CN219643070U - Battery cell - Google Patents

Abstract

The utility model relates to the technical field of batteries, and proposes a battery, comprising: a battery case, along the thickness direction of the battery, the distance between two opposite outer surfaces of the battery case is a, along the thickness direction of the battery, The battery has two opposite large surfaces; the cell, the cell is arranged in the battery case, the cell includes the cell body and the tab, the tab is drawn out from the cell body, and the tab is formed by a plurality of single-piece tabs. The distance between the end of the first single-piece tab and the end of the second single-piece tab is b; the pole, the pole is arranged on the battery case, and the pole and the tab are welded to form a welding mark , along the thickness direction of the battery, the maximum width of the solder print is c, b≤(a‑c)/2, which can not only ensure the energy density of the battery, but also avoid the influence of the excessive length of the staggered layer of the monolithic tab. The welding quality of the pole and the tab can be improved, and the problem of blasting holes in the welding of the pole and the tab can be avoided, thereby improving the safe use performance of the battery.

Description

Battery

technical field

The utility model relates to the technical field of batteries, in particular to a battery.

Background technique

In the related technology, the battery includes a battery case and a battery cell arranged in the battery case, and the battery cell is mostly electrically connected to the pole. However, due to the structural limitations of the tab itself, unstable connection between the tab and the pole is prone to occur. question.

Utility model content

The utility model provides a battery to improve the service performance of the battery.

The utility model provides a battery, comprising:

The battery casing, along the thickness direction of the battery, the distance between the two opposite outer surfaces of the battery casing is a, and along the thickness direction of the battery, the battery has two opposite large surfaces;

The battery, the battery is set in the battery case, the battery includes the main body of the battery and the tabs, the tabs are drawn out from the main body of the battery, and the tabs are formed by folding together a plurality of single-piece tabs, along the leading direction of the tabs, Among the multiple single-piece tabs that are folded, the end that is closest to the main body of the battery cell is the first single-piece tab, and among the multiple single-piece tabs that are folded, the end that is farthest from the main body of the battery cell is the second single-piece tab. ear, the distance between the end of the first monolithic tab and the end of the second monolithic tab is b;

The pole, the pole is set on the battery case, and the pole is welded to the tab to form a weld mark. Along the thickness direction of the battery, the maximum width of the weld mark is c, b≤(a-c)/2.

The battery of the embodiment of the utility model includes a battery case, a battery cell and a pole. The battery cell is arranged in the battery case, the pole is arranged on the battery case, and the pole is welded to the tab of the battery cell. The distance between the two opposite outer surfaces of the battery case is a, and the tabs are formed by folding together a plurality of single-piece tabs. The closest to the main body of the core is the first single-piece tab, and the end of the folded multiple single-piece tabs is the farthest from the core body is the second single-piece tab, and the end of the first single-piece tab is connected to the second The distance between the ends of the two monolithic tabs is b, that is, the staggered length of the monolithic tab is b, and along the thickness direction of the battery, the maximum width of the solder print 1 is c, by making b≤(a-c )/2, not only can ensure the energy density of the battery, but also can avoid the excessive length of the staggered layer of a single tab and affect the welding quality of the pole and the tab, and can avoid the problem of blasting holes in the welding of the pole and the tab. In this way, the safe use performance of the battery can be improved.

Description of drawings

For a better understanding of the present disclosure, reference may be made to the embodiments illustrated in the following figures. Components in the drawings are not necessarily to scale, and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present disclosure. In addition, related elements or components may be arranged differently as known in the art. In addition, in the drawings, the same reference numerals denote the same or similar components in the respective drawings.

in:

Fig. 1 is a schematic structural view of a battery according to an exemplary embodiment;

Fig. 2 is a schematic structural diagram of a partially assembled state of a battery according to an exemplary embodiment;

Fig. 3 is a partial structural schematic diagram of a battery according to an exemplary embodiment;

Fig. 4 is a schematic diagram showing the distribution structure of a single tab of a battery according to an exemplary embodiment.

