Patent Description:
At present, the demand for high-rate charge and discharge batteries is increasing, and the application of multi-layer electrode tabs is becoming wider and wider. The multi-tab wound structure is currently widely used in batteries, and its multi-tab structure enables parallel connection between the layers of the wound cells. Compared with the conventional mono-tab battery, the internal resistance of the wound cell using the multi-tab structure is greatly reduced, and the dynamic performance of the battery can be significantly improved, such as improvement of charge and discharge rate, temperature rise and low temperature discharge.

The multi-tab is made of metal and cannot be packaged directly with the package, an adapter electrode tab is required, which is provided with an electrode tab adhesive that is fused with the package through heat fusion, and the adapter electrode tab is soldered with the electrode tab.

The method for adapting the electrode tab in current multi-tab lithium battery requires a large battery space and causes the energy density to be reduced. Moreover, manual application of adhesive is required, so automatic production cannot be realized, and there are problems such as low efficiency, high manufacturing cost, and quality stability depending on people. Therefore, it is necessary to improve the way in which the electrode tab adhesive of the multi-tab structure is applied.

<CIT> Al discloses a stack type battery including positive and negative electrode lead tabs. In particular, a stacked electrode assembly is provided, which includes sheets of pouch-type separators in each of which positive electrode plates are disposed and sheets of negative electrode plates, which form the outermost electrode layers. Further provided is a polypropylene based spacer including a first cover portion and a second cover portion including sub-portions covering the outermost electrode layers of the electrode assembly. Not disclosed is an insulating layer, which is disposed between a first electrode tab and a second electrode plate. In all cases, the insulating layers form the outermost layers of the electrode assembly.

For the problems in the related art, the present application intends to provide an electrode assembly and a battery as defined in the appended claims, so as to improve the safety performance of the battery.

According to one aspect of present application, an electrode assembly including a first electrode plate, a second electrode plate and a separator disposed therebetween is provided. The first electrode plate and the second electrode plate are wound or stacked to form the electrode assembly. Wherein the electrode assembly further includes a first electrode tab disposed on the first electrode plate, and an insulating layer including a first portion disposed on the first electrode plate. No second electrode plate is disposed between the first portion and the first electrode tab and the insulating layer is disposed between the first electrode tab and the second electrode plate.

According to an embodiment of present application, the first electrode tab includes a plurality of first electrode tab units, including an innermost first electrode tab unit adjacent to the insulating layer; no second electrode plate is disposed between the insulating layer and the innermost first electrode tab unit.

According to an embodiment of present application, an orthographic projection of the insulating layer covers an orthographic projection of the first electrode tab in a thickness direction of the electrode assembly.

According to an embodiment of present application, the first electrode tab includes a plurality of first electrode tab units disposed in a stack, including an innermost first electrode tab unit adjacent to the insulating layer; no second electrode plate is disposed between the insulating layer and the innermost first electrode tab unit; a width of the insulating layer is greater than a width of the first electrode tab in a width direction of the electrode assembly.

According to an embodiment of present application, the first electrode tab includes a plurality of first electrode tab units disposed in a stack, including an innermost first electrode tab unit adjacent to the insulating layer; the insulating layer further includes a second portion disposed on an outer surface of the electrode assembly.

According to an embodiment of present application, the second portion partially overlaps the first portion.

According to an embodiment of present application, the insulating layer at least partially covers the first electrode tab in a length direction of the electrode assembly.

According to an embodiment of present application, the first electrode plate is disposed between the insulating layer and the first electrode tab.

According to an embodiment of present application, the first electrode tab includes a tail segment extends beyond the electrode assembly and used for soldering to an adapter electrode tab, wherein the tail segment extends in a thickness direction of the electrode assembly; the insulating layer covers the tail segment.

According to an embodiment of present application, the first electrode plate is either one of a cathode plate or an anode plate, and the second electrode plate is the other of the cathode plate or the anode plate.

