WO2003077349A1 - An rechargeable lithium-ion power battery and manufacture method of the same - Google Patents

Abstract

A rechargeable lithium-ion power battery, each mono-cell is consisted of a cover plate, a negative pole , a safety valve, a positive pole, an electrolyte solution and a case. The positive pole is connected with the positive electrode, and the negative pole is connected with the negative electrode. Positive electrode substrate is selected from an aluminum foil with certain thickness, which is coated with positive active material on both sides. Negative electrode substrate is selected from copper foil with certain thickness, which is coated with negative active material on both sides. It is characterized in that an inner body of the battery is an electrode assembly which has multi-layer laminated structure which is composed of one or more pairs of electrodes, that is positive electrode, negative electrode, and separator, in this electrode assembly, the positive electrode sheet and the negative electrode sheet are separately positioned in sequence. Either the positive electrode sheet or the negative electrode sheet is shaped into rectangle sheet with big-leaf single tab or big-leaf multiple tabs, current flows to the poles by means of current-collecting clamp. The positive electrode has one or more electrode poles; the negative electrode has one or more electrode poles. Amount of the positive pole can be same with that of the negative pole, or different; diameter of the pole can be same, or different.

Description

 Lithium-ion power battery capable of being repeatedly charged and discharged and manufacturing method thereof

 The present invention relates to an environmentally friendly battery that can be repeatedly charged and discharged, and more particularly, the present invention relates to a lithium ion power battery that can be repeatedly charged and discharged and a method for manufacturing the same.

 Background technique

 Due to the requirements of environmental protection and energy saving, the world's demand for energy is more and more urgent. Therefore, it is an inevitable trend for social development and technological progress to seek for efficient and clean power sources.

 There have been many studies in the field of power batteries. Currently common power batteries include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and sodium-sulfur batteries. But because of its low energy density, it takes a long time to charge, and it cannot meet the needs of high-power charge and discharge. It directly affects the practicality of these power batteries. In recent years, zinc-air batteries, lithium-ion batteries, and proton exchange membrane fuel cells have been considered as the best power batteries for power battery development. However, because it cannot meet the requirements of high-power charging and discharging, its practical problems have seriously hindered the practical application of power batteries.

 Chinese patent application 001 01 356 · 4 discloses "a kind of chrome-fluoride lithium solid power battery that can be repeatedly charged and discharged". Although it is nominally a chrome-fluoride lithium solid power battery that can be repeatedly charged and discharged, its structure and composition are not fully disclosed in practice, so it has little practicality and application value, and it has not fundamentally solved high-power charging and discharging. The problem. The biggest problem of lithium-ion power batteries is the heat generated during the charging and discharging process, and the heat generated during the charging and discharging process has a great adverse effect on the lithium-ion power batteries.

 Therefore, an object of the present invention is to provide a lithium ion power battery capable of being repeatedly charged and discharged, which can solve the problem of high power charging and discharging of the lithium ion power battery.

 Summary of the Invention

The invention belongs to an environmentally-friendly battery that can be repeatedly charged and discharged. The purpose is to hope that the positive and negative electrode tabs of the large-leaf tab and the separator, which have a unique design, have a multi-layered structure. Negative electrode plates are arranged at regular intervals, and the electrode assembly is more sensitive to internal pressure, so it is more reliable and safer. Safety valve, current collecting performance and heat dissipation performance are better. High-power repeated charge and discharge requirements, so as to achieve the wide application of lithium-ion power batteries.

 The present invention provides a lithium-ion power battery that can be repeatedly charged and discharged. Each single battery consists of a cover plate, a negative pole, a safety valve, a positive pole, a current collector plywood, an inner body, an electrolyte, a cylindrical shape or a square shape. (Including rectangle) The shell is composed of the following features: The positive and negative electrode groups, that is, the positive electrode sheet, the negative electrode sheet and the separator together form an electrode assembly with a disc structure; the positive electrode post is connected to the positive electrode, and the negative electrode post It is connected to the negative electrode. The positive electrode is made of aluminum foil of a certain thickness, and the positive electrode active material is evenly coated on both sides. The negative electrode is made of copper foil of a certain thickness, and the negative electrode active material is evenly coated on both sides. Unipolar ears or large-leaf multipolar ears with different intervals are shaped as long and narrow rectangular pieces (also known as flattened pieces). Large-leaf monopoles and large-leaf multipolar ears are collectively referred to as large-leaf polar ears. Large-leaf poles can be either raised or hidden, and the current is exported to the pole through the current collector splint; the positive pole has one or several pole poles, the negative pole has one or several pole poles, The number can be equal or different, and the diameters of the poles can be equal or different.

 The present invention adopts a structure with large leaf poles that can reduce the current density, which can avoid the extremely harmful heat generated in the lithium ion power battery to the greatest extent.

 The invention also provides a safety valve for a lithium ion power battery that can be repeatedly charged and discharged. The compression spring is installed in the inner hole of the adjustment bolt, and the inner hole of the adjustment bolt is used to hold the compression spring and seal the steel ball. Stable, the compression spring can slide down vertically in the inner hole of the adjustment bolt, the sealing steel ball can slide down vertically in the inner hole of the adjustment bolt, and the outer diameter of the adjustment bolt is machined with a thread that matches the safety valve body; adjustment Bolts are processed with several vertical exhaust grooves, and exhaust holes are opened in the lower part of the exhaust groove; the compression spring is pressed on the upper part of the steel ball, and the lower hole of the sealed steel ball is trapped in the fluorine on the cover injection port. On the rubber 圏; the pressure relief hole at the bottom of the safety valve communicates with the injection hole on the cover.

The invention also provides a lithium ion power battery proportion and its manufacturing method that can be repeatedly charged and discharged, including the following steps: batching-→ coating (pulling)-slicing (if the tabs are directly cut, there is no Welding lugs)-→ rolling-→ making (welding) lugs-→ winding (including casing and sealing)-filling-→ forming into one → dividing. The invention has a uniquely designed current collecting (current collecting) terminal, that is, an inner body formed by winding positive and negative electrodes of a large leaf tab and a diaphragm at the same time, which is more sensitive to internal pressure, and thus more reliable, safe and secure. The current collecting plywood with better valve, current collecting performance and heat dissipation performance can solve the high-power repeated charging and discharging requirements of the lithium ion power battery, thereby realizing the wide application of the lithium ion power battery.

 BRIEF DESCRIPTION OF THE DRAWINGS

 The present invention is described in detail below with reference to the drawings, in which the same reference numerals indicate the same components. among them:

 Figure 1-1 is a sectional view of a stacked lithium-ion power battery;

 Figure 1-2 shows a top view of a stacked lithium-ion power battery;

 Figures 1 A, 1 A-1, 1B, IB-1, 1 C, 1 C-1, 1D, 1D-1, 1E, and I E-1 represent the schematic diagrams of the large leaf pole ears on the pole pieces;

 FIG. 2 is a cross-sectional view of a lithium ion power battery according to the present invention;

 FIG. 3 and FIG. 4 are stacking methods of pole pieces in the lithium ion power battery of the present invention;

 Figures 5 and 6 show the structure of a pressure spring type and a plate type safety valve, respectively.

 detailed description

 In terms of appearance, the basic structure of a lithium-ion power battery is shown in Figure 1-1. Each unit battery is composed of a cover plate 1, a negative pole 2, a safety valve 3, and a positive pole.

4 and open case 9; and in the inner cavity of the lithium-ion power battery, there is a current collector plywood (also known as a pole piece plywood) 6, an electrolyte 8, a negative piece 1 2 and a positive piece

1 3 and diaphragm 1 9 (or 1 9-1). The outer shell 9, the negative pole 2 on the cover plate 1, the safety valve 3, and the positive pole 4 constitute the outer body of the lithium-ion power battery; multiple pairs of positive and negative electrode groups, the diaphragm, and the current collector plye constitute the inner body of the lithium-ion power battery

7 (also known as laminated body). The structure and manufacturing process (method) of the laminated lithium-ion power battery are described below:

 Structure of laminated lithium-ion power battery

 The laminated inner body 7 of a lithium-ion power battery is composed of one or more pairs of positive and negative electrode sheet groups and a separator. The electrode assembly has a multi-layer structure, and the positive and negative electrode sheets are arranged at regular intervals. The smallest lithium-ion power battery can consist of a pair of positive and negative electrode groups and a separator.

