CN113764677A

CN113764677A - Current collecting structure of battery and battery

Info

Publication number: CN113764677A
Application number: CN202110951214.7A
Authority: CN
Inventors: 刘振
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2021-12-07
Anticipated expiration: 2041-08-18
Also published as: CN113764677B

Abstract

The invention provides a current collecting structure of a battery, wherein the battery comprises a battery cell, the current collecting structure comprises a current collecting disc and a current collecting column, one end face of the current collecting disc is welded with one electrode end face of the battery cell, and the other end face of the current collecting disc is welded with the current collecting column; the flow collecting column comprises a welding disc and an annular boss formed on the welding disc, a through hole matched with the annular boss is formed in the flow collecting disc, the protruding height of the annular boss is the same as the depth of the through hole, and the annular boss is fixedly welded with the flow collecting disc at the through hole. Through the area of contact between increase current collection dish and the mass flow post to adopt and carry out the girth welding along seam welding's mode, make the mass flow structure can promote the multiplying power performance of battery through heavy current, save space, and the same space can store more electric quantities and have higher energy density. When the current collecting structure provided by the invention passes a large current, the current conduction rate is high, and the resistance is low and the heating rate is small.

Description

Current collecting structure of battery and battery

Technical Field

The invention relates to the technical field of lithium battery design and production, in particular to a current collecting structure of a battery and the battery.

Background

The lithium battery stands out in numerous types of batteries by virtue of the advantages of high energy density, high voltage, high rate performance, long service life and the like, and is generally divided into a cylindrical lithium battery, a square lithium battery and a soft package lithium battery according to the packaging type, wherein the cylindrical lithium battery is widely applied due to the characteristics of high product yield, high capacity and the like. The improvement of the large-current charge and discharge performance is always a hot point direction of cylindrical lithium battery research, and the design of the current collecting mode has a non-negligible influence on the realization of the large-current charge and discharge performance.

The traditional current collection mode comprises the mode that a single or a plurality of tabs are connected with poles to serve as a current collection mode, and the current collection mode has the defects of low current conduction capability, high internal resistance, uneven current distribution in the charge-discharge process and difficulty in realizing large-current charge-discharge. As a further improvement, a current collector is introduced into an end face of an electrode, and a bendable metal sheet welded or integrally connected with the current collector is used to connect the current collector with a pole. In addition, the design of the current collecting mode has the defect of high internal resistance, so that the metal sheet is easy to be blown during high-current charging and discharging, the battery is failed, and even safety accidents are caused.

Disclosure of Invention

In order to solve the problems, the invention adopts the technical scheme that:

a current collecting structure of a battery comprises a battery cell, the current collecting structure comprises a current collecting disc and a current collecting column, one end face of the current collecting disc is welded with one electrode end face of the battery cell, and the other end face of the current collecting disc is welded with the current collecting column;

the flow collecting column comprises a welding disc and an annular boss formed on the welding disc, a through hole matched with the annular boss is formed in the flow collecting disc, the protruding height of the annular boss is the same as the depth of the through hole, and the annular boss is fixedly welded with the flow collecting disc at the through hole.

The invention also provides a battery, which comprises a shell and a battery cell arranged in the shell, wherein a positive current collecting structure and a negative current collecting structure are respectively arranged at two ends of the battery cell, and the positive current collecting structure adopts the battery current collecting structure.

Furthermore, the battery further comprises a positive sealing cover, wherein an assembling through hole matched with the outer diameter of the positive current collecting column is formed in the positive sealing cover, a first welding opening groove is formed in the inner wall of the assembling through hole, a second welding opening groove is formed in the outer wall of the positive current collecting column, the depth of the assembling through hole is the same as the height of the positive current collecting column, the positive sealing cover is sleeved on the positive current collecting column, and the positive sealing cover and the positive current collecting column are welded at the welding opening formed by the first welding opening groove and the second welding opening groove in a surrounding mode.

Further, the depth of the welding port formed by the first welding port groove and the second welding port groove is 1/4-1/3 of the height of the positive current collecting column.

Further, the outer diameter of the positive current collecting column is set to 2/5-4/5 of the outer diameter of the positive current collecting disk.

Furthermore, the axial direction section of the surface of the welding disc is arc-shaped, so that an arc surface of the welding disc is formed, the height of the arc surface is not more than 1/3 of the height of the annular boss, and the anode current collecting disc is attached to the surface of the current collecting disc through the arc surface.

Furthermore, the opening direction of the cambered surface faces one side of the welding disc, or the opening direction of the cambered surface faces one side of the positive current collecting disc,

when the opening direction of the cambered surface faces one side of the welding disc, the welding disc is connected with the positive current collecting disc in a spot welding mode along the inner ring and the outer ring of the welding disc;

when the opening direction of the cambered surface faces one side of the anode current collecting disc, the welding disc is connected with the anode current collecting disc in a mode of surrounding spot welding along the middle part of the welding disc.

