阅读说明：本技术 电化学装置和用电装置 (Electrochemical device and electricity utilization device ) 是由 周权 于 2020-12-22 设计创作，主要内容包括：电化学装置包括壳体(30)、电极组件(10)、第一导电端子(22)和第二导电端子(23)。电极组件(10)包括间隔设置的第一极片(11)和第二极片(12)；壳体(30)收容电极组件(10)。第一导电端子(22)电连接第一极片(11)；第二导电端子(23)电连接第二极片(12)。其中,第一导电端子(22)和第二导电端子(23)层叠设置并伸出壳体(30)。(The electrochemical device includes a housing (30), an electrode assembly (10), a first conductive terminal (22), and a second conductive terminal (23). The electrode assembly (10) comprises a first pole piece (11) and a second pole piece (12) which are arranged at intervals; the case (30) houses the electrode assembly (10). The first conductive terminal (22) is electrically connected with the first pole piece (11); the second conductive terminal (23) is electrically connected with the second pole piece (12). The first conductive terminal (22) and the second conductive terminal (23) are stacked and extend out of the shell (30).)

1. An electrochemical device, comprising:

the electrode assembly comprises a first pole piece and a second pole piece which are arranged at intervals;

a case accommodating the electrode assembly;

the first conductive terminal is electrically connected with the first pole piece; and

the second conductive terminal is electrically connected with the second pole piece;

the first conductive terminal and the second conductive terminal are stacked and extend out of the shell.

2. The electrochemical device of claim 1, wherein an insulating layer is disposed between said first conductive terminal and said second conductive terminal.

3. The electrochemical device of claim 2, wherein said first conductive terminal is a first metal layer formed on a first surface of said insulating layer; the second conductive terminal is a second metal layer formed on a second surface of the insulating layer, and the second surface is opposite to the first surface.

4. The electrochemical device of claim 3, wherein the first pole piece comprises a copper current collector and the second pole piece comprises an aluminum current collector; the first metal layer is a nickel metal layer or a copper metal layer with a nickel metal film covered on the surface, and the second metal layer is an aluminum metal layer.

5. The electrochemical device as claimed in claim 1, wherein said first pole piece is provided with a plurality of first tab units arranged in a stacked arrangement, said plurality of first tab units collecting and electrically connecting said first pole piece and said first conductive terminal.

6. The electrochemical device as claimed in claim 5, wherein the second pole piece is provided with a plurality of second pole ear units arranged in a stacked manner, and the plurality of second pole ear units are gathered and electrically connected with the second pole piece and the second conductive terminal.

7. The electrochemical device of claim 6, further comprising:

the first insulating piece is arranged between the adjacent first lug unit and the second lug unit.

8. The electrochemical device of claim 7, further comprising:

a second insulator disposed between the electrode assembly and the case.

9. The electrochemical device according to claim 8, wherein the first insulator is attached to the second tab unit among the plurality of second tab units that is closest to the first tab unit, and the first insulator extends from a first position overlapping the active material layer of the second tab to a second position overlapping the second conductive terminal in a length direction of the second tab unit;

the second insulator is attached to the second tab unit closest to the housing among the plurality of second tab units, and extends from a first position overlapping with the active material layer of the second tab to a second position overlapping with the second conductive terminal in a length direction of the second tab unit.

10. The electrochemical device of claim 5 wherein an Nth first tab unit of said plurality of first tab units is closer to said housing than an Mth first tab unit, said Nth first tab unit having a greater tab length than said Mth first tab unit.

11. The electrochemical device according to claim 10, wherein the tab lengths of the plurality of first tab units are in an equal difference sequence, and the tab lengths of two adjacent first tab units are different by a sum of: the thickness of the first pole piece, the thickness of the second pole piece and the thickness of the isolating film.

12. An electrical device comprising a load and an electrochemical device according to any one of claims 1 to 11, said electrochemical device providing power to said load.

Technical Field

The application relates to the technical field of electrochemistry, in particular to an electrochemical device and an electric device.

Background

The lithium ion battery is widely applied due to the advantages of environmental friendliness, high working voltage, large specific capacity, long cycle life and the like, and becomes a novel green chemical power supply with the most development potential in the world today.

