Current collector, bipolar battery and electric equipment

Abstract

The utility model provides a current collector, a bipolar battery and electric equipment. The current collector comprises a supporting structure, and a first fixing structure and a second fixing structure which are respectively arranged on two opposite sides of the supporting structure; when the at least two current collectors are stacked, in the two adjacent current collectors of the bipolar battery, the first fixing structure of one current collector is detachably connected with the second fixing structure of the other current collector; the first fixing structure and the second fixing structure are detachably connected with each other, so that a containing cavity is defined by every two adjacent supporting structures and the first fixing structure and the second fixing structure which are detachably connected with each other, and the containing cavities are used for containing electrolyte. Temporary positioning is achieved through matched fastening of the first fixing structure and the second fixing structure, and the assembling efficiency and safety are improved; and the first fixing structure and the second fixing structure are matched to separate parts in the accommodating cavity, and a channel can be opened at the joint to facilitate exhaust under the condition that the internal air pressure in the formation process is increased, so that the safety and the cycle life of the battery in the use process are improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a current collector, a bipolar battery and an electrical device. Background Art

[0002] Bipolar pole pieces are formed by coating active materials of different polarities on opposite sides of current collectors, and stacking multiple bipolar pole pieces and multiple electrolytes in series to form a bipolar battery. However, during the stacking process, the current collectors are prone to sliding under the action of gravity or vibration, resulting in misalignment, which causes active materials of different polarities to contact and cause short circuits, thereby causing safety problems. In addition, it is difficult to seal adjacent current collectors, and sealing before formation is not conducive to the timely discharge of gas produced by battery formation, which can easily have an adverse effect on the safety performance of the battery. Utility Model Content

[0003] The present application provides a current collector, a bipolar battery and an electrical device that are conducive to improving assembly efficiency and safety.

[0004] In the first aspect, an embodiment of the present application provides a current collector, which includes a support structure and a first fixed structure and a second fixed structure respectively arranged on opposite sides of the support structure; when at least two of the current collectors are stacked, in two adjacent current collectors, the first fixed structure of one current collector is detachably connected to the second fixed structure of the other current collector, so that the two adjacent support structures and the first fixed structure and the second fixed structure detachably connected to each other jointly form a containing cavity, and the containing cavity is used to contain an electrolyte.

[0005] According to the first aspect, in a possible implementation, the first fixing structure and the second fixing structure are both snap-fit ​​structures, and in two adjacent current collectors, the first fixing structure of one current collector is snap-fitted to the second fixing structure of the other current collector.

[0006] According to the first aspect, in a possible implementation, the first fixing structure is provided with a first clamping groove; the first clamping groove is used to clamp the second fixing structure on the adjacent current collector when at least two current collectors are stacked.

[0007] According to the first aspect, in a possible implementation, the second fixed structure is provided with a second card groove, and when at least two of the current collectors are stacked, in the first fixed structure and the second fixed structure that are engaged with each other, the end of the first fixed structure is inserted into the second card groove of the second fixed structure, and the end of the second fixed structure is inserted into the first card groove of the first fixed structure, so as to form a continuously bent sealing surface between the first fixed structure and the second fixed structure.

[0008] According to the first aspect, in a possible implementation manner, the first fixing structure is bent to form the first clamping slot, and the second fixing structure is bent to form the second clamping slot.

[0009] According to the first aspect, in a possible implementation manner, an end portion of the first fixing structure and an end portion of the second fixing structure are arc-shaped.

[0010] According to the first aspect, in a possible implementation manner, one of the first fixing structure and the second fixing structure has thermal adhesion.

[0011] According to the first aspect, in a possible implementation manner, both opposite sides of the support structure have current collecting layers, and the first fixing structure and the second fixing structure are arranged on the periphery of the current collecting layer on the same side.

[0012] According to the first aspect, in a possible implementation manner, the support structure includes a support layer and two metal foils, and the two metal foils are disposed on opposite sides of the support layer to form the current collecting layer.

[0013] According to the first aspect, in a possible implementation manner, at least a portion of the support layer exposed from the metal foil is insulated, and the first fixing structure and the second fixing structure are disposed on the insulating portion of the support layer.

[0014] According to the first aspect, in a possible implementation manner, a region of the support layer covered by the current collecting layer is at least partially conductive.

[0015] In a second aspect, an embodiment of the present application further provides a bipolar battery, comprising a positive electrode plate, a negative electrode plate and the current collector described in the first aspect, wherein a plurality of the current collectors are stacked between the positive electrode plate and the negative electrode plate and are stacked in a direction from the positive electrode plate to the negative electrode plate.

[0016] According to the second aspect, in a possible implementation, a third fixing structure is provided on the side of the positive electrode plate facing the current collector, and the third fixing structure of the positive electrode plate is engaged with the first fixing structure of the adjacent current collector to form a receiving cavity between the positive electrode plate and the adjacent supporting structure of the current collector; a fourth fixing structure is provided on the side of the negative electrode plate facing the current collector, and the fourth fixing structure of the negative electrode plate is engaged with the second fixing structure of the adjacent current collector to form a receiving cavity between the negative electrode plate and the adjacent supporting structure of the current collector.