According to another aspect of present application, a battery including an electrode assembly as described above is provided. According to an embodiment, the battery contains a housing for receiving the electrode assembly.

The present application has the following beneficial technical effects:
A novel electrode tab introducing method is provided to save space, increase energy density, and provide superior safety, as compared with the prior process. The novel electrode tab introducing method may effectively reduce the risk of cell corrosion, internal short circuit, etc. The present application further provides a novel adhesive application method for replacing the current manual adhesive application method, so that the improved adhesive application method may achieve the automation or semi-automation for the adhesive application, thereby reducing manufacturing costs and solving the problem of low automation and quality stability caused by the existing adhesive application method.

The present application will be further described below in conjunction with <FIG>.

<FIG> illustrates a schematic cross-sectional view of an electrode assembly <NUM> according to an embodiment of the present application, which 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 to form the electrode assembly <NUM>, and the first electrode plate <NUM> and the second electrode plate <NUM> may also be alternately stacked to form the electrode assembly <NUM>. In an embodiment, the electrode assembly <NUM> further includes a first electrode tab <NUM> disposed on the first electrode plate <NUM>, and an insulating layer <NUM> including a first portion <NUM> disposed on the first electrode plate <NUM>, no second electrode plate <NUM> being disposed between the first portion <NUM> and the first electrode tab <NUM>. In other words, the insulating layer <NUM> is disposed between the first electrode tab <NUM> and the second electrode plate <NUM> to achieve a better isolation effect, preventing the occurrence of an internal short circuit of the battery.

In an embodiment of the present application, the insulating layer <NUM> may be an adhesive tape or an insulating coating. The first portion <NUM> has a first end portion <NUM> and a second end portion disposed opposite the first end portion <NUM>, and the first end portion <NUM> extends inside of the electrode assembly <NUM> to prevent the first end portion <NUM> itself from falling off. The installation of the first end portion <NUM> can be implemented by the gluing department of the winding machine during winding.

According to an embodiment of the present application, the first electrode tab <NUM> includes a plurality of first electrode tab units <NUM>, and the plurality of first electrode tab units <NUM> includes an innermost first electrode tab unit <NUM> adjacent to the insulating layer <NUM>. Wherein no second electrode plate <NUM> is disposed between the insulating layer <NUM> and the innermost first electrode tab unit <NUM>. In other words, the embodiment of the present application is applicable to a multi-tab electrode assembly, which may effectively prevent the first electrode tab <NUM> and the second electrode plate <NUM> from contacting, thereby reducing the risk of internal short circuit.

In an embodiment of the present application, the first electrode tab <NUM> may only have one first electrode tab unit, the first portion <NUM> of the insulating layer <NUM> is disposed on the first portion <NUM> of the first electrode plate <NUM>. And no second electrode plate <NUM> is disposed between the first portion <NUM> and the first electrode tab <NUM>. The provision of the insulating layer prevents the first electrode tab <NUM> from contacting the second electrode plate <NUM>, which may result in an internal short circuit.

According to an embodiment of the present application, an orthographic projection of the insulating layer <NUM> covers an orthographic projection of the first electrode tab <NUM> in a thickness direction of the electrode assembly <NUM>. That is to say, the insulating layer <NUM> extends beyond the first electrode tab <NUM> toward the main body of the electrode assembly in a length direction of the electrode assembly <NUM>, and a width of the insulating layer <NUM> is greater than a width of the first electrode tab <NUM> in a width direction of the electrode assembly <NUM>. Among them, the width direction of the electrode assembly <NUM> is perpendicular to a plane formed by the length direction and the thickness direction.