The manufacturing process of the electric core of the lithium ion battery is briefly described as follows: the laminated positive plate, the isolating membrane and the negative plate are wound to form a winding structure, wherein a positive active material layer is arranged on the positive plate, and a negative active material layer is arranged on the negative plate; tabs are projected out of each winding layer of the winding structure, and the tabs are subjected to transfer welding with a positive electrode conductor and a negative electrode conductor and then packaged by an aluminum plastic film to form an MTW (Multiple tabs connected) battery cell. The multi-tab connection design is equivalent to that the inside of the battery cell is connected in parallel for multiple times, so that the resistance of the positive and negative pole pieces is greatly reduced, the impedance of the whole battery cell is reduced, and the heating of the battery is controlled from the source.

At present, lithium ion batteries develop towards a narrow and long type and high multiplying power direction. Due to the requirement of high-rate discharge (such as 6C discharge) on the current-carrying capacity of the conductive terminals, the width of the conductive terminals cannot be reduced, and the width of the MTW cell is limited.

Disclosure of Invention

In view of this, the present application provides an electrochemical device and an electric device to solve the problem that the conventional narrow-long lithium ion battery cannot satisfy high-rate discharge.

An embodiment of the present application provides an electrochemical device including a housing, an electrode assembly, a first conductive terminal, and a second conductive terminal. The electrode assembly comprises a first pole piece and a second pole piece which are arranged at intervals; the case houses the electrode assembly. The first conductive terminal is electrically connected with the first pole piece; the second conductive terminal is electrically connected with the second pole piece. The first conductive terminal and the second conductive terminal are stacked and extend out of the shell.

In some embodiments, an insulating layer is disposed between the first conductive terminal and the second conductive terminal.

In some embodiments, the first conductive terminal is a first metal layer formed on a first surface of the insulating layer; the second conductive terminal is a second metal layer formed on a second surface of the insulating layer, and the second surface is opposite to the first surface.

In some embodiments, the first pole piece comprises a copper current collector and the second pole piece comprises an aluminum current collector; the first metal layer is a nickel metal layer or a copper metal layer with a nickel metal film covered on the surface, and the second metal layer is an aluminum metal layer.

In some embodiments, the first pole piece is provided with a plurality of first tab units arranged in a stacked manner, and the plurality of first tab units collect and electrically connect the first pole piece and the first conductive terminal.

In some embodiments, the second pole piece is provided with a plurality of second pole ear units which are arranged in a stacked mode, and the plurality of second pole ear units collect and are electrically connected with the second pole piece and the second conductive terminal.

In some embodiments, the electrochemical device further includes a first insulator disposed between the adjacent first and second tab units.

In some embodiments, the electrochemical device further comprises a second insulator disposed between the electrode assembly and the case.

In some embodiments, the first insulator is attached to the second tab unit closest to the first tab unit among the plurality of second tab units, and the first insulator extends from a first position overlapping the active material layer of the second tab to a second position overlapping the second conductive terminal in a length direction of the second tab unit. The second insulator is attached to the second tab unit closest to the housing among the plurality of second tab units, and extends from a first position overlapping with the active material layer of the second tab to a second position overlapping with the second conductive terminal in a length direction of the second tab unit.

In some embodiments, the first pole piece is an anode pole piece and the second pole piece is a cathode pole piece; or the first pole piece is a cathode pole piece, and the second pole piece is an anode pole piece.

In some embodiments, the first insulator and the second insulator are insulating glue.

In some embodiments, the first tab unit of the plurality of first tab units is closer to the housing than the mth first tab unit, and the nth first tab unit has a greater tab length than the mth first tab unit.

In some embodiments, the tab lengths of the plurality of first tab units are in an equal difference array, and the difference between the tab lengths of two adjacent first tab units is the sum of the following values: the thickness of the first pole piece, the thickness of the second pole piece and the thickness of the isolating film.

Another embodiment of the present application further provides an electric device, including a load and the electrochemical device described above, wherein the electrochemical device supplies power to the load.

In the electrochemical device, the first conductive terminal electrically connected with the first pole piece and the second conductive terminal electrically connected with the second pole piece are stacked and extend out of the housing of the electrochemical device, so that the problem that the width design space of the conductive terminals is insufficient under the size of a narrow product can be solved, the narrow product can be ensured to have the conductive terminals with sufficient width, and the requirement of a high-rate product on the current-carrying capacity is ensured.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and the drawings in the following description are only some embodiments of the present application.