Furthermore, one end of the positive current collecting column, which is far away from the positive current collecting plate, is also provided with a threaded column.

Further, the negative current collecting structure is the same as the positive current collecting structure. The negative pole sealing cover is provided with an assembling through hole matched with the outer diameter of the negative pole current collecting column, the negative pole sealing cover is connected with the shell in a limiting and sealing mode, and the negative pole current collecting column is insulated from the shell.

Furthermore, the negative current collecting structure comprises a negative current collecting disc, a diversion copper sheet, a negative pole post and a negative pole cover plate, the negative current collecting disc and the diversion copper sheet are connected into a whole, the negative current collecting disc is welded with the negative pole end face of the battery core, the diversion copper sheet is bent and welded or riveted with the negative pole post, and the negative pole post is in insulation sealing connection with the negative pole cover.

The invention has the beneficial effects that:

the invention provides a current collecting structure of a battery, which can improve the multiplying power performance of the battery through large current by increasing the contact area between a current collecting disc and a current collecting column and performing girth welding in a seam welding mode, saves space, and can store more electric quantity in the same space and have higher energy density. When the current collecting structure provided by the invention passes a large current, the current conduction rate is high, and the resistance is low and the heating rate is small.

The invention also provides a battery, wherein the positive electrode is of the current collecting structure, so that the battery has higher energy density and can carry out charging and discharging of large current.

Drawings

FIG. 1 is a schematic diagram illustrating a current collector and a terminal post welding in the prior art;

FIG. 2 is a schematic view of a current collector and a terminal post riveting in the prior art;

FIG. 3 is a schematic connection diagram according to embodiment 1 of the present invention;

FIG. 4 is a schematic sectional view of a current collecting plate according to embodiment 1 of the present invention;

FIG. 5 is a schematic cross-sectional view of a battery according to example 2 of the present invention;

FIG. 6 is a schematic view of the structure of a collector column according to example 2 of the present invention;

fig. 7 is a schematic structural view of the positive electrode cap in embodiment 2 of the present invention;

FIG. 8 is a schematic end view of a current collecting plate according to embodiment 2 of the present invention;

fig. 9 is a schematic sectional view of the collector bar and the positive cover plate according to embodiment 2 of the present invention;

FIG. 10 is an enlarged view taken at A in FIG. 9;

FIG. 11 is a schematic view showing the weld quality when the weld groove is too deep in example 2 of the present invention;

fig. 12 is a schematic cross-sectional view of a negative current collecting structure according to example 2 of the present invention;

fig. 13 is a schematic cross-sectional view of another negative current collecting structure according to example 2 of the present invention;

fig. 14 is a schematic view of another negative current collecting structure according to example 2 of the present invention;

fig. 15 is a schematic connection diagram of the positive current collecting column and the positive current collecting disk when the opening direction of the arc surface faces one side of the welding disk in embodiment 2 of the present invention;

fig. 16 is a schematic connection diagram of the positive current collecting column and the positive current collecting disk when the opening direction of the arc surface faces one side of the positive current collecting disk in embodiment 2 of the present invention;

fig. 17 is a schematic diagram of a battery installation provided in embodiment 2 of the present invention.

Reference numerals: casing 11 and battery cell 12

The current collecting plate 21, the through hole 211, the current collecting column 22, the welding plate 221 and the annular boss 222;

the positive current collecting structure 30, the positive sealing cover 31, the assembling through hole 311, the first welding notch groove 3111, the positive current collecting column 32, the second welding notch groove 321, the threaded column 33 and the positive current collecting disc 34;

the negative current collecting structure 40, the negative sealing cover 41, the negative current collecting post 42, the negative pole 421, the negative current collecting plate 43, the diversion copper sheet 431 and the insulating sealing sleeve 44.

Detailed Description

The present invention will be described in further detail below with reference to the accompanying drawings and embodiments thereof.

Example 1

Referring to fig. 3-4, an embodiment of the present invention provides a current collecting structure of a battery, where the battery includes a battery cell 12, the current collecting structure includes a current collecting tray 21 and a current collecting post 22, one end surface of the current collecting tray 21 is welded to one electrode end surface of the battery cell 12, and the other end surface of the current collecting tray 21 is welded to the current collecting post 22;

the current collecting column 22 comprises a welding disc 221 and an annular boss 222 formed on the welding disc 221, a through hole 211 matched with the annular boss 222 is formed in the current collecting disc 21, the protruding height of the annular boss 222 is the same as the depth of the through hole 211, and the annular boss 222 is fixedly welded with the current collecting disc 21 at the through hole 211.