The reference signs are explained as follows:

1. Welding mark; 2. Pre-connected welding mark; 10. Battery shell; 11. Shell parts; 12. Cover plate; 20. Battery core; 21. Main body of battery core; 22. Tabs; ear; 30, pole.

Detailed ways

The following will clearly and completely describe the technical solutions in the exemplary embodiments of the present disclosure with reference to the accompanying drawings in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are for illustrative purposes only, and are not intended to limit the protection scope of the present disclosure, so it should be understood that various modifications can be made to the exemplary embodiments without departing from the protection scope of the present disclosure. modifications and changes.

In the description of the present disclosure, unless otherwise clearly specified and limited, the terms "first" and "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance; the term "plurality" is means two or more; the term "and/or" includes any and all combinations of one or more of the associated listed items. In particular, references to "the" or "an" are likewise intended to mean one of a possible plurality of such objects.

Unless otherwise specified or explained, the terms "connected" and "fixed" should be interpreted in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or integral connection, or electrical connection, or Connection; "connection" can be a direct connection or an indirect connection through an intermediary. Those skilled in the art can understand the specific meanings of the above terms in the present disclosure according to specific situations.

Furthermore, in the description of the present disclosure, it should be understood that the orientation words such as "upper", "lower", "inner" and "outer" described in the exemplary embodiments of the present disclosure are based on the angles shown in the drawings It should not be construed as limiting the example embodiments of the present disclosure. It also needs to be understood that in this context, when an element or feature is referred to as being "on," "under," or "inside" or "outside" another element(s), it is not only a direct connection In other (one or more) elements "on", "under" or "inside", "outside", it can also be indirectly connected to another (one or more) elements "on", "under" or "outside" through intermediate elements inside and outside".

An embodiment of the present invention provides a battery, please refer to Figure 1 to Figure 4, the battery includes: a battery case 10, along the thickness direction of the battery, the distance between the two opposite outer surfaces of the battery case 10 is a, along the thickness direction of the battery, the battery has two opposite large surfaces; the battery cell 20, the battery cell 20 is arranged in the battery case 10, the battery cell 20 includes a battery cell main body 21 and a tab 22, the tab 22 Leading out from the main body 21 of the battery cell, the tab 22 is formed by gathering a plurality of single-piece tabs 221 . Along the direction in which the tab 22 is pulled out, the middle ends of the folded multiple single-piece tabs 221 are closest to the main body 21 of the battery cell. It is the first single-piece tab, and the end of the multiple single-piece tabs 221 after being folded is the second single-piece tab. The distance between the ends of the tab tabs is b; the pole 30, the pole 30 is arranged on the battery case 10, and the pole 30 is welded to the tab 22 to form a welding mark 1, along the thickness direction of the battery , the maximum width of solder print 1 is c, b≤(a-c)/2.

The battery of one embodiment of the present invention includes a battery case 10, a cell 20 and a pole 30, the cell 20 is arranged in the battery case 10, the pole 30 is arranged on the battery case 10, the pole 30 and the cell 20 tabs 22 are welded. The distance between the two opposite outer surfaces of the battery case 10 is a, and the tab 22 is formed by folding together a plurality of single-piece tabs 221 . The one whose middle end is the closest to the cell main body 21 is the first single-piece tab, and the middle end of the folded multiple single-piece tabs 221 is the second single-piece tab which is farthest from the cell main body 21, and the first single-piece tab is the farthest. The distance between the end of the sheet tab and the end of the second single sheet tab is b, that is, the staggered length of the single sheet tab 221 is b, and along the thickness direction of the battery, the maximum width of the solder print 1 is c, by making b≤(a-c)/2, not only the energy density of the battery can be guaranteed, but also the excessive length of the single tab 221 can be avoided from affecting the welding quality of the pole 30 and the tab 22, and it can be avoided The welding of the pole 30 and the tab 22 has the problem of blast holes, thereby improving the safe performance of the battery.