FIG. 1 is a schematic view illustrating a structure of a wound electrode assembly used in an electrochemical device according to an embodiment of the present application;

FIG. 2 is a front view of the end face C of FIG. 1;

FIG. 3 is a schematic cross-sectional view of FIG. 1;

FIG. 4 is a schematic structural diagram of the first pole piece in FIG. 1;

FIG. 5 is an enlarged partial schematic view of FIG. 4;

fig. 6 is a schematic view of a second pole piece and first and second insulating members according to an embodiment of the present disclosure;

FIG. 7 is an exploded schematic view of the coiled electrode assembly of the present application;

FIG. 8 is a schematic structural view of a composite electrical conductor provided herein;

FIG. 9 is a schematic cross-sectional view of the composite electrical conductor according to FIG. 8;

FIG. 10 is a schematic view of the connection of a composite electrical conductor to a wound electrode assembly provided herein;

FIG. 11 is a schematic cross-sectional view of FIG. 10;

FIG. 12 is a schematic view showing the electrochemical device after the composite electrical conductor is press-fit connected to the wound electrode assembly;

FIG. 13 is a schematic diagram of a finished electrochemical device provided herein;

FIG. 14 is a schematic cross-sectional view of an electrochemical device provided herein;

FIG. 15 is a flow chart of a method of making an electrochemical device provided herein;

FIG. 16 is a flow chart of another method of making an electrochemical device provided herein;

fig. 17 is a schematic view illustrating a manufacturing process of an electrochemical device according to the present application.

Detailed Description

The technical solutions of the various exemplary embodiments provided in the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The following embodiments and their technical features may be combined with each other without conflict.

Directional phrases used herein, such as, for example, upper, lower, top, bottom, front, rear, left, right, inner, outer, side, central, peripheral, horizontal, transverse, vertical, longitudinal, radial, axial, uppermost or lowermost, etc., refer only to the orientation of the figure. Accordingly, the directional terminology is used for purposes of illustration and understanding, and is in no way limiting.

The electrochemical device of the present application includes all devices in which electrochemical reactions occur. By way of example, electrochemical devices include, but are not limited to, all kinds of primary, secondary, fuel cells, solar cells, and capacitor (e.g., supercapacitor) electrochemical devices. The electrochemical device is particularly preferably a lithium secondary battery including, but not limited to, a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.

For the sake of understanding, the following description will be made by taking a lithium ion polymer secondary battery as an example. The examples are given solely for the purpose of illustration and understanding of the present application and are not to be construed as limiting.

FIG. 10 is a schematic view of the connection of a composite electrical conductor to a wound electrode assembly of an electrochemical device according to an embodiment of the present disclosure; fig. 11 is a schematic cross-sectional view of fig. 10. Fig. 13 is a schematic structural diagram of an appearance of a finished electrochemical device according to an embodiment of the present disclosure.

Referring to fig. 10, 11 and 13, an embodiment of the present application provides an electrochemical device including: electrode assembly 10, case 30, and composite electrical conductor 20. The composite electrical conductor 20 includes a first conductive terminal 22 and a second conductive terminal 23. The case 30 houses the electrode assembly 10, and the electrode assembly 10 includes a first pole piece 11 and a second pole piece 12 arranged at an interval. For example, the electrode assembly 10 may be a wound electrode assembly 10 formed by continuously winding a first pole piece 11, a separator 13, and a second pole piece 12, which are stacked. The first conductive terminal 22 is electrically connected with the first pole piece 11; the second conductive terminal 23 is electrically connected to the second pole piece 12. The first and second conductive terminals 22 and 23 are stacked and extend out of the housing 30.

The high-rate discharge requires that the conductive terminals of the electrochemical device have a certain width, and for a narrow and long product, for example, when the product width is about 30mm and the high-rate requirement (such as 6C discharge) is superimposed, the product width cannot accommodate the positive conductive terminal and the negative conductive terminal at the same time. In the electrochemical device, the first conductive terminal electrically connected with the first pole piece and the second conductive terminal electrically connected with the second pole piece are arranged in a stacked mode, the problem that the width design space of the conductive terminals is insufficient under the condition of a narrow product size can be solved, the conductive terminals with enough width can be guaranteed for a narrow product, and the requirement of a high-magnification product on current-carrying capacity is met.

As shown in fig. 9, in some embodiments, an insulating layer 24 is disposed between the first conductive terminal 22 and the second conductive terminal 23 to prevent the first conductive terminal 22 and the second conductive terminal 23 from being shorted.

The present application does not limit the specific shape and structure of the first conductive terminal 22 and the second conductive terminal 23. In some embodiments, the first conductive terminal 22 is a first metal layer formed on a first surface of the insulating layer 24; the second conductive terminal 23 is a second metal layer formed on a second surface of the insulating layer 24, and the second surface of the insulating layer 24 is disposed opposite to the first surface. The first metal layer, the second metal layer and the intermediate insulating layer 24 may be thermally laminated together to form the composite electrical conductor 20 shown in fig. 9.