The through holes 211 of the current collecting plate 21 and the annular bosses 222 are welded in an annular mode along contact gaps, the current collecting plate 21 and the welding plate 221 except the annular bosses 222 are welded in an annular laser spot welding mode, laser spot welding is conducted on the other side, where the current collecting plate 21 is in contact with the welding plate 221, of the current collecting plate 21, the welding plate 221 is tightly attached to the welding plate 221 through a plurality of annular arrays of welding spots, the contact area of the welding plate 221 and the current collecting plate 21 is increased, and the internal resistance of a current collecting structure is reduced.

The traditional mass flow mode of using single or a plurality of utmost point ears to be connected the electrode of electric core and utmost point post, the arrangement requirement of utmost point ear is higher, the current maldistribution of charge-discharge process appears easily, and the cross-sectional dimension of utmost point ear is less, it is higher to hinder than its in the charge-discharge process, the electric current conducting capacity is lower, very easily generate heat in the use of battery, generally need just can reach required electric current conduction volume to a plurality of utmost point ears when using utmost point ear to connect in addition, just need counterpoint and weld a plurality of utmost point ears, need consume more time.

In the technical scheme provided by the invention, a mode of directly welding the current collecting disc 21 with the end face of the electric core is adopted, the current collecting disc 21 is set to be the same as the end face of the electric core 12 in shape and size, and the current collecting disc 21 is welded with the end face of the electric core 12 in a spot welding mode, so that the contact area between the end face of the electric core 12 and the current collecting disc 21 is increased, the current conduction quantity is increased, the internal resistance between the current collecting disc 21 and the end face of the electric core 12 is reduced, the heat productivity between the current collecting disc 21 and the end face of the electric core 12 when the current passes through is also reduced, and the battery can charge and discharge larger current.

The current collector is welded at the end face of the battery cell 12, current collection is carried out on the electrode of the battery cell 12 through the current collector, then the current collector and the pole are connected through a bendable metal sheet, or after the current collector is welded with the end face of the battery cell 12, the pole is directly welded on the current collector, and the current two modes have the problem of increasing the internal resistance of the battery. The bendable metal sheet is generally connected with the end face of the pole in a welding or riveting mode between the bendable metal sheet and the pole, because the thickness of the bendable metal sheet is thinner, the rivet is forced to deform by a large force during riveting, the metal sheet is limited between the deformed part of the rivet and the pole, the rivet is pressed to deform during riveting, the rivet deforms until the rivet contacts with the metal sheet and then deforms, so that the metal sheet is extruded unevenly, the rest parts of the metal sheet and the end surface of the pole are easy to tilt after extrusion except the part pressed at the deformed part of the rivet, as shown in figure 2, wherein the hatched portion is represented as a current collector, resulting in a reduction of the contact area of the metal sheet with the post after riveting, the current conduction capability of the riveting part is reduced and the resistance is increased in the use process of the battery, and the part generates heat seriously after long-time use, so that large current cannot pass through the part.

The problem of increased internal resistance of the battery after welding also exists in the mode that the current collector is welded with the end surface of the battery core 12, and then the pole is welded on the surface of the current collector, the pole is welded along the exposed gap after being contacted with the end surface of the current collector, and the mode easily causes that the gap is left between the contact surfaces except the welding point for electrifying, so that only the welding point has current circulation; in addition, the existing lithium battery core generally adopts a structure that a diaphragm is added between a positive plate and a negative plate, then the diaphragm is rolled up, one end of a rolled battery core 12 is extended out of the positive plate, the other end of the rolled battery core is extended out of the negative plate, the extended positive plate and the extended negative plate are respectively pressed into a flat surface, the flat surface can be well attached to a current collector, but the supported flat positive plate or the supported flat negative plate is not a complete whole though being rolled up, and is inclined when being pressed, when welding is carried out between current collecting polar posts, a welding gun slightly applies a force to a welding position when welding is carried out between the current collecting polar posts, the current collector is tilted, so that the gap between the welded current collector and the polar posts is increased, the welding quality is deteriorated, the internal resistance of the battery is increased, as shown in figure 1, a shadow part marked at the position 01 is a welding flux, and the heights of the welding fluxes which are not uniformly stressed during welding are different, the contact surface between the bottom of the pole and the current collector has an inclination angle, so that the pole and the current collector cannot be attached and contacted, and the welding gap shown in the 02 position is actually in false connection, and the pole and the current collector cannot be conducted without contact. No contact exists between the pole at the 02 position and the welding surface of the current collector, air is filled in the gap, and when a large current flows through the gap, the air in the gap is easy to break down between the two conductors to discharge, so that high heat is generated, and the temperature in the battery is increased. The applicant actually detects that if the effective bottom area of the pole is S1 in the conventional connection mode, the effective conductive area is less than 1/10S1, and the bottom area cannot be effectively utilized.