According to an embodiment of the present application, the first electrode tab <NUM> includes a plurality of first electrode tab units <NUM> disposed in a stack. And the plurality of first electrode tab units <NUM> includes an innermost first electrode tab unit <NUM> adjacent to the insulating layer <NUM>. Wherein no second electrode plate <NUM> is disposed between the insulating layer <NUM> and the innermost first electrode tab unit <NUM>. The width of the insulating layer <NUM> is greater than the width of the first electrode tab <NUM> in the width direction of the electrode assembly. In other words, the insulating layer <NUM> has a width sufficient to achieve better isolation between the first electrode tab <NUM> and the second electrode plate <NUM>. The insulating layer <NUM> penetrates the main body of the electrode assembly <NUM> in the length direction of the electrode assembly <NUM> to prevent falling off.

According to an embodiment of the present application, the first electrode tab <NUM> includes a plurality of first electrode tab units <NUM> disposed in a stack. The plurality of first electrode tab units <NUM> includes an innermost first electrode tab unit <NUM> adjacent to the insulating layer <NUM>, and the insulating layer <NUM> further includes a second portion <NUM> disposed on an outer surface of the electrode assembly <NUM>. The installation of the second portion <NUM> can be implemented with the cooperation of the automatic tab welding machine after the winding is completed, thereby realizing the automatic production of the adhesive application.

According to an embodiment of the present application, the second portion <NUM> partially overlaps the first portion <NUM>. The second portion <NUM> partially overlaps the first portion <NUM> to achieve better isolation between the first electrode tab <NUM> and the second electrode plate <NUM>. In an embodiment, the insulating layer <NUM> at least partially covers the first electrode tab <NUM> in the length direction of the electrode assembly <NUM>.

According to an embodiment of the present application, the first electrode tab <NUM> includes a tail segment <NUM> located outside the electrode assembly <NUM> and soldered to an adapter electrode tab <NUM>, wherein the tail segment <NUM> extends in the thickness direction of the electrode assembly <NUM>. The insulating layer <NUM> covers the tail segment <NUM>. In an embodiment, the electrode assembly <NUM> includes an upper portion and a lower portion. Wherein the first electrode tab <NUM> is disposed on the first electrode plate <NUM> of the upper portion and extends parallel to the length direction of the electrode assembly <NUM>, bends for the first time toward the lower portion of the electrode assembly <NUM> after exceeding the main body of the electrode assembly <NUM>, and then bends for the second time away from the lower portion of the electrode assembly <NUM> and toward the upper portion. In an embodiment, an angle at which the bending occurs for the first time is about <NUM> degrees and an angle at which the bending occurs for the second time is about <NUM> degrees. The first electrode tab <NUM> is welded to the adapter electrode tab <NUM> to form a welding region <NUM> after bending for the second time. The welding may be ultrasonic welding or other welding suitable for actual production. With such an arrangement, the welding region <NUM> is transited from an existing flat state to a vertical state, thereby reducing the space occupied by the electrode tab welding region <NUM> and increasing the energy density of the electrode assembly.

According to an embodiment of the present application, the insulating layer <NUM> further includes a third portion <NUM> disposed on an outermost first electrode tab unit of the first electrode tab <NUM>; the third portion <NUM> extends to the outer surface of the electrode assembly <NUM> in the length direction of the electrode assembly <NUM>, and extends to a portion that is substantially close to the portion where the bending occurs for the second time along the outermost first electrode tab unit. So as to separate the welding region <NUM> from the multi-tab body structure. Among which, the outermost first electrode tab unit is a first electrode tab unit disposed at the outermost portion of the electrode assembly <NUM>, corresponding to the innermost first electrode tab unit <NUM>.

According to an embodiment of the present application, the first electrode plate <NUM> is either one of a cathode plate or an anode plate, and correspondingly, the second electrode plate <NUM> is the other of the cathode plate or the anode plate. And the first electrode tab <NUM> and the second electrode tab do not overlap in the thickness direction of the electrode assembly. <FIG> shows an embodiment in which the first electrode plate <NUM> is a cathode plate, and <FIG> and <FIG> show an embodiment in which the first electrode plate <NUM> is an anode plate. In other embodiments, similar to the first electrode plate <NUM>, a second electrode tab is further disposed on the second electrode plate <NUM>, the insulating layer <NUM> may further be disposed on the second electrode plate <NUM>, and there is no first electrode plate <NUM> between the insulating layer <NUM> and the second electrode tab <NUM>. In other words, the insulating layer <NUM> may be disposed between the cathode tab and the anode plate, and between the anode tab and the cathode plate, simultaneously, to achieve a better isolation effect, preventing the occurrence of an internal short circuit of the battery.

