CN213278324U

CN213278324U - Winding battery

Info

Publication number: CN213278324U
Application number: CN202021857315.5U
Authority: CN
Inventors: 蔡培彬; 于子龙; 胡本安; 陈杰; 杨山; 李载波; 项海标
Original assignee: Zhejiang Liwei Energy Technology Co ltd
Current assignee: Zhejiang Liwei Energy Technology Co ltd
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2021-05-25
Anticipated expiration: 2030-08-31

Abstract

The utility model provides a winding battery, which comprises an electric core formed by sequentially stacking and winding a positive plate, a diaphragm and a negative plate, wherein the starting end and the tail end of the winding of the positive plate are both provided with a first empty foil area, positive lugs are welded on the first empty foil area, two positive lugs are at least partially overlapped or arranged at intervals in the orthographic projection direction of the electric core after winding, and the two positive lugs are electrically connected together; and a second empty foil area is arranged on the negative pole piece, and negative pole lugs are welded on the second empty foil area. Compared with the prior art, the design of the positive tab is optimized, the mode that the empty foil area is arranged in the middle section of the positive tab to weld the positive tab in an embedded mode is converted into the mode that the empty foil area at the head and the tail of the positive tab is utilized to weld the positive tab in a double-tab mode, the limitation of a laser cleaning process window of the positive tab is avoided, the energy density is higher than that of an existing gap coating structure, and the improvement of the energy density of a battery cell is facilitated.

Description

Winding battery

Technical Field

The utility model relates to a lithium cell field, concretely relates to winding battery.

Background

With the updating and development of the technology, the requirement of a user on the charging time of the lithium battery is higher and higher, so that the lithium battery is required to meet the requirement of high-rate charging and also consider low charging temperature rise.

The lithium battery with a winding structure at present mainly comprises the following two structures:

1) and respectively welding the positive and negative lugs on the empty foil areas at the starting ends of the positive and negative pole pieces. However, the battery wound by the structure has the problems that the pole piece is long, the pole lug is arranged at one end of the pole piece, the internal resistance is high, the polarization and the ohm generate heat seriously, and the charging time is influenced;

2) welding positive and negative lugs in the empty foil area between the middle sections of the positive and negative pole pieces, and embedding the lugs into the grooves. Compared with the battery in 1), the structure improves the current density distribution on the pole piece, reduces the problems of internal resistance, polarization and heat generation, and improves the dynamic performance of the battery.

At present, aiming at an embedded pole lug structure, a common process for arranging grooves on a pole piece is gap coating and laser cleaning. The gap coating process is mature, and does not need equipment transformation, but due to the limitation of the coating process, only a penetrating gap can be set, and a small slot position cannot be set, as shown in fig. 1, so that energy density loss is caused. The laser cleaning process is contactless, has high precision, does not need chemical agents, can realize small slot positions, as shown in figure 2, and can also take energy density into consideration. However, certain problems still exist in the laser cleaning technology at present: aiming at the negative plate, the current collector is made of copper foil, so that the heat resistance is high, the temperature of about 1300 ℃ can be borne, the process window of laser cleaning is met, and the process of laser cleaning the small groove position of the negative plate is gradually popularized and introduced; however, for the positive plate 1 ', the current collector material is aluminum foil, and because the aluminum foil has poor heat resistance, the current collector material can only bear the temperature of about 600 ℃, and cannot meet the process window of laser cleaning, if the positive tab 12 ' is directly welded to the small slot position formed by the empty foil area 11 ' by laser cleaning, the pole piece is easily damaged after laser cleaning, so that the popularization of the structure of the small slot position of the positive electrode is blocked, and the energy density is influenced.

In view of the above, it is necessary to provide a technical solution to the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: the winding battery is provided, the existing battery structure is optimized, so that the limit of a positive plate laser cleaning process window can be avoided, and the energy density is higher than that of the existing gap coating structure and is close to the target of laser cleaning of a small groove structure.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a winding battery comprises an electric core formed by sequentially laminating and winding a positive plate, a diaphragm and a negative plate, wherein a first empty foil area is arranged at the starting end and the tail end of the winding of the positive plate, positive lugs are welded on the first empty foil area, after the winding, the two positive lugs are at least partially overlapped or arranged at intervals in the positive projection direction of the electric core, and the two positive lugs are electrically connected together; and a second empty foil area is arranged on the negative pole piece, and negative pole lugs are welded on the second empty foil area.