In the technical scheme provided by the invention, the end face of the current collecting plate 21 and the current collecting post 22 can be welded by firstly placing the current collecting plate 21 on the welding plate 221 of the current collecting post 22, the current collecting plate 21 also comprises an annular boss 222, the peripheral surface of the annular boss 222 is contacted with the inner surface of the through hole 211 formed in the current collecting plate 21, in such a way, besides the surface of the current collecting plate 21 is contacted with the welding plate 221, a group of contact surfaces are additionally arranged, the contact area between the current collecting plate 21 and the current collecting post 22 is enlarged, the resistance between the current collecting plate 21 and the current collecting post 22 is also reduced, the conductivity of a battery is improved, and the heat generation is reduced. In addition, the annular boss 222 is additionally arranged between the collecting tray 21 and the collecting column 22, and after the collecting tray 21 is placed on the welding tray 221, the annular boss 222 is matched with the through hole 211, so that the positioning step between the collecting column 22 and the collecting tray 21 is completed, and an additional alignment step and an auxiliary tool are not required to be added.

The height of the annular boss 222 is the same as the depth of the through hole 211, that is, after the current collecting plate 21 is mounted on the welding plate 221 of the current collecting column 22, the end face of the annular boss 222 is flush with the surface of the adjacent current collecting plate 21, a welding gun is used for welding a circle along the contact gap between the through hole 211 and the annular boss 222, a space placing mode of the welding plate 221 on the lower current collecting plate 21 is adopted during welding, because the end faces of the two annular bosses 222 are flush with the surface of the adjacent current collecting plate 21, high-temperature molten solder during welding can be left downwards along the contact gap to fill the gap, so that better welding quality can be obtained, and the situation that a certain edge is tilted can not occur. The welding mode can obtain uniform welding marks, the connection between the annular boss 222 and the current collecting plate 21 is stable, the current conduction rate between the current collecting plate 21 and the current collecting column 22 is further improved, the resistance of a contact point is reduced, and the requirement of a large-current battery on a current collecting structure is met.

The thickness of the bendable metal sheet at the anode in the prior art is not too thick, because the metal sheet needs to be bent during assembly, and too thick can occupy more space and cause waste, and the general situation is 0.2-0.4 mm. In the charge and discharge experiment of large current by using the bendable metal sheet at the conventional positive electrode, the applicant found that the bendable metal sheet is immediately fused when 1300A of transient pulse current is discharged.

The current collecting disc 21 and the welding disc 221 are welded in a spot welding mode, gaps of the through hole 211 and the annular boss 222 are welded in a ring welding mode, and then the current collecting disc 21 and the welding disc 221 are subjected to ring spot welding, so that the contact area can be further increased, and the phenomenon that a large gap is formed between the current collecting disc 21 and the welding disc 221 after the use time is long, the contact area is reduced, and the resistance is increased is avoided. Compared with the mode of connecting the bendable metal sheets, the volume of each cross section of the current collecting disc 21 and the current collecting column 22 is larger than that of the bendable metal sheets, and when a large current passes through the large cross section, the large cross section is not easy to generate heat, even the metal sheets are burnt out, and large current charging and discharging can be carried out.

After the current collecting plate 21 is welded with the current collecting post 22, the current collecting plate 21 is welded with the electrode end face of the electric core 12, and because the end face of the annular boss 222 is flush with the end face of the current collecting plate 21, when the current collecting plate is welded with the end face of the electric core 12, the boss end face at the position of the through hole 211 can also contact with the end face of the electric core 12 to collect current, and the current collecting post 22 is further provided with a liquid injection hole for adding electrolyte.

In addition, compared with the mode of connecting the current collector and the pole by adopting a bendable metal sheet, the current collecting post 22 directly connected with the current collecting disc 21 can effectively improve the space utilization rate in the battery, the metal sheet can occupy the space with the height of 7mm-8mm in the axial direction of the battery after being bent, and the space occupied by the structure except the battery cell 12 can be effectively utilized after the current collecting disc 21 is directly connected with the current collecting post 22, so that the battery with the same size can be loaded into the battery cell 12 with larger electric capacity, the energy density of the battery is increased, compared with the prior battery adopting the current collecting structure provided by the invention, the capacity of the battery can be improved by 8% -10% on the basis of the prior battery, the energy density of the battery is increased, and the battery with the current collecting structure provided by the invention is installed on using equipment under the condition of not changing the volume of the battery, for example, on the electric automobile, the structural design of the automobile is not changed, but the endurance mileage of the electric automobile can be effectively improved by 8-10%.

