Patent Description:
Lithium-ion batteries, due to their high volume and mass energy density, long cycle life, high nominal voltage, low self-discharge rate, small volume, and light weight, are widely used in consumer electronics. With the rapid development of electric vehicles and mobile devices, demand for energy density, safety, and cycle performance of such a lithium-ion battery is higher and higher.

A current collector, as an important part of the lithium-ion battery, has a function of collecting current generated by an active material of the lithium-ion battery to form a larger current for output. By applying a composite current collector, energy density is further improved, toughness and elongation become better, and process optimization in production is achieved, and energy density per unit mass and safety are enhanced. However, metal layers on both sides of the composite current collector are isolated by a middle insulation layer and cannot conduct, which affects the performance of the lithium ion battery.

In the prior art, <CIT> discloses a current collector electrode structure for a secondary battery. <CIT> discloses a battery cell including an electrode assembly formed by winding a first electrode sheet and a second electrode sheet, wherein an isolation film is sandwiched between the first electrode sheet and the second electrode sheet. <CIT> discloses an electrode assembly, the electrode assembly including a furcated tab and a first current collector.

In view of the above problems, the present disclosure provides an electrode plate in which metal layers on both sides of a composite current collector are capable of being easily conductive between each other, a battery cell including the electrode plate, and an electrochemical device.

In some embodiments, the electrode plate further includes an active material layer disposed on each of the first metal layer and the second metal layer, and covering a portion of the at least one first electrode tab on the first metal layer and a portion of the at least one second electrode tab on the second metal layer.

In the present disclosure, the first electrode tab can be connected to the second electrode tab by soldering to be conductive with the second electrode tab, thus the first metal layer and the second metal layer on both sides of the composite current collector are conductive between each other.

In some embodiments, the electrode plate further includes a plurality of the first electrode plate and a plurality of the second electrode tabs respectively arranged at intervals in the length direction of the electrode plate.

In some embodiments, in a thickness direction of the electrode plate, a projection of each first electrode tab overlaps with a projection of the corresponding one of the plurality of second electrode tabs, wherein the thickness direction of the first electrode plate refers to a stacking direction of a multi-layer structure of the first electrode plate.

In some embodiments, in the length direction of the electrode plate, projections of the first electrode tabs in the thickness direction of the electrode plate and projections of the second electrode tabs in the thickness direction of the electrode plate are alternating, wherein the thickness direction of the first electrode plate refers to a stacking direction of a multi-layer structure of the first electrode plate.

In some embodiments, a distance between adjacent two first electrode tabs is equal, and a distance between adjacent two second electrode tabs is equal.

In some embodiments, a distance between adjacent two first electrode tabs can increase or decrease along the length direction of the electrode plate, and a distance between adjacent two second electrode tabs correspondingly increases or decreases along the length direction of the electrode plate.

In some embodiments, in the length direction of the electrode plate, the electrode plate includes a head portion, a middle portion, and tail portion connected in order, the at least one first electrode tab is disposed on at least one of a head portion, a middle portion, and a tail portion of the first metal layer, and the at least one second electrode tab corresponds to the at least one first electrode tab to be disposed on at least one of a head portion, a middle portion, and a tail portion of the second metal layer corresponding to the at least one first electrode tab.

In some embodiments, the electrode plate includes a first end face adjacent to the head portion and a second end face adjacent to the tail portion, when the first electrode tab and the second electrode tab are both disposed on the head portion of the electrode plate, in the length direction of the electrode plate, a distance between the first end face and each of the first electrode tab and the second electrode tab is less than <NUM>/<NUM> of a length of the electrode plate, wherein when the first electrode tab and the second electrode tab are both on the tail portion of the electrode plate, in the length direction of the electrode plate, a distance between the second end face and each of the first electrode tab and the second electrode tab is less than <NUM>/<NUM> of a length of the electrode plate.

In some embodiments, the insulation layer extends beyond the first metal layer and the second metal layer in the width direction of the electrode plate, sides of the first electrode tab and the second electrode tab away from the insulation layer are provided with an insulating sheet.

In some embodiments, the at least one first electrode tab is attached to a surface of the first metal layer, and the at least one second electrode tab is attached to a surface of the second metal layer.

The present disclosure further provides a battery cell including a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate. The first electrode plate is any one of the above electrode plates, the at least one first electrode tab is electrically connected to the at least one second electrode tab.

In some embodiments, the first electrode plate and the second electrode plate are stacked or wound to form the battery cell.

In some embodiments, in a thickness direction of the battery cell, a projection of the at least one first electrode tab overlaps with a projection of the at least one second electrode tab.

