CN214848699U - Bipolar current-collecting battery - Google Patents

Abstract

The utility model discloses a bipolar current collector battery, which comprises a composite structure of a positive electrode material layer arranged on one side surface of the bipolar current collector, a negative electrode material layer arranged on the other side surface of the bipolar current collector and a diaphragm in a laminated or winding way; the bipolar current collector comprises an insulating flame-retardant film, a positive electrode conducting layer and a negative electrode conducting layer; the side, close to the anode material layer, of the insulating flame-retardant film is the anode conducting layer, and the side, close to the cathode material layer, of the insulating flame-retardant film is the cathode conducting layer; therefore, on one hand, the energy density of the battery is improved due to the small mass of the bipolar current collector; on the other hand, as the bipolar current collector comprises the high-temperature stable insulating flame-retardant film, the safety of the battery can be ensured under the condition of thermal runaway.

Description

Bipolar current-collecting battery

Technical Field

The utility model relates to an energy storage device technical field especially relates to a bipolar current-collecting battery.

Background

The lithium ion battery is a novel battery developed in the last 10 years, is a portable chemical power supply with the highest specific energy at present, and has the advantages of high voltage, high specific energy, stable discharge voltage, good low-temperature performance, high safety performance, long storage time and service life and the like.

At present, the structure of a lithium ion battery is generally as follows: the electrolyte consists of a negative electrode, a diaphragm, a positive electrode, a diaphragm, … … and a negative electrode, and an electrolyte is arranged between the positive electrode, the diaphragm and the negative electrode. The positive electrode and the negative electrode respectively comprise a current collector and a positive active material or a negative active material coated on the surface of the current collector, and the current collector is generally an aluminum foil or a copper foil and mainly used for transmitting carriers. Two layers of current collectors (a positive current collector and a negative current collector respectively) exist in a cell unit of each secondary battery, the weight of the current collectors occupies 10-20% of the total weight of a cell of the secondary battery, the weight of the current collectors is increased along with the increase of the number of layers of positive electrodes and negative electrodes in the secondary battery, how to reduce the weight of the current collectors is reduced, and meanwhile, the improvement of the specific energy density of the battery becomes a research focus of the secondary battery.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiments of the present invention provide a bipolar current collector battery, which improves the specific energy density of the battery while improving the safety of the battery thermal runaway condition.

In order to achieve the above purpose, the technical scheme of the utility model is realized like this:

in a first aspect, an embodiment of the present invention provides a bipolar current collector battery, which includes a composite structure of a positive electrode material layer on one side surface of the bipolar current collector, a negative electrode material layer on the other side surface of the bipolar current collector, and a separator, which are stacked or wound; the bipolar current collector comprises an insulating flame-retardant film, a positive electrode conducting layer and a negative electrode conducting layer; the side, close to the anode material layer, of the insulating flame-retardant film is the anode conducting layer, and the side, close to the cathode material layer, of the insulating flame-retardant film is the cathode conducting layer.

Wherein the conductivity of the positive electrode conducting layer and the negative electrode conducting layer is more than 20S/cm.

Wherein the positive electrode conductive layer and the negative electrode conductive layer are any one of metal, alloy, carbon or conductive polymer or a combination of at least two of the same.

The surfaces of the positive electrode conducting layer and the negative electrode conducting layer comprise regularly arranged arc-shaped structures, snake-shaped structures, Y-shaped structures, sawtooth-shaped structures or irregular structures.

Wherein, the insulating flame-retardant film comprises at least one of PET, PP, PE and PI.

The insulating flame-retardant film further comprises a flame retardant, and the flame retardant is at least one of phosphate esters, carbonates and phosphazenes.

The insulating flame-retardant film comprises a main body, a first welding and printing area and a second welding and printing area; the positive conductive layer overlaps the first solder printing area and the body, and the negative conductive layer overlaps the second solder printing area and the body.

The bipolar current collector battery further comprises a positive tab welded in the first welding and printing area and a negative tab welded in the second welding and printing area.