Example 2

Referring to fig. 5 to 10, and fig. 12 to 17, an embodiment of the present invention provides a battery, including a case 11 and a battery cell 12 disposed in the case 11, where two ends of the battery cell 12 are respectively provided with a positive current collecting structure 30 and a negative current collecting structure 40, and the positive current collecting structure 30 adopts the battery current collecting structure provided in embodiment 1.

The positive pole potential of battery is high for the electric current through the positive pole is great, has great examination to the internal resistance and the current conduction efficiency of the current collecting structure at positive pole position, especially in the process of carrying out the charge-discharge of heavy current, the condition that generates heat appears very easily in current collecting structure, current conduction efficiency also can not reach the demand of using, the current collecting structure that adopts embodiment 1 to provide has advantages such as internal resistance is low, current conduction rate height, is applicable to carrying out the mass flow to the positive pole of heavy current battery, improves the current conduction efficiency of battery positive pole, and the internal resistance is low reduces generating heat of battery positive pole.

Referring to fig. 5, 7 and 9, the battery further includes a positive sealing cover 31, the positive sealing cover 31 is provided with an assembly through hole 311 matched with the outer diameter of the positive current collecting post 32, the inner wall of the assembly through hole 311 is provided with a first welding opening groove 3111, the outer wall of the positive current collecting post 32 is provided with a second welding opening groove 321, the depth of the assembly through hole 311 is the same as the height of the positive current collecting post 32, the positive sealing cover 31 is sleeved on the positive current collecting post 32, and the positive sealing cover 31 and the positive current collecting post 32 are welded at the welding opening surrounded by the first welding opening groove 3111 and the second welding opening groove 321.

At the positive pole of the existing battery, an insulating sealing ring is sleeved on the pole for insulation and sealing, and then the cover plate is hermetically welded with the shell 11 of the battery. The electrolyte leakage condition easily appears between utmost point post and the apron after long-time use of this kind of sealed mode, the main reason lies in that insulating seal ring adopts materials such as the rubber that has certain elasticity to make, realize sealing between utmost point post and the apron through extrusion insulating seal ring when sealed, after long-time use to the battery, the heat that produces when the battery is inside takes place the chemical reaction can make electrolyte produce gas, thereby cause the inside pressure increase of battery, promote the relative apron of utmost point post and remove, insulating seal ring is extrudeed deformation repeatedly at the promotion in-process that relapse, lead to fatigue damage, lead to sealed being destroyed, the condition that electrolyte leakage appears.

In this embodiment, the positive current collecting post 32 and the negative current collecting post 42 are welded to each other, so that the positive current collecting post 32 and the positive sealing cap 31 are directly and fixedly connected to each other, and the sealing condition is prevented from being damaged in the process of repeated movement. In order to ensure that the joint is completely welded during welding and avoid leaks, a first crater groove 3111 is arranged on the inner wall of the assembly through hole 311, the depth of the assembly through hole 311 is the same as the height of the positive current collecting column 32, a welding opening is formed by the first crater groove 3111 and the second crater groove 321 together, when the positive current collecting column 32 and the positive current collecting column 31 are welded, welding is directly performed at the welding opening, the welding opening is of a groove-shaped structure, molten solder can flow into the welding opening during welding and fill the welding opening, and after the welding opening is welded for a circle, the solder performs closed filling on a gap between the positive current collecting column 32 and the positive current collecting column 31, so that the fixation and the sealing between the collection cover plate and the positive current collecting column 32 are realized. And then the positive electrode cover 31 and the battery shell 11 are welded in a sealing welding mode.

Adopt the welded mode to seal another beneficial effect of fixing between anodal closing cap 31 and the anodal utmost point post and embody, adopt insulating connection between the anodal post of the higher current battery of voltage at battery positive pole department and the apron for higher potential difference has appeared in this insulating position, lead to appearing the galvanic corrosion phenomenon easily between anodal post and the apron in the use, produce the corruption to the adjacent surface of anodal post and anodal closing cap 31, finally lead to sealed the inefficacy, the condition of weeping appears. In this embodiment, the positive current collecting column 32 and the positive sealing cap 31 are directly welded, and have a large welding area and a small resistance, so that a potential difference between the positive current collecting column 32 and the positive sealing cap 31 is eliminated, and the sealing between the positive current collecting column 32 and the positive sealing cap 31 is ensured.

The depth of the assembling through hole 311 is the same as the height of the positive current collecting post 32, and the positive current collecting post 32 can be directly used as the positive electrode of the battery at the position of the battery positive electrode sealing cover 31 after being electrically installed.

Referring to fig. 10, the depth of the weld formed by the first weld notch groove 3111 and the second weld notch groove 321 is 1/4-1/3 of the height of the positive current collecting post 32.