The present disclosure further provides an electrochemical device including an adapter plate and the above battery cell, the at least one first electrode tab and the at least one second electrode tab are stacked to form a multi-tab structure, the multi-tab structure is connected to the adapter plate.

To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings and following descriptions show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

Implementations of the disclosure will now be described, by way of embodiments only, with reference to the drawing. The disclosure is illustrative only, and changes may be made in the detail within the principles of the present disclosure. It will, therefore, be appreciated that the embodiments may be modified within the scope of the claims.

It is noted that, when one component is considered as "being connected to" another component, the one component may be connected directly to the other component or an intermediate component might be present simultaneously. When a component is referred to as "being disposed on" another component, the component may be disposed on the other component or an intermediate component might be present simultaneously. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The technical terms used herein are to provide a thorough understanding of the embodiments described herein, but are not to be considered as limiting the scope of the embodiments. The term "and/or" used herein includes any and all combinations of one or more of the associated listed items.

<FIG> illustrates a first embodiment of an electrochemical device <NUM> including a battery cell <NUM> and an adapter plate <NUM>. The battery cell <NUM> includes a first electrode plate <NUM>, a second electrode plate <NUM>, and a separator <NUM> disposed between the first electrode plate <NUM> and the second electrode plate <NUM>. The first electrode plate <NUM> and the second electrode plate <NUM> are wound or stacked to form the battery cell <NUM>. The first electrode plate <NUM> includes a composite current collector <NUM>, a first electrode tab <NUM> and a second electrode tab <NUM>. The first electrode tab <NUM> and the second electrode tab <NUM> are disposed on opposite surfaces of the composite current collector <NUM> and located on a same side of the first electrode plate <NUM>. The first electrode tab <NUM> and the second electrode tab <NUM> extends in a same side. The first electrode tab <NUM> is electrically connected to the second electrode tab <NUM> via the adapter plate <NUM> to conduct between two surfaces of the composite current collector <NUM>.

The composite current collector <NUM> includes a first metal layer <NUM>, a second metal layer <NUM>, and an insulation layer <NUM> sandwiched between the first metal layer <NUM> and the second metal layer <NUM>. The first electrode tab <NUM> is disposed on an edge of the first metal layer <NUM> and extends beyond the insulation layer <NUM>. The second electrode tab <NUM> is disposed on an edge of the second metal layer <NUM> and extends beyond the insulation layer <NUM>. Referring to <FIG>, in one embodiment, the first electrode tab <NUM> is disposed on the edge of the first metal layer <NUM> in a length direction L of the first electrode plate <NUM> and extends beyond the insulation layer <NUM> along a width direction W of the first electrode plate <NUM>, the second electrode tab <NUM> is disposed on the edge of the second metal layer <NUM> in the length direction L of the first electrode plate <NUM> and extends beyond the insulation layer <NUM> along the width direction W of the first electrode plate <NUM>. In the present disclosure, the length direction L of the first electrode plate <NUM> refers to an extending direction of the first electrode plate <NUM>, that is along a winding direction of the battery cell <NUM>, the width direction W of the first electrode plate <NUM> refers to an extending direction of the electrode tab, and is substantially perpendicular to the length direction L.

The first electrode tab <NUM> and the second electrode tab <NUM> are stacked to form a multi-tab structure <NUM>, which is electrically connected to the adapter plate <NUM> to conduct between the first metal layer <NUM> and the second metal layer <NUM>. Specifically, the battery cell <NUM> in <FIG> shows two layers of the first electrode plate <NUM> for illustration, the second electrode tab <NUM> on one layer of the first electrode plate <NUM> is bent towards the first electrode tab <NUM> on other layer of the first electrode plate <NUM> and stacked with such first electrode plate <NUM> to form the multi-tab structure <NUM>.

The insulation layer <NUM> can be made of a material selected from a group consisting of poly (butylene terephthalate), poly (ethylene naphthalate) (PEN), poly-ether-ether-ketone, polyimide, polyamide, polyethylene glycol, polyamide imide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, poly tetra fluoroethylene, polynaphthylmethylene, polyvinylidene difluoride, poly (naphthalenedicarboxylicacid), poly propylene carbonate, poly (vinylidene difluoride-co-hexafluoropropylene), poly (vinylidene difluoride-co-chlorotrifluoroethylene), polysiloxane, vinylon, polypropylene, polyethylene, polyvinyl chloride, polystyrene, poly (cyanoarylether), polyurethane, polyphenylene oxide, polyester, polysulfone, derivatives thereof, and any combination thereof.