It should be noted that, along the thickness direction of the battery, the distance between the two opposite outer surfaces of the battery case 10 is a, and along the direction in which the tabs 22 are led out, the length of the staggered layers of the single tab 221 is b. However, the maximum width of the welding mark 1 formed after the pole 30 and the tab 22 is welded is c, and the length of the staggered layer of the single-piece tab 221 is too small, that is, the folded and bent size of the single-piece tab 221 will be relatively small, which can be It is considered that the thickness of the battery is small, which affects the energy density of the battery; and when the staggered length of the single tab 221 is too large, it may affect the welding quality of the pole 30 and the tab 22, for example, the pole 30 and the tab 22 The connection strength is weak, and when the staggered length of the single-piece tab 221 is too large, in severe cases, the problem of blast holes may occur, which seriously affects the welding quality of the pole 30 and the tab 22 . In this implementation, by making b≦(a-c)/2, the problem that the length of the single tab 221 is too long can be avoided, thereby fully ensuring the welding quality of the pole 30 and the tab 22 .

As shown in FIG. 1 , the thickness direction of the battery can be considered as a direction perpendicular to the large surface of the battery case 10 , that is, along the thickness direction of the battery, the battery has two opposite large surfaces. Further, the thickness direction of the battery can be considered to be a direction perpendicular to the large surface of the battery cell 20, and the large surface of the battery cell 20 can be considered to be the surface with the largest area of the battery cell 20. Further, the large surface of the battery cell 20 can be considered to be The area of the battery cell 20 with the largest heat generation, for example, the battery cell 20 is a square battery cell, and the battery cell 20 has two large surfaces, and the two large surfaces of the battery cell 20 are arranged opposite to each other.

Correspondingly, the lead-out direction of the tab 22 can be considered as the extension direction of the tab 22 after the tab 22 is straightened. Further, the tab 22 can be formed by gathering a plurality of single-piece tabs. After the ear is straightened, the direction in which the single-piece tab extends from the pole piece is the lead-out of the tab 22 .

As shown in FIG. 2 , the battery case 10 includes a case part 11 and a cover plate 12 . Along the thickness direction of the battery, the distance between the two opposite outer surfaces of the battery case 10 is a, which can further be regarded as the width of the cover plate 12 as a, as shown in FIG. 2 .

As shown in FIG. 4 , the tab 22 is formed by gathering a plurality of single-piece tabs 221 . For example, a plurality of single-piece tabs 221 can be gathered toward the middle single-piece tab 221 , so that multiple single-piece tabs can be folded together. The ear 221 forms a staggered layer, and the end of the plurality of single-piece tabs 221 after being folded is the first single-piece tab that is closest to the cell main body 21, that is, the single-piece tab 221 located in the middle is the first single-piece tab. ear, and the end of the plurality of single-piece tabs 221 after being folded is the second single-piece tab, that is, the single-piece tab 221 located on the outermost side is the second single-piece tab. The distance between the end of the first monolithic tab and the end of the second monolithic tab is denoted as b. Of course, multiple monolithic tabs 221 can also be folded towards other positions, for example, towards the outermost monolithic tab 221. At this time, the first monolithic tab and the second monolithic pole can still be determined. ear, and the distance b between the end of the first monolithic tab and the end of the second monolithic tab can be obtained.

As shown in Figure 2, the pole 30 and the tab 22 are welded to form a solder mark 1. Along the thickness direction of the battery, the maximum width of the solder mark 1 is denoted as c, and the width of the solder mark 1 can ensure that the pole 30 and the tab 22 welding quality.

In one embodiment, as shown in FIG. 1 , the battery can be a quadrangular prism battery, that is, the battery can include two opposite large surfaces and four small surfaces surrounding the large surfaces.

