阅读说明：本技术 一种提高电池安全性能的结构件和电池及制备方法 (Structural component for improving safety performance of battery, battery and preparation method ) 是由 李娟� 刘妮娜 马艳 邱扬 孙延先 于 2020-05-11 设计创作，主要内容包括：本发明涉及一种提高电池安全性能的结构件和电池及制备方法,属于锂电池技术领域。该结构件由中间基材层及设置在基材层两面的粘接剂层组成,或者仅由粘接剂层组成,粘接剂层包括粘接剂或粘接剂和添加剂,粘接剂为聚偏氟乙烯、聚丙烯酸酯、聚丙烯酸、聚酰胺、聚氨酯、环氧树脂、丁苯橡胶、丁腈、聚氧化乙烯、聚吡咯、聚噻吩和聚苯胺中的一种或两种以上；添加剂为增稠剂；结构件上设置供极耳和电解液穿过或通过的空位。本发明还公开了结构件的制备方法和电池及制备方法。本发明的结构件不仅可以避免电芯入壳时极片和隔膜翻折,还可以提高振动、撞击和跌落过程中的稳定性避免极片和隔膜错位,提高电池的电化学性能和安全性能。(The invention relates to a structural component for improving the safety performance of a battery, the battery and a preparation method, and belongs to the technical field of lithium batteries. The structural member consists of an intermediate base material layer and adhesive layers arranged on two surfaces of the base material layer, or only consists of the adhesive layers, each adhesive layer comprises an adhesive or an adhesive and an additive, and the adhesive is one or more than two of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline; the additive is a thickening agent; the structural member is provided with a vacancy for the pole lug and electrolyte to pass through or pass through. The invention also discloses a preparation method of the structural member, a battery and a preparation method. The structural member of the invention can not only prevent the pole piece and the diaphragm from being folded when the battery cell is placed into the shell, but also improve the stability in the processes of vibration, impact and falling, prevent the pole piece and the diaphragm from being misplaced and improve the electrochemical performance and the safety performance of the battery.)

1. The utility model provides an improve battery safety performance's structure which characterized in that: the adhesive layer comprises an adhesive or an adhesive and an additive, and the adhesive is one or more than two of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene-butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline; the additive is a thickening agent; and the structural member is provided with a vacancy for the pole lug and the electrolyte to pass through or pass through.

2. The structural member for improving the safety of a battery according to claim 1, wherein: the middle base material layer is a PET film, a PP film, a PE film or a non-woven fabric; the thickening agent is sodium carboxymethyl cellulose.

3. The structural member for improving the safety of a battery according to claim 1, wherein: for the structural member with the middle base material layer, the thickness of the middle base material layer is 0.025-0.08mm, and the thickness of the adhesive layer is 5-15 μm; for structural members without an intermediate substrate layer, the thickness of the adhesive layer is 15-45 μm.

4. The structural member for improving the safety of a battery according to claim 1, wherein: the structural part comprises a top structural part and a bottom structural part which are respectively assembled at the top and the bottom of the battery cell; the top structural member is provided with a pole lug position for a pole lug to pass through and an electrolyte channel for electrolyte to pass through; and an electrolyte channel for passing electrolyte is arranged on the bottom structural member.

5. The structural member for improving the safety of a battery according to claim 4, wherein: the pole ear position is a single pole ear or a plurality of pole ears, and the position and the shape can be adjusted according to the aluminum-plastic film single-pit or aluminum-plastic film double-pit battery; the electrolyte channel is round, oval or square; the area and shape can be adjusted according to the size of the battery.

6. The method for preparing a structural member for improving the safety of a battery according to any one of claims 1 to 5, comprising the steps of:

(1) uniformly mixing the adhesive, the solvent and the thickening agent to obtain a mixed solution; the binder is one or more of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline, the solvent is water, ethanol, acetone or ethyl acetate, and the thickening agent is sodium carboxymethylcellulose;

(2) coating the obtained mixed solution on two surfaces or one surface of a base material to obtain a binder layer, and drying and then rolling;

(3) punching and forming the dried coil material by using a die machine to obtain a battery structural member; or the adhesive layer is peeled off from the intermediate substrate after die-cutting to obtain a battery structure without the intermediate substrate.