Referring to <FIG>, according to an embodiment of the present application, an edge of the cathode may be provided with a cathode insulating protective layer with a thickness lower than that of the cathode plate; and the cathode insulating protective layer extends beyond an anode active substance layer in the length direction of the cell. The cathode insulating protective layer may be used to protect the cathode current collector empty foil region and prevent the aluminum foil from short-circuiting with the anode active substance layer. Of course, the cathode insulating protective layer is optional. That is to say, the edge of the cathode plate may not be provided with a cathode insulating protective layer.

According to an embodiment of the present application, specifically referring to <FIG>, the first electrode plate <NUM> is disposed between the insulating layer <NUM> and the first electrode tab <NUM>. In other words, the first portion <NUM> of the insulating layer <NUM> may be adhered to the second electrode plate <NUM> adjacent to the first electrode plate <NUM>, and the first portion <NUM> and the second portion <NUM> may constitute a monolithic insulating layer <NUM>. The first portion <NUM> penetrates the main body of the electrode assembly <NUM> to prevent the first end portion <NUM> itself from falling off, and the installation of the first portion <NUM> may be completed by the gluing department of the winding machine during winding while reserving the second portion <NUM> with a sufficient length, so that the second portion <NUM> may be adhered to the outer surface of the electrode assembly <NUM>. The second portion <NUM> may be adhered to the outer surface of the electrode assembly <NUM> through a manual wrapping method after the winding is completed. Therefore, semi-automation of the adhesive application is achieved.

The first electrode tab <NUM> may be first gathered in the direction of the lower portion of the electrode assembly and then cut, so as to ensure that the head of the first electrode tab <NUM> is neat during welding. Referring to <FIG> and <FIG>, the insulating layer <NUM> further includes a fourth portion <NUM> disposed on the surface of the welding region <NUM>. The fourth portion <NUM> is adhered on the surface of the welding region <NUM> after the welding. And, the third portion <NUM> is adhered to the surface of the electrode assembly, so as to prevent the inner short circuit caused by the solder burr or the like coming into contact with the battery housing after penetrating the separator. After the insulating layer <NUM> is disposed, the first electrode tab <NUM> and the adapter electrode tab <NUM> are bent and shaped. The provision of the insulating layer <NUM> may reduce the possibility that the bent first electrode tab <NUM> or the welding region <NUM> contact with the electrode plate of the lower portion of the electrode assembly <NUM>, so as to prevent the inner short circuit.

Another aspect of the present application provides a battery including the electrode assembly <NUM> and a housing for receiving the electrode assembly <NUM>, wherein the electrode assembly <NUM> is the electrode assembly <NUM> of any of the above embodiments. The adapter electrode tab <NUM> extends out of the housing and is connected to the housing by a sealant <NUM>.

Claim 1:
An electrode assembly (<NUM>), comprising 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>), and the first electrode plate (<NUM>) and the second electrode plate (<NUM>) being wound or stacked to form the electrode assembly (<NUM>);
wherein the electrode assembly (<NUM>) further comprises:
a first electrode tab (<NUM>) disposed on the first electrode plate (<NUM>); and
an insulating layer (<NUM>) comprising a first portion (<NUM>), wherein the first portion (<NUM>) is disposed on the first electrode plate (<NUM>), characterized in that
no part of the second electrode plate (<NUM>) is disposed between the first portion (<NUM>) and the first electrode tab (<NUM>), wherein
the insulating layer (<NUM>) is disposed between the first electrode tab (<NUM>) and the second electrode plate (<NUM>).