Preferably, the second empty foil area is at least arranged at the middle position of the negative plate.

Preferably, when the two positive electrode tabs are at least partially overlapped in the orthogonal projection direction of the battery core after winding, the thickness of the positive electrode tab is less than or equal to one half of the thickness of the negative electrode tab.

Preferably, the thickness of the two overlapped positive electrode tabs is equal to the thickness of the negative electrode tab.

Preferably, the two positive electrode lugs are completely overlapped in the orthographic projection direction of the battery core.

Preferably, tab glue is arranged on both sides of the two wound positive tabs and between the two positive tabs; the tab glue is connected with the two positive tabs in a pressing mode.

Preferably, when the two positive electrode tabs are arranged at intervals in the orthogonal projection direction of the battery core after winding, the thickness of the positive electrode tab is equal to that of the negative electrode tab.

Preferably, the winding battery further comprises a protection plate, three connecting pieces are welded on the protection plate, any two connecting pieces are mutually conducted and are connected with the two positive lugs in a one-to-one correspondence mode, and the remaining one connecting piece is connected with the negative lug.

Preferably, the second empty foil area is arranged on the negative pole piece in a laser cleaning mode.

Preferably, the second empty foil area is arranged at the head end and the tail end of the negative plate, negative electrode lugs are welded on the second empty foil area, the positive projection direction of the battery cell is at least partially overlapped or arranged at intervals after winding, and the negative electrode lugs are electrically connected together after winding.

Compared with the prior art, the beneficial effects of the utility model reside in that: the battery provided by the utility model optimizes the design of the positive electrode tab, changes the mode of setting the empty foil area in the middle section of the positive electrode plate for embedded welding the positive electrode tab into the mode of using the original head and tail empty foil areas of the positive electrode plate for welding the double electrode tab, reduces the influence of the double-sided empty foil area reserved due to the influence of welding the electrode tab on the energy density compared with the prior structure, the battery of the structure only needs to shrink the active material layer of the single film area at the ending part of the positive electrode plate by a certain size, the single film area at the ending part of the positive plate is in safety consideration, the empty foil area with a certain size is reserved as the overlap area in the length direction of the positive and negative electrodes, the size of the empty foil area only needs to be properly enlarged, the welding of the double tabs of the positive plate can be finished, the influence on the size of the single-film area at the ending part is small, and only the energy density of the single-film area of the tab welding area at the ending part of the positive plate is lost; the double-sided empty foil area reserved in the middle of the battery can be normally coated, so that the energy density of the battery is higher than that of the battery obtained by the existing gap coating process, the limitation of a laser cleaning process window of the positive plate is avoided, and the battery is more suitable for the requirements of the current industry on the battery.

Drawings

Fig. 1 is a schematic structural diagram of a conventional embedded pole piece after gap coating.

Fig. 2 is a schematic structural diagram of an existing embedded pole piece after laser cleaning.

Fig. 3 is a schematic view of a winding structure of the battery of the present invention.

Fig. 4 is a schematic structural view of a positive electrode sheet of the battery of the winding structure of fig. 3.

Fig. 5 is a schematic structural diagram of a battery cell of the winding structure in fig. 3 after winding.

Fig. 6 is a schematic diagram of a forward projection direction of the battery cell of fig. 5.

Fig. 7 is a schematic structural diagram of the battery cell of fig. 5 before two positive electrode tabs are pressed.

Fig. 8 is a schematic structural diagram of the battery cell of fig. 5 after two positive electrode tabs are pressed.

Fig. 9 is a schematic structural diagram of connection between the battery cell and the protection board in fig. 8.

Fig. 10 is a schematic view of another winding structure of the battery of the present invention.

Fig. 11 is a schematic view of the positive electrode sheet of the battery of fig. 10 in a wound structure.

Fig. 12 is a schematic structural diagram of a battery cell of the winding structure of fig. 10 after winding.

Fig. 13 is a schematic structural diagram of connection between the battery cell and the protection board in fig. 12.

In the figure: 1' -positive plate; 11' -empty foil regions; 12' -the tab of the positive electrode; 1-electric core; 11-positive plate; 111-a first empty foil area; 112-positive tab; 12-negative pole piece; 121-negative tab; 13-tab glue; 2-protecting the board; 21-connecting piece.