7. The method for preparing a structural member for improving the safety of a battery according to claim 6, wherein: the adhesive accounts for 5-15% of the mixed solution, the solvent accounts for 84-95%, and the thickening agent accounts for 0-1%.

8. The method for preparing a structural member for improving the safety of a battery according to claim 6, wherein: the coating mode adopted for preparing the adhesive layer is a gravure coating mode, a spraying machine or a scraper coater, and the coating speed is 10-30 m/min; the drying temperature is 55-90 ℃; the base material is a PET film, a PP film, a PE film or a non-woven fabric, and the thickness of the base material is 0.025-0.08 mm; for the structural member with the intermediate base material layer, the thickness of the adhesive layer is 5-15 μm; for structural members without an intermediate substrate layer, the thickness of the adhesive layer is 15-45 μm.

9. A battery using the structural member for improving the safety of a battery according to any one of claims 1 to 5.

10. A battery preparation method comprises the following steps:

(1) adhering one surface of a top structural member and one surface of a bottom structural member to the top and the bottom of a wound or laminated battery after welding tabs by adopting the structural member of any one of claims 1 to 6 to obtain a battery core;

(2) placing the battery cell in the well-punched aluminum-plastic film, and adhering the other surfaces of the top structural member and the bottom structural member to the aluminum-plastic film so as to stably fix the battery cell in the aluminum-plastic film;

(3) then packaging and injecting the battery, wherein electrolyte enters the battery core from the electrolyte channel of the top structural member and the electrolyte channel of the bottom structural member, and soaks each layer of pole piece;

(4) and finally, forming and sorting the batteries.

Technical Field

The invention relates to a structural component for improving the safety performance of a battery, the battery and a preparation method, and belongs to the technical field of lithium batteries.

Background

Lithium ion batteries have the advantages of high operating voltage, high specific energy, long cycle life, low self-discharge rate, no pollution and the like, are widely used in small electronic devices such as mobile phones, portable computers, digital products and the like, and have shown wide application prospects in vehicles such as Electric Vehicles (EV) and Hybrid Electric Vehicles (HEV).

With the increasing number and scale of Lithium Ion Batteries (LIBs) in the fields of electric vehicles and energy storage, the safety problem becomes more and more prominent. Among them, the processes of vibration resistance, impact resistance and drop are important indexes affecting the safety of the lithium battery. In the process, the cell structure is easy to loosen, the interface impedance between the pole piece and the diaphragm is increased, lithium crystal branches are easy to generate, and finally the diaphragm is punctured and the internal short circuit is caused; in addition, the pole piece and the diaphragm are easy to dislocate, so that the anode and the cathode are in contact to form an internal short circuit, and the safety performance of the lithium battery is seriously influenced.

The CN106733487A patent provides a chip gluing device and method, which includes a bottom plate, a heating device, a first motor, a flattening device, a bearing table, a second motor, a first transmission member, a measuring instrument, a vacuum cover and a material pushing frame, wherein the bearing table and glue solution in the bearing table are heated to a specific temperature on the heating device, the bearing table is pushed and placed onto the bearing table through the material pushing frame, the first motor drives the flattening device to rotate through the first transmission member, the thickness of the glue layer is controlled through the first transmission member and the measuring instrument, the second motor drives the bearing table on the bearing table to rotate, the flattening device is matched with the bearing table to perform a rotary pressing process, and the rotary pressing process is in a vacuum negative pressure state, so that bubbles can be prevented from being generated, the uniformity of the glue layer is ensured, the integrity of a pattern after the chip is ground is ensured, and the reliability and stability of the device are improved. The defects of complex gluing equipment, high cost and long development time; in addition, the glue solution is required to be heated in the gluing process so as to have certain fluidity, then is sprayed or blade-coated on the core bottom coat, and then is naturally or artificially cooled. When the lithium ion battery is sprayed or blade-coated to the bottom of the winding core, the flowing glue solution enters the inside of the winding core due to the self-flowing part, so that the migration of lithium ions is hindered, and the whole electrochemical performance of the battery is influenced.