The positive electrode 1 3 is composed of an aluminum foil and a positive electrode active material (not shown in the figure). The aluminum foil is a thin metal foil, and the positive electrode active material is evenly coated on both sides (either Lithium cobaltate, or lithium manganate or lithium nickelate, lithium nickel cobaltate). The surface of the aluminum foil is usually smooth, but the aluminum foil with a rougher surface has better adhesion for coating active materials. A suitable aluminum foil thickness ranges from 10 μm to 80 μm. When the area of the positive electrode piece is less than or equal to 1 0 0 001 111 5 0 0 mm and greater than or equal to 10 0 mm x 50 mm, charge and discharge When 1 C ~ 2 C is required, exclude other influencing factors, and the optimal thickness of aluminum foil is 15 μm ~ 2 5 μm; when charging and discharging requirements are 2 C ~ 3 C or greater, other factors are excluded, and aluminum foil is used. The optimal thickness is 20 μm to 4 5 μm or more.

 Negative electrode 1 2 is composed of copper foil and negative electrode active material (not shown in the figure). Copper foil is a thin metal foil, and the negative electrode active material is evenly coated on both sides (either natural graphite, flake graphite, artificial Graphite or petroleum coke). The surface of the copper foil is usually smooth, but the copper foil with a rougher surface has better adhesion for coating active materials. The suitable thickness of copper foil is 6 μm ~ 50 μm. When the area of the negative electrode piece is less than or equal to 100 mm x 50 mm and greater than or equal to 100 mm x 50 mm, charge and discharge requirements When 1 C-2 C, exclude other influencing factors, the optimal thickness of copper foil is 8 μm ~ 20 μm; when charging and discharging requirements are 2 C ~ 3 C or greater, other influencing factors are excluded, and copper foil is selected The optimal thickness is 15 μm ~ 3 5 μ ηι or more.

 Neither the positive aluminum foil nor the negative copper foil should be too thick. The thickness of the metal foil (aluminum foil / copper foil) is not only related to the area of the current collector, but also to the capacitance of each single pole piece. The thickness of the metal foil with a larger capacitance should be slightly larger than that of the metal foil with a small capacitance. thick. Where possible, the metal foil should be as thin as possible in order to obtain a larger electrode sheet area when applying the same amount of active material, thereby obtaining better electrical properties.

 In order to reduce the weight and volume of the metal foil, as well as to increase the flexibility of the metal foil, in order to manufacture the lithium-ion power battery into a shape that can meet the needs of various forms, whether the metal foil used for the positive electrode or the negative electrode can also be separately Use wire mesh or flat mesh metal foil. The so-called flat mesh metal foil is formed by punching a number of fine small holes mechanically or chemically or by other methods on a thin aluminum or copper foil, and stretching it in the vertical and horizontal directions.

Active materials (excluding conductive agents, binders, and dispersants) of previous lithium-ion batteries accounted for about 90% of the total ingredients, and the remaining about 10% were conductive agents, binders, and dispersants. The active material of the lithium ion power battery according to the present invention The amount has increased greatly regardless of the positive or negative electrode, which is about 93% to 95% or even higher. The density of the positive electrode active material is 0.02 g to 0.06 g per square centimeter, when the area of the positive electrode piece is less than or equal to 1 0 0 O mmx 5 0 0 mm and greater than or equal to 1 0 0 mm x 5 0 0 m 2, the optimal density of the positive electrode active material per square centimeter is 0. 0 2 2 g ~ 0. 0 4 2 g; the density of the negative electrode active material per square centimeter is approximately 0. 0 1 § ~ 0. 0 3 ₈ ， When the area of the negative electrode piece is less than or equal to 100 mm x 500 mm and greater than or equal to 100 mm x 50 mm, the optimal density of the negative electrode active material per square centimeter is 0.04 g ~ 0. 0 2 1 g.

 The main characteristics of lithium-ion power batteries should be suitable for power applications, and they must meet the requirements of high-power charge and discharge. An important structure in the present invention is to use a large-area collector (current-collection) terminal, that is, a large leaf tab, which is more conducive to current conduction and heat dissipation, and can fully meet the requirements of high-power charge and discharge. In order to have the same name and reflect the characteristic image of the current collecting (collecting) terminal in the present invention as much as possible, the current collecting (collecting) terminal is called a large leaf tab. As shown in FIGS. 1A-1 and IB-1, it can be seen that there is a large leaf tab 1 1 on the positive electrode 13, and as shown in FIG. 1A and FIG. 1B, there is only one large leaf tab 1 0 on the negative electrode 12, It is called a large-leaf monopole ear; as shown in Figures 1C and 1C-1, it can be seen that there are multiple large-leaf pole ears on the positive and negative plates, which are called large-leaf multipole ears. Large-leaf monopoles and large-leaf multipoles are collectively referred to as large-leaf poles.

 Large leaf tabs should use a larger cross-sectional area as far as possible, that is, the tabs should be as wide and thick as possible, and the current collecting (collecting) path should be as short as possible, which is beneficial to the current. Export and cooling. For a lithium-ion power battery with a smaller capacity, the positive and negative electrodes usually have only one large leaf tab; for a large-capacity lithium-ion power battery, there are several large leaf tabs. Compared with large-leaf monopolar ears, large-leaf multipolar ears can better conduct and dissipate heat than large-leaf monopolar ears.

 The large-leaf monopole ears can also be as shown in Figure ID and Figure ID-1. The large-leaf pole ears of the positive and negative poles can be drawn from the side ends of the pole pieces in different directions. The maximum width of the large leaf tabs from the side ends of the pole pieces in different directions can be the same as the side where the large leaf tabs are located, which is more conducive to the flow and heat dissipation of lithium ion power batteries.

If the large leaf tabs on the positive and negative electrodes are led from the same direction or the same side, for example, upward, as shown in Figures 1A and 1A-1, the width of the large leaf monopoles must not be greater than the location of the large leaf tabs. The side of the side is half (half) long. In general, the maximum height of the lobe poles is not greater than its own (lobe poles) width, preferably smaller than its width. The smaller the height of the lobe pole, the better.

 The tabs of a large-capacity power battery, and the tabs of a relatively small-capacity power battery, obviously need to be wider to meet the requirements in terms of the performance of flow guidance, heat dissipation, and high-rate charge and discharge. Or try to locate on the longer side of the positive and negative plates. Large lobe tabs are located on the longer sides of the positive and negative tabs, and are tentatively referred to as horizontal tabs. Large lobe tabs are located on the shorter sides of the positive and negative tabs, and can be referred to as vertical tabs. In terms of current collecting performance, the horizontal film is better than the vertical film, so if the conditions permit, the horizontal film should be used as much as possible.

 In fact, as long as no short circuit is guaranteed, the large-leaf multipole ears can be arbitrarily set at any position on the long or short sides of the positive and negative plates as required.

 If the large-leaf monopole ears on the positive and negative plates are led out from the same direction or the same side, for example, as shown in Figure 1A, Figure 1 A-1; Figure 1B, Figure IB-1, The centerline position should be located at about 1/4 or 3/4 of the side length of the laminated positive and negative plates as much as possible. The inner edge line of the large leaf tab should be as close as possible to the center line of the side where the large leaf tab is located, but it must not obstruct the other tab's tab. Insulation measures must be taken to prevent short-circuiting with the other tab's tab.

 The positive and negative electrodes of a laminated lithium-ion power battery are usually cut into rectangular pieces. The best aspect ratio for rectangular tablets is 6.2: 3.8 or 6: 4. In addition to the rectangular shape, the positive and negative electrode pieces can also be made into a circle or other desired shapes.

 The dimensions of the positive and negative electrode sheets are different due to their process requirements. Since the active material of the positive electrode is much more expensive than the active material of the negative electrode, the length and width of the negative electrode sheet are slightly larger than the positive electrode sheet when cutting. This approach not only saves resources, but also gives full play to the material properties of the positive electrode.

 The positive electrode 1 3 and the negative electrode 1 2 are usually directly cut into rectangular pieces with large leaf monopoles or large leaf multipoles. In addition to cutting, the method of making large-leaf pole tabs can also be directly processed to form pole pieces by rolling or shearing.

In general, the width of the large leaf tabs on the positive electrode 13 is the same as the width of the large leaf tabs on the negative electrode 12. Of course, the width of the respective large leaf tabs on the positive and negative electrodes can also be unequal under special requirements. For large-capacity lithium-ion power batteries, when fast high-power charging and discharging are required, the tab widths on the positive and negative electrodes should be equal. In the case of fast high-power charging without high-power discharge, the width of the large leaf tabs on the negative electrode 12 can be larger than the large leaf tabs on the positive electrode 1 3 Ear; in the case of high power discharge without fast high power charging, the positive electrode

The width of the large lobes on the negative electrode 12 may be greater than the width of the large lobes on the negative electrode 12.