When the applicant performs a tightness verification experiment on the welded joint between the positive current collecting post 32 and the positive sealing cap 31, there is still a certain possibility that the sealing is not tight between the positive current collecting post and the positive sealing cap 31, as shown in fig. 11, after slicing the non-tight sealing position, it is found that the solder does not flow into the bottom of the welding port, and the sealing is not tight due to the occurrence of the false welding at the position. The reason why the cold joint occurs is that, since the groove depths of the first crater groove 3111 and the second crater groove 321 are too deep, the solder fluidity in the molten state and the amount of solder do not reach the condition for the solder to flow to the bottom of the groove, as a result of analysis and repeated verification by the applicant.

In the embodiment, the depth of the welding opening is set to be 1/4-1/3 of the height of the positive current collecting column 32, so that molten solder can completely flow to the bottom of the welding opening when the welding opening is welded, a good welding effect is obtained, and the condition of insufficient welding is avoided. Meanwhile, the height of 1/4-1/3 can obtain excellent flow guide effect between the positive current collecting column 32 and the positive sealing cover 31; when the height is less than 1/4, the contact area is reduced, which can lead to the increase of contact resistance and the weakening of flow guiding effect, and when the height is more than 1/3, the welding quality is poor, so that cold joint easily occurs, and the sealing effect is poor.

Referring to fig. 8, further, the outer diameter of the positive current collecting post 32 is set to 2/5-4/5 of the outer diameter of the positive current collecting disk, wherein the dotted line represents the maximum overlapping profile of the positive current collecting post and the positive current collecting disk.

In the battery current collecting structure provided by the invention, the current collecting column and the positive current collecting disc are welded firstly, then the positive current collecting disc is welded on the electrode end face of the battery cell 12, the welding machine between the positive current collecting disc and the end face of the battery cell 12 is only welded with the current collecting column within the range covered by the current collecting column, the welding machine between the positive current collecting disc and the end face of the battery cell 12 is only carried out outside the range covered by the outer diameter of the current collecting column, and the size of the welding range also influences the welding quality and the resistance of the welded current collecting structure.

For the larger the outer diameter of the current collecting column between the current collecting column and the positive current collecting disc is, the larger the contact area between the welding disc 221 on the current collecting column and the positive current collecting disc is, the higher the welding quality after welding is, the resistance is reduced, and the current conduction rate is better; similarly, the connection between the positive current collecting plate and the electrode end face of the battery cell 12 is also the same, and the larger the welding area is, the better the effect is. However, the area between the two welding positions is conflicting, and if the area of the current collecting column is increased, the welding area between the positive current collecting disc and the end face of the battery cell 12 is reduced, and vice versa; therefore, the outer diameter of the flow column was set to 2/5-4/5 of the outer diameter of the positive current collecting disk in the present embodiment. The welding area between the positive current collecting disc and the end surface of the battery cell 12 and between the positive current collecting columns 32 is balanced, so that the minimization of contact resistance and the optimal current conduction efficiency are realized.

Preferably, the diameter of the annular boss on the current collecting column is 2/3-3/5 of the diameter of the welding disc, so that the increase of the annular welding ring between the annular boss and the through hole of the positive current collecting disc correspondingly increases the welding area, reduces the internal resistance, increases the current conductivity, and leaves a welding area for welding the positive current collecting disc and the welding disc 221 so as to balance the contact resistance between the two contact surfaces.

Referring to fig. 15-16, the axial section of the surface of the welding disc is arc, the opening direction of the arc is in the radial direction of the positive current collecting disc, the arc rotates for a circle along the center of the welding disc to form the arc surface of the welding disc, the height of the arc surface is not more than 1/3 of the height of the annular boss, and the positive current collecting disc and the surface of the current collecting disc are attached through the arc surface.

The planes are connected through a plurality of welding points which are distributed in a dispersed mode, the surfaces which are not welded on the microstructure can not be completely attached, and the condition that the contact surface is reduced due to thermal expansion and arching between two welding points after a microcosmic pit is formed between the contact surfaces and a thinner positive current collecting plate is heated can also exist, so that the difference between the effective contact area and the overlapping area is larger.

Set up the surface of welding disk into the arc in this application, extrude thinner anodal current collecting disk and welding disk overlap portion when carrying out spot welding and contact to the arc with the welding disk, then weld, the trend that the anodal current collecting disk that is extruded deformation after the welding can be to welding disk surface motion lets positive current collecting disk and welding disk surface contact all the time, has increased effective area of contact, has reduced the internal resistance of contact.

Meanwhile, after the contact internal resistance between the positive current collecting disc and the positive current collecting column is reduced, the ratio between the outer diameter of the positive current collecting column and the outer diameter of the positive current collecting disc can be reduced from 2/5-4/5 to 3/5-1/5, the welding area between the corresponding positive current collecting disc and the end face of the battery cell is increased, the integral internal resistance can be reduced, and the current passing capacity is increased.