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the present invention and its advantageous effects will be described in further detail below with reference to the accompanying drawings of the detailed description and the specification, but the present invention is not limited thereto.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The utility model discloses the standard part that uses all can purchase from the market, and dysmorphism piece all can be customized according to the description with the record of drawing of description, and the concrete connection mode of each part all adopts conventional means such as ripe bolt, rivet, welding among the prior art, and machinery, part and equipment all adopt prior art, and conventional model, including circuit connection adopts conventional connection mode among the prior art, does not detailed here again.

As shown in fig. 3 to 13, a wound battery includes a cell 1 formed by sequentially stacking and winding a positive electrode sheet 11, a separator, and a negative electrode sheet 12.

The positive plate 11 includes a positive current collector, a positive active material area and a first empty foil area 111, the positive active material area is coated on the positive current collector, the first empty foil area 111 is arranged at the start end and the end of the positive current collector, and can be integrally formed with the positive current collector, positive lugs 112 are welded on the first empty foil area 111, two positive lugs 112 are at least partially overlapped or spaced in the positive projection direction of the electric core 1 after winding, and the two positive lugs 112 are electrically connected together. Specifically, the positive electrode current collector may be an aluminum foil, the positive electrode tab 112 is also made of an aluminum material, and the positive electrode tab 112 may be welded to the first empty foil area 111 by a welding method such as laser welding, ultrasonic welding, or resistance welding.

The negative plate 12 includes a negative current collector, a negative active material area and a second empty foil area, the negative active material area is coated on the negative current collector, the second empty foil area is reserved on the negative current collector, and the negative tab 121 is welded on the second empty foil area. Specifically, the negative electrode current collector may be a copper foil, the negative electrode tab 121 may be a nickel material or a nickel-to-aluminum material, and the negative electrode tab 121 is welded to the second empty foil area by welding methods such as laser welding, ultrasonic welding, and resistance welding.

In addition, the surfaces of the positive tab 112 and the negative tab 121 are covered with an insulating adhesive layer for insulating and protecting the tabs and the pole pieces, and the insulating adhesive layer may be green glue, hot melt glue or other adhesive layer materials that can perform insulating and protecting functions.

The utility model discloses a first embodiment does: the second empty foil region is disposed at the middle position of the negative electrode tab 12. The middle-section embedded negative electrode tab 121 is adopted, and the middle-section embedded negative electrode tab and the positive electrode tab 112 adopting the head-tail bipolar tab design have the main functions together, so that the path of current conducted to the whole pole piece through the tab can be effectively shortened, and the electrode has the advantages of low internal resistance, low polarization and low heat production. Preferably, the second empty foil area is arranged on the negative electrode sheet 12 in a laser cleaning manner, and the current mature structural process of cleaning the small slot position with laser is used, so that the second empty foil area is properly cleaned according to the specific length to be welded of the negative electrode tab 121, the loss of energy density is reduced to the greatest extent, and the advantage of high energy density of the small slot position of the negative electrode is ensured. Of course, the negative electrode sheet 12 may be provided with the second empty foil region by other methods, such as solvent cleaning, pre-pasting, pre-coating with polymer layer, etc. The pre-gummed paper sticking method and the pre-coating polymer layer method are that gummed paper or a pre-coating polymer layer is pre-gummed at a specified position, and then substances in the specified position area fall off through cold pressing or baking, so that a second hollow foil area is formed. But relatively speaking, the laser cleaning mode is more convenient for industrial application.

On the one hand, as shown in fig. 3 to 9, when the two positive electrode tabs 112 are at least partially overlapped in the orthogonal projection direction of the battery cell 1 after winding, the thickness of the positive electrode tab 112 is less than or equal to one half of the thickness of the negative electrode tab 121. Preferably, the overlapping thickness of the two positive tabs 112 is equal to that of the negative tab 121, and the overlapping thickness of the two positive tabs 112 is equal to that of the negative tab 121, which is beneficial for packaging of the subsequent battery.

When the positive tab 112 is welded to the first empty foil area 111, the positive tab 112 is the positive tab 112 without the tab glue 13, and after winding, the tab glue 13 is placed on the positive tab 112. After finishing preliminary coiling, because the undulant influence of coiling processing procedure, there is the dislocation of certain degree in electric core 1 orthographic projection direction in two anodal ears 112, and is preferred, and usable cutter cuts counterpoint to two anodal ears 112 to make two anodal ears 112 overlap completely in electric core 1 orthographic projection direction. Then, tab glue 13 is respectively arranged on two sides of the two positive tabs 112 and between the two positive tabs 112, and the three tab glue 13 and the two positive tabs 112 are connected together by hot pressing. Since the thickness of the positive tab 112 is less than or equal to one half of the thickness of the negative tab 121, the overall thickness after the positive tab 112 and the tab glue 13 are laminated is often equal to the thickness of the negative tab 121 with the tab glue 13, which is more suitable for the subsequent battery packaging.