 The connection between the lobe pole and the current collector can be a clear angle (that is, the connection is a right angle, an obtuse angle without an arc), or a smooth arc connection (that is, the connection has an R angle), as shown in Figure 1A. The R in the connection of Figure 1A-1 not only has higher mechanical strength, but also helps to prevent the concentration of heat and cause the pole tabs or even the pole pieces to melt.

 Under normal circumstances, the positive and negative plates of lithium-ion power batteries use corresponding tabs, that is, when the positive electrode 1 3 uses large-leaf monopole ears, and the negative electrode 12 usually uses large-leaf monopole ears; the positive electrode 1 3 uses large-leaf multipoles. The ears and the negative poles 1 2 should also adopt large leaf multipole ears. In order to meet the needs of high-power charging and discharging, when the large-capacity lithium-ion power battery needs fast high-power charging and discharging, the tabs on the positive and negative electrodes should be equivalent and the number should be equal. In the case of fast high-power charging without high-power discharge, large-leaf multipole ears can be used for the negative electrode, and large-leaf monopoles can be used for the positive pole; in the case of high-power discharge without fast high-power charging, Large-leaf multipole ears can be used for the positive pole, and large-leaf monopole ears can be used for the negative pole.

 The manufacturing method of the tabs is whether the directly cut tabs 10/1 1 or the welded tabs are raised heads. It can be seen that the tabs are significantly higher than the active material coated on the tabs. The advantage is that it is convenient Scraping powder.

 In addition to the raised-ear type tabs, the large-leaf tabs shown in Figure ID and Figure 1D-1 are hidden-head style tabs. This hidden-head-style large tabs 17/1 8 can make fuller use of lithium. Space inside the ion battery. The form of the hidden head is exactly the opposite of that of the raised head.

 The raised and hidden large leaf tabs can be on the long sides of the rectangular positive and negative tabs, or on the short sides of the positive and negative tabs. From the perspective of rationality, the large leaf tabs should be as positive and negative as possible. The long side of the pole piece.

In order to prevent the high temperature fuse of the lithium ion power battery from melting and thinning the tabs, the tabs can be fabricated by welding as shown in Figures 1B and 1B-1 (15/16). The welding of several metal pieces not only increases the mechanical strength, improves the conductivity, but also improves the heat dissipation performance. Therefore, it is best to use welded large leaf poles to make large leaf poles. Welds 1 4 must be firm. Welding The advantage of the tab is that the cut pole piece has less burrs. The material of the tabs used for welding. The positive electrode is made of aluminum, and the negative electrode is made of nickel or copper.

 The shape of the large leaf tabs can be designed and processed into square, rectangular, semi-circular, trapezoidal or other shapes that facilitate flow and heat dissipation. The best tab shape is a trapezoid with R rounded corners at the connection.

 The basic function of the separator is to isolate the positive and negative electrodes, prevent the battery from short circuit, and adsorb and maintain the electrolyte. In addition to having good insulation properties, stable chemical and electrochemical properties, the separator must have a certain mechanical strength and high electrical conductivity. Therefore, porous polyolefin materials are the most suitable. In view of the characteristics that lithium-ion power batteries must be charged and discharged with high power, higher safety performance is required.

 The lithium ion power battery involved in the present invention mainly uses a polyethylene separator having a microporous structure and a low current cut-off temperature of 15 to 80 μm. The selection principle of the separator is as thin as possible, but when the area of the positive or negative electrode piece is less than or equal to 1

0 0 0 mm 5 0 0 mm and greater than or equal to 10 O mm x 5 O mm, charge and discharge requirements of 1 C ~ 2 C, excluding other factors, the optimal thickness of the separator is 20 μ ηι ~ 4 0 μ π; When charge and discharge require 3 C or more, excluding other influencing factors, the optimal thickness of the separator is 40 μ m or more. When the internal temperature of the battery is higher than the limit value (whether caused by a short circuit or not), a separator with this feature automatically closes the pores and blocks the passage of lithium ions, and the battery no longer reacts. The separator used in lithium-ion power batteries can also be made of polypropylene.

 The separator of the lithium ion power battery can also be directly coated with a slurry of a polyolefin-based material containing a reasonable amount of a pore-forming agent on the surface of the positive electrode sheet after rolling (the immersion method can also be used to immerse the positive electrode sheet in In the above slurry), the positive electrode sheet is put into a specific solvent to extract a pore-forming agent to form a satisfactory separator integrated with the positive electrode sheet.

 The shape of the separator is generally consistent with the shape of the positive and negative electrode sheets. Because all positive

The area of 1 3 is slightly smaller than that of the negative electrode 12, so the positive electrode 1 3 is wrapped with a separator. The separator is usually made into a bag shape 19 or a book shape 19-1 in order to fit or clamp the positive electrode 13. The bag-shaped diaphragm can heat-seal three sides, or only the adjacent two sides; a diaphragm that only heat-seals adjacent two sides is easier to assemble.

The area of the separator is larger than the positive and negative electrodes in both length and width. Except for the ears, the separator 19/1 9-1 must completely surround the positive electrode 1 13 and not expose the edges to prevent short circuit. The material of the lithium ion power battery pole is a metal material with excellent electrical conductivity and thermal conductivity. In addition to a certain strength, it must also have good heat dissipation performance. The pole can be cylindrical or sheet-shaped to facilitate faster heat dissipation by lithium ion power.

 Under different requirements, the poles can be installed on any side surface of the lithium-ion power battery; according to different needs, the positive and negative poles can also be installed on different side surfaces of the lithium-ion power battery. Generally, one positive pole and one negative pole of a lithium-ion power battery can meet the needs. In order to meet the needs of high-power charging and discharging, more poles of a larger-capacity lithium ion power battery can be installed, for example, two positive poles and two negative poles can be installed at the same time. When several poles need to be installed, the number of positive and negative poles can be equal or different. In the case of fast high power charging and discharging, the number of positive and negative poles should be equal; in the case of fast high power charging without high power discharge, the number of negative poles can be equal to or greater than the number of positive poles The number of positive poles; in the case of high power discharge without fast high power charging, the number of positive poles can be equal to or greater than the number of negative poles.

 The diameter of the pole can also be adjusted to meet the above needs. For example, in the case of fast high-power charging and discharging, the diameters of the positive and negative poles should be equal; in the case of fast high-power charging without high-power discharge, the negative pole The diameter of the pole can be equal to or larger than the diameter of the positive pole; in the case of high power discharge without fast high power charging, the diameter of the positive pole can be equal to or larger than the diameter of the negative pole The diameter of the pole.

 Lithium-ion power batteries use multiple electrolytes to accommodate wider temperature changes. Multi-component electrolyte refers to a mixture of two or more solvents and lithium hexafluorophosphate. The lithium-ion power battery uses:

 (1), LIPF 6 (lithium hexafluorophosphate) / EC (ethylene carbonate): DMC (dimethyl carbonate): DEC (diethyl carbonate), the solvent ratio is 0.95 ~ 1.05: 0.95-1.05: 0.95-1.05; Or

 (2), L I P F 6 / E C: E M C (ethyl methyl carbonate): D E C), the solvent ratio is 0.95 ~ 1.05: 0.95 ~ 1.05: 0.95 ~ 1.05; or

(3), LIPF 6 / EC: DMC: EMC, and the solvent ratio is 0.95-1.05: 0.95-1.05: 0.95-1.05; or (4). LIPF 6 / EC: DMC: EMC: DEC. The solvent ratio is 0.95 to 1.05: 0.95 to 1.05: 0.95 to 1.05: 0.95-1.05.

 The lithium-ion power battery case according to the present invention is a part of a lithium-ion power battery, and is also called a battery case. In smaller batteries, the cell case is also one of the positive and negative poles. In this case, the cell case is also referred to as an electrode case. Unless necessary by design, the cell case of high-power lithium-ion power batteries should be avoided as much as possible. The enclosure must be insulated from the pole. However, in special cases, the case can also become an electrode case.

 The square case 9 of a lithium-ion power battery consists of several flat surfaces.

 Lithium-ion power battery cell shells have higher airtightness requirements and higher strength, usually metal shells with a certain rigidity, such as stainless steel cell shells. The cell shell of the lithium-ion power battery of the present invention can be either a metal shell, or made of polytetrafluoroethylene or polypropylene or other suitable plastics, and can be bonded or injection-molded. The safety performance is better than that of metal cells. shell.

 In addition to the case of lithium-ion power batteries, in addition to rigid packaging (such as stainless steel casing), flexible packaging can also be used.