The height direction of the arc surface is the vertical distance between the highest point and the highest point of the arc surface, and because the height of the annular boss is not high, the macroscopic influence on the current collecting structure caused by 1/3 that the welding disc protrudes out or is recessed into the height of the annular boss is small, and the effective contact area between the positive current collecting disc and the positive current collecting column can be increased microscopically.

as shown in fig. 15, when the opening direction of the arc surface faces one side of the welding disk, the welding disk and the positive current collecting disk are connected by spot welding along the inner ring and the outer ring of the welding disk;

as shown in fig. 16, when the opening direction of the arc surface faces one side of the positive current collecting plate, the welding plate and the positive current collecting plate are connected by surrounding spot welding along the middle portion of the welding plate.

The inner ring and the outer ring of the welding disc are the maximum diameter part and the minimum diameter part of a contact surface between the inner ring and the current collecting disc, when the opening direction of the arc surface faces one side of the welding disc, namely the arc surface of the welding disc is outwards protruded, the current collecting disc is subjected to annular spot welding at the outer ring and the inner ring, so that the current collecting disc and the welding disc are in close contact to increase the contact area;

when the opening direction of the cambered surface faces one side of the positive current collecting disc, the current collecting disc and the welding disc can be in close contact to increase the contact area only by adopting annular welding from the middle part between the outer ring and the inner ring of the welding disc.

Referring to fig. 6, further, the end of the positive current collecting post 32 remote from the positive current collecting plate 34 is also provided with a threaded post 33.

The threaded post 33 provided on the positive electrode of the electrode can be fixed by bolts and nuts to connect a plurality of batteries, which together form a battery pack for use in electric vehicles or other devices requiring a large capacity. Compared with the conventional battery pack, the battery pack composed of the batteries provided by the embodiment has higher energy density, namely, the battery pack with the same volume can release more electric energy, so that the electric vehicle has longer cruising ability on the premise of not changing the structure of the electric vehicle.

Further, the negative current collecting structure 40 is the same as the positive current collecting structure 30.

The current collecting structure provided by embodiment 1 is adopted for both the negative electrode and the positive electrode of the battery, so that the internal resistance of the negative electrode of the battery can be reduced, the current conduction efficiency of the current negative electrode can be improved, and meanwhile, after the current collecting structure provided by embodiment 1 is adopted for the negative electrode, the original bendable metal sheet is replaced, the length of the battery core 12 in the shell 11 can be further increased, and the battery has higher energy density.

Further, the negative current collecting structure 40 further includes a negative sealing cover 41, an assembly through hole matched with the outer diameter of the negative current collecting column 42 is formed in the negative sealing cover 41, the negative sealing cover 41 is connected with the housing 11 in a limiting and sealing manner, and the negative current collecting column 42 is insulated from the housing 11.

Because the positive current collecting column 32 and the positive sealing cover 31 are connected by welding, the potential difference between the positive current collecting column 32 and the positive sealing cover 31 is eliminated, so that the battery shell 11 and the positive electrode of the battery are conducted at the moment, and the negative current collecting column 42 and the shell 11 are insulated for separating the positive electrode and the negative electrode of the electrode.

Referring to fig. 12, preferably, the negative current collecting post and the battery case 11 are insulated in such a manner that the outer diameter of the negative electrode cover is set to be the same as the inner diameter of the case 11, and when the negative electrode cover is connected to the positive electrode cover 31, an insulating sealing sleeve 44 is fitted over the outer diameter of the negative electrode cover, and then the negative electrode cover is press-fitted into the case 11 in such a manner that both sides of the negative electrode cover outside the case 11 are pressed and trimmed, so that the negative electrode cover is hermetically connected to the case 11, and the negative current collecting post 42 and the negative electrode cover are hermetically welded in the same manner as the positive electrode.

Alternatively, referring to fig. 13, the negative current collecting post 42 and the negative cover plate are hermetically and insulatively connected by sleeving an insulating sealing sleeve 44, and the negative cover plate and the housing 11 are welded in the same manner as the positive electrode.

Referring to fig. 14, further, the negative current collecting structure 40 includes a negative current collecting disc 43, a current guiding copper sheet 431, a negative electrode post 421 and a negative electrode cover plate, the negative current collecting disc 43 and the current guiding copper sheet 431 are connected into a whole, the negative current collecting disc 43 is welded to the negative electrode end surface of the electric core 12, the current guiding copper sheet 431 is bent and welded or riveted to the negative electrode post 421, and the negative electrode post 421 is connected to the negative electrode cover 41 in an insulating and sealing manner.