[0017] According to the second aspect, in a possible implementation, along the direction from the positive electrode plate to the negative electrode plate, a positive electrode material layer, a separator and a negative electrode material layer are sequentially stacked in the accommodating cavity, the positive electrode material layer is arranged on the positive electrode plate / the current collector, and the negative electrode material layer is arranged on the negative electrode plate / the current collector.

[0018] According to the second aspect, in a possible implementation manner, a projection of the separator along the stacking direction at least completely covers a projection of the positive electrode material layer along the stacking direction and a projection of the negative electrode material layer along the stacking direction.

[0019] According to the second aspect, in a possible implementation manner, the diaphragm is coated with a solid electrolyte; or the containing cavity is filled with a liquid electrolyte.

[0020] According to the second aspect, in a possible implementation, the bipolar battery further includes a shell, the current collector, the positive electrode material layer, the separator and the negative electrode material layer are all arranged in the shell, and part of the positive electrode plate / the negative electrode plate extends out of the shell to form a positive electrode lead-out portion / a negative electrode lead-out portion.

[0021] In the third aspect, the embodiment of the present application also provides a bipolar battery, which includes a positive electrode plate, a negative electrode plate and the current collector described in the first aspect, a plurality of the current collectors are stacked between the positive electrode plate and the negative electrode plate and are stacked in the direction from the positive electrode plate to the negative electrode plate, and in two adjacent current collectors, the first fixing structure of one current collector is adhered to the second fixing structure of the other current collector to seal the accommodating cavity.

[0022] In a fourth aspect, an embodiment of the present application further provides an electrical device, wherein the electrical device comprises the bipolar battery described in the second aspect or the third aspect.

[0023] The current collector, bipolar battery and electrical equipment provided by the present application, the first fixed structure and the second fixed structure are arranged on opposite sides of the support structure of the current collector, and in the multiple current collectors of the bipolar battery, the first fixed structure and the second fixed structure are fastened to realize temporary positioning between the two adjacent support structures, which can prevent the dislocation between the two adjacent current collectors during the battery assembly process, thereby improving the assembly efficiency; and the temporary positioning of the two adjacent current collectors during stacking can improve the position accuracy of the two adjacent current collectors, avoid short circuit between the two adjacent current collectors, and improve safety. And the first fixed structure and the second fixed mechanism form a receiving cavity between the two adjacent support structures, and the components in the receiving cavity are isolated by the first fixed structure and the second fixed mechanism, reducing the probability of electrolyte leakage and short circuit of the internal and external structures of the sealed cavity, and improving the sealing and safety of the finished battery. And in the formation process, the internal gas production of the battery increases the internal air pressure, and the connection between the first fixed structure and the second fixed structure can open a channel under the action of the internal air pressure to facilitate exhaust, thereby increasing the safety and cycle life of the battery during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments are briefly introduced below.

[0025] Figure 1 Schematic diagram of a bipolar battery provided in the first embodiment of the present application.

[0026] Figure 2 Schematic diagram of a current collector of a bipolar battery provided in the first embodiment of the present application.

[0027] Figure 3 It is a schematic diagram of the stacking state of two current collectors provided in the first embodiment of the present application.

[0028] Figure 4 It is a schematic diagram of exhaust during the formation process of two current collectors in a stacked state provided in the first embodiment of the present application.

[0029] Figure 5 yes Figure 2 Schematic diagram of the current collector coated with the positive electrode material layer.

[0030] Figure 6 It is a schematic diagram of the assembly of a bipolar battery provided in the first embodiment of the present application.

[0031] Description of reference numerals:

[0032] 100-bipolar battery; 10-current collector; 11-support structure; 111-support layer; 112-metal foil; 12-first fixing structure; 121-first slot; 13-second fixing structure; 131-second slot; 20-positive plate; 21-third fixing structure; 22-positive electrode lead-out portion; 30-negative plate; 31-fourth fixing structure; 32-negative electrode lead-out portion; 40-positive electrode material layer; 50-diaphragm; 60-negative electrode material layer;

[0033] 101 - housing; 105 - receiving chamber; 103 - battery cell. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] The following descriptions of the various embodiments are made with reference to the attached drawings to illustrate specific embodiments that may be implemented in the present application. Directional terms mentioned herein, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are intended to better and more clearly describe and understand the present application, rather than to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0036] In addition, the serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0037] The present application provides an electric device, including a bipolar battery. The bipolar battery is used to supply power to the electric device. The electric device may be a vehicle. It is understood that the present application does not limit the application of the bipolar battery to vehicles. The bipolar battery may also be applied to other fields, for example, the electric device may also be power equipment, communication equipment, medical equipment, industrial automation equipment, etc.