Each of the first metal layer <NUM> and the second metal layer <NUM> can be formed by sputtering, vacuum vapor deposition, ion plating, or pulse laser deposition. Since only the insulation layer <NUM> needs to be cut, metal burrs are avoided, and the voltage drop per unit time (K value) is reduced, thus safety of the battery is improved. Each of the first metal layer <NUM> and the second metal layer <NUM> can be made of a material selected from a group consisting of Ni, Ti, Cu, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, In, Zn, and any combination (alloy) thereof. Optionally, the first metal layer <NUM> and the second metal layer <NUM> can be made of different materials or a same material.

Each of the first electrode tab <NUM> and the second electrode tab <NUM> is a metal sheet, which can be made of a material selected from a group consisting of Ni, Ti, Cu, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, In, Zn, and any combination (alloy) thereof.

In a thickness direction H of the battery cell <NUM>, a projection of the first electrode tab <NUM> overlaps with a projection of the second electrode tab <NUM>. In other words, in the thickness direction H of the battery cell <NUM>, the first electrode tab <NUM> and the second electrode tab <NUM> are overlapped together, so connecting the first electrode tab <NUM> and the second electrode tab <NUM> is easier. The first electrode plate <NUM> can further includes a plurality of the first electrode tabs <NUM> and a plurality of the second electrode tabs <NUM> respectively arranged at intervals along the first electrode plate <NUM>. A distance between adjacent two of the plurality of first electrode tabs <NUM> increases or decreases along the first electrode plate <NUM>, and a distance between adjacent two of the plurality of second electrode tabs <NUM> correspondingly increase or decreases along the first electrode plate <NUM>. In the thickness direction H of the battery cell <NUM>, the first electrode tabs <NUM> and the second electrode tabs <NUM> are overlapped together, so connecting the first electrode tabs <NUM> and the second electrode tabs <NUM> is easier. In the present disclosure, the thickness direction H of the battery cell <NUM> refers to a stacking direction of a multi-layer structure formed by winding the electrode plates of the battery cell <NUM> or a stacking direction of stacking the electrode plates of the battery cell <NUM>.

Optionally, the insulation layer <NUM> extends beyond the first metal layer <NUM> and the second metal layer <NUM> along the width direction W of the first electrode plate <NUM>. The insulation layer <NUM> includes a coated area <NUM> and a non-coated area <NUM> connected to the coated area <NUM>. The coated area <NUM> is configured to carry the first metal layer <NUM> and the second metal layer <NUM>. The first electrode tab <NUM> and the second electrode tab <NUM> are respectively attached to surfaces of the first metal layer <NUM> and the second metal layer <NUM> away from the insulation layer <NUM>, extend to cover the non-coated area <NUM>, and then extend beyond the insulation layer <NUM>. Referring to <FIG> again, the first electrode plate <NUM> further includes a first active material layer <NUM>. The first active material layer <NUM> is disposed on each of the first metal layer <NUM> and the second metal layer <NUM>, and covers portions of the first electrode tab <NUM> and the second electrode tab <NUM> on the non-coated area <NUM>. In the width direction W of the first electrode plate <NUM>, the coated area <NUM>, the first metal layer <NUM>, the second metal layer <NUM>, and the first active material layer <NUM> are aligned with each other.

In the thickness direction H of the battery cell <NUM>, a thickness of an edge of the first electrode plate <NUM> on which the electrode tab is disposed is equal to a total thickness of the insulation layer <NUM>, the first electrode tab <NUM>, and the second electrode tab <NUM>, which does not include thicknesses of the first metal layer <NUM> and the second metal layer <NUM>, thereby reducing the thickness of the edge of the first electrode plate <NUM>, reducing a space occupied by the battery cell <NUM> in the thickness direction H, and further improving energy density of the electrochemical device <NUM>.

In this embodiment, the first electrode plate <NUM> is a cathode electrode plate, the second electrode plate <NUM> is an anode electrode plate. The second electrode plate <NUM> includes a current collector <NUM> and a second active material layer <NUM> coated on opposite surfaces of the current collector <NUM>. The current collector <NUM> is a metal foil. In the width direction W of the first electrode plate <NUM>, the current collector <NUM> is aligned with the second active material layer <NUM>, and the second active material layer <NUM> exceeds the first active material layer <NUM>. The battery cell <NUM> further includes an insulating sheet <NUM>. The insulating sheet <NUM> is disposed on sides of the first electrode tab <NUM> and the second electrode tab <NUM> away from the insulation layer <NUM>, covers portions of the first electrode tab <NUM> and the second electrode tab <NUM> on the non-coated area <NUM>, and is configured to insulate the first electrode tab <NUM> from the second electrode tab <NUM>.

