Bipolar current collector, pole piece, battery and electric device

Abstract

The utility model relates to the technical field of batteries, in particular to a bipolar current collector, a pole piece, a battery and an electric device. The bipolar current collector comprises a positive electrode current collector, an insulating support plate, a negative electrode current collector and a PTC material; the positive electrode current collector and the negative electrode current collector are respectively arranged on two side surfaces of the insulating support plate along the thickness direction; a plurality of through holes are formed in the insulation supporting plate in the thickness direction in a penetrating mode, the through holes are filled with PTC materials, the resistance value of the PTC materials can be increased when the temperature rises to a preset value, and the positive electrode current collector and the negative electrode current collector are electrically conducted through the PTC materials. The pole piece, the battery and the electric device comprise the bipolar current collector, and the positive current collector and the negative current collector are electrically conducted through the PTC material. And when the temperature of the battery rises to a preset value, the resistance value of the PTC material is increased to limit the current, so that the heat spreading between the single battery cells is effectively prevented, the failure of the battery caused by thermal runaway is avoided, and the safety of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a bipolar current collector, a pole piece, a battery and an electrical device. Background Art

[0002] A bipolar battery is a battery in which bipolar pole pieces are assembled in series inside the battery, and the requirements of high voltage and high energy density are simultaneously achieved in the form of a single cell. In the bipolar current collector of an existing bipolar battery, an insulating support plate made of PET material is added in the middle of the composite current collector, and then a positive electrode metal layer and a negative electrode metal layer are plated on the two surfaces of the insulating support plate respectively to reduce the weight of the bipolar current collector and increase the energy density. When a bipolar battery experiences thermal runaway, a chain reaction occurs between the internal single cells, and the heat quickly spreads to the entire bipolar battery, causing the bipolar battery to fail, reducing the safety of the bipolar battery. Utility Model Content

[0003] The utility model aims to provide a bipolar current collector, a pole piece, a battery and an electric device to solve the technical problem of failure of bipolar batteries due to thermal runaway in the prior art.

[0004] To achieve this purpose, the technical solution adopted by the utility model is:

[0005] A bipolar current collector comprises a positive current collector, an insulating support plate, a negative current collector and a PTC material, wherein the positive current collector and the negative current collector are respectively arranged on two sides of the insulating support plate along the thickness direction; the insulating support plate is penetrated by a plurality of through holes along the thickness direction, the through holes are filled with the PTC material, the resistance value of the PTC material can increase when the temperature rises to a preset value, and the positive current collector and the negative current collector are electrically conductive through the PTC material.

[0006] As an optional solution for the bipolar current collector, the positive electrode current collector is an aluminum current collector, and the aluminum current collector is plated on one side of the insulating support plate along the thickness direction.

[0007] As an optional solution for the bipolar current collector, the thickness of the aluminum current collector is 1 μm to 8 μm.

[0008] As an optional solution of the bipolar current collector, the negative electrode current collector is a copper current collector, and the copper current collector is plated on the other side surface of the insulating support plate along the thickness direction.

[0009] As an optional solution for the bipolar current collector, the copper current collector has a thickness of 1 μm to 6 μm.

[0010] As an optional solution for the bipolar current collector, the insulating support plate is one of a PP plate, a PE plate, a PET plate, and a PVC plate.

[0011] As an optional solution for a bipolar current collector, the preset value is greater than or equal to 60°C.

[0012] The pole piece comprises a negative electrode layer, a positive electrode layer and the above-mentioned bipolar current collector, wherein the positive electrode layer is arranged on the surface of the positive electrode current collector of the bipolar current collector away from the insulating support plate, and the negative electrode layer is arranged on the surface of the negative electrode current collector of the bipolar current collector away from the insulating support plate.

[0013] A battery comprises a shell and an electrode assembly, wherein the electrode assembly comprises a plurality of the above-mentioned pole pieces, the plurality of pole pieces are stacked to form a pole piece group, and the electrically opposite sides of two adjacent pole pieces are arranged opposite to each other.

[0014] An electrical device comprises the above-mentioned battery.

[0015] The beneficial effects of the utility model are:

[0016] The bipolar current collector, pole piece, battery and electrical device proposed by the utility model fill the through hole of the insulating support plate with PTC material (i.e., positive temperature coefficient material) so that the positive current collector and the negative current collector are electrically connected through the PTC material. When the battery has thermal runaway and the temperature rises to a preset value, the resistance value of the PTC material increases accordingly to limit the current, thereby effectively preventing the heat from spreading between the single cells, avoiding the battery from failing due to thermal runaway, and improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a longitudinal cross-sectional view of a pole piece provided in an embodiment of the utility model.

[0018] The names and numbers of the components in the figure are as follows:

[0019] 1. Positive electrode current collector; 2. Insulating support plate; 21. Through hole; 3. Negative electrode current collector; 4. PTC material; 5. Negative electrode layer; 6. Positive electrode layer. DETAILED DESCRIPTION

[0020] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of them.