[0038] See also Figure 1 and Figure 2The present application provides a bipolar battery 100. In a first embodiment, the bipolar battery 100 includes a housing 101 and a battery cell 103 accommodated in the housing 101. The housing 101 is used to protect the battery cell 103. The battery cell 103 includes a plurality of current collectors 10, a positive electrode plate 20, a negative electrode plate 30, a positive electrode material layer 40, a separator 50, and a negative electrode material layer 60. The plurality of current collectors 10 are stacked along a first direction and are located between the positive electrode plate 20 and the negative electrode plate 30. Along the first direction and in the direction from the positive electrode plate 20 to the negative electrode plate 30, a positive electrode material layer 40, a separator 50, and a negative electrode material layer 60 are stacked between the positive electrode plate 20 and the adjacent current collector 10, between two adjacent current collectors 10, and between the current collector 10 and the negative electrode plate 30. The separator 50 is a specially formed polymer film having a microporous structure that allows metal ions to pass freely, but electrons cannot pass. The accommodating cavity 105 contains an electrolyte, and electrons run from the negative electrode material layer 60 to the positive electrode material layer 40 through an external circuit; metal ions (carriers in the electrolyte, such as sodium ions or lithium ions, etc.) reach the positive electrode material layer 40 from the negative electrode material layer 60 through the electrolyte and the microporous structure on the diaphragm 50, and combine with the electrons that reach the positive electrode material layer 40 through the external circuit to complete the discharge process.

[0039] Among them, the positive electrode material layer 40 can be selected from the positive electrode active materials commonly used in the art, such as Na / Ni / Fe / Mn layered oxides, sodium vanadium phosphate, sodium iron pyrophosphate, lithium iron phosphate, lithium iron manganese phosphate and at least one of ternary materials. The negative electrode material layer 60 can be selected from the negative electrode active materials commonly used in the art, such as soft carbon, hard carbon, artificial graphite and natural graphite. The shell 101 can be a two-component outer packaging film of PP (polypropylene) and PET (polyethylene terephthalate). Of course, the shell 101 can also be an aluminum-plastic film. The present application does not limit the material of the shell 101. Part of the positive electrode plate 20 extends out of the outer shell 101 to form a positive electrode lead-out portion 22, and part of the negative electrode plate 30 extends out of the outer shell 101 to form a negative electrode lead-out portion 32. The positive electrode lead-out portion 22 and the negative electrode lead-out portion 32 are used to connect to electrical equipment to supply power to the electrical equipment. The positive electrode lead-out portion 22 and the negative electrode lead-out portion 32 can be located on the same side of the outer shell 101, or on different sides of the outer shell 101.

[0040] See also Figure 2 and Figure 3The current collector 10 includes a support structure 11 and a first fixed structure 12 and a second fixed structure 13 disposed on opposite sides of the support structure 11. The support structure 11 includes a support layer 111 and metal foils 112 disposed on both sides of the support layer 111, and the metal foils 112 serve as current collecting layers of the support structure 11. The positive electrode material layer 40 and the negative electrode material layer 60 are coated on the metal foils 112 on both sides, respectively, and the current collecting layer is used to collect the current formed between the positive electrode material layer 40 and the negative electrode material layer 60. The support layer 111 is provided between the two layers of the current collector 10 to prevent the occurrence of internal short circuit and negative electrode oxidation when the traditional metal foil has holes. The first fixed structure 12 is connected to the side of the support layer 111 where the negative electrode material layer 60 is located, and the first fixed structure 12 is arranged at the periphery of the metal foil 112 connected to the negative electrode material layer 60; the second fixed structure 13 is connected to the side of the support layer 111 where the positive electrode material layer 40 is located, and the second fixed structure 13 is arranged at the periphery of the metal foil 112 connected to the positive electrode material layer 40.

[0041] The support structure 11 is a plate-like structure, and the projections of the first fixed structure 12 and the second fixed structure 13 on the support structure 11 are both ring-shaped. The projection shapes of the first fixed structure 12 and the second fixed structure 13 are adapted according to the shape of the support structure 11, that is, when the support structure 11 is a square plate, the corresponding first fixed structure 12 and the second fixed structure 13 are square rings as a whole; when the support structure 11 is a circular plate, the corresponding first fixed structure 12 and the second fixed structure 13 are circular rings as a whole. Of course, the support structure 11, the first fixed structure 12 and the second fixed structure 13 can also be other shapes.

[0042] See also Figure 2 and Figure 4 When at least two current collectors 10 are stacked, in two adjacent current collectors 10, the first fixed structure 12 of one current collector 10 is detachably connected to the second fixed structure 13 of the other current collector 10, so that the two adjacent support structures 11 and the first fixed structure 12 and the second fixed structure 13 that are detachably connected to each other jointly form a accommodating cavity 105.