 The upper or side of the shell of the lithium-ion power battery is designed and processed with plug-in ports that are convenient for series and parallel connection, so that the batteries can be connected in series or in parallel to form a battery pack.

 If the heat generated by a lithium-ion power battery under working conditions cannot be dissipated in a timely manner, it will adversely affect the battery's safety and cycle life. Especially when a large number of batteries are arranged in parallel, the heat generated is greater, and the heat dissipation problem is more obvious. Therefore, a horizontal or vertical or crisscross air guide groove can be processed on the rectangular shell, which is beneficial to heat dissipation as soon as possible.

 In order to dissipate heat as quickly as possible, heat sinks (thermal bridges) 9-1 can be designed and processed on or inside the housing.

 The cover of the lithium-ion power battery must match the battery case, and the airtightness is high. The cover of the lithium-ion power battery can also be made of PTFE or polypropylene or any other strong acid-resistant plastic with a certain strength and injection molding.

The safety valve 3 of the lithium-ion power battery is very important. It is a safety device provided to prevent other accidents such as overcharging and short-circuiting. It can instantly remove the pressure exceeding the design. The pressure relief hole at the bottom of the safety valve is also the injection port of the lithium-ion power battery. There are two types of safety valves related to the present invention. One is a spring (compression spring type) as a reset mechanism as shown in Figures 5-1, 5-2, 5-3, 5 -4, 5 -5; the other is an anti-bow spring. (Tablet type) The reset mechanism is shown in Figure 6-1, 6-2, 6-3, 6-4, 6-5, 6-6. They are as follows:

 The structure of the pressure spring safety valve is shown in Figure 5 -1, 5-2. The compression spring (spring) 2 5 is installed in the inner hole of the adjustment bolt 2 3. The inner hole of the adjustment bolt is actually a compression spring, a cage of 'sealed steel ball 2 2', and the compression spring can be longitudinal in the inner hole of the adjustment bolt. It can move up and down without being able to swing laterally. The sealing steel ball can also be moved up and down in the inner hole of the adjustment bolt without being able to swing horizontally. The outer diameter of the adjustment bolt is machined with a thread that matches the safety valve body 21, so the adjustment bolt is installed on the safety valve body, and the height can be adjusted at will through the keyhole 27. The keyhole also serves as an exhaust. When the rotary adjusting bolt applies pressure to the compression spring, the sealing steel ball is fixed by the compression spring. The adjusting bolt is processed with a plurality of vertical exhaust grooves 2 4. The adjusting bolt can be rotated through the exhaust groove to rotate it, and an exhaust hole 2 8 is opened at the lower part of the exhaust groove. The lowest layer is fluoro rubber 圏 26 or other corrosion-resistant aprons. It is pressed or attached to the liquid injection hole on the lid 1 of the lithium ion battery, and the sealed steel ball is trapped under fluoro rubber 圏 26 or other resistant materials. Corroded rubber pad. The pressure relief hole on the bottom of the safety valve is in communication with the injection hole on the cover plate 1, so the pressure relief hole is the injection hole when the liquid is injected.

 In addition, fluororubber or other corrosion-resistant rubber mats must have some elasticity, so that when the steel ball is pressed against the fluororubber or other corrosion-resistant rubber mats, the fluororubbers or other corrosion-resistant rubber mats will deform. The injection hole can be sealed. The compression spring with its bottom inner ring just snaps on the upper part of the sealing steel ball, and the lower part of the sealing steel ball is trapped on the fluoro rubber ring 26 or other corrosion-resistant rubber pad on the battery cover, which restrains the sealing steel ball from slipping. open. When the pressure inside the lithium-ion power battery is less than the set value, the sealed steel ball automatically closes the injection port due to the pressure of the compression spring to keep the inside of the battery isolated from the external environment. When the pressure inside the battery is greater than the set value, it will Automatically lift the sealed steel ball to release pressure, and the gas will be discharged from the pressure release hole 29 in an instant, and escape along the exhaust groove 2 4 along the exhaust hole 28. When the internal pressure is removed, the pressure of the compression spring is sufficient to compress the sealing steel ball again to seal the pressure relief hole.

The structure of the tablet safety valve is shown in Figures 6-1 and 6-2. Half-moon-shaped (reverse bow spring can be processed into a flat shape as required) The reverse bow spring 30 is installed on the lower part of the adjustment bolt 23, and the adjustment bolt is processed with a thread matching the safety valve body 21, so the adjustment bolt is installed on the safety valve body The bottom is pressed tightly on the anti-bow shrapnel. Turn the height adjustment bolt of the keyhole 8 to adjust the tension of the anti-bow spring. The safety valve body is processed with a rectangular exhaust groove 3 1. The anti-bend spring is installed in the rectangular groove and can not be rotated horizontally except that it can spring up and down. The inner diameter of the lower part of the safety valve body is small, forming a cage, and the sealing steel balls 22 can be vertically moved down in the cage. The anti-bow shrapnel is processed with a process assembling hole 3 3, which is crimped on the upper part of the steel ball to fix and seal the steel ball. The lower hole of the sealed steel ball is trapped on the fluorine rubber ring or other corrosion-resistant rubber pad on the cover injection port, which not only fixes the sealed steel ball, but also seals the battery.

 In addition, fluoro rubber 圏 or other corrosion-resistant rubber pads must have a certain elasticity, so that when the steel ball is pressed against the fluoro rubber 圏 or other corrosion-resistant rubber pads, the fluoro rubber 圏 or other corrosion-resistant stock pads will deform. The injection hole can be sealed. The compression spring is pressed against the upper part of the sealed steel ball with the inner inner part of the bottom part, and the lower part of the sealed steel ball is trapped on the fluorine rubber on the battery cover 圏 2 6 or other corrosion-resistant rubber pads to restrain the sealed steel ball from slipping. open. When the pressure inside the lithium-ion power battery is less than the set value, the sealed steel ball automatically closes the injection port due to the pressure of the compression spring to keep the inside of the battery isolated from the external environment. When the pressure inside the battery is greater than the set value, it will Automatically lift the sealed steel ball to release the pressure, and the gas will be immediately discharged from the pressure release hole 2 9 and escape along the exhaust groove 31 from the exhaust hole 3 2 and the key hole 2 7. When the internal pressure is removed, the pressure of the anti-bow spring is sufficient to compress the sealing steel ball again to seal the pressure relief hole.

 The anti-bow shrapnel can be designed and processed into a flat-shaped anti-bow shrapnel. The flat-shaped anti-bow shrapnel works like a half-moon anti-bow shrapnel.

 The pressure of the tablet-type safety valve can also be adjusted by the screws 3 4 as shown in Figure 6-2.

 In order to evacuate more quickly, the safety valve can also be designed with several vent holes 3 5 in the body.

 The pressure relief hole 2 9 on the fluorine rubber 圏 2 6 is the communication hole with the liquid injection hole on the cover plate 1 and also communicates with the pressure relief hole on the bottom of the safety valve, so it is not marked separately.

 The fluoro rubber 圏 26 may be replaced by any other suitable apron.

 The anti-bow shrapnel can be designed and processed into a flat shape or a half-moon shaped anti-bow shrapnel as shown in Figure 6-1. The working principle of the flat-shaped anti-bow shrapnel is the same as that of the half-moon anti-bow shrapnel.

Regardless of the pressure spring-type safety valve or the plate-type safety valve, the sealed steel ball 2 2 can be designed and processed into a ball 2 2-1 with a horizontal transverse groove, and fluoro rubber 2 6- One is clamped in the horizontal groove on the sealed steel ball 2 2-1. When the compression spring or reverse bow spring presses down the sealing steel ball 2 2-1, the fluorine rubber 圏 2 6-1 seals the injection hole. In order to prevent the sealed steel ball 2 2-1 from swinging, a fixed small handle 3 5 can also be processed thereon, and a compression spring or an anti-bow spring is sleeved on the fixed small handle. When the internal pressure is less than the allowable value, the compression spring or reverse bow spring presses the sealing steel ball 2 2-1 and the fluoro rubber 圏, 6-1 tightly seals the injection hole. When the internal pressure is greater than the permissible value and the sealing steel ball 2> 2-1 is jacked up, the fluorine rubber 圏 2 6-1 is lifted upward at the same time, and the internal pressure is quickly removed.