The CN205810981U patent provides a lithium ion battery rolls up core rubberizing structure, includes that positive pole piece, barrier film and negative pole piece are in turn laminated the core that rolls up that the back formed along same direction, its characterized in that: the flat adhesive paper is adhered to the bottom end of the winding core; in the direction perpendicular to the winding direction of the winding core, the bottom edge of the isolating film exceeds the bottom edge of the negative pole piece by 0.2-0.6 mm, and the bottom edge of the negative pole piece exceeds the bottom edge of the positive pole piece by 0.1-0.5 mm; and the flat adhesive paper is stuck to the positive pole piece and the isolating film at the same time. The method can solve the safety problems of internal short circuit and the like caused by the outward turning of the anode, the cathode and the diaphragm in the packaging process of the battery cell. However, because the battery cell and the shell are not adhered together, the battery cell rocks back and forth in the shell in vibration, drop and other tests, the tab welding is easy to fall off, the aluminum-plastic film packaging fails, the local dislocation and looseness in the battery cell finally affect the electrochemical performance and the safety performance of the battery cell.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a structure for improving the safety of a lithium ion battery, which comprises a battery cell top assembly structure and a battery cell bottom assembly structure, and can improve the electrochemical performance and the safety performance of the battery in the vibration, impact and falling processes.

In order to achieve the purpose, the invention adopts the following technical scheme:

a structural member for improving the safety performance of a battery comprises an intermediate base material layer and adhesive layers arranged on two surfaces of the base material layer, or only comprises the adhesive layers, wherein the adhesive layers mainly comprise adhesives or adhesives and additives, and the adhesives are one or more of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene-butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline, or other organic matters with electrolyte resistance and viscosity; the additive is a thickening agent; the structural member is provided with a vacancy (hole) for the pole lug and electrolyte to pass through or pass through.

The middle substrate layer is a PET film, a PP film, a PE film, a non-woven fabric or other polymers capable of playing a supporting role. The thickening agent is sodium carboxymethyl cellulose (CMC) and the like.

The thickness of the middle base material layer and the adhesive layer can be adjusted according to the size of the battery; preferably, for a structure having an intermediate substrate layer, the thickness of the intermediate substrate layer is 0.025 to 0.08mm and the thickness (double sides) of the adhesive layer is 5 to 15 μm. For structural members without an intermediate substrate layer, the adhesive layer has a thickness of 15-45 μm.

The structural component for improving the safety performance of the battery comprises a top structural component and a bottom structural component which are respectively assembled at the top and the bottom of the battery core; the top structural member is provided with a pole lug position for a pole lug to pass through and an electrolyte channel for electrolyte to pass through; and an electrolyte channel for passing electrolyte is arranged on the bottom structural member.

The pole ear position is a single pole ear or a plurality of pole ears, and the position and the shape can be adjusted according to the aluminum-plastic film single-pit or aluminum-plastic film double-pit battery.

The electrolyte channel is round, oval, square or any other shape; meanwhile, the area and the shape of the battery can be adjusted according to the size of the battery.

Preferably, the middle part of the top structural member is provided with two pole ear positions, two ends of the top structural member are respectively provided with a first electrolyte channel, and two second electrolyte channels are symmetrically arranged between the pole ear positions and the first electrolyte channels respectively; and two ends of the bottom structural member are respectively provided with an electrolyte channel III, and the middle of the bottom structural member is provided with six electrolyte channels IV.