[0043] In this embodiment, the first fixing structure 12 is disposed on the side of the support structure 11 connected to the negative electrode material layer 60, and the second fixing structure 13 is disposed on the side of the support structure 11 connected to the positive electrode material layer 40. The first fixing structure 12 and the second fixing structure 13 are disposed opposite to each other along a first direction.

[0044] The support structure 11 of the current collector 10 is provided with a first fixing structure 12 and a second fixing structure 13 on both sides along the first direction. In the multiple current collectors 10 of the bipolar battery 100, the first fixing structure 12 and the second fixing structure 13 cooperate to form a receiving cavity 105 between two adjacent support structures 11, and a pair of positive / negative electrode material layers generating current are separated from other pairs of positive / negative electrode material layers; and when the electrolyte in the receiving cavity 105 is a liquid electrolyte, the receiving cavity 105 formed by the first fixing structure 12 and the second fixing structure 13 can also reduce the leakage risk of the internal liquid electrolyte during battery assembly, thereby reducing the short circuit risk between different electrodes and improving the sealing and safety of the finished battery; at the same time, the first fixing structure 12 and the second fixing structure 13 cooperate to tighten to realize the temporary positioning of the two adjacent current collectors 10, prevent the dislocation between the two adjacent current collectors 10 during the battery assembly process, improve the position accuracy of the two adjacent current collectors 10, avoid the short circuit between the two adjacent current collectors 10, improve the assembly efficiency and improve the safety. During the formation process, the internal gas production of the battery increases the internal air pressure. Under the action of the internal air pressure, a passage can be opened at the connection between the first fixing structure 12 and the second fixing structure 13 to facilitate exhaust, thereby increasing the safety and cycle life of the battery during use.

[0045] In the above embodiment, the first fixing structure 12 and the second fixing structure 13 can be connected by snap-fit, or temporarily fixed by interference fit, clamp, slot, etc. The present application does not limit the connection form of the first fixing structure 12 and the second fixing structure 13.

[0046] The following description assumes that the first fixing structure 12 and the second fixing structure 13 can be connected by a snap-fit ​​manner. For the convenience of description, the current collector 10 close to the positive electrode plate 20 of the two adjacent current collectors 10 is defined as the first current collector, and the current collector 10 close to the negative electrode plate 30 is defined as the second current collector.

[0047] The first fixing structure 12 is provided with a first slot 121. When at least two current collectors 10 are stacked, the end of the second fixing structure 13 of the first current collector is clamped in the first slot 121 formed by the first fixing structure 12 of the second current collector. At this time, the end of the second fixing structure 13 is in contact with the inner wall surface of the first slot 121 to achieve sealing. And when stacking the current collectors 10, the first fixing structure 12 and the second fixing structure 13 can be used to achieve positioning and locking, without additionally controlling the position accuracy of the current collectors 10 when stacking, to ensure the consistency of the finished battery.

[0048] The first slot 121 can be formed on the inner side or outer side of the first fixed structure 12. The inner side of the first fixed structure 12 refers to the side facing the accommodating cavity 105, and the outer side of the first fixed structure 12 refers to the side away from the accommodating cavity 105. This embodiment is described by taking the first slot 121 formed on the inner side of the first fixed structure 12 as an example, that is, the first slot 121 is concave on the inner side of the first fixed structure 12, and the end of the second fixed structure 13 can be inserted into the first slot 121 and fit with the inner wall surface of the first slot 121, then the end of the first fixed structure 12 and the end of the first fixed structure 12 have a certain interference. The second fixed structure 13 moves in the direction close to the second current collector as the first current collector moves as a whole, and the second fixed structure 13 squeezes the first fixed structure 12 to deform the first fixed structure 12, so that the end of the second fixed structure 13 slides smoothly into the first slot 121.

[0049] The end of the first fixed structure 12 can be set as an arcuate end face. It can be understood that the arcuate end face is located at the end of the first fixed structure 12 away from the supporting structure 11. In this way, the second fixed structure 13 contacts the arcuate end face of the first fixed structure 12 during the movement. The arcuate end face can decompose the pressure on the first fixed structure 12 during the movement of the second fixed structure 13 into an extrusion force that pushes the first fixed structure 12 to deform inwardly, which facilitates the sliding of the second fixed structure 13 and can also play a centering role. The position of the first current collector is adjusted during the buckling process to avoid jamming of the second fixed structure 13 during the movement along the first direction.

[0050] In the cross section along the first direction, the thickness of the first fixed structure 12 shows a trend of first decreasing and then increasing in the direction away from the support structure 11, that is, the first fixed structure 12 has a thinnest point, which is conducive to the deformation of the end of the first fixed structure 12. Specifically, from the connection between the first fixed structure 12 and the support structure 11 to the first clamping groove 121, the thickness of the first fixed structure 12 is gradually reduced in the direction away from the support structure 11, that is, the thickness of the connection between the first fixed structure 12 and the support structure 11 is relatively large, which increases the connection area between the first fixed structure 12 and the support structure 11 and improves the connection stability.