Because two anodal ears 112 overlap completely in electric core 1 orthographic projection direction after coiling, accomplish subsequent battery encapsulation after, can directly adopt the tradition only have two connecting piece 21 the protection shield 2 be connected with positive and negative pole ear 121 can, this connecting piece 21 can be the nickel piece, welding modes such as accessible laser welding, ultrasonic welding, resistance weld between nickel piece and the utmost point ear weld.

The conventional multi-tab welding method generally comprises the steps of firstly welding a bipolar tab of a pure metal belt, and then transferring the bipolar tab to a tab with tab glue 13; or a pure metal band lug and a lug with lug glue 13 are adopted, and the pure metal band lug is welded on the lug with lug glue 13. However, in any of the above-described methods, the size for welding the bipolar tab needs to be reserved in the longitudinal direction of the winding core, and the battery length is occupied. And the utility model discloses then adopt the bipolar ear of pure strap to combine the technology of the 13 direct hot pressing pressfittings of utmost point ear gum, reduced the welding position that utmost point ear welding was reserved for behind the bipolar ear hot pressing pressfittings of this battery, roll up the size of core on length direction and traditional unipolar ear winding structure battery and do not have obvious difference in length direction's ascending size, promoted the energy density of traditional many utmost point ear battery, this battery has obvious advantage on improving battery energy density.

Compared with the traditional structure of the battery cell 1, the battery cell 1 obtained by the structure has no obvious difference from the traditional structure of the battery cell 1, has certain complexity in the process of arranging the positive tab 112 in the earlier stage, does not need to change too many subsequent working procedures, and still has high potential when being applied to actual production.

On the other hand, as shown in fig. 10 to 13, when the two positive electrode tabs 112 are disposed at an interval in the orthogonal projection direction of the battery cell 1 after winding, the thickness of the positive electrode tab 112 is equal to the thickness of the negative electrode tab 121. That is, in the battery having such a structure, the thickness of the positive electrode tab 112 welded to the leading end and the trailing end of the positive electrode sheet 11 is equal to the thickness of the negative electrode tab 121, and the positive electrode tab 121 and the negative electrode tab 121 are tabs with tab adhesives 13. After the battery of this kind of structure accomplished the encapsulation, two positive ears 112 set up the structure for the interval, then need to adopt the protection shield 2 that has three connection piece 21 with the protection shield 2 that utmost point ear is connected, wherein, arbitrary two connection pieces 21 switch on each other, and two connection pieces 21 accessible protection shield 2 inside copper layer circuits link to each other and switch on, and are connected with two positive ears 112 one-to-one, and a surplus connection piece 21 is connected with negative pole ear 121. The connecting sheet 21 can be a nickel sheet, and the nickel sheet and the electrode lug can be welded by welding modes such as laser welding, ultrasonic welding, resistance welding and the like.

The core that rolls up that this kind of structure obtained compares and only goes out a utmost point ear position in traditional roll core structure, only needs to change traditional protection shield 2's setting, optimizes the mode that the circuit switched on for protection shield 2 with original many utmost points ear welding, compares in the tradition for many utmost points ear welding reserves the mode of welding the position, equally has obvious advantage on improving battery energy density, and the feasibility of this kind of structure at the direct volume production in industry is higher.

The utility model discloses a second kind of embodiment does, sets up the empty foil district of second in the head end and the middle section position of negative pole piece 12, and all welded on the empty foil district of second has negative pole ear 121, and two negative pole ears 121 set up or the interval sets up for at least partly overlapping in electric core 1 orthographic projection direction after coiling, and two negative pole ears 121 electricity after coiling are connected together. The negative electrode tab 12 may also be provided with a second empty foil region by laser cleaning, and for the arrangement of the negative electrode tab 121 with such a structure, reference may be made to the arrangement of the positive electrode tab 112, which is not described herein in any further detail.

The utility model discloses a third kind of embodiment does, sets up the empty foil district of second in the end and the middle section position of negative pole piece 12, and all welded on the empty foil district of second has negative pole ear 121, and two negative pole ears 121 set up or the interval setting for at least partial overlapping in electric core 1 orthographic projection direction after coiling, and two negative pole ears 121 electricity after coiling are connected together. The negative electrode tab 12 may also be provided with a second empty foil region by laser cleaning, and for the arrangement of the negative electrode tab 121 with such a structure, reference may be made to the arrangement of the positive electrode tab 112, which is not described herein in any further detail.