A preparation method of a structural member for improving the safety performance of a battery comprises the following steps:

(1) uniformly mixing the adhesive, the solvent, the thickening agent and the like to obtain a mixed solution; the binder is one or more of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline, or other organic matters with electrolyte resistance and viscosity; the solvent is polar solvent such as water, ethanol, acetone or ethyl acetate; the thickening agent is sodium carboxymethyl cellulose (CMC) and the like;

(2) coating the obtained mixed solution on two surfaces or one surface of a base material to obtain a binder layer, and drying and then rolling;

(3) punching and forming the dried coil material by using a die machine to obtain a battery structural member; or stripping the adhesive layer from the intermediate substrate after punching and forming to obtain the battery structural member without the intermediate substrate.

In the step (1), in the mixed solution composed of the adhesive, the solvent and the thickening agent, the adhesive accounts for 5-15% of the mass of the whole mixed solution, the solvent accounts for 84-95% of the mass of the whole mixed solution, and the thickening agent accounts for 0-1% of the mass of the whole mixed solution.

In the step (2), the coating mode for preparing the adhesive layer is a gravure coating mode, a spray coater or a blade coater coating mode and the like, and the coating speed is 10-30 m/min; the drying temperature is 55-90 ℃.

In the step (2), the base material is a PET film, a PP film, a PE film, a non-woven fabric or other polymers capable of playing a supporting role. The thickness of the base material is 0.025-0.08 mm; for structures with an intermediate substrate layer, the adhesive layer has a thickness of 5-15 μm on both sides. For structural members without an intermediate substrate layer, the adhesive layer has a thickness of 15-45 μm. The thickness of the base material and the adhesive layer can be adjusted according to the size of the battery.

A battery adopting the structural member for improving the safety performance of the battery is provided.

A battery preparation method comprises the following steps:

(1) adhering one surface of a top structural part and one surface of a bottom structural part to the top and the bottom of the battery wound or laminated after welding the lugs respectively by adopting the structural parts to obtain a battery core;

(2) the battery cell is placed in the aluminum-plastic film with the punched hole, and the other sides of the top structural part and the bottom structural part are adhered to the aluminum-plastic film, so that the battery cell is stably fixed in the aluminum-plastic film, the dislocation of the diaphragm and the pole piece in the vibration, impact or falling process is prevented, meanwhile, the turnover of the diaphragm or the pole piece can be avoided, and the battery yield is improved;

(3) then, packaging and injecting the battery, wherein electrolyte enters the battery cell from the electrolyte channel of the top structural member and the electrolyte channel of the bottom structural member and infiltrates each layer of pole piece, so that the battery is not easy to soften;

(4) and finally, forming and sorting the batteries.

The invention is not limited to the top and bottom cell assembly structure, but also can be any other structure which can meet the requirement of adhesion and the requirement of effectively soaking the pole piece by electrolyte.

The invention has the advantages that:

the structural component for improving the safety of the lithium ion battery comprises a cell top assembly structural component and a cell bottom assembly structural component. The battery can avoid the turnover of the pole piece and the diaphragm when the battery core is placed into the shell, can also improve the stability in the processes of vibration, impact and falling, avoids the dislocation of the pole piece and the diaphragm, and improves the electrochemical performance and the safety performance of the battery.

Drawings

Fig. 1 is a side view schematically illustrating a structure for improving the safety of a battery according to the present invention.

Fig. 2 is a schematic structural diagram of a cell top structural member.

Fig. 3 is a schematic structural diagram of a cell bottom structural member.

Description of the main reference numerals:

11 intermediate base material layer 12 adhesive layer

21 electrolyte channel one 22 electrolyte channel two

23 tab site 24 bonding part

31 electrolyte channel three 32 electrolyte channel four

33 bonding part

Detailed Description

As shown in fig. 1, a schematic side view of the structural member of the present invention is shown, and the structural member is composed of an intermediate substrate layer 11 and outer adhesive layers 12 disposed on both sides of the substrate layer, or only the adhesive layers 12. The thickness of the intermediate base material layer 11 and the adhesive layer 12 can be adjusted according to the size of the battery; the middle substrate layer 11 may or may not be a PET film, PP, PE, a non-woven fabric, or other polymer capable of supporting; the adhesive layer 12 mainly comprises an adhesive, or the adhesive layer 12 mainly comprises an adhesive and a small amount of additive (thickening agent), wherein the adhesive can be one or a mixture of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline, and can also be any other organic matter with electrolyte resistance and viscosity; the additive is thickener such as sodium carboxymethylcellulose (CMC); the structural member is provided with a vacancy or a hole for the pole lug and electrolyte to pass through or pass through.