[0051] The first fixing structure 12 and the second fixing structure 13 have thermal adhesiveness. Specifically, the first fixing structure 12 can be made of a material with thermal adhesiveness. Since the working environment when stacking the current collector 10 is a normal temperature environment, the first fixing structure 12 does not have adhesiveness at this time, which is conducive to the stacking of the current collector 10. After the battery cell 103 is assembled and the formation process is carried out, the entire battery cell 103 can be heated. At this time, the temperature of the first fixing structure 12 rises until it has adhesiveness, so that the buckling parts of the first fixing structure 12 and the second fixing structure 13 are bonded together. After cooling to room temperature, the first fixing structure 12 and the second fixing structure 13 are connected into a whole, that is, the first fixing structure 12 and the second fixing structure 13 are engaged to form a sealing structure for bonding to form a secondary enhanced sealing effect. And it can avoid the fixation failure caused by the loosening of the first fixing structure 12 and the second fixing structure 13 during the subsequent use of the bipolar battery 100.

[0052] In some other embodiments, a thermal adhesive layer may be provided on the outer side of the first fixed structure 12 . The thermal adhesive layer is a film made of thermal adhesive material. The thermal adhesive layer is provided at least on the portion of the first fixed structure 12 that contacts the second fixed structure 13 .

[0053] The hot adhesive material can be selected from commonly used hot adhesive materials in the art. In addition to olefin polymers containing (meth)acrylate units with glycidyl groups, the hot adhesive material can also contain other resins, curing agents, catalysts, etc. For example, epoxy resins, phenolic resins, polyurethane resins, acrylic resins, and silicone resins can be selected. The present application does not limit the hot adhesive material, as long as it has electrical insulation and is adhesive at 100°C to 250°C.

[0054] It can be understood that the above description about the position of the first fixed structure 12 and the second fixed structure 13 on the current collector 10 is only for the convenience of description. That is to say, in actual application, the first fixed structure 12 can also be set on the side of the support structure 11 where the positive electrode material layer 40 is located, and the second fixed structure 13 can be set on the side of the support structure 11 where the negative electrode material layer 60 is located.

[0055] The first fixed structure 12 and the second fixed structure 13 can also meet the above conditions at the same time. Specifically, the first fixed structure 12 is bent to form a first slot 121, and the slot of the first slot 121 is set inward; the second fixed structure 13 is bent to form a second slot 131, and the slot of the second slot 131 is set outward. In the two stacked current collectors 10, the end of the second fixed structure 13 of the first current collector is inserted into the first slot 121 of the first fixed structure 12 of the second current collector, and the end of the first fixed structure 12 of the second current collector is inserted into the second slot 131 of the second fixed structure 13 of the first current collector, thereby forming a secondary sealing structure to further improve the sealing performance. And the buckle joint of the first fixed structure 12 and the second fixed structure 13 forms a S-shaped continuous bending sealing surface. Increase the overlapping part of the first fixed structure 12 and the second fixed structure 13, provide a sealing surface of sufficient length, and improve the sealing reliability.

[0056] In this embodiment, the first fixed structure 12 and the second fixed structure 13 can be an integrally formed bending structure, so that a first card slot 121 is formed in the bending portion of the first fixed structure 12; and a second card slot 131 is formed in the bending portion of the second fixed structure 13; in other embodiments, the first card slot 121 can be formed on the first fixed structure 12 and the second card slot 131 can be formed on the second fixed structure 13 by machining. The present application does not limit the formation method of the first card slot 121 and the second card slot 131.

[0057] In some embodiments, at least the portion of the support layer 111 exposed to the metal foil 112 is insulated, and the first fixed structure 12 and the second fixed structure 13 are arranged on the insulating portion of the support layer 111. That is, the portion of the support layer 111 used to install the first fixed structure 12 and the second fixed structure 13 is made of insulating material, which can prevent the occurrence of short circuits at the edge of the current collector 10, is beneficial to the packaging process of the bipolar battery 100, and increases the safety of the battery under high voltage conditions. In addition, the first fixed structure 12 and the second fixed structure 13 are also made of insulating material, and the portion of the support layer 111 used to install the first fixed structure 12 and the second fixed structure 13 is made of insulating material, which can increase the adhesion between the first fixed structure 12, the second fixed structure 13 and the support layer 111.

[0058] The support layer 111 may be made of insulating materials commonly used in the art, for example, at least one of polyethylene terephthalate (PET), polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene and polyimide.

[0059] The area of ​​the support layer 111 covered by the current collecting layer is at least partially conductive, so that the current collector 10 can better transmit the collected electrons in the battery. The portion of the support layer 111 corresponding to the current collecting layer can be filled with conductive particles, which can cooperate with the current collecting layers on both sides of the support layer 111 to ensure the conductive performance of the current collector 10.