The utility model discloses a fourth kind of implementation mode does, sets up the empty foil district of second in head end, terminal and middle section position of negative pole piece 12, and all welded on the empty foil district of second has negative pole ear 121, and three negative pole ear 121 sets up or the interval sets up for at least partial overlapping in electric core 1 orthographic projection direction after coiling, and two negative pole ears 121 electricity after coiling are connected together. The negative electrode sheet 12 may also be provided with a second empty foil region by laser cleaning, and for the arrangement of the negative electrode tab 121 with such a structure, reference may also be made to the arrangement of the positive electrode tab 112, which is not described herein in any further detail.

The fifth embodiment of the present invention is to set the second empty foil area at the head end and the tail end of the negative electrode sheet 12, and the negative electrode tabs 121 are welded on the second empty foil area, and the two negative electrode tabs 121 are overlapped or spaced in the orthogonal projection direction of the battery cell 1 after winding, and the two negative electrode tabs 121 are electrically connected together after winding. For the arrangement of the negative electrode tab 121 with such a structure, reference may be made to the arrangement of the positive electrode tab 112, which is not described in detail herein.

The utility model discloses a battery provides the encapsulation of multiple electric core 1 and the connected mode of protection shield 2, not only has obvious advantage on improving battery energy density, and the bigger degree promotes leading-in of actual volume production, solves traditional battery energy density and is subject to the problem of process window.

Variations and modifications to the above-described embodiments may become apparent to those skilled in the art from the disclosure and teachings of the above description. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious modifications, replacements or variations made by those skilled in the art on the basis of the present invention belong to the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A winding battery comprises an electric core (1) formed by sequentially laminating and winding a positive plate (11), a diaphragm and a negative plate (12), and is characterized in that the starting end and the tail end of the winding of the positive plate (11) are respectively provided with a first empty foil area (111), positive lugs (112) are welded on the first empty foil areas (111), after the winding, the two positive lugs (112) are at least partially overlapped or arranged at intervals in the orthographic projection direction of the electric core (1), and the two positive lugs (112) are electrically connected together; and a second empty foil area is arranged on the negative plate (12), and negative lugs (121) are welded on the second empty foil area.

2. The wound battery according to claim 1, wherein the second empty foil region is provided at least at a middle position of the negative electrode sheet (12).

3. The wound battery according to claim 2, wherein when the two positive electrode tabs (112) are at least partially overlapped in the orthographic projection direction of the battery core (1) after winding, the thickness of the positive electrode tab (112) is less than or equal to one half of the thickness of the negative electrode tab (121).

4. The wound battery according to claim 3, wherein the thickness of the two positive electrode tabs (112) after overlapping is equal to the thickness of the negative electrode tab (121).

5. The winding battery according to claim 3, characterized in that the two positive electrode tabs (112) are arranged in a completely overlapping manner in the orthographic projection direction of the battery core (1).

6. The wound battery according to any one of claims 3 to 5, wherein tab glue (13) is arranged on both sides of the two positive tabs (112) and between the two positive tabs (112) after winding; the tab glue (13) is connected with the two positive tabs (112) in a pressing mode.

7. The wound battery according to claim 2, wherein when the two positive electrode tabs (112) are arranged at intervals in the orthogonal projection direction of the battery cell (1) after winding, the thickness of the positive electrode tab (112) is equal to the thickness of the negative electrode tab (121).

8. The wound battery according to claim 7, further comprising a protective plate (2), wherein three connecting pieces (21) are welded on the protective plate (2), any two of the connecting pieces (21) are conducted with each other and are connected with two positive tabs (112) in a one-to-one correspondence, and the remaining one connecting piece (21) is connected with the negative tab (121).

9. The wound battery according to claim 2, wherein the negative electrode sheet (12) is provided with the second empty foil region by laser cleaning.

10. The wound battery according to claim 1, wherein the second empty foil regions are arranged at the head end and the tail end of the negative electrode sheet (12), negative electrode tabs (121) are welded on the second empty foil regions, the two negative electrode tabs (121) are at least partially overlapped or spaced in the orthogonal projection direction of the battery cell (1) after winding, and the two negative electrode tabs (121) are electrically connected together after winding.