Referring to <FIG>, a plurality of the first electrode tabs <NUM> is disposed on the edge of the first metal layer <NUM>, and arranged at intervals along the length direction L of the first electrode plate <NUM>. A plurality of the second electrode tabs <NUM> is disposed on the edge of the second metal layer <NUM>, and arranged at intervals along the length direction L of the first electrode plate <NUM>.

In the length direction L of the first electrode plate <NUM>, projections of the first electrode tabs <NUM> along a thickness direction H of the first electrode plate <NUM> and projections of the second electrode tabs <NUM> along the thickness direction H of the first electrode plate <NUM> are alternately arranged. In the present disclosure, the thickness direction H of the first electrode plate <NUM> refers to a stacking direction of a multi-layer structure of the first electrode plate <NUM>. It is to be understood, the thickness H of the first electrode plate <NUM> is the same as the thickness H of the battery cell <NUM>. A distance between adjacent two first electrode tabs <NUM> increases along the length direction L, and a distance between adjacent two second electrode tabs <NUM> correspondingly increases along the length direction L. After the first electrode plate <NUM> is wound to form the battery cell <NUM>, the projection of the first electrode tab <NUM> in the thickness direction H overlaps with the projection of the second electrode tab <NUM> in the thickness direction H. In the drawings, the length direction L is labeled as extending from left hand side to right hand side, it is to understood that when the length direction L is labeled as extending from right hand side to left hand side, the distance between adjacent two first electrode tabs <NUM> decreases along the length direction L, and the distance between adjacent two second electrode tabs <NUM> decreases correspondingly along the length direction L.

<FIG> illustrates a second embodiment of an electrochemical device which is substantially the same as the electrochemical device <NUM> of the first embodiment except for the arrangement of a first electrode tab <NUM> and a second electrode tab <NUM> on a first electrode plate <NUM>. Specifically, the first electrode tabs <NUM> are disposed on an edge of a first metal layer <NUM> and arranged at intervals along the length direction L, the second electrode tabs <NUM>, corresponding to the first electrode tabs <NUM>, are disposed on an edge of a second metal layer <NUM> and arranged at intervals along the length direction L. In the length direction L, a projection of each first electrode tab <NUM> along the thickness direction H overlaps with a projection of a corresponding second electrode tab <NUM> along the thickness direction H. A distance between adjacent two of the first electrode tabs <NUM> increases along the length direction L, and a distance between adjacent two of the second electrode tabs <NUM> increases correspondingly along the length direction L. Compared with the first embodiment, by adding the first electrode tab <NUM> and the second electrode tabs <NUM> in this second embodiment, the positions of the first electrode tabs <NUM> correspond to the positions of the second electrode tabs and <NUM> in the thickness direction H, thereby reducing an impedance of the electrochemical device.

<FIG> illustrates a third embodiment of an electrochemical device which is substantially the same as the electrochemical device of the second embodiment except for the arrangement of a first electrode tab <NUM> and a second electrode tab <NUM> on a first electrode plate <NUM>. Specifically, a distance between adjacent two first electrode tabs <NUM> is equal, and a distance between adjacent two second electrode tabs <NUM> is equal. Compared with the second embodiment, the first electrode plate <NUM> is stacked to form a battery cell in this third embodiment.

<FIG> illustrates a fourth embodiment of an electrochemical device which is substantially the same as the electrochemical device <NUM> of the first embodiment except for the arrangement of a first electrode tab <NUM> and a second electrode tab <NUM> on a first electrode plate <NUM>. Specifically, in the length direction L, the first electrode plate <NUM> includes a head portion <NUM>, a middle portion <NUM>, and a tail portion <NUM> connected in that order, the first electrode tab <NUM> is disposed on the head portion <NUM> of a first metal layer <NUM>, the second electrode tab <NUM>, corresponding to the first electrode tab <NUM>, is disposed on the head portion <NUM> of a second metal layer <NUM>. The first electrode plate <NUM> further includes a first end face <NUM> and a second end face <NUM> opposite to the first end face <NUM>, the first end face <NUM> is a starting end of the first electrode plate <NUM> in the length direction L, the second end face <NUM> is a tail end of the first electrode plate <NUM> in the length direction L. In the present disclosure, the head portion <NUM> of the first electrode plate <NUM> is adjacent to the first end face <NUM>, the tail portion <NUM> of the first electrode plate <NUM> is adjacent to the second end face <NUM>, and the middle portion <NUM> of the first electrode plate <NUM> is adjacent to a center of the first electrode plate <NUM>. For example, the first electrode plate <NUM> is evenly divided, from the first end face <NUM> to the second end face <NUM>, into a first section, a second section, and a third section. The first section adjacent to the first end face <NUM> is the head portion <NUM>, the third section adjacent to the second end face <NUM> is the tail portion <NUM>, and the second section is the middle portion <NUM>. Optionally, in the length direction L, a distance between the first electrode tab <NUM> and the first end face <NUM> is less than <NUM>/<NUM> of a length of the first electrode plate <NUM>, and a distance between the second electrode tab <NUM> and the first end face <NUM> is less than <NUM>/<NUM> of a length of the first electrode plate <NUM>. The first electrode plate <NUM> in this fourth embodiment can be stacked or wound to form a battery cell. The second electrode tab <NUM> can also be disposed on the middle portion <NUM> or the tail portion <NUM> of the second metal layer <NUM>.