[0021] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0023] In the description of this embodiment, the terms "upper", "lower", "right", "left" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0024] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0025] A bipolar battery is a battery in which bipolar pole pieces are assembled in series inside the battery, and the requirements of high voltage and high energy density are simultaneously achieved in the form of a single cell. In the bipolar current collector of an existing bipolar battery, an insulating support plate made of PET material is added in the middle of the composite current collector, and then a positive electrode metal layer and a negative electrode metal layer are plated on the two surfaces of the insulating support plate respectively to reduce the weight of the bipolar current collector and increase the energy density. When a bipolar battery experiences thermal runaway, a chain reaction occurs between the internal single cells, and the heat quickly spreads to the entire bipolar battery, causing the bipolar battery to fail, reducing the safety of the bipolar battery.

[0026] To solve the above problems, Figure 1As shown, this embodiment proposes a bipolar current collector, which includes a positive current collector 1, an insulating support plate 2, a negative current collector 3 and a PTC material 4. The positive current collector 1 and the negative current collector 3 are respectively arranged on the two sides of the insulating support plate 2 along the thickness direction. The insulating support plate 2 is provided with a plurality of through holes 21 along the thickness direction, and the through holes 21 are filled with PTC materials 4. The resistance value of the PTC material 4 can increase when the temperature rises to a preset value, and the positive current collector 1 and the negative current collector 3 are electrically connected through the PTC material 4. By filling the PTC material 4 in the through holes 21 of the insulating support plate 2, the positive current collector 1 and the negative current collector 3 are electrically connected through the PTC material 4. When the battery has thermal runaway and the temperature rises to a preset value, the resistance value of the PTC material 4 increases accordingly to limit the current, thereby effectively preventing the heat from spreading between the single cells, avoiding the failure of the battery due to thermal runaway, and improving the safety of the battery.

[0027] It should be noted that the PTC material 4 is a thermistor conductive material with a positive temperature coefficient. The through hole 21 is filled with granular PTC material 4 to achieve electrical conduction between the positive current collector 1 and the negative current collector 3. At the same time, the PTC material 4 has a thermistor function. When the temperature rises, the resistance of the PTC material 4 in the through hole 21 increases rapidly to limit the current increase, play a good overcurrent protection role, reduce heat generation, and thus reduce the risk of thermal runaway. When the temperature is within the normal range (lower than the preset value), the resistance of the PTC material 4 in the through hole 21 returns to normal, and the positive current collector 1 and the negative current collector 3 are electrically connected again.

[0028] It should be noted that the preset value of this embodiment is greater than or equal to 60° C. When the temperature rises to 60° C., the resistance of the PTC material 4 in the through hole 21 increases rapidly, effectively reducing the current between the positive current collector 1 and the negative current collector 3, greatly reducing the heat generation, and effectively preventing the heat spread between the single cells.

[0029] The insulating support plate 2 of this embodiment is one of PP plate, PE plate, PET plate, and PVC plate. The above-mentioned PP plate, PE plate, PET plate, and PVC plate are all conventional plastic plates, which are easy to process and have low cost. At the same time, the density of the above-mentioned plastic plates is relatively small, so that the weight of the insulating support plate 2 is relatively light, which is conducive to reducing the total weight of the bipolar current collector and improving the energy density of the battery using the bipolar current collector. In other embodiments, the insulating support plate 2 can also be made of other insulating materials, which are not listed here one by one.

[0030] like Figure 1 As shown, the positive electrode current collector 1 is an aluminum current collector, which is plated on one side of the insulating support plate 2 along the thickness direction. In other embodiments, the positive electrode current collector 1 can also be other materials that can serve as a positive electrode, such as zinc, magnesium, etc., which are not specifically limited here.

[0031] Specifically, the thickness of the aluminum current collector is 1 μm to 8 μm. The thickness of the aluminum current collector of this embodiment can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm or 8 μm, so that the positive electrode current collector 1 is light in weight and thin in thickness, thereby improving the specific capacity of the bipolar current collector.

[0032] like Figure 1 As shown, the negative electrode current collector 3 is a copper current collector, which is plated on the other side of the insulating support plate 2 along the thickness direction. In other embodiments, the negative electrode current collector 3 can also be other materials that can serve as a negative electrode, such as aluminum foil, stainless steel, etc., which are not specifically limited here.

[0033] Specifically, the thickness of the copper current collector is 1 μm to 6 μm. The thickness of the copper current collector of this embodiment can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm or 6 μm, so that the negative electrode current collector 3 is light and thin, thereby improving the specific capacity of the bipolar current collector.

[0034] like Figure 1 As shown, this embodiment also proposes a pole piece, which is a bipolar pole piece, specifically including a negative electrode layer 5, a positive electrode layer 6 and the above-mentioned bipolar current collector, the positive electrode layer 6 is arranged on the surface of the positive electrode current collector 1 of the bipolar current collector away from the insulating support plate 2, and the negative electrode layer 5 is arranged on the surface of the negative electrode current collector 3 of the bipolar current collector away from the insulating support plate 2. The arrangement method of the negative electrode layer 5 and the positive electrode layer 6 can be wet coating or dry pressing.