The embodiment of the utility model provides a bipolar current collector battery, including the positive pole material layer that sets up at bipolar current collector one side surface of stromatolite or coiling, bipolar current collector, the negative pole material layer and the composite construction of diaphragm at bipolar current collector opposite side surface; the bipolar current collector comprises an insulating flame-retardant film, a positive electrode conducting layer and a negative electrode conducting layer; the side, close to the anode material layer, of the insulating flame-retardant film is the anode conducting layer, and the side, close to the cathode material layer, of the insulating flame-retardant film is the cathode conducting layer; therefore, on one hand, the energy density of the battery is improved due to the small mass of the bipolar current collector; on the other hand, as the bipolar current collector comprises the high-temperature stable insulating flame-retardant film, the safety of the battery can be ensured under the condition of thermal runaway.

Description of the drawings:

fig. 1 is a schematic structural diagram of a bipolar current collector battery according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a stacked bipolar current collector according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a rolled bipolar current collector according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a bipolar current collector according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a bipolar current collector according to another embodiment of the present invention;

fig. 6 is a schematic structural view of a welding tab provided in the prior art;

fig. 7 is a schematic structural view illustrating welding of a bipolar current collector and a tab according to an embodiment of the present invention.

In the figure, a positive electrode material layer 1, a bipolar current collector 2, a negative electrode material layer 3, a diaphragm 4, an insulating flame-retardant film 5, a positive electrode conducting layer 6, a negative electrode conducting layer 7, a tab 8, a winding needle 9, a main body 10, a first welding and printing area 11 and a second welding and printing area 12 are arranged.

Detailed Description

For the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The specific meaning of the above terms in the present invention can be understood in specific cases for those skilled in the art. The technical solution of the present invention will be further explained with reference to the accompanying drawings and examples.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

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

Referring to fig. 1 to 3, a bipolar current collector battery provided in an embodiment of the present invention includes a composite structure of a positive electrode material layer 1 on one side surface of a bipolar current collector 2, the bipolar current collector 2, a negative electrode material layer 3 on the other side surface of the bipolar current collector 2, and a separator 4, which are stacked or wound; the bipolar current collector 2 comprises an insulating flame-retardant film 5, a positive electrode conducting layer 6 and a negative electrode conducting layer 7; the side, close to the anode material layer 1, of the insulating flame-retardant film 5 is the anode conducting layer 6, and the side, close to the cathode material layer 3, of the insulating flame-retardant film 5 is the cathode conducting layer 7. So, on the one hand because bipolar current collector 2 quality is little, the energy density of battery can improve, on the other hand, because including high temperature stable insulating fire-retardant film 5 in bipolar current collector 2 for the battery guarantees the security under the thermal runaway's the condition.

Here, the diaphragm 4 is a thin film for separating the positive and negative electrodes during the electrolytic reaction to prevent the direct reaction loss energy in the electrolytic cell, and in the embodiment of the present invention, the diaphragm 4 may be used in a conventional battery, or may be a solid electrolyte for isolating the positive and negative electrodes.

The utility model discloses in do not make specific restrictions to bipolar current collection body battery's type, for example, can be lithium ion battery, sodium ion secondary battery, potassium ion battery, magnesium ion battery or calcium ion battery.

Here, the positive electrode active material in the positive electrode material layer 1 may be conventionally selected and combined from lithium cobaltate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium iron phosphate, lithium manganate, lithium rich manganese base, lithium iron manganese phosphate, lithium vanadium fluoride phosphate, sulfur element, polyacrylonitrile sulfide, oxygen, sodium cobaltate, sodium iron phosphate, or sodium manganate.

Here, the negative electrode active material in the negative electrode material layer 3 may be conventionally selected and combined from artificial graphite, natural graphite, mesocarbon microbeads, hard carbon, soft carbon, lithium titanate, silicon-based negative electrode, tin-based negative electrode, graphene, metallic lithium, or zinc alloy.

Here, for example, when a winding manner is employed, a composite structure of the positive electrode material layer 1 on one side surface of the bipolar current collector 2, the negative electrode material layer 3 on the other side surface of the bipolar current collector 2, and the separator 4 is formed around the winding needle 9.