<FIG> illustrates a fifth embodiment of an electrochemical device which is substantially the same as the electrochemical device of the fourth embodiment except for the arrangement of a first electrode tab <NUM> and a second electrode tab <NUM> on a first electrode plate <NUM>. Specifically, the first electrode tab <NUM> is disposed on a tail portion <NUM> of a first metal layer <NUM>, and the second electrode tab <NUM>, corresponding to the first electrode tab <NUM>, is disposed on the tail portion <NUM> of a second metal layer <NUM>. Optionally, in the length direction L, a distance between each of the first electrode tab <NUM> and the second electrode tab <NUM> and the second end face <NUM> is less than <NUM>/<NUM> of a length of the first electrode plate <NUM>. The second electrode tab <NUM> can also be disposed on the middle portion or the head portion of the second metal layer <NUM>.

<FIG> illustrates a sixth embodiment of an electrochemical device which is substantially the same as the electrochemical device of the fourth embodiment except for the arrangement of a first electrode tab <NUM> and a second electrode tab <NUM> on a first electrode plate <NUM>. Specifically, the first electrode tab <NUM> is disposed on a middle portion <NUM> of a first metal layer <NUM>, and the second electrode tab <NUM>, corresponding to the first electrode tab <NUM>, is disposed on the middle portion <NUM> of a second metal layer <NUM>. The second electrode tab <NUM> can also be disposed on the head portion or the tail portion of the second metal layer <NUM>.

<FIG> illustrates a seventh embodiment of an electrochemical device which is substantially the same as the electrochemical device of the fourth embodiment except for the arrangement of two first electrode tabs <NUM> and two second electrode tabs <NUM> on a first electrode plate <NUM>. Specifically, the first electrode tabs <NUM> are disposed on a head portion <NUM> and a tail portion <NUM> of a first metal layer <NUM>, and the second electrode tabs <NUM>, corresponding to the first electrode tab <NUM>, are disposed on the head portion <NUM> and the tail portion <NUM> of a second metal layer <NUM>.

<FIG> illustrates an eighth embodiment of an electrochemical device which is substantially the same as the electrochemical device of the fourth embodiment except for the arrangement of two first electrode tabs <NUM> and two second electrode tabs <NUM> on a first electrode plate <NUM>. Specifically, the first electrode tabs <NUM> are disposed on a head portion <NUM> and a middle portion <NUM> of a first metal layer <NUM>, and the second electrode tabs <NUM>, corresponding to the first electrode tabs <NUM>, are disposed on the head portion <NUM> and the middle portion <NUM> of a second metal layer <NUM>.

Claim 1:
An electrode plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a composite current collector (<NUM>) comprising a first metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), a second metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and an insulation layer (<NUM>) directly sandwiched between the first metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the second metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a first electrode tab (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) disposed on an edge of the first metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), attached to a surface of the first metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) away from the insulation layer (<NUM>), and extending beyond the insulation layer (<NUM>);
a second electrode tab (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) disposed on an edge of the second metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), attached to a surface of the second metal layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) away from the insulation layer (<NUM>), and extending beyond the insulation layer (<NUM>), and the first electrode tab (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the second electrode tab (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) extending from a same side,
characterized in that
the insulation layer includes a coated area (<NUM>) and a non-coated area (<NUM>) connected to the coated area (<NUM>), the coated area (<NUM>) being configured to carry the first metal layer (<NUM>) and the second metal layer (<NUM>), the first electrode tab (<NUM>) and the second electrode tab (<NUM>) extending to cover the non-coated area (<NUM>) beyond the insulation layer (<NUM>)