 The sealing steel ball 2 2 can also be designed and processed into a sealing head 2 2-2. Compared with the steel ball 2 2 or 2 2 1 1, the lower part of the sealing frustum protrudes into the injection hole, so the reset is more reliable. The sealing frustum can also be processed with a fixed small handle 3 6, and a compression spring or a reverse bow spring is sleeved on the fixed small handle. When the internal pressure is less than the allowable value, the compression spring or reverse bow spring presses the sealing frustum 2 2-2. The pressure of the fluoro rubber 圏 2 6 deforms in the sealing frustum and tightly seals the injection hole. When the internal pressure is greater than the allowable value, the top sealing cone 2 2-2 is quickly released. The sealing frustum can also be designed and processed into 2 2-3 with a horizontal horizontal groove on it, and the fluoro rubber 圏 2 6-1 is hooped in the horizontal horizontal groove on the sealing frustum 2 2-3. When the compression spring or reverse bow spring presses down the sealing cone 2 2-3, the fluoro rubber ring 2 6-1 seals the injection hole. When the internal pressure is greater than the allowable value and the sealing cone 2 2-3 is lifted up, the fluorine rubber 圏 2 6-1 is lifted upward at the same time, and the internal pressure is quickly removed.

 The sealing steel ball 2 2 or 2 2-1 or the sealing frustum 2 2-2, 2 2-3 can also be designed as a hollow sleeve, and the compression spring is inserted into a hollow sleeve with better guiding performance. in.

 Generally, the safety valve and the pole should be installed on the same side surface of the lithium-ion battery case, but they can also be installed on different side surfaces as required.

 According to different needs, safety valves and poles can be installed on any side surface of the lithium-ion power battery.

 For safety, a large-capacity lithium-ion power battery can be installed with thousands of safety valves on the same side surface or on different side surfaces.

 Mixing ratio and preparation method

In the production process of lithium-ion batteries, the preparation (batch) process and coating process are extremely critical and have the greatest impact on the electrical performance of lithium-ion power batteries. Preparation of slurry. The medium for preparing the slurry includes NMP (N-fluorenyl-2-pyrrolidone) as the medium or water as the medium; the preparation methods include the wet method and the dry method. In the description of the present invention, according to the medium, the NMP medium is described first, and then the water medium is described. In accordance with the preparation method, the wet method is first described (there are also wet methods: sequential preparation method and mixed preparation method), and then the dry method is described. (Positive). It is described below:

 positive electrode. Use NM P as the medium. Materials required: PVDF (polyvinylidene fluoride) 2.5% ~ 3.5%, lithium cobaltate 93% ~ 95%, conductive agent graphite 1% ~ 2% (or acetylene black 0.5% ~ 1%), carbon black 2% ~ 3%. The amount of NM P is limited by the aforementioned substances, especially by the particle size and particle size distribution of lithium cobaltate, so it is about 30% ~ 100% of the total amount of all the aforementioned substances, that is, the solid-liquid ratio = 1 (the solid content of the active substance ) ： 0. 3 ~ 1 (NM P); Under normal circumstances, the best solid-liquid ratio = 1: 0.3 5 to 0.7. P V D F, graphite (or acetylene black), and carbon black all need to be baked in an oven at about 120 ° C for about 2 to 3 hours.

 Sequential preparation method. After adding PVDF to NMP and stirring for about 3 to 4 hours, add conductive agent graphite (or acetylene black), carbon black and stir for about 0.5 to 1 hour, and finally add lithium cobaltate and stir for about 2.5 to 4 hours to become viscous. Pasty.

 Mixed formulation method. Add P V D F to N M P and stir for about 3 to 4 hours. Add conductive agent graphite (or acetylene black), carbon black, and lithium cobaltate and stir for about 2.5 to 4 hours to form a thick paste.

 positive electrode. Use water as the medium. Required materials: C M C (Sodium carboxymethyl cellulose) 0.6 ° /. ~ 0.9%, SBR (styrene-butadiene latex emulsion) actual solid content 2% ~ 4%, conductive agent graphite 1% ~ 2% or acetylene black 0.5% ~ 1%, carbon black 1.5% ~ 3% , Lithium cobaltate 93% ~ 95%. The amount of water (deionized water, distilled water, purified water) is limited by the particle size and particle size distribution of the aforementioned substances, especially lithium cobaltate, so it is about 40% ~ 130% of the total amount of all the aforementioned substances. Liquid ratio-1: 0 · 4 ~ 1 · 3; Under normal circumstances, the best solid-liquid ratio = 1: 0.6 ~ 1. S B R can be replaced with P T F E (polytetrafluoroethylene).

Sequential preparation method. After adding CMC to water and stirring for about 3 to 4 hours, add SBR to it and stir for about 0.5 to 1 hour, then add conductive agent graphite (or acetylene black), carbon black and stir for about 0.5 to 1 hour, and finally add cobalt Lithium acid Mix for about 2.5 to 4 hours to form a thicker paste. Sieve out agglomerates and other impurities.

 Mixed formulation method. First add CMC to water and stir for 3 ~ 4 hours, then add SBR and stir for about 0.5 ~ 1 hour, add conductive agent graphite (or acetylene black), carbon black, lithium cobaltate and stir for about 2.5 ~ 4 hours It becomes a thick viscous slurry, and finally it is sieved to remove agglomerates and other impurities.

 In view of the fact that lithium ion power batteries need to meet their high rate charge and discharge characteristics, the preparation of the positive electrode must be slightly larger than the conductive agent.

 negative electrode. Use N M P as the medium. Materials required: Graphite 93% ~ 95%, PVDF 5% ~ 7%, NM P is about 80% ~ 150% of the total amount of all the aforementioned substances, that is, the solid-liquid ratio = 1: 0.8 to 1 5; The best solid-liquid ratio = 1: 1 ~ 1.3. P V D F should be baked in an oven at a temperature of about 120 ° C for 2 to 3 hours, while graphite needs to be baked at a temperature of 300 ° C to 500 ° C for 4 to 8 hours.

 Sequential preparation method. Add P V D F to N M P and stir for about 3 to 4 hours, then add the graphite that has been sifted through a 3 2 5 mesh sieve and shake it for about 3 to 4 hours to form a thick slurry.

 negative electrode. Use water as the medium. Materials required: Graphite 93% ~ 95%, CMC 0.9% ~ 1.5%, SBR solid content 2% ~ 4%, water (deionized water, distilled water, purified water) approximately all of the foregoing 80%-60% of the total amount of material is the solid-liquid ratio-1: 0.8 ~ 1.6; under normal circumstances, the best solid-liquid ratio = 1: 1 ~ 1.3. C M C needs to be baked at 120 ° C for 2 ~ 3 hours, and graphite needs to be baked at 300 ° C ~ 50 0! : Baking for 4 to 8 hours. S B R can be replaced by P T F E.

 Sequential preparation method. Add CMC to water and stir for about 3 to 4 hours, then add SBR to it and stir for about 0.5 to 1 hour. Finally, add the graphite after baking and sieving through 300 mesh to stir for about 3 to 4 hours. Pasty.

 Dry preparation. Dry preparation of the positive electrode with N M P as the medium. Materials required: Materials required: P V D F 2.5% to 3.5%, lithium cobaltate 93% to 95%, conductive agent graphite 1.5% to 2 ° /. (Or acetylene black 0.8% ~ 1.

2%), carbon black 2% ~ 3%. The amount of NM P is restricted by the particle size and particle size distribution of the foregoing substances, especially lithium cobaltate, so it is about the total amount of all the foregoing substances.

3 0% ~ 1 0 0% means solid-liquid ratio = 1 (solid content): 0.3-1 (NM P), under normal circumstances, the optimal solid-liquid ratio = 1: 0.3 5 to 0.7. PVDF, graphite (or acetylene black), and carbon black need to be baked in an oven at about 120 ° C for 2 to 3 hours.

 First put lithium cobaltate, conductive agent graphite (or acetylene black), carbon black into the mixer and stir for 3 hours; at the same time, stir PVDF and NM P for about 2 hours. After it is completely dissolved (slurry), it will be mixed. The mixed powder after being stirred by the feeder is put into the clear slurry of the stirred PVDF and NM P and continued to be stirred for about 3 hours to form a thick slurry.

 Dry preparation of positive electrode with water as medium. Materials required: CMC 0.6% to 0.9%, SBR actual solid content 2% to 4%, conductive agent graphite 1% to 2% or acetylene black 0.5% to 1%, carbon black 1.5% ~ 3%, lithium cobaltate 93-95%. The amount of water (deionized water, distilled water, purified water) is limited by the particle size and particle size distribution of the aforementioned substances, especially lithium cobaltate, so it is about 40% ~ 130% of the total amount of all the aforementioned substances. Liquid-to-liquid ratio = 1: 0.4 to 1.3; Under normal circumstances, the optimal solid-liquid ratio is 1: 0.6 to 1. S B R can be replaced by P T F E (polytetrafluoroethylene).