In one embodiment, the conductivity of the positive electrode conductive layer 6 and the negative electrode conductive layer 7 is greater than 20S/cm, and the positive electrode conductive layer 6 and the negative electrode conductive layer 7 are any one of or a combination of at least two of metals, alloys, carbon, or conductive polymers. Here, the insulating flame-retardant film 5 is plated with a copper layer or lithium complex on the side close to the negative electrode material layer 3, and the insulating flame-retardant film 5 is plated with an aluminum layer or titanium layer on the side close to the positive electrode material layer 1.

The thickness of the positive electrode conducting layer 6 and the negative electrode conducting layer 7 can be 50nm-10um, the appropriate film thickness is favorable for keeping effective electronic conduction of the current collector under high mechanical deformation, and the overall longer cycle life of the electrode is ensured.

The positive electrode conducting layer 6 and the negative electrode conducting layer 7 can be prepared on the insulating flame-retardant film 5 by adopting one or more methods of a liquid phase method, a gas phase method, a thermal spraying method, a sputtering method, a laser pulse deposition method, an electrostatic spinning method, an electrochemical deposition method and an electron beam evaporation method.

In one embodiment, the surfaces of the positive electrode conductive layer 6 and the negative electrode conductive layer 7 include an arc, a snake, a Y, a zigzag structure or an irregular structure in a regular arrangement.

Here, the flame retardant coating film may be flatly spread on the insulating flame retardant film 5 as shown in fig. 4, or may have an arc, serpentine, Y-shaped, zigzag structure or random structure in a regular arrangement as shown in fig. 5. Here, when the conductive layer has an irregular structure, the transverse and longitudinal dimensions of the conductive layer after the structure is completely spread are 110 to 300% of the original transverse and longitudinal dimensions of the insulating flame-retardant film 5.

The insulating flame-retardant film 5 provided by the embodiment of the invention is used as a substrate, and the positive and negative conductive layers with the fold structures are arranged on the surface of the substrate, so that the substrate of the insulating flame-retardant film 5 has certain stretch-resistant performance, can ensure that a conductive network is continuous and does not break under mechanical deformation of stretching, bending, twisting and the like to a certain degree, and can meet the special application scene of a flexible energy storage system.

In one embodiment, the insulating flame retardant film 5 comprises at least one of PET, PP, PE, PI, wherein the thickness of the insulating flame retardant film 5 may be 5um to 50 um. Because the insulating flame-retardant film 5 and the conductive layers on the two surfaces are used as the bipolar current collector 2, on one hand, the weight is reduced, on the other hand, the bipolar current collector has certain flexibility, the energy density of the battery is improved, and the bipolar current collector can also be used for producing flexible batteries; meanwhile, for example, in the case of PET, after the battery is short-circuited, the melting of the insulating flame-retardant film 5 can reduce the internal resistance of the battery.

In one embodiment, the insulating flame-retardant film 5 further includes a flame retardant, and the flame retardant is at least one of phosphates, carbonates, and phosphazenes. Here, the fire retardant is added into the bipolar current collector 2, and after PET or PP and the like are dissolved, the fire retardant can effectively prevent the electrolyte from burning, so that the safety of the battery is high under the condition of thermal runaway.

In one embodiment, the insulating flame retardant film 5 includes a body 10, a first solder print area 11 and a second solder print area 12; the positive conductive layer 6 overlaps the first solder land 11 and the main body 10, and the negative conductive layer 7 overlaps the second solder land 12 and the main body 10.

Here, since most of the bipolar current collector 2 is a plastic polymer, the tab 8 cannot be welded firmly with the positive electrode conductive layer 6 and the negative electrode conductive layer 7 by ordinary ultrasonic welding, and if the bipolar current collector 2 is directly subjected to ultrasonic welding, the welding may cause short circuit between the positive electrode and the negative electrode; therefore, it is required to firstly leave regions without plating layers on both sides of the bipolar current collector 2 by a special transfer process, see fig. 4, and then die-cut the tab 8 in the regions, and then firmly weld the tab 8 on both sides of the bipolar current collector 2 by adjusting welding parameters (welding time, welding amplitude, vibration falling time, cooling time, welding pressure, etc.); specifically, the insulating flame-retardant film 5 may be cut with a groove, i.e., the groove may be flanked by the first and second solder-printed regions 11 and 12 and the body 10 to constitute the insulating flame-retardant film 5. Correspondingly, the positive electrode conductive layer 6 on one surface of the insulating flame-retardant film 5 overlaps the first solder land 11 and the main body 10, and the negative electrode conductive layer 7 on the other surface overlaps the second solder land 12 and the main body 10.