The technical solution of the present application is further described below with reference to the accompanying drawings.

Fig. 1 is a schematic view of a wound electrode assembly applied to an electrochemical device according to the present application. Fig. 2 is a front view of the end face C in fig. 1. Fig. 3 is a schematic cross-sectional view of fig. 1. Fig. 4 is a schematic structural view of a first pole piece of a wound electrode assembly. Fig. 5 is an enlarged schematic view of fig. 4. Fig. 6 is a schematic structural view of a second pole piece of the wound electrode assembly. FIG. 7 is an exploded view of one embodiment of the coiled electrode assembly of the present application.

Referring to fig. 1 to 4, a wound electrode assembly 10 for an electrochemical device according to the present invention is formed by continuously winding a first electrode sheet 11, a separator 13, and a second electrode sheet 12, which are stacked. In the first radial direction OA of the wound electrode assembly 10, a plurality of first tab units 111 connected to the first pole piece 11 are provided, and the plurality of first tab units 111 are stacked one on another. On a second radial direction OA' opposite to the first radial direction OA, a plurality of second pole ear units 121 connected to the second pole piece 12 are disposed, and the plurality of second pole ear units 121 are stacked one on another. The plurality of first tab units 111 and the plurality of second tab units 121 extend opposite to and are electrically connected to conductive terminals (not shown in fig. 1-4) of the electrochemical device.

The first radial direction OA and the second radial direction OA 'are directions perpendicular to the central axis BB' of the wound electrode assembly 10. In the wound electrode assembly shown in fig. 2, the first radial direction OA and the second radial direction OA are directed from the center of the wound electrode assembly to the periphery of the wound electrode assembly. As shown in fig. 2, the first and second pole pieces 11 and 12 in the wound electrode assembly protrude oppositely from the tab unit. The plurality of first tab units 111 connected to the first pole piece 11 in the jelly-roll electrode assembly 10 are arranged in the first radial direction OA and are stacked one on another. The plurality of first tab units 111 are concentrated on the upper side of fig. 2. The plurality of second tab units 121 connected to the second pole piece 12 in the jelly-roll type electrode assembly 10 are arranged in the second radial direction OA' and are stacked one on another. The plurality of second tab units 121 are concentrated on the lower side of fig. 2. The plurality of first tab units 111 and the plurality of second tab units 121 are opposite and insulated from each other, extend to a conductive terminal of the electrochemical device in an opposite and insulated state, and are connected to an output terminal of the electrochemical device through the conductive terminal.

One of the first pole piece 11 and the second pole piece 12 is a cathode pole piece, and the other is an anode pole piece. Correspondingly, the first tab unit 111 and the second tab unit 121 are a cathode tab unit and an anode tab unit, respectively. A plurality of negative pole utmost point ear units in this application range upon range of each other and concentrate on one and form negative pole utmost point ear unit group, and a plurality of positive pole utmost point ear units range upon range of each other and concentrate on one and form positive pole utmost point ear unit group, and negative pole utmost point ear unit group and positive pole utmost point ear unit group also extend relatively in addition, and a utmost point ear design width can be shared to positive and negative utmost point ear unit like this, can possess sufficient utmost point ear width under the condition that satisfies the requirement of narrow and long product width, satisfies the high rate demand that discharges.

The pole piece and the pole ear can be cut from the same metal foil. As shown in fig. 4, the first pole piece 11 with a plurality of first tab units 111 is cut from the same metal foil.

As shown in fig. 4 and 5, the pitch of the plurality of first tab units 111 may be increased one by one in the winding direction with respect to the first pole piece 11. Similarly, as shown in fig. 6, the pitch of the plurality of second tab units 121 of the second pole piece 12 may also be increased one by one along the winding direction, but the distribution position of the second tab units 121 is different from the distribution position of the first tab units 111. When the first and second pole pieces 11 and 12 are laminated, the first and second tab units 111 and 121 are alternately arranged. After the wound electrode assembly 10 is formed by continuous winding, the plurality of first tab units 111 are concentrated on one side (e.g., an upper side in fig. 2) of the wound electrode assembly 10, and the plurality of second tab units 121 are concentrated on the other side (e.g., a lower side in fig. 2) of the wound electrode assembly 10 opposite to the first tab units 111. In this embodiment, a scheme for accommodating as many tab units as possible is provided on the basis of the above embodiments, that is, one tab unit is disposed on each layer of the pole piece in the radial direction of the wound electrode assembly, so that the resistances of the positive and negative pole pieces are greatly reduced, and the impedance of the whole battery cell is reduced.