 First put lithium cobaltate, conductive agent graphite (or acetylene black), carbon black into the mixer and stir for about 3 hours; at the same time, stir the CMC with water for about 3 hours. After it is completely dissolved, it will become a clear slurry. The mixed powder after the machine is stirred is put into the clear slurry of the stirred CMC and water, and the stirring is continued for about 3 hours to form a thick slurry. Finally, the agglomerates and other impurities are sieved.

 In the preparation of the positive electrode, it is necessary to pay attention to the selection of the conductive agent, and the particle size of the conductive agent must be equal to or smaller than the positive electrode material (lithium cobaltate, lithium manganate, lithium nickel cobaltate). .

In order to ensure the wide range of the prepared slurry, whether the water (deionized water, distilled water, purified water) or NMP is used as the medium during the preparation of the slurry, it must be based on the particle size, particle size distribution, and conductivity of the positive electrode material. The dosage of the agent is calculated carefully, and the medium is added once and cannot be added halfway. As for the negative electrode, the same is true, whether water (deionized water, distilled water, purified water) or NMP is used as the medium, the anode material and The amount of additives is carefully calculated, and the medium should be filled in one time. Do not add it halfway. Otherwise, it is difficult to ensure the quality of the positive electrode slurry or the negative electrode slurry. In addition to the lithium cobaltate, the active material used for the positive electrode of the lithium-ion power battery can also be lithium manganate, lithium nickelate, or lithium nickel cobaltate. The preparation method is basically the same as the foregoing method using lithium cobaltate.

 The particle size of the lithium ion battery positive electrode material (lithium cobaltate, lithium manganate, lithium nickelate, or lithium nickel cobaltate) can be selected in the range of 2 μm to 12 μm, but the optimal particle size should be 5 μ m ~ 8 μ m; The particle size distribution of the cathode material must also be as narrow as possible. Taking 5 μm particle size as an example, too fine (less than 2 μ π) or too thick (more than 12 μm) powder The total is usually not more than 40%.

 Cathode material (lithium cobaltate, lithium manganate, lithium nickelate, or lithium nickel cobaltate) Preparation method of fine powder below 2 μm, coarser powder above 1 μm and 2 μm ~ 1 2 μ The preparation method in the range of m is the same except that the solid-liquid ratio is different.

 The solid-liquid ratio of fine powders below 2 μm should be increased by 20% to 50% based on the original solid-liquid ratio, and the solid-liquid ratio of coarser powders above 12 μm should be based on the original solid-liquid ratio. Up to 10% ~ 30%.

 The anode material graphite is screened by 300 mesh vibration, and the remaining ones on the Internet are usually not suitable for use. The conductive agent involved in the present invention includes graphite, acetylene black, carbon black, etc .; except that graphite is used as a negative electrode material for high-temperature treatment (300 ° C ~ 500 ° C), the rest are dried. The baking material can be placed in a vacuum box for vacuum treatment, without the need for high temperature treatment.

 Production method

 The production process of lithium-ion power battery is as follows: ingredients-→ coating-→ production-→ rolling-→ winding and assembly into the inner body (including casing, sealing)-→ injection-→ chemical formation-→ volume .

 Each process is described below.

 The ingredients process has been described in detail above, and will not be repeated here.

 Coating (also known as drawing pulp). There is no difference between the application of the positive electrode and the application of the negative electrode, so they are not described separately: The stirred positive electrode (or negative electrode) slurry is hook-coated on the metal foil current collector, pulled out by a roller knife, and baked into the oven. After baking, it will become a semi-finished current collecting piece. Care must be taken during coating to avoid scratches, exposed substrates, lightness and weight in the vertical and horizontal directions.

In the coating process, the temperature control is very important: the temperature of the preheating section should not be too high, usually the temperature is selected at 90 ° C or below, and the temperature of the intermediate temperature section is between 1 10 ° C ~ 1 3 0 ° Between C, ± 1 0 ° C, the temperature in the high temperature section is 1 2 0 ° C ~ 1 40 ° C, ± 10 ° C. Under the aforementioned temperature conditions, the temperature of the negative electrode slurry can be slightly higher than the temperature of the positive electrode slurry by about 10 to 15 ° C during coating and baking, and the temperature of the slurry using water as a medium can be higher than that of NMP as a medium. The temperature of the slurry is slightly higher than about 10 ~ 15 ° C.

 After the prepared slurry is coated on the metal foil, both the positive electrode and the negative electrode must enter the drying tunnel of the coating machine (also known as the puller) from the preheating section, and must not be inverted. If the slurry (especially the negative electrode slurry) first enters the high-temperature area of the coater and bakes suddenly at high temperature, the surface is dried quickly, and it is easy to form a dry shell, which is slightly wrinkled, which will form cracked fine lines. The slurry under the dry shell is sugar-smeared and forms a liquid film invisible to the naked eye between the metal foil. The slurry is actually virtually attached to the surface of the metal foil, so it is easy to remove powder and even flakes ( (Ie, large pieces of active material fall off the metal foil), which seriously affects the electrical performance of lithium-ion power batteries. Most of the current coating processes are single-sided coating, and then the other side is coated; however, double-sided coating can also be applied at the same time. The positive and negative electrode sheets to which the present invention is applied may be coated with active materials on both sides of the metal foil, or may be coated with active materials only on one side of the metal foil. During assembly, pole pieces of the same polarity (negative electrode and negative electrode, positive electrode and positive electrode) The back surface (metallic surface without active material coating) can be attached to form a current collector with active materials on both sides. In this case, the thickness of the metal foil used for single-sided coating must be thinner than the thickness of the aforementioned metal foil, which is about 1/2 to 1/3 of the thickness of the aforementioned metal foil.

 Line speed control in the coating process is also important. Under the above temperature conditions, the linear speed can be adjusted within the range of 800mm ~ 5000mm per minute. The best linear speed is 1200mm ~ 35 00mm per minute.

 In addition to coating, which can be used to produce pole pieces of lithium-ion power batteries in the traditional drawing method, high-pressure spraying can also be used. Under a certain pressure of the dry protective gas, the slurry is sprayed evenly on the metal foil from the high-speed nozzle, which not only has better adhesion, but also significantly increases the production capacity.

 Production. Making (soldering) the tabs, if you cut the tabs directly, there is no process of making the tabs. Cutting pole pieces can be completed by shears, slitters or other equipment

Roll. The role of rolling in the production process of lithium-ion power batteries cannot be ignored. Excessive line pressure not only causes pole pieces to deform, but also impedes the penetration of the electrolyte and affects the insertion and extraction of lithium ions. It will eventually affect the high-power charge and discharge performance of the lithium ion power battery. If the line pressure is too small, it will affect the active material. To metal foil Adhesion, affect electrical performance. The more moderate line pressure of the positive electrode is about 100 ~ 180kg / CM, and the negative electrode is about 80 ~ 160kg / CM.

 Generally, the thickness of the positive electrode before rolling is about 170 μ η to 270 μ m, and the thickness of the positive electrode after rolling is about 110 μ ιη to 165 μ ιη; the thickness of the negative electrode before rolling is about 185 μ m to 275 μ m , 110 μ ιη ~ 165 μ ηι after rolling. The optimal thickness of the positive electrode before rolling is 195 μ π ~ 235 μ ηι, and the optimal thickness of the positive electrode after rolling is 135 μ ιη ~ 155 μ m; the optimal thickness of the negative electrode before rolling is 220 μ ιη ~ 250 μ ιη, The optimal thickness after rolling is 135 μ π ~ 155 μ ιη.

 Battery assembly. When assembling, first put the positive electrode sheet into the clip of the bag-shaped separator 19 or the book-shaped separator 19-1, and then arrange the positive electrode tabs in parallel to one end of the inner body 7 and clamp it with a current collector plywood The negative electrode tabs are arranged neatly in parallel to the other end of the inner body, and are also clamped with a current collecting plywood. The positive electrode sheet 1 3 and the negative electrode sheet 12 must be stacked and spaced apart, that is, a negative electrode sheet is stacked, then a positive electrode sheet is stacked, then a negative electrode sheet is stacked, and so on.

 Unless necessary for design, based on economic considerations, both sides of the outermost layer of the inner body are usually negative plates. In other words, in the case of special needs, both sides of the outermost layer of the inner body may also be positive electrode sheets. The positive pole 4 is connected to the positive piece 1 3, and the negative pole 2 is connected to the negative piece 1 2. The assembled inner body must be tightly wrapped with a diaphragm or clamped with a polyethylene or polypropylene frame.