The quadrangular prismatic battery mainly refers to the shape of a prism, but it is not strictly limited whether each side of the prism must be a straight line in the strict sense, and the corners between sides are not necessarily right angles, but can be arc transitions. It should be noted that the battery can be a prismatic battery, for example, the battery can be a pentagonal prism battery, the battery can be a hexagonal prism battery, the battery can be a heptagonal prism battery, etc., as long as it is ensured that along the thickness direction of the battery, It is sufficient for the battery to have two large opposing surfaces.

In one embodiment, the distance b between the end of the first monolithic tab and the end of the second monolithic tab is ≤ 10 mm, so as to prevent the excessive length of the monolithic tab 221 from affecting the The welding quality of the pole post 30 and the tab 22 can be improved, and the problem of blast holes in the welding of the pole post 30 and the tab 22 can be avoided.

In one embodiment, the distance b between the end of the first monolithic tab and the end of the second monolithic tab is greater than or equal to 0.5mm, thereby ensuring that the battery core body 21 has a certain thickness, thereby ensuring The capacity of the battery cell 20.

In one embodiment, the distance b between the end of the first monolithic tab and the end of the second monolithic tab can be 0.5mm-10mm, so that the staggered layers of the monolithic tab 221 can be reliably controlled length, and the capacity of the battery cell 20 can be guaranteed.

The distance b between the end of the first monolithic tab and the end of the second monolithic tab can be 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5 mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm or 10mm, etc.

In one embodiment, the pole 30 and the tab 22 can be connected through other components, for example, the pole 30 and the tab 22 can be connected through an adapter piece, and the pole 30, the pole ear 22 and the adapter piece can be directly connected to each other. Soldering, thereby forming a solder print 1. Alternatively, the pole post 30 is welded to the adapter piece, and the adapter piece is welded to the tab 22 . At this time, the adapter piece and the tab 22 form a welding mark 1 .

In one embodiment, the pole post 30 and the tab 22 are directly welded, thereby reducing the number of parts of the battery. Reducing the use of battery components can not only reduce the cost and weight of the battery, but also increase the energy density of the battery, as shown in Figure 3.

In one embodiment, the welding mark 1 is a laser welding mark, so that the connection strength between the pole 30 and the tab 22 can be improved, thereby improving the safe use performance of the battery, avoiding the risk of connection failure, and improving to a certain extent battery life.

In one embodiment, as shown in FIG. 2 , a plurality of monolithic tabs 221 are welded to form pre-soldering marks 2, and soldering marks 1 cover pre-soldering marks 2, and pre-soldering marks 2 and soldering marks 1 are formed sequentially, namely The tab 22 is welded twice, so that the welding energy can be better controlled, the damage to the tab 22 can be prevented, and the connection strength between the pole post 30 and the tab 22 can be ensured.

Solder mark 1 covers pre-weld mark 2, that is, after the first welding to form pre-weld mark 2, when performing the second welding, welding is still performed in the area of pre-weld mark 2, so that the pre-weld mark 2 can be welded Solder print 1 is formed on print 2.

The whole of the solder print 1 may be located in the pre-soldering pad 2; or, part of the solder pad 1 may be located in the pre-soldered pad 2.

The tab 22 includes a plurality of single-piece tabs 221, and the plurality of single-piece tabs 221 are welded to form a pre-welding mark 2, that is, the pre-welding mark 2 can be formed by directly pre-welding the tab 22, that is, on the opposite pole Before welding the lug 22 and the pole 30, the lug 22 is pre-welded, so that the multiple single-piece lugs 221 of the lug 22 are combined together, and the structural strength of the lug 22 is also improved to a certain extent. All the individual pieces of tabs 221 in the tabs 22 are combined together, and the strength of the tabs 22 is relatively high, so that when the tabs 22 and the poles 30 are welded, even if the welding energy is relatively large, due to the pre-connection The existence of soldering mark 2, and soldering mark 1 is carried out on the basis of pre-welded soldering mark 2, pre-welded soldering mark 2 strengthens the strength of tab 22, so that the probability of damage to tab 22 is greatly increased during secondary welding decline.

