, greatly improving the safety performance of the battery cell.

[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 410 is connected to the side 420, part of the top 410 is arranged between the cover body and the pole ear 100, 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 the installation of the top 410 from the second side of the pole base 211. In this way, the top 410 is arranged between the pole ear 100 / cover pole and the cover body (for example, including the top cover sheet 250), which plays an insulating role.

[0070] The side portion 420 is connected to the top portion 410, and the side portion 420 is disposed between the cover plate body and the pole group 300, and the side portion 420 is disposed around the pole lug 100 and the cover plate pole column. In this way, the side portion 420 is disposed with the pole group 300, and around the pole lug 100 and the cover plate pole column, which can protect the cover plate pole column and the pole lug 100 while providing installation space.

[0071] The bottom 430 is connected to the side 420 , and the bottom 430 is attached between the pole base and the pole group 300 . The bottom 430 can provide support for the pole base 211 while serving as insulation, thereby facilitating welding of the pole tab 100 .

[0072] It is also worth mentioning that Figure 3 and Figure 7As shown, the battery assembly of the present application also includes a sealing plate 500. The cover plate body (for example, including the top cover sheet 250) and the insulating member 400 are both provided with through holes (opening windows 201) penetrating through them, and the through holes of the cover plate body and the through holes of 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 specifically assembled, the tabs 100 can be bent and welded through the through holes of the cover plate body (for example, including the top cover sheet 250) and the insulating member 400, and then sealed with the sealing plate 500 after welding.

[0073] The specific process is as follows:

[0074] The assembly process of the single cell is as follows: lamination - pre-welding and cutting of the pole lugs - assembly of the pole group and the cover plate - bending and welding of the pole lugs to the pole column base of the cover plate - welding of the cover plate sealing plate - pole group into the shell - welding and sealing of the opposite side cover plate.

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

[0076] Furthermore, if Figure 7 and Figure 8 As shown, the single cell includes a first cover plate and a second cover plate, which are respectively arranged at 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 cell of the present application (the two cover plates at both ends in the length 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 length 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 protection scope 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 protection scope 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, and the pole base (211) is in contact with the pole group (300); The pole lug 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, and an area where the weld mark is formed is defined as a welding area (121); When 180N≤F≤300N, the battery assembly meets the following requirements: 800μm≤t≤1200μm, and 90mm 2 ≤S≤150mm 2 ; Wherein, S is the area of ​​the welding area (121), F is the thrust when the battery assembly undergoes thermal runaway, and t is the welding penetration of the welding area (121).

2. The battery assembly according to claim 1, characterized in that: When 130N≤F<180N, the battery assembly meets the following requirements: 400μm≤t≤800μm, and 50mm 2 ≤S≤90mm 2 .

3. 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).

4. The battery assembly according to claim 3, 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).

5. The battery assembly according to claim 3, characterized in that: The cover plate (200) further comprises a cover plate body, a riveting 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 riveting block (240); The dimension of the rivet 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 side portion (420) and a bottom portion (430) connected to each other, the side portion (420) being arranged between the cover plate body and the pole group (300), and the side portion (420) being arranged around the pole lug (100) and the cover plate pole; The bottom (430) is fitted between the pole base (211) and the pole group (300).

7. The battery assembly according to claim 6, characterized in that: The insulating member (400) further includes a top portion (410) connected to the side portion (420); The top portion (410) is disposed between the cover plate body and the pole lug (100), and the top portion (410) is disposed between the cover plate body and the cover plate pole; A gap is provided between the pole ear (100) and the second side of the pole base (211) for installing the top portion (410).

8. 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.

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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