[0060] In other embodiments, the portion of the support layer 111 corresponding to the current collecting layer is a thermoplastic elastomer layer with pores. Specifically, the material of the support layer 111 can be the same as the material of the diaphragm 50, which not only ensures that the current collector 10 has a certain strength to meet the battery production requirements, but also ensures the normal permeability of metal ions.

[0061] The metal foil 112 can be bonded to a preset position of the support layer 111, or the metal foil 112 can be formed on the surface of the support layer 111 by vacuum distillation of chemical vapor deposition or vacuum distillation of physical vapor deposition. Depending on the type of the bipolar battery 100, the material of the metal foil 112 can be copper, aluminum, metal oxide, or a polymer filled with conductive particles. For example, when the bipolar battery 100 is a lithium-ion battery, the metal foil 112 connecting the support layer 111 and the negative electrode material layer 60 can be copper, and the metal foil 112 connecting the support layer 111 and the positive electrode material layer 40 can be aluminum; when the bipolar battery 100 is a sodium-ion battery, the metal foil 112 on both sides of the support layer 111 can be aluminum.

[0062] A third fixing structure 21 is provided at the bottom of the positive electrode plate 20, one end of the positive electrode plate 20 extends out of the housing 101, and the portion of the positive electrode plate 20 extending out of the housing 101 forms a positive electrode lead-out portion 22. The third fixing structure 21 can be engaged with the first fixing structure 12 of the current collector 10 located at the top layer, and a receiving cavity 105 is formed between the positive electrode plate 20 and the support structure 11 at the top layer.

[0063] Similar to the structure of the positive electrode plate 20, a fourth fixing structure 31 is provided on the top of the negative electrode plate 30, one end of the negative electrode plate 30 extends out of the housing 101, and the portion of the negative electrode plate 30 extending out of the housing 101 forms a negative electrode lead-out portion 32. The fourth fixing structure 31 can be engaged with the second fixing structure 13 of the current collector 10 at the bottom layer, and a receiving cavity 105 is formed between the negative electrode plate 30 and the support structure 11 at the bottom layer.

[0064] By providing a third fixing structure 21 on the positive plate 20 and a fourth fixing structure 31 on the negative plate 30, a sealed space is formed where all the positive electrode material layers 40, the separator 50 and the negative electrode material layers 60 are located, and the paired positive / negative electrode material layers are separated from other structures, thereby reducing the risk of short circuits between different electrodes and improving the sealing and safety of the finished battery. The positive electrode lead-out portion 22 and the negative electrode lead-out portion 32 are electrically connected to external electrical appliances when the bipolar battery 100 is used in a vehicle. The electrolyte can be a liquid electrolyte, which is filled in the accommodating cavity 105. The structure formed by the first fixing structure 12 and the second fixing structure 13 can also reduce the risk of preventing the liquid electrolyte from leaking.

[0065] In other embodiments, the electrolyte may also be a solid electrolyte, which is coated on the surface of the diaphragm 50 ; or the diaphragm 50 may be replaced by a solid electrolyte, which is filled between the positive electrode material layer 40 and the negative electrode material layer 60 .

[0066] The third fixing structure 21 can be consistent with the specifications of the first fixing structure 12, and the fourth fixing structure 31 can be consistent with the specifications of the second fixing structure 13. The consistency of specifications can be understood as the consistency of parameters such as materials, shapes, and sizes. Therefore, the third fixing structure 21 and the fourth fixing structure 31 are not described in detail in this application.

[0067] The process flow of the bipolar battery 100 is as follows. Figure 5 , firstly, positive and negative electrode materials are coated on the front and back sides of the current collector 10 to form a positive electrode material layer 40 and a negative electrode material layer 60, and then the diaphragm 50 coated with a solid electrolyte is covered on the negative electrode material layer 60 of the current collector 10; the projection of the diaphragm 50 along the stacking direction at least completely covers the projection of the positive electrode material layer 40 along the stacking direction and the projection of the negative electrode material layer 60 along the stacking direction, that is, the diaphragm 50 can completely separate the positive electrode material layer 40 and the negative electrode material layer 60 to avoid short circuit between the internal positive electrode material layer 40 and the negative electrode material layer 60. Until the positive electrode plate 20 is stacked. The metal foil 112 corresponding to the negative electrode material layer 60 is used as a substrate and stacked n times in layers to form n bipolar units, and the outermost layer is covered with a positive electrode plate 20 and led out as a positive electrode lead-out portion 22, and finally the entire battery cell 103 is wrapped and sealed with an outer packaging film (housing 101).

[0068] When a liquid electrolyte is selected as the electrolyte, the step of covering the diaphragm 50 coated with a solid electrolyte on the negative electrode material layer 60 of the current collector 10 is replaced by: covering the diaphragm 50 on the negative electrode material layer 60 of the current collector 10, and then injecting a liquid electrolyte between the diaphragm 50 and the support structure 11.