The pre-welding mark 2 and the welding mark 1 are formed sequentially, that is, in the process of forming the welding mark 1, because it is carried out in the pre-welding mark 2, even though the welding energy is relatively large, because the pre-welding mark 2 strengthens the pole The strength of the ear 22, so the damage to the pole ear 22 is avoided.

In one embodiment, along the thickness direction of the battery, the maximum width of the pre-welding mark 2 is d, and along the extending direction of the tab 22, the distance between the pre-welding mark 2 and the main body 21 of the battery cell is e, (d-c)/2<e<4+(a-c)/2, so as to ensure that the distance between the pre-soldered solder mark 2 and the battery core body 21 is kept within a certain range, and the basis for avoiding the redundancy of the tab 22 In addition, it can also avoid the problem that the pre-soldering print 2 is too close to the staggered layer area of the monolithic tab 221.

As shown in FIG. 2 , along the thickness direction of the battery, the maximum width of the pre-welding mark 2 is denoted as d, and along the extension direction of the tab 22, the distance between the pre-welding mark 2 and the main body 21 of the battery is denoted as is e, that is to say, after the cover plate 12 and the shell part 11 are separated, during the welding process of the tab 22 and the pole 30, along the direction of the tab 22, the tab 22 and the main body of the cell The distance between one end connected with 21 and the side of the pre-soldering mark 2 close to the cell main body 21 is denoted as e, as shown in FIG. 2 .

If the distance e between the pre-welding print 2 and the battery main body 21 is too small, at this time, the free end of the tab 22 may be relatively large, thereby causing the problem of redundancy of the tab 22; while the pre-welding print 2 and the When the distance e between the cell main bodies 21 is too large, the pre-welding marks 2 will be biased towards the staggered positions of the single-piece tabs 221 for welding, which may cause the problem of poor welding quality of multiple single-piece tabs 221 . Poor welding problems may occur between certain monolithic tabs 221 .

In one embodiment, the pre-welding mark 2 is an ultrasonic welding mark, which can not only ensure the connection ability between multiple single-piece tabs 221 , but also avoid the problem of damage to the single-piece tab 221 during the welding process.

In one embodiment, the number of multiple single-piece tabs 221 is 30-150, so as to reliably control the number of single-piece tabs 221, ensure the capacity of the battery cell 20, and avoid single-piece tabs 221 to a certain extent. The problem of too serious dislocation.

The number of multiple single tabs 221 can be 30, 31, 32, 33, 35, 40, 45, 50, 55, 60, 70, 80, 90, 95, 100, 105, 110, 115, 120, 125 , 130, 135, 140, 145 or 150 and so on.

In one embodiment, along the lead-out direction of the tabs 22, the dimensions of the plurality of single-piece tabs 221 after straightening are consistent, so that the manufacture of the battery cell 20 can be facilitated, and the forming efficiency of the battery can be improved to a certain extent. .

In one embodiment, as shown in FIG. 1 , the battery case 10 includes a case part 11 and a cover plate 12, the case part 11 forms an accommodation space, the cover plate 12 is a flat plate, and the pole 30 is arranged on the cover plate 12 , so that the setting of the pole 30 can be facilitated, and the connection between the pole 30 and the tab 22 can also be facilitated, and when the pole 30 and the tab 22 are connected, the battery cell 20 can also be conveniently installed on the casing 11 in the accommodation space.

The pole 30 is arranged on the cover plate 12, and the cover plate 12 is a flat plate. Therefore, when the pole 30 and the tab 22 are welded, other structures can be avoided from affecting the welding of the pole 30 and the tab 22. After 30 is connected to the tab 22 , the battery cell 20 can be installed in the accommodation space of the housing part 11 , and the connection between the cover plate 12 and the housing part 11 is completed.

Along the thickness direction of the battery, the width of the cover plate 12 is a.