The conductivity of the metal copper is higher than that of the metal aluminum, but the metal copper can only be used as a negative electrode in the lithium battery, because the positive electrode potential of the battery is high, the copper is easily oxidized under the high potential, the oxidation potential of the aluminum is high, and the surface layer of the aluminum is provided with a compact oxidation film, so that the internal aluminum is well protected, therefore, when the battery is manufactured, a copper sheet can be adopted between the negative current collecting disc 43 of the negative electrode and the negative electrode pole 421 as a connecting sheet, the copper sheet has good conductivity, in the charging and discharging process of large current, the copper sheet has small resistance and low heat productivity, and the connection requirement on the negative electrode of the battery can be met.

A preferred embodiment: as shown in fig. 17, when assembling a battery whose negative electrode is connected by a diversion copper sheet, first, a laser spot welding method is adopted between the positive current collecting plate 34 and a welding plate of the positive current collecting column to perform circumferential welding, then, a gap between the positive current collecting plate and an annular projection of the positive current collecting column is welded, and then, the welded positive current collecting column 32 and the welded positive current collecting plate 34 are welded to the positive electrode of the battery cell; then welding the negative current collecting plate 43 to the negative electrode of the battery cell, and connecting the negative current collecting plate 43 with the negative electrode sealing cover 41; then the shell is sleeved from the positive pole of the battery core, the positive pole cover plate and the positive pole current collecting column are welded, and finally the negative pole sealing cover and the positive pole sealing cover are respectively welded on the end face of the shell.

In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "inner", "outer", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for the purpose of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present invention. Where "inside" refers to an interior or enclosed area or space. "periphery" refers to an area around a particular component or a particular area.

In the description of the embodiments of the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", "third", "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "assembled" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the description of the embodiments of the invention, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

In the description of the embodiments of the present invention, it should be understood that "-" and "-" indicate the same range of two numerical values, and the range includes the endpoints. For example, "A-B" means a range greater than or equal to A and less than or equal to B. "A to B" means a range of not less than A and not more than B.

In the description of the embodiments of the present invention, the term "and/or" herein is only one kind of association relationship describing an associated object, and means that there may be three kinds of relationships, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A current collection structure of battery, the battery includes electric core, its characterized in that: the current collecting structure comprises a current collecting disc and a current collecting column, one end face of the current collecting disc is welded with one electrode end face of the battery cell, and the other end face of the current collecting disc is welded with the current collecting column;

2. The utility model provides a battery, includes the casing and sets up the electric core in the casing, and electric core both ends are provided with anodal mass flow structure and negative pole mass flow structure, its characterized in that respectively: the positive current collecting structure adopts the battery current collecting structure of claim 1.

3. The battery of claim 2, wherein: still include anodal closing cap, set up on the anodal closing cap with the external diameter assorted assembly through-hole of anodal mass flow post, the inner wall of assembly through-hole is provided with first welding mouth groove, the outer wall of anodal mass flow post is provided with second welding mouth groove, the degree of depth and the anodal mass flow post of assembly through-hole are the same, and anodal closing cap cover is located on the anodal mass flow post, and just anodal closing cap cover is in with anodal mass flow post first welding mouth groove with the welding mouth department that the second welding mouth groove encloses forms the welding.

4. The battery of claim 3, wherein: the depth of a welding port defined by the first welding port groove and the second welding port groove is 1/4-1/3 of the height of the positive current collecting column.

5. The battery of claim 3, wherein: the outer diameter of the positive current collecting column is set to 2/5-4/5 of the outer diameter of the positive current collecting disc.

6. The battery of claim 5, wherein: the axial direction section of the surface of the welding disc is arc-shaped, so that an arc surface of the welding disc is formed, the height of the arc surface is not more than 1/3 of the height of the annular boss, and the anode current collecting disc is attached to the surface of the current collecting disc through the arc surface.

7. The battery of claim 6, wherein: the opening direction of the cambered surface faces one side of the welding disc, or the opening direction of the cambered surface faces one side of the positive current collecting disc,

8. The battery of claim 2, wherein: and a threaded column is further arranged at one end of the positive current collecting column, which is far away from the positive current collecting disc.

9. The battery according to claims 1-8, wherein: the negative current collecting structure is the same as the positive current collecting structure,

the negative pole sealing cover is provided with an assembling through hole matched with the outer diameter of the negative pole current collecting column, the negative pole sealing cover is connected with the shell in a limiting and sealing mode, and the negative pole current collecting column is insulated from the shell.

10. The battery of claim 2, wherein: the negative pole current collecting structure comprises a negative pole current collecting disc, a diversion copper sheet, a negative pole post and a negative pole cover plate, the negative pole current collecting disc and the diversion copper sheet are connected into a whole, the negative pole current collecting disc is welded with the negative pole end face of the battery core, the diversion copper sheet is bent and welded or riveted with the negative pole post, and the negative pole post is in insulation sealing connection with a negative pole cover.