[0069] During the stacking process, the second fixed structure 13 of the first current collector can be engaged with the first fixed structure 12 of the second current collector, so that the first fixed structure 12 and the second fixed structure 13 are used to enclose a accommodating cavity 105 between the supporting structure 11 of the first fixed structure 12 and the supporting structure 11 of the second fixed structure 13, and the positive electrode material layer 40, the diaphragm 50 and the negative electrode material layer 60 arranged in the accommodating cavity 105 are preliminarily sealed, thereby reducing the risk of leakage of the liquid electrolyte in the accommodating cavity 105 and improving the sealing and safety of the finished battery.

[0070] After the current collector 10, the positive electrode plate 20, the negative electrode plate 30, the positive electrode material layer 40, the negative electrode material layer 60 and the separator 50 are stacked in a certain order to form the battery cell 103, the charging and discharging process is performed to complete the formation process. During the formation process, the battery will produce gas to increase the internal gas pressure.

[0071] In the present application, at least one of the first fixing structure 12 and the second fixing structure 13 is an elastic structure. In this embodiment, the first fixing structure 12 is an elastic structure as an example for explanation. During the stacking process, after each layer of the current collector 10 is stacked, a certain force is applied along the first direction to keep the sealing structure mutually buckled, and the rebound force of the positive electrode material layer 40, the negative electrode material layer 60 and the separator 50 and the external restraining force are balanced to achieve the purpose of buckling; in the formation process, please refer to Figure 6 When the battery produces gas, the external restraining force is adjusted and the internal air pressure is used to lift the second fixed structure 13 relative to the first fixed structure 12 to form a gap. When the gap becomes larger, its force-bearing area gradually increases. Finally, when the effect of the internal air pressure exceeds the deformation of the first fixed structure 12 and the effect of the external restraining force, a channel is opened between the first fixed structure 12 and the second fixed structure 13, thereby successfully realizing the exhaust function.

[0072] In practical applications, the second fixing structure 13 may be elastic, or both the first fixing structure 12 and the second fixing structure 13 may be elastic.

[0073] After the formation process is completed, the battery core 103 is heated so that the first fixing structure 12 and the second fixing structure 13 are bonded together to form a whole, and finally the entire battery core 103 is wrapped and sealed with a shell.

[0074] For the finished product of the bipolar battery 100, the current collector 10 can be made into a standard structure by setting the first fixing structure 12 and the second fixing structure 13 on both sides of the support structure 11 of the current collector 10. When the stacking process of the current collector 10 is carried out, the first fixing structure 12 and the second fixing structure 13 are matched to automatically achieve positioning and fastening, without additionally controlling the position of the current collector 10 of the two adjacent layers; based on the structure of the current collector 10, the present application makes adaptive adjustments to the structure of the positive plate 20 and the negative plate 30, and sets the third fixing structure 21 on the positive plate 20 to cooperate with the first fixing structure 12 of the current collector 10, and sets the fourth fixing structure 31 on the negative plate 30 to cooperate with the second fixing structure 13 of the current collector 10. In the stacking process, the negative plate 30, the current collector 10 and the positive plate 20 can be pre-assembled together and connected by snap-fitting, reducing the displacement between the negative plate 30, the current collector 10 and the positive plate 20, thereby improving the consistency of the finished product and reducing the production and processing costs.

[0075] The bipolar battery 100 provided in the second embodiment of the present application has a substantially similar structure to the bipolar battery 100 provided in the first embodiment, except that, in two adjacent current collectors 10 of the bipolar battery 100 , the first fixing structure 12 of one current collector 10 is adhered to the second fixing structure 13 of the other current collector 10 to seal the accommodating cavity 105 .

[0076] In this embodiment, after the formation process is completed, the battery cell 103 is heated so that the first fixed structure 12 and the second fixed structure 13 are bonded together to form a whole. At this time, the accommodating cavity 105 is a sealed cavity, thereby avoiding leakage of electrolyte in the accommodating cavity 105 during the use of the bipolar battery 100, reducing the short circuit of the positive electrode material layer 40 and the negative electrode material layer 60 in different accommodating cavities 105, and improving the sealing and safety of the finished bipolar battery 100.

[0077] It is understandable that the first fixed structure 12 and the second fixed structure 13 will adhere to each other during the hot pressing process, and the hot pressing process may cause the shape of the first / second fixed structure to change. The above description of the shape of the first fixed structure 12 and the second fixed structure 13 is applicable to the first fixed structure 12 and the second fixed structure 13 before hot pressing. After hot pressing, the shapes of the first fixed structure 12 and the second fixed structure 13 are no longer limited. It is only necessary to ensure that the first fixed structure 12 and the second fixed structure 13 are adhered together to form an integral structure, and the first fixed structure 12, the second fixed structure 13 and the two adjacent support structures 11 together form a sealed accommodating cavity 105.