It should be noted that the shell part 11 and the cover plate 12 can be provided independently, and the shell part 11 and the cover plate 12 can be welded. In some embodiments, it is not excluded that the housing part 11 and the cover plate 12 may be an integral structure, and the accommodating space for the electric core 20 is formed by stamping, and then sealed and connected by welding.

The housing part 11 may be a structure with one end closed. At this time, two poles 30 may be provided on the cover plate 12, and the two poles 30 may be respectively connected to the two tabs 22 of the electric core 20. At this time, The two tabs 22 of the battery cell 20 can be positive tabs and negative tabs respectively; or, the housing part 11 can include a cover plate and a shell with openings at both ends. At this time, the two opposite cover plates can be respectively A pole 30 is provided. The specific structural form of the housing part 11 is not limited.

In one embodiment, along the thickness direction of the battery, only one battery cell 20 is disposed in the battery case 10 , so that the installation of the battery cell 20 is facilitated, and the connection between the tab 22 and the pole 30 is also facilitated.

In one embodiment, along the thickness direction of the battery, at least two battery cells 20 are arranged in the battery casing 10, so that the capacity of the battery can be improved, and the battery cells 20 with a smaller thickness can also be selected to facilitate the battery cell 20. production.

It should be noted that a battery includes a battery cell and an electrolyte, and is the smallest unit capable of electrochemical reactions such as charging/discharging. The battery core refers to a unit formed by winding or laminating a stacked part, and the stacked part includes a first pole piece, a separator, and a second pole piece. When the first pole piece is a positive pole piece, the second pole piece is a negative pole piece. Wherein, the polarities of the first pole piece and the second pole piece can be interchanged. The first pole piece and the second pole piece are coated with active material.

The battery can be a stacked battery, which is not only convenient for grouping, but also can be processed to obtain a battery with a long length. Specifically, the electric core is a laminated electric core, and the electric core has a first pole piece stacked on each other, a second pole piece electrically opposite to the first pole piece, and a pole piece arranged between the first pole piece and the second pole piece. The separator sheet, so that multiple pairs of the first pole piece and the second pole piece are stacked to form a laminated battery cell.

Alternatively, the battery can be a wound battery, that is, the first pole piece, the second pole piece electrically opposite to the first pole piece, and the diaphragm sheet arranged between the first pole piece and the second pole piece are wound, Obtain a coiled battery. The tabs 22 formed by the wound battery can be full tabs. At this time, the multiple single-piece tabs 221 can be considered as multiple adjacent single-piece tabs 221 stacked along the thickness direction of the battery core 20, or, The tabs 22 formed by the wound battery may also be non-full tabs.

An embodiment of the present invention also provides a battery pack, including the above-mentioned battery.

The battery pack in one embodiment of the present invention includes a battery, and the battery includes a battery case 10, a cell 20 and a pole 30, the cell 20 is arranged in the battery case 10, the pole 30 is arranged on the battery case 10, and the pole The post 30 is welded to the tab 22 of the cell 20 . The distance between the two opposite outer surfaces of the battery case 10 is a, and the tab 22 is formed by folding together a plurality of single-piece tabs 221 . The one whose middle end is the closest to the cell main body 21 is the first single-piece tab, and the middle end of the folded multiple single-piece tabs 221 is the second single-piece tab which is farthest from the cell main body 21, and the first single-piece tab is the farthest. The distance between the end of the sheet tab and the end of the second single sheet tab is b, that is, the staggered length of the single sheet tab 221 is b, and along the thickness direction of the battery, the maximum width of the solder print 1 is c, by making b≤(a-c)/2, not only the energy density of the battery can be guaranteed, but also the excessive length of the single tab 221 can be avoided from affecting the welding quality of the pole 30 and the tab 22, and it can be avoided The welding of the pole post 30 and the tab 22 has the problem of blast holes, thereby improving the safe use performance of the battery pack.