[0035] When the battery thermal runaway occurs and the temperature rises to a preset value, the resistance value of the PTC material 4 in the pole piece increases accordingly to limit the current, thereby effectively preventing the heat spread between the single cells, avoiding battery failure due to thermal runaway, and improving the safety of the battery.

[0036] In the bipolar pole piece, the negative electrode layer 5 may be made of graphite, silicon or other materials that can serve as negative electrode active materials, and the positive electrode layer 6 may be made of ternary materials, lithium iron phosphate materials or other materials that can serve as positive electrode active materials.

[0037] This embodiment also proposes a battery, which is a bipolar battery, specifically including a housing and an electrode assembly, wherein the electrode assembly includes a plurality of the above-mentioned pole pieces, wherein the plurality of pole pieces are stacked to form a pole piece group, and the electrically opposite sides of two adjacent pole pieces are arranged relative to each other, so that the plurality of pole pieces are connected in series. When the battery has thermal runaway and the temperature rises to a preset value, the resistance value of the PTC material 4 in the pole piece increases accordingly to limit the current, thereby effectively preventing the heat from spreading between the single cells, avoiding the failure of the battery due to thermal runaway, and improving the safety of the battery.

[0038] It should be noted that the battery of this embodiment also includes an isolation layer, which is located between two adjacent pole pieces and is used to electrically isolate the two adjacent pole pieces and for the passage of active ions. Specifically, the isolation layer is a solid electrolyte layer, and the two adjacent pole pieces and the solid electrolyte layer together constitute a pole piece group, which is a single cell. In some embodiments, the isolation layer can be a semi-solid electrolyte or an isolation membrane. When the isolation layer is an isolation membrane, each pole piece group also includes an electrolyte and a sealing structure. In each pole piece group, a space for accommodating an electrolyte is provided between two pole pieces, and a sealing structure is used to seal the space, so that each pole piece group is sealed and isolated from each other to ensure that the electrolyte in each pole piece group does not flow between each other.

[0039] This embodiment also proposes an electric device, including the above-mentioned battery. The electric device can be a car, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool. The car can be a fuel car, a gas car or a new energy car, and the new energy car can be a pure electric car, a hybrid car or an extended-range car; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers. This embodiment does not impose special restrictions on the above-mentioned electric devices. The electric device of this embodiment can effectively prevent the heat from spreading between the single cells in the battery, avoid the battery from failing due to thermal runaway, and improve the safety of the battery and the electric device.

[0040] The above embodiments are only to illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and modifications, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A bipolar current collector, characterized in that: The invention comprises a positive electrode current collector (1), an insulating support plate (2), a negative electrode current collector (3) and a PTC material (4); the positive electrode current collector (1) and the negative electrode current collector (3) are respectively arranged on two side surfaces of the insulating support plate (2) in the thickness direction; the insulating support plate (2) is provided with a plurality of through holes (21) penetrating in the thickness direction; the through holes (21) are filled with the PTC material (4); the resistance value of the PTC material (4) can increase when the temperature rises to a preset value; the positive electrode current collector (1) and the negative electrode current collector (3) are electrically connected through the PTC material (4).

2. The bipolar current collector according to claim 1, characterized in that: The positive electrode current collector (1) is an aluminum current collector, and the aluminum current collector is plated on a side surface of the insulating support plate (2) along the thickness direction.

3. The bipolar current collector according to claim 2, characterized in that: The aluminum current collector has a thickness of 1 μm to 8 μm.

4. The bipolar current collector according to claim 1, characterized in that: The negative electrode current collector (3) is a copper current collector, and the copper current collector is plated on the other side surface of the insulating support plate (2) along the thickness direction.

5. The bipolar current collector according to claim 4, characterized in that: The copper current collector has a thickness of 1 μm to 6 μm.

6. The bipolar current collector according to any one of claims 1 to 5, characterized in that: The insulating support plate (2) is one of a PP plate, a PE plate, a PET plate and a PVC plate.

7. The bipolar current collector according to any one of claims 1 to 5, characterized in that: The preset value is greater than or equal to 60°C.

8. A pole piece, characterized in that: The invention comprises a negative electrode layer (5), a positive electrode layer (6) and a bipolar current collector according to any one of claims 1 to 7, wherein the positive electrode layer (6) is arranged on the surface of the positive electrode current collector (1) of the bipolar current collector facing away from the insulating support plate (2), and the negative electrode layer (5) is arranged on the surface of the negative electrode current collector (3) of the bipolar current collector facing away from the insulating support plate (2).

9. A battery, characterized in that It comprises a shell and an electrode assembly, wherein the electrode assembly comprises a plurality of pole pieces as claimed in claim 8, wherein the plurality of pole pieces are stacked to form a pole piece group, and the electrically opposite sides of two adjacent pole pieces are arranged relative to each other.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

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