[0078] The above are some implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A current collector, characterized in that: The current collector includes a supporting structure and a first fixed structure and a second fixed structure respectively arranged on opposite sides of the supporting structure; when at least two of the current collectors are stacked, in two adjacent current collectors, the first fixed structure of one current collector is detachably connected to the second fixed structure of the other current collector, so that the two adjacent supporting structures and the first fixed structure and the second fixed structure detachably connected to each other jointly form a containing cavity, and the containing cavity is used to contain an electrolyte.

2. The current collector according to claim 1, characterized in that: The first fixing structure and the second fixing structure are both snap-fit ​​structures. Among two adjacent current collectors, the first fixing structure of one current collector is snap-fitted to the second fixing structure of the other current collector.

3. The current collector according to claim 2, characterized in that: The first fixing structure is provided with a first clamping groove; the first clamping groove is used to clamp the second fixing structure on the adjacent current collector when at least two current collectors are stacked.

4. The current collector according to claim 3, characterized in that: The second fixing structure is provided with a second slot. When at least two of the current collectors are stacked, in the first fixing structure and the second fixing structure that are engaged with each other, the end of the first fixing structure is inserted into the second slot of the second fixing structure, and the end of the second fixing structure is inserted into the first slot of the first fixing structure, so as to form a continuously bent sealing surface between the first fixing structure and the second fixing structure.

5. The current collector according to claim 4, characterized in that: The first fixing structure is bent to form the first slot, and the second fixing structure is bent to form the second slot.

6. The current collector according to claim 2, characterized in that: The end of the first fixing structure and the end of the second fixing structure are arc-shaped.

7. The current collector according to claim 1, characterized in that: At least one of the first fixing structure and the second fixing structure has thermal adhesiveness.

8. The current collector according to claim 1, characterized in that: The supporting structure has current collecting layers on both opposite sides, and the first fixing structure and the second fixing structure are arranged on the periphery of the current collecting layer on the same side.

9. The current collector according to claim 8, characterized in that: The support structure includes a support layer and two metal foils, and the two metal foils are arranged on two opposite sides of the support layer to form the current collecting layer.

10. The current collector according to claim 9, characterized in that: At least a portion of the support layer exposed from the metal foil is insulated, and the first fixing structure and the second fixing structure are arranged on the insulating portion of the support layer.

11. The current collector according to claim 9, characterized in that: The region of the support layer covered by the current collecting layer is at least partially conductive.

12. A bipolar battery, characterized in that: The bipolar battery comprises a positive plate, a negative plate and a plurality of current collectors according to any one of claims 1 to 11, wherein the plurality of current collectors are stacked between the positive plate and the negative plate in a direction from the positive plate to the negative plate.

13. The bipolar battery according to claim 12, characterized in that: A third fixing structure is provided on one side of the positive electrode plate facing the current collector, and the third fixing structure of the positive electrode plate is engaged with the first fixing structure of the adjacent current collector to form a receiving cavity between the positive electrode plate and the supporting structure of the adjacent current collector; A fourth fixing structure is provided on one side of the negative electrode plate facing the current collector, and the fourth fixing structure of the negative electrode plate is engaged with the second fixing structure of the adjacent current collector to form a receiving cavity between the negative electrode plate and the supporting structure of the adjacent current collector.

14. The bipolar battery according to claim 13, characterized in that: Along the direction from the positive electrode plate to the negative electrode plate, the positive electrode material layer, the separator and the negative electrode material layer are sequentially stacked in the accommodating cavity, the positive electrode material layer is arranged on the positive electrode plate / the current collector, and the negative electrode material layer is arranged on the negative electrode plate / the current collector.

15. The bipolar battery according to claim 14, characterized in that: The projection of the separator along the stacking direction at least completely covers the projection of the positive electrode material layer along the stacking direction and the projection of the negative electrode material layer along the stacking direction.

16. The bipolar battery according to claim 14, characterized in that: The diaphragm is coated with a solid electrolyte; or the containing cavity is filled with a liquid electrolyte.

17. The bipolar battery according to claim 14, characterized in that: The bipolar battery further comprises a shell, wherein the current collector, the positive electrode material layer, the separator and the negative electrode material layer are all arranged in the shell, and a portion of the positive electrode plate / the negative electrode plate extends out of the shell to form a positive electrode lead-out portion / a negative electrode lead-out portion.

18. A bipolar battery, characterized in that: The bipolar battery includes a positive plate, a negative plate, and a plurality of current collectors as described in any one of claims 1 to 11, wherein the plurality of current collectors are stacked between the positive plate and the negative plate and are stacked in a direction from the positive plate to the negative plate, and among two adjacent current collectors, a first fixing structure of one current collector is adhered to a second fixing structure of the other current collector to seal the accommodating cavity.

19. An electrical equipment, characterized in that: The electrical device comprises the bipolar battery according to any one of claims 12 to 17 or claim 18.

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