 The inner body of the assembled state is excluded. The thickness of the separator 19 is excluded. The distance between the positive electrode and the negative electrode must not be greater than 25 μm (the maximum gap between the positive electrode and the negative electrode-the thickness of the separator + 2 5 μm).

 It must be noted that the positive electrode pole 4 is connected to the positive electrode sheet 1 3, and the negative electrode pole 2 is connected to the negative electrode sheet 12.

In order to clamp the tabs, whether the integral current collecting splint or the split type current collecting plywood, the surface of the current collecting plywood in contact with the tabs is processed with raised spines. In general, the coverage of the current collector plywood should be larger than the large leaf tab. The method of clamping is also divided into perforated clamps and two-sided clamps. The integrated current collector ply is cut on a solid metal into several wire grooves that can be compressed and can be springed off. The pole ears are inserted into the wire grooves of the current collector ply A or D and fastened with metal bolts 5. The split-type current collecting plywood B or C is connected in series by a plurality of independent metal pieces through a series rod 20, and clamps the tabs respectively and fastens them with metal bolts 5. The integrated current collector plywood can be perforated or double-sided. Similarly, the split current collector plywood can also be perforated or double-sided. From efficiency As far as the effect is concerned, the efficiency and effect of the perforated clip are better than the two-sided clip.

 In order to prevent the bolts connecting the pole ears and poles from loosening, the bolts need to be fixed with curing glue.

 Inject fluid. Before injection, the normal air in the inner cavity of the lithium ion power battery must be drawn out. Except for the moisture in the inner cavity, the inner cavity of the battery must be in a negative pressure state, and then an appropriate amount of electrolyte is injected from the safety valve port. The injection volume of a lithium-ion power battery must be calculated based on its capacity. If the injection volume is too large, it will easily leak and cause the drum shell. If the injection volume is too small, it will easily cause the deterioration of the positive and negative electrode active materials. The injection volume of lithium ion power battery is usually adjusted in the range of 0.1 5 Ah / g ~ 0.6 Ah / g; the optimal injection volume is 0.2 Ah / g ~ 0.3 5 Ah / g between. The environmental control of the injection is very important, so the injection must be completed in the operation box or other environment that can meet the requirements. Because the pressure relief hole of the safety valve communicates with the liquid injection hole on the cover plate, the injection liquid is usually injected from the pressure relief hole of the safety valve; the liquid injection hole can also be processed on the housing or the cover plate separately.

 After the lithium-ion power battery is installed in the inner body and filled with liquid, a certain cavity should still be maintained. In order to reduce the volume or save the shell material, the internal cavity of the lithium-ion power battery must be intentionally filled with solid substances or electrolyte. Depending on the capacity of the lithium-ion power battery, the cavity is about 1% to 10% of the total volume of the internal cavity. The cavity can be filled with a protective gas.

 Into. Formation is the last key to battery production. The formation principle of high-power lithium-ion batteries must be low current and low voltage. High current must never be formed. Higher voltage formation can fully activate the active materials on the positive and negative current collector substrates. The formation process must be completed uninterrupted at one time, and cannot be stopped or stopped at will. The formation curve should be smoothly connected, and the current should be controlled between 0. 0 1 C / 10 hours-→ 0. 2 C / 5 hours-→ 0. 0 5 C / 5 hours-→ 0. 1 C / 4 hours-→ 0.2 C / 1 hour, after the constant current is full, it will be switched to constant pressure to continue charging, so as to ensure sufficient one time.

 Divide. Put batteries with electrical performance indicators that meet the process requirements and batteries with electrical performance indicators that do not meet the process requirements, respectively.