In one embodiment, the battery pack is a battery module or a battery pack.

The battery module includes a plurality of batteries, and the battery module may further include end plates and side plates, which are used to fix the plurality of batteries.

The battery pack includes a plurality of batteries and a case body, and the case body is used to fix the plurality of batteries.

It should be noted that the battery pack includes batteries, and there may be multiple batteries, and the multiple batteries are arranged in the case. Wherein, a plurality of batteries can be installed in the casing after forming a battery module. Alternatively, a plurality of batteries can be directly arranged in the case, that is, it is not necessary to group the plurality of batteries, and the case is used to fix the plurality of batteries.

Other embodiments of the present disclosure will be readily apparent to those skilled in the art from consideration of the specification and practice of the utility model innovation disclosed herein. This disclosure is intended to cover any modification, use or adaptation of the present utility model, and these modifications, uses or adaptations follow the general principles of this disclosure and include common knowledge or conventional techniques in the technical field not disclosed in this disclosure means. The specification and example embodiments are to be considered as exemplary only, with the true scope and spirit of the disclosure indicated by the appended claims.

It should be understood that the present disclosure is not limited to the precise constructions which have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of protection of the present disclosure is limited only by the appended claims.

Claims (12)

1. A battery, characterized in that, comprising: The battery casing (10), along the thickness direction of the battery, the distance between the two opposite outer surfaces of the battery casing (10) is a, and along the thickness direction of the battery, the battery has Two large opposing surfaces; A battery cell (20), the battery cell (20) is arranged in the battery casing (10), the battery cell (20) includes a battery cell main body (21) and a tab (22), and the tab (22) is led out from the main body (21) of the battery core, and the tab (22) is formed by gathering a plurality of single tabs (221). Along the drawing direction of the tab (22), the folded The end of the plurality of single-piece tabs (221) closest to the cell body (21) is the first single-piece tab, and the middle ends of the plurality of single-piece tabs (221) after being folded are The farthest away from the cell main body (21) is the second monolithic tab, and the distance between the end of the first monolithic tab and the end of the second monolithic tab is b; A pole (30), the pole (30) is arranged on the battery casing (10), and the pole (30) is welded to the tab (22) to form a welding mark (1) , along the thickness direction of the battery, the maximum width of the solder print (1) is c, b≤(a-c)/2. 2. The battery according to claim 1, characterized in that, the pole (30) is directly welded to the tab (22). 3. The battery according to claim 1, characterized in that the welding mark (1) is a laser welding mark. 4. The battery according to claim 1, characterized in that, a plurality of single-piece tabs (221) are welded to form a pre-welding mark (2), and the welding mark (1) covers the pre-welding mark (2), the pre-soldering print (2) and the soldering print (1) are sequentially formed. 5. The battery according to claim 4, characterized in that, along the thickness direction of the battery, the maximum width of the pre-welding print (2) is d, along the extending direction of the tab (22) Above, the distance between the pre-soldering marks (2) and the battery core body (21) is e, (d-c)/2<e<4+(a-c)/2. 6. The battery according to claim 5, characterized in that the pre-soldering weld (2) is an ultrasonic weld. 7. The battery according to claim 1, characterized in that the number of the plurality of single tabs (221) is 30-150. 8 . The battery according to claim 1 , characterized in that, along the direction in which the tabs ( 22 ) are pulled out, the dimensions of the plurality of single tabs ( 221 ) after straightening are consistent. 9. The battery according to claim 1, characterized in that, the battery case (10) comprises a case part (11) and a cover plate (12), and the case part (11) is formed with an accommodating space, The cover plate (12) is a flat plate, the pole (30) is arranged on the cover plate (12), and along the thickness direction of the battery, the width of the cover plate (12) is a. 10. The battery according to claim 1, wherein b≤10mm. 11. The battery according to claim 10, wherein b≧0.5mm. 12. The battery according to claim 1, wherein the battery is a quadrangular prism battery.