The tab widths of the first tab units 111 and the second tab units 121 are equal. The first and second pole lug units are stacked and have equal width, and the width of the pole lug unit can be designed to be wider as much as possible under the condition of limiting the width size of a product, namely, the pole lug width maximization design can be realized so as to meet the high-rate discharge requirement of a narrow and long product.

As shown in fig. 3 and 11, the first tab unit 111, which is farther from the central axis of the wound electrode assembly 10, has a greater tab length. For example, the nth first tab unit has a greater tab length than the mth first tab unit, the farther the nth first tab unit is relatively from the central axis of the wound electrode assembly 10, the closer the nth first tab unit is to the case 30 than the mth first tab unit. Wherein N, M is a natural number greater than zero.

In some embodiments, the tab lengths of the plurality of first tab units 111 are in an equal difference array, and the tab lengths of two adjacent first tab units 111 are different by the sum of the following values: the thickness of the first pole piece 11, the thickness of the second pole piece 12 and the thickness of the isolation film. The isolation film may include a first isolation film and a second isolation film. In this way, the ends of the plurality of first tab units 111 are substantially concentrated at one location to facilitate press-fit connection with an electrically conductive member (e.g., the composite electrical conductor 20) of the electrochemical device. The tab lengths of the plurality of second tab units 121 also have similar variation rules.

In some embodiments, as shown in fig. 2, 6 and 12, the electrode assembly further includes a first insulating member 14, the first insulating member 14 being disposed between the first and second opposite tab units 111 and 121. The first insulator 14 is used to prevent the first pole piece 11 and the second pole piece 12 from being shorted at the pole ear and the conductive terminal. At the lamination position of the first tab 111 and the second tab 121, especially when the first tab 111 and the second tab 121 are extended to the conductive component in an opposite state, a short circuit is easily generated, and the first insulating member 14 is sandwiched between the adjacent first tab unit 111 and the second tab unit 121 to isolate the first tab 111 from the second tab 121. The first insulating member 14 may be an insulating paste, and may be a tab protection paste 141, for example.

In some embodiments, as shown in FIGS. 2, 6 and 12, the electrode assembly further includes a second insulating member 15, and the second insulating member 15 is disposed between the jelly-roll type electrode assembly 10 and the case of the electrochemical device. The first tab unit 111 or the second tab unit 121 is generally formed by cutting, and the edges are prone to burrs which may pierce the separator 13 or the housing, particularly when the housing is a soft-packed housing such as an aluminum-plastic film. The second insulator 15 may be an insulating paste, such as tab protection paste 151.

In some embodiments, the electrode assembly includes a first insulating member 14 and a second insulating member 15. The first insulating member 14 and the second insulating member 15 may be both insulating paste. In some embodiments, as shown in fig. 6, 7 and 11, the first insulating member 14 is a tab protection paste 141 extending from the active material layer of the pole piece to the conductive member; the second insulator 15 is a tab protection paste 151 attached to the outside of the jelly-roll type electrode assembly 10, covering the tab portion and extending to the conductive member.

One of the first pole piece 11 and the second pole piece 12 is a cathode pole piece, and the other is an anode pole piece. In some embodiments, at least one of the first insulator 14 and the second insulator 15 is attached to the cathode tab. In the current electrochemical device, the capacity of the anode is larger than that of the cathode, and in order to make the CB value meet the design requirement, the first insulator 14 and the second insulator 15 (i.e. tab protection glue) are generally attached to the cathode plate. The CB value (cell balance) refers to the ratio of the anode capacity to the cathode capacity per unit area.

As shown in fig. 6 and 11, the first insulating member 14 may be attached to one side of the first cathode tab 122 of the cathode sheet near the central axis of the wound electrode assembly 10, and the first insulating member 14 extends at least from a first position C overlapping with the cathode active material layer of the cathode sheet to a second position C overlapping with the conductive member (e.g., the composite electrical conductor 20) in the length direction of the first cathode tab 122, where the first cathode tab 122 is the first tab of the cathode sheet in the winding direction. The first insulator 14 may also extend over the active material layer, laminated with the active material layer.

As shown in fig. 6 and 11, the second insulator 15 is attached to the last cathode tab 123 of the cathode plate on the side away from the central axis of the wound electrode assembly 10, and in the length direction of the cathode tab, the second insulator 15 extends at least from the first position C overlapping with the cathode active material layer of the cathode plate to the second position C overlapping with the conductive component (e.g., the composite electrical conductor 20), and the last cathode tab 123 is the last tab of the cathode plate in the winding direction.