Claims

Body sheet foil 2  Rights request  1. A lithium-ion power battery that can be repeatedly charged and discharged. Each single battery consists of a cover plate (1), a negative pole (2), a safety valve (3), a positive pole (4), and an electrolyte (8). ) And casing (9), the positive pole (4) is connected to the positive pole (1 3), the negative pole (2) is connected to the negative pole (1 2); the positive pole (1 3) is selected from a certain thickness of aluminum foil, The positive electrode active material is evenly coated on both sides. The negative electrode (1 2) is made of copper foil of a certain thickness, and the negative electrode active material is evenly coated on both sides. It is characterized in that the inner body (7) is composed of one or more pairs of positive and negative electrode sheets. The positive electrode (1 3), the negative electrode (1 2), and the separator (19, 19-1) together form an electrode assembly having a multi-layered structure, and the positive and negative electrode sheets are arranged in a regular order; The forms are rectangular pieces with large leaf monopoles or large leaf multipoles, and the current is led to the poles through the current collector splint (6); the positive pole has one or several pole poles, and the negative pole has one or several pole poles. The number of positive and negative poles can be Equal or different, the diameter of the poles can be equal or different; in addition to the shape of the poles, the poles can also be sheet-shaped and mounted on the same or different surfaces of the housing (9); The shape of the negative electrode sheet can be made into other shapes besides the rectangular shape. The positive electrode sheet (1 3) and the negative electrode sheet (1) must be stacked and spaced apart. The inner body (7) can be either a negative electrode or both sides of the outermost layer. It can be a positive electrode sheet; the inner body (7) must be tightly wrapped with a diaphragm or clamped with a polyolefine or polypropylene frame; the positive electrode tabs (1 1) are neatly arranged in parallel with one end of the internal electrode (7), and the negative electrode tabs (1) 0) neatly arranged in parallel to one end of the inner body; the positive electrode (1 3) or negative electrode (1 2) can be separately selected as a mesh metal; the active material of the positive electrode (1 3) can be either lithium cobaltate or lithium manganate , Lithium nickelate or lithium nickel cobaltate; the active material of the negative electrode (1 2) can be either natural graphite, flake graphite, artificial graphite or petroleum coke.  2. The rechargeable lithium-ion power battery according to claim 1, characterized in that: the density of the positive electrode (1 3) active material per square centimeter is 0. 0 2 g to 0. 0 6 g, preferably 0 0 3 2 g ~ 0. 0 4 2 g; the density of the negative electrode (1 2) active material per square centimeter is about 0. 0 1 g ~ 0. 0 3 g, preferably 0. 0 1 4 g ~ 0. 0 2 1 g. 3. The lithium ion power battery capable of being repeatedly charged and discharged according to claim 1, characterized in that: if the large leaf tabs on the positive and negative electrodes are led from the same direction or the same side, the maximum width of the large leaf monopole ears Must not be larger than where the large leaf poles are located The side of that side is half the length; if the large leaf tabs on the positive and negative electrodes are led from the same direction or the same side, the center line position of the large leaf monopoles should be about 1 on the side length of the laminated pole sheet / 4 or 3/4; The large leaf tabs of the positive and negative poles can also be drawn from the side ends of the pole pieces in different directions, and the large leaf tabs drawn from the side ends of the pole pieces in different directions can have a maximum width of It is as long as the side of the large leaf that the pole ears are located on.  4. The lithium ion power battery capable of being repeatedly charged and discharged according to claim 1, characterized in that: in general, the maximum height of the large leaf tab is not larger than its own width, and preferably smaller than its width.  The lithium ion power battery capable of being repeatedly charged and discharged according to claim 1, characterized in that: the shape of the large leaf tabs can be square, rectangular, semi-circular, trapezoidal, or other shapes that are favorable for conducting and dissipating heat. The best shape is a trapezoid with an R angle. The connection between the root of the pole ear and the pole piece can be either a clear angle connection or a smooth arc connection. In addition to the large leaf pole ear, it can be cut directly and can be made separately. After the pole piece is rolled and welded to the pole piece, it is best to use the large leaf pole piece; the big leaf pole piece can be either a raised head type or a hidden head type; the big leaf pole piece can be used on the positive and negative pole pieces. On the long side, it can also be on the short side of the positive and negative plates.  The lithium ion power battery capable of being repeatedly charged and discharged according to claim 1, characterized in that: the integrated current collecting ply has a plurality of wire grooves which can be compressed and can be opened; the split current collecting ply is Several independent metal pieces are connected in series through a series rod (20); whether the integrated current collector plywood or the split current collector plywood, the current collector plywood should cover the tabs, and the surface in contact with the tabs has raised thorns . The lithium ion power battery capable of being repeatedly charged and discharged according to claim 1, characterized in that: the separator is made of polyethylene or polyimide having a microporous structure and a low current cut-off temperature of 15 μm to 80 μm. Acrylic material is made into bag shape (1 9) or book page shape (1 9-1); bag-shaped diaphragm (1 9) can be heat-sealed from three sides, or only two adjacent sides can be heat-sealed; area of diaphragm (1 9) Both the length and the width are larger than the positive and negative electrodes. Except for the ears, the separator (19) must completely shield the positive electrode (1 3) or negative electrode (1 2) from the periphery, and the edges must not be exposed to prevent short circuit. When the discharge requirement is 1 C to 2 C, the optimal thickness of the separator (19) is 2 Ομπι to 4 Ομπι; when the charge and discharge requirements are 3 C or more, the optimal thickness of the separator is 4 Ομηι or more. 8. A safety valve for a lithium ion power battery that can be repeatedly charged and discharged, characterized in that: the compression spring (2 5) is installed in the inner hole of the adjustment bolt (2 3), and the inner hole of the adjustment bolt is used for In order to maintain the stability of the compression spring and the sealing steel ball (2 2), the compression spring (2 5) can slide down vertically in the inner hole of the adjustment bolt, and the sealing steel ball (2 2) can longitudinally move in the inner hole of the adjustment bolt Up and down, the outer diameter of the adjustment bolt is processed with threads that match the safety valve body (2 1); the adjustment bolt is processed with a number of vertical exhaust grooves (2 4). Air holes (2 8); compression springs (2 5) are pressed on the upper part of the steel ball, sealing the steel ball (2 The lower hole of 2) is trapped on the fluorine rubber 圏 (2 6) on the injection port of the cover plate; the pressure relief hole at the bottom of the safety valve is in communication with the injection hole on the cover plate (1); (25) The reverse bow spring (30) can also be replaced. The reverse bow spring (30) is installed on the lower part of the adjustment bolt (23), and the adjustment bolt is processed with the safety valve body (2 1) The matching thread is adjusted by turning the keyhole (2 7) to adjust the tension of the reverse bow spring; a rectangular exhaust groove (3 1) is processed in the safety valve body, and the reverse bow spring (30) can be in the exhaust groove The inner ball springs up and down and cannot be rotated horizontally; the sealed steel ball (2 2) can be moved vertically down in the holder of the safety valve body, and the anti-bow spring (30) is processed with a process assembly hole (3 3), which is buckled in On the upper part of the steel ball, the lower hole of the dense steel ball (2 2) is trapped on the fluoro rubber 圏 (2 6) on the injection port of the cover plate; on the pressure relief hole on the bottom of the safety valve and on the cover plate (1) The injection hole is connected; the safety valve body (2 1) can be separately processed with a vent hole (3 5); sealed steel balls can be processed into spheres with horizontal grooves (2 2- 1), Viton (2 6-1) is hooped in the horizontal horizontal groove on the sealing steel ball (2 2-1); the sealing steel ball (2 2) can be processed into a sealing cone (2 2- 2); The sealing frustum (2 2-3) can process a horizontal horizontal groove, and the fluoro rubber 圏 (2 6-2) is hooped in the horizontal lateral groove on the sealing frustum (2 2-3); safety valve It can be installed on any surface of the casing (9); a large-capacity lithium-ion power battery can install several safety valves on the same side surface or different side surfaces; usually, the safety valve (3) and the pole It can be installed on the same surface of the housing (9) or on different surfaces.  A method for manufacturing a lithium-ion power battery capable of being repeatedly charged and discharged, comprising the following steps: (1) Ingredients, including the following methods: A. The sequential preparation method is used to prepare the positive electrode slurry with NM P as the medium. The required materials are: PVDF (polyvinylidene fluoride) 2.5% to 3.5%, lithium cobaltate 93% to 95% 1, graphite conductive agent 1% ~ 2% or acetylene black 0.5% ~ 1%, carbon black 2% ~ 3%; the amount of NMP is limited by the particle size and particle size distribution of lithium cobaltate, usually solid-liquid Ratio = 1 (solid content): 0.3-1 (NM P); optimal solid-liquid ratio = 1: 0.3 to 0.5; PVDF, graphite (or acetylene black), and carbon black all need to be in Bake in an oven at about 120 ° C for about 2 to 3 hours; add PVDF to NMP and stir for about 3 to 4 hours, then add conductive agent graphite (or acetylene black), carbon black and stir for about 0.5 to 1 hour, and finally Add lithium cobaltate and stir for about 2.5 to 4 hours to form a thick slurry;  A-2. The positive electrode slurry with water as a medium is prepared by a sequential preparation method, and the required materials are: C M C 0.6 °. ~ 0.9%, S B R actual solid content 2% ~ 4 ° /. 、 Conductive agent graphite 1% ~ 2% or acetylene black 0.5% ~ 1%, carbon black 1.5% ~ 3%, lithium cobaltate 93% ~ 95%; water (deionized water, distilled water, pure The amount of water) is 40% ~ 130% of the total amount of all the aforementioned substances, that is, the solid-liquid ratio-1: 0. 4 ~ 1.3; usually, the best solid-liquid ratio = 1: 0.6 ~ 1; SBR can be replaced by PTFE; CMC is added to water and stirred for about 3 to 4 hours, then SBR is added to it and stirred for about 0.5 to 1 hour, and then conductive agent graphite (or acetylene black) and carbon black are added and stirred for about 0 · 5 to 1 hour, finally add lithium cobaltate and stir for about 2.5 to 4 hours to form a thicker slurry, sieve out agglomerates and other impurities; A-3. Dry preparation of positive electrode slurry with NMP as the medium, the required materials are: PVDF 2.5% ~ 3.5%, lithium cobaltate 93% ~ 95%, conductive agent graphite 1.5 % ~ 2% (or acetylene black 0.8% ~ 1.2%), carbon black 2% ~ 3%, the amount of NM P is restricted by the particle size and particle size distribution of lithium cobaltate, which is the total amount of all the aforementioned substances 35% ~ 90% of the solid-liquid ratio = 1 (solid content): 0.3 ~ 1, the best solid-liquid ratio-1: 0 · 3 5 ~ 0.7; PVDF, graphite (or acetylene black) ), Carbon black should be baked in an oven at about 120 ° C for 2 to 3 hours; put lithium cobaltate, conductive agent graphite (or acetylene black), carbon black into the mixer and stir for 3 hours; at the same time PVDF and NM P are stirred for about 2 hours. After it is completely dissolved (slurry), put the mixed powder after mixing by the mixer into the stirred slurry of PVDF and NM P and continue to stir for about 3 hours to become thick. Pasty A-4. Dry preparation of the positive electrode slurry with water as the medium, the required materials are: CMC 0.6% ~ 0.9%, SBR actual solid content 2% ~ 4%, conductive agent graphite 1% ~ 2 % Or acetylene black 0.5% ~ 1%, carbon black 1. 5% ~ 3%, lithium cobaltate 93% ~ 95%; the amount of water (deionized water, distilled water, purified water) is 40% ~ 130% of the total amount of all the aforementioned substances, that is, the solid-liquid ratio = 1: 0. 4 ~ 1.3; Under normal circumstances, the best solid-liquid ratio = 1: 0. 6-0. 1; Put lithium cobaltate, conductive agent graphite (or acetylene black), carbon black into the mixer and stir for about 3 hours; at the same time, stir CMC with water for about 3 hours, wait for it to be completely After dissolving, it becomes a clear slurry. That is, the mixed powder mixed by the mixer is placed in the clear slurry of the stirred CMC and water and stirred for about 3 hours to form a thick slurry. Finally, the agglomerates and other impurities are sieved out;  B. Preparation of the negative electrode slurry with NM P as the medium, the required materials are: graphite 93% ~ 95%, PVDF 5% ~ 7%, NMP is 80%-150% of the total amount of all the foregoing substances That is, the solid-liquid ratio = 1: 0.8 to 1. 5; The best solid-liquid ratio = 1: 1 ~ 1.3; P V D F, need to be at about 1 Bake in an oven at 20 ° C for 2 to 3 hours. Graphite needs to be baked at 300 ° C to 500 ° C for 4 to 8 hours. The anode material is screened by 3 2 5 mesh vibration. It is generally not suitable to use; add PVDF to NM P and stir for about 3 to 4 hours, and then add spare graphite that has been screened through a 3 2 5 mesh screen and stir for about 3-hour into a thick paste;  B-1. To prepare the negative electrode slurry with water as the medium, the required materials are: graphite 93% ~ 95%, CMC 0.8% ~ 1.5%, SBR solid content 2% ~ 4%, water ( Deionized water, distilled water, purified water) is 80%-160% of the total amount of all the aforementioned substances, that is, the solid-liquid ratio = 1: 0.8 to 1.6; the optimal solid-liquid ratio = 1 to 1 to 