The structural member for improving the safety performance of the battery comprises a top structural member for the top of the battery core and a bottom structural member for the bottom of the battery core. The top structural member is provided with a pole lug position for a pole lug to pass through and an electrolyte channel for electrolyte to pass through; an electrolyte channel for passing electrolyte is arranged on the bottom structural member. The tab position can be a single-pole tab, a multi-tab, an aluminum-plastic film single-pit or an aluminum-plastic film double-pit battery for position and shape adjustment; the first, second, third and fourth electrolyte channels can be round, oval, square or any other shape; meanwhile, the area and the shape of the battery can be adjusted according to the size of the battery.

As shown in fig. 2, the schematic diagram of the top assembly structure of the battery cell is shown, where the top structural member is a structure a, a row of two rectangular tab positions 23 are arranged in the middle of the structure a, two elliptical electrolyte channels 21 are respectively arranged at two ends of the structure a, and a row of two elliptical electrolyte channels two 22 are respectively arranged between the tab positions 23 and the electrolyte channels one 21 and are symmetrically distributed; the structure a has an adhesive portion 24 except for the tab 23 and the electrolyte passage. The first electrolyte channel 21 and the second electrolyte channel 22 can ensure that electrolyte enters each layer of the battery core from the top of the battery core and soaks the pole pieces.

As shown in fig. 3, the schematic diagram of the bottom assembly structure of the battery cell is shown, where the bottom structural member is a structure B, two ends of the structure B are respectively provided with an oval electrolyte channel three 31, the middle of the structure B is provided with three rows of six oval electrolyte channels four 32, and the structure B is provided with an adhesive portion 33 except the electrolyte channels. The third electrolyte channel 31 and the fourth electrolyte channel 32 can ensure that electrolyte enters each layer of the battery core from the bottom of the battery core and soaks the pole pieces.

The preparation method of the structural member for improving the safety performance of the battery comprises the following steps:

(1) mixing an adhesive, a solvent, a thickening agent and the like to obtain a mixed solution; the binder is one or more of polyvinylidene fluoride, polyacrylate, polyacrylic acid, polyamide, polyurethane, epoxy resin, styrene butadiene rubber, butyronitrile, polyethylene oxide, polypyrrole, polythiophene and polyaniline, or other organic matters with electrolyte resistance and viscosity, and accounts for 5-15 wt% of the whole mixed solution, the solvent can be water, ethanol, acetone, ethyl acetate and other polar solvents, and accounts for 84-95% of the whole mixed solution, and the thickening agent can be organic matters such as CMC, and can also be not added, and accounts for 0-1% of the whole mixed solution.

(2) Preparing an adhesive layer: the mixed solution is coated on two sides of the base material, and the adhesive layer can be coated by adopting a gravure coating mode, and a spray coater, a scraper coater or other coating modes can also be adopted. The coating speed is 10-30m/min, and the baking temperature is 55-90 ℃. And (5) drying and then rolling.

(3) And punching and forming the dried coil material by using a die machine to obtain the battery structural member.

The structural member is adopted for assembling the battery, and the specific implementation steps are as follows:

(1) respectively adhering one surface of the structure A shown in fig. 2 and one surface of the structure B shown in fig. 3 to the top and the bottom of a wound (or laminated) battery after welding of tabs to obtain a battery core;

(2) the battery cell is placed in the aluminum-plastic film with good pit punching, and the other side of the structure A and the other side of the structure B can be adhered to the aluminum-plastic film, so that the battery cell can be stably fixed in the aluminum-plastic film, the dislocation of the diaphragm and the pole piece in the vibration, impact or falling process is prevented, meanwhile, the turnover of the diaphragm or the pole piece can be avoided, and the battery yield is improved.