The application also provides a brand-new composite conductor design which can be applied to the design scheme of the laminated type relative lug,

fig. 8 is a schematic structural diagram of an embodiment of the composite electrical conductor 20 provided in the present application. Fig. 9 is a schematic cross-sectional structure along a sectional line L1 according to the composite conductive in fig. 8. Fig. 10 is a schematic view of the composite electrical conductor 20 provided herein interposed between opposing first and second sets of tab elements. Fig. 11 is a schematic cross-sectional view of fig. 10. Fig. 12 is a schematic view of an electrochemical device after the composite electrical conductor and the rolled electrode assembly 10 are press-fit connected. Fig. 13 is a schematic diagram of a finished electrochemical device provided herein. Fig. 14 is a schematic cross-sectional structure view of an electrochemical device provided in the present application.

As shown in fig. 8 to 11, the composite electrical conductor 20 of the present application includes a first metal layer 22, a second metal layer 23, and an insulating layer 24 disposed between the first metal layer 22 and the second metal layer 23. The first metal layer 22, the second metal layer 23 and the intermediate insulating layer 24 can be integrated by high temperature. To ensure insulation, the insulating layer 2 generally needs to extend beyond the edges of the first metal layer 22 and the second metal layer 23.

As shown in fig. 10 and 11, the composite conductor of the present invention is inserted between the first tab unit 111 and the second tab unit 121 facing each other when being mounted, and the first metal layer 22 of the composite conductor 20 faces the first tab unit 111 and is electrically connected to each of the first tab units 111. The second metal layer 23 of the composite electrical conductor 20 faces the second tab element 121 and is electrically connected to the plurality of second tab elements 121. The first metal layer 23 and the second metal layer 23 of the composite conductor 20 adopt a stacked design, so that the problem that the width of the MTW (methanol to methane) cell cannot accommodate the side-by-side positive and negative composite conductors 20 in a use scene with a narrow and long product stacked high-rate requirement can be solved.

The first metal layer 22 may be made of the same material as the first tab unit 111, and the second metal layer 23 may be made of the same material as the second tab unit 121. For example, the first pole piece 11 includes a copper current collector, and the first metal layer 22 is a nickel metal layer or a copper metal layer whose surface is covered with a nickel metal film; the second pole piece 12 comprises an aluminum current collector and the second metal layer 23 is an aluminum metal layer.

Illustratively, the first pole piece 11 includes a copper foil, and the copper foil includes a first pole piece region and a first tab region, the first pole piece region is further provided with an anode active material layer, and the first tab region is formed with a plurality of first tab units 111. The second electrode 12 includes an aluminum foil, the aluminum foil includes a second electrode region and a second electrode tab region, the second electrode region is further provided with a cathode active material layer, and the second electrode tab region is formed with a plurality of second electrode tab units 121. The first metal layer 22 of the composite conductor 20 is a nickel metal layer or a copper metal layer with a nickel metal film covering the surface, and the second metal layer 23 is an aluminum metal layer. In some embodiments, the tab protection pastes 141, 151 of the first and last cathode tab 122, 123 of the cathode pole piece may be extended directly to a position C' overlapping the composite electrical conductor 20.

As shown in fig. 8-11, 14, the other end of the composite electrical conductor 20 of the present application may also be provided with a seal 21. As shown in fig. 9, the sealing member 21 may be formed by a first sealing member 211 and a second sealing member 212 which are pressed at a high temperature around the integrated first metal layer 22, insulating layer 24, and second metal layer 23.

The wound electrode assembly 10 is disposed in a case 30, and the case 30 is, for example, an aluminum plastic film. A first end of the composite electrical conductor 20 is interposed between the first tab unit 111 and the second tab unit 121, and a second end of the composite electrical conductor 20 extends to the outside of the housing 30. An electrolyte is contained in the case 30, and the wound electrode assembly 10 is immersed in the electrolyte. A seal 21 is disposed around the composite electrical conductor 20 and the housing 30 is connected to the composite electrical conductor 20 through the seal 21.

The first end of the composite electrical conductor 20 is interposed between the first tab unit 111 and the second tab unit 121. The first and second metal layers of the first end are electrically connected with the first and second pole pieces respectively. The second end of the composite electrical conductor 20 extends from the housing 30, and the first and second metal layers of the second end are used to electrically connect to the positive and negative electrodes of the electrochemical device, respectively.