In one embodiment, the battery further comprises a positive tab 8 welded to the first weld region 11 and a negative tab 8 welded to the second weld region 12.

Here, the welding parameter changes to make the welding mechanism different from the conventional mechanism, taking the bipolar current collector 2 and the positive electrode tab 8 as an example, as shown in fig. 6, the conventional welding generally makes the tab 8 and the surface of the bipolar current collector 2 welded together, and the welding strength is low; as shown in fig. 7, the welding method and the welding parameters adopted in the present application enable the positive and negative electrode tabs 8 and the bipolar current collector 2 to be mutually fused in the first welding print area 11 or the second welding print area 12, respectively, and form a rivet joint after solidification, thereby greatly improving the welding strength.

The embodiment of the utility model provides an electric equipment is still provided, including the bipolar current collector battery that above-mentioned bipolar current collector battery or above-mentioned manufacturing method obtained.

The utility model provides an electric equipment includes but not limited to intelligent wrist-watch, cell-phone, computer, flat board, electric automobile or communication base station.

In summary, compared with the prior art, the embodiment of the utility model provides a bipolar current collector battery, manufacturing method and consumer thereof, the innovative composite structure who provides positive material layer 1/bipolar current collector 2/negative material layer 3/diaphragm 4 because bipolar current collector 2 is of small quality on the one hand, the energy density of battery can improve, on the other hand, because including insulating fire-retardant film 5 in bipolar current collector 2 for the battery guarantees the security under the condition of thermal runaway; in addition, the use of the bipolar current collector 2 allows the core manufacturing process to be optimized. Specifically, the method comprises the following steps:

1. when the battery is out of control thermally, the temperature inside the battery can be rapidly raised due to a large amount of heat generation, even fire can happen, and the bipolar current collector 2 can effectively resist the fire due to the fact that the bipolar current collector contains the insulating flame-retardant film 5 which is stable at high temperature.

2. From the perspective of the manufacturing process, the bipolar current collector 2 is used to reduce the materials participating in the winding process into a pole piece and a membrane 4, which is more beneficial to controlling the winding alignment and reducing the defects caused by dislocation.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and scope of the present invention are all included within the protection scope of the present invention.

Claims (5)

1. A bipolar current collector battery, characterized by comprising a composite structure of a positive electrode material layer on one surface of the bipolar current collector, a negative electrode material layer on the other surface of the bipolar current collector, and a separator, which are arranged in a stacked or wound manner; the bipolar current collector comprises an insulating flame-retardant film, a positive electrode conducting layer and a negative electrode conducting layer; the side, close to the anode material layer, of the insulating flame-retardant film is the anode conducting layer, and the side, close to the cathode material layer, of the insulating flame-retardant film is the cathode conducting layer.

2. The bipolar current collector battery of claim 1, wherein said positive conductive layer and said negative conductive layer have an electrical conductivity greater than 20S/cm.

3. The bipolar current collector of claim 1, wherein said positive conductive layer and said negative conductive layer have surfaces comprising a regular array of arcs, serpentines, Y-shapes, saw tooth structures, or random structures.

4. The bipolar current collector battery of claim 1, wherein said insulating flame retardant film comprises a body, a first solder print area and a second solder print area; the positive conductive layer overlaps the first solder printing area and the body, and the negative conductive layer overlaps the second solder printing area and the body.

5. The bipolar current collector battery of claim 4, wherein said bipolar current collector battery further comprises a positive tab welded to said first weld footprint area and a negative tab welded to said second weld footprint area.

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