(3) And then packaging and injecting the battery, wherein electrolyte enters the battery core from the first electrolyte channel and the second electrolyte channel of the top assembly structure and the third electrolyte channel and the fourth electrolyte channel of the bottom assembly structure, and soaks each layer of pole piece. The battery is not easy to soften.

(4) And finally, forming and sorting the batteries.

The invention is not limited to the top and bottom cell assembly structure as shown in the figure, but also can be any other structure which can meet the adhesion and can effectively infiltrate the pole piece with electrolyte.

Example 1

A certain amount of mixed solution (6% of polyacrylate and 94% of ethanol) is taken out of a coating tank and coated on two sides of a PET substrate (with the thickness of 0.030mm) by adopting a gravure coater, the coating speed is 28m/min, and the baking temperature is 75 ℃. After drying, the thickness of the double-side coating is 6 mu m. And carrying out die cutting and punching on the coated PET substrate.

One side of the die-cut structure (structure a and structure B shown in fig. 2-3) was adhered to the top and bottom of the cell to obtain a cell. And the battery core is placed in the aluminum-plastic film with the pit, and the other side of the structural member is adhered to the inner wall of the aluminum-plastic film. And then carrying out top side sealing, liquid injection, secondary sealing, standing, formation and sorting on the battery to obtain the LIB1 battery.

The non-structural reference battery LIB0 was prepared according to the same process described above.

Finally, the battery LIB1 and the reference battery LIB0 are subjected to safety tests such as dropping and vibration.

Example 2

A certain amount of mixed liquor (8 percent of polyurethane and 92 percent of acetone) is taken to be arranged in a coating tank, and is coated on two sides of a PET substrate (with the thickness of 0.045mm) by adopting a gravure coater, the coating speed is 25m/min, and the baking temperature is 60 ℃. After drying, the thickness of the double-side coating is 9 μm. And carrying out die cutting and punching on the coated PET substrate.

The die-cut structures (structures a and B shown in fig. 2-3) were applied to the battery in the same manner as in example 1, and the battery LIB2 was subjected to safety tests such as dropping and vibration.

Example 3

A certain amount of mixed solution (10% of epoxy resin and 90% of acetone) is taken to be arranged in a coating tank, and is coated on two sides of a PET substrate (with the thickness of 0.060mm) by adopting a gravure coater, the coating speed is 25m/min, and the baking temperature is 65 ℃. After drying, the thickness of the double-side coating is 15 mu m. And carrying out die cutting and punching on the coated PP substrate.

The die-cut structures (structures a and B shown in fig. 2-3) were applied to the battery in the same manner as in example 1, and the battery LIB3 was subjected to safety tests such as dropping and vibration.

Example 4

Taking a certain amount of mixed solution (15% of polyacrylic acid, 84.2% of water and 0.8% of CMC) in a coating tank, coating the mixed solution on a PET substrate (with the thickness of 0.060mm) by adopting a gravure coater, wherein the coating speed is 25m/min, and the baking temperature is 90 ℃. And punching and forming the dried sample, and stripping the coating on the surface of the PET substrate to obtain the structural member with the thickness of 35 mu m and without an intermediate substrate layer.

The die-cut structures (structures a and B shown in fig. 2-3) were applied to the battery in the same manner as in example 1, and the battery LIB4 was subjected to safety tests such as dropping and vibration.

Table 1 results of performance tests of batteries of examples 1 to 4

Remarking: LIB0 is a battery without the addition of structural elements as described in the present invention. The experimental cell size was 3.8mm 62mm 83 mm.

The above embodiments are only used for illustrating but not limiting the technical solutions of the present invention, and although the above embodiments describe the present invention in detail, those skilled in the art should understand that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and any modifications and equivalents may fall within the scope of the claims.