Fig. 15 is a flow chart of a method of making an electrochemical device provided by an embodiment of the present application; fig. 16 is a flow chart of another method of making an electrochemical device provided by an embodiment of the present application; fig. 17 is a schematic view illustrating a manufacturing process of an electrochemical device according to an embodiment of the present application, in which a1 illustrates a wound electrode assembly, a2 illustrates a schematic view illustrating insertion of a composite electrical conductor 20 into the wound electrode assembly, A3 illustrates a schematic view illustrating tab transfer welding, and a4 illustrates a schematic view illustrating bending of a first tab unit and a second tab unit to a predetermined shape after the tab transfer welding.

Embodiments of the present application also provide a method of manufacturing an electrochemical device, as shown in fig. 15, including a process of manufacturing a wound electrode assembly 10, wherein the process of manufacturing the wound electrode assembly 10 includes:

s101, cutting the first metal foil into a first substrate, and cutting the edge of the first substrate into a plurality of first tab units 111 with different pitches, as shown in fig. 4.

S102, cutting the second metal foil into a second substrate, and cutting the edge of the second substrate into a plurality of second tab units 121 with different pitches, as shown in fig. 6.

S103, coating the positive electrode active material layer and the negative electrode active material layer on the pole piece areas of the first substrate and the second substrate respectively, wherein the edges of the first substrate and the second substrate, namely the areas of the first pole ear unit 111 and the second pole ear unit 121, are not coated. The positive electrode active material is lithium cobaltate, lithium manganate, lithium iron phosphate, ternary material and the like, and the negative electrode active material is graphite or Si and the like.

S104, the first pole piece 11, the separator 13, and the second pole piece 12 are laminated, and the wound electrode assembly 10 is formed by continuous winding.

When the first and second pole pieces 11 and 12 are laminated, the first and second tab units 111 and 121 are alternately arranged. After the wound electrode assembly 10 is wound, a plurality of first tab units 111 are stacked and collected on each other in a first radial direction OA of the wound electrode assembly 10; on a second radial direction OA' opposite to the first radial direction OA, a plurality of second pole ear units 121 are stacked and collected. The first tab unit 111 and the second tab unit 121 extend to the conductive terminal of the electrochemical device in opposition and are used to be electrically connected with the conductive terminal. The first and second pole pieces 11 and 12 are finally electrically connected to the positive and negative electrodes of the electrochemical device via the tab unit and the conductive terminals. One of the first pole piece 11 and the second pole piece 12 is a cathode pole piece, and the other is an anode pole piece.

In some embodiments, the process of preparing the wound electrode assembly 10 further includes: firstly, a first insulating part 14 is pasted on the inner side of a first cathode tab 122 of the cathode pole piece along the winding direction, and a second insulating part 15 is pasted on the outer side of a last cathode tab 123 of the cathode pole piece along the winding direction; the first separator, the anode sheet, the second separator, and the cathode sheet to which the first insulator 14 and the second insulator 15 are applied are laminated, and the wound electrode assembly 10 is formed by continuous winding. The inner side refers to the side of the cathode pole piece that is closer to the central axis of the wound electrode assembly 10, and the outer side refers to the side of the cathode pole piece that is farther from the central axis of the wound electrode assembly 10. The first insulating member 14 and the second insulating member 15 are shown as a1 in fig. 17.

And S105, electrically connecting the first pole piece 11 and the second pole piece 12 with a first conductive terminal and a second conductive terminal which are arranged in a stacked mode, wherein the first conductive terminal and the second conductive terminal extend out of the shell in a stacked mode. And continuing the subsequent flow to finish the preparation of the electrochemical device.

As shown in fig. 16, the method for manufacturing an electrochemical device according to the present application includes, in addition to the step 201 of manufacturing a winding core, the steps of:

s202, a step of preparing the composite conductor 20.

The process for preparing the composite electrical conductor 20 includes: the first metal layer 22, the second metal layer 23 and the insulating layer 24 disposed between the first metal layer 22 and the second metal layer 23 are compounded into a whole by a high temperature method.

The process for producing the composite electrical conductor 20 further includes: preparing a first sealing component 211 and a second sealing component 212 which are mutually matched; the first metal layer 22, the insulating layer 24 and the second metal layer 23 which are compounded into a whole are placed between the first sealing component 211 and the second sealing component 212, and the first sealing component 211 and the second sealing component 212 are pressed on the second end of the composite electric conductor 20 through high-temperature pressing.

And S203, transfer welding of the lug and the composite conductor 20. In this step, as shown in a2 in fig. 17, the first end of the composite conductor 20 is inserted between the first tab unit 111 and the second tab unit 121 of the wound electrode assembly; as shown in a3 in fig. 17, the first metal layer 22 of the composite conductor 20 is electrically connected to the first tab units 111 of the first tab units 111 by welding, and the second metal layer 23 is electrically connected to the second tab units 121 of the second tab units 121. 40 is an ultrasonic horn used in the transfer welding process.

In the tab and composite conductor 20 transfer welding process, the first end of the composite conductor 20 is inserted between the first tab unit 111 and the second tab unit 121, and the first metal layer 22 and the second metal layer 23 of the first end of the composite conductor 20 can be electrically connected to the plurality of first tab units 111 and the plurality of second tab units 121, respectively, by ultrasonic welding. The ultrasonically welded first tab unit 111 and second tab unit 121 are bent to a predetermined shape, which may be, for example, as shown at a4 in fig. 17.

For example, in some embodiments, the process for making the composite electrical conductor 20 is as follows: firstly, compounding a nickel metal layer, an aluminum metal layer and an intermediate insulating layer into a whole in a high-temperature mode; and then the two separated sealing components and the compounded nickel metal layer, insulating layer and aluminum metal layer are compounded into a whole at high temperature to form the composite conductor 20. The thickness range of the nickel metal layer and the aluminum metal layer is between 0.03mm and 0.20 mm; the middle insulating layer can be a PP material with the melting point of more than 200 ℃ and lower than the melting temperature of the nickel/aluminum metal layer, and has insulating, electrolyte resistance and bending resistance or other plastic materials with the same performance requirements. The sealing component can also be made of PP (polypropylene) material, and the thickness of the single-layer material is 0.055-0.100 mm.

And S204, packaging the shell and filling electrolyte.

The wound electrode assembly 10 and the composite conductor 20, which are bent through the tabs, may be encapsulated by a casing, such as an aluminum-plastic film, and an electrolyte is poured into the aluminum-plastic film casing 30 formed by the encapsulation, wherein the second end of the composite conductor 20 extends to the outside of the aluminum-plastic film casing 30, the casing 30 and the composite conductor 20 are hermetically connected through a sealing member 21 by high-temperature pressing during the encapsulation, and the sealing member 21 includes a first sealing member 211 and a second sealing member 212 surrounding the composite conductor 20.

The upper end enclosure and the lower end enclosure are pressed relatively at a certain temperature, so that effective sealing is formed between a sealing assembly in the composite electric conductor 20 and the aluminum-plastic film; the groove depth of the upper end socket and the lower end socket is designed to ensure that the sealing component after hot melting fills the gap of the groove position of the end socket, thereby ensuring the sealing reliability.

And S205, carrying out formation and test processes on the packaged battery cell.

In the formation and testing process, the activation and voltage and internal resistance test of the electrochemical device can be performed by using a mode that the anode and the cathode clamp the second end of the composite conductor 20.

Embodiments of the present application also provide an electrical device comprising a load and the electrochemical device of any of the above, the electrochemical device of any of the above providing power to the load.

The use of the electrochemical device of the present application is not particularly limited, and it can be used for any electric device known in the art. In some embodiments, the electrochemical device of the present application can be used in, but is not limited to, notebook computers, pen-input computers, mobile computers, electronic book players, cellular phones, portable facsimile machines, portable copiers, portable printers, headphones, video recorders, liquid crystal televisions, portable cleaners, portable CDs, mini-discs, transceivers, electronic organizers, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, household large batteries, lithium ion capacitors, and the like. The electrochemical device of this application still can be used to vehicles such as electric automobile to and unmanned aerial vehicle etc..

Although the application has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. This application is intended to embrace all such modifications and variations and is limited only by the scope of the appended claims.

In particular regard to the various functions performed by the above described components, the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the specification. In addition, while a particular feature of the specification may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for a given or particular application. Furthermore, to the extent that the terms "includes," has, "" contains, "or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term" comprising.

Further, it should be understood that reference to "a plurality" herein means two or more. For the steps mentioned in the text, the numerical suffixes are only used for clearly expressing the embodiments, so that the understanding is easy, the execution sequence of the steps is not completely represented, and the logical relationship should be controlled by the precedence setting.

The above-mentioned embodiments are only examples of the present application, and not intended to limit the scope of the present application, and all equivalent structures or equivalent flow transformations made by the contents of the specification and the drawings, such as the combination of technical features between the embodiments and the direct or indirect application to other related technical fields, are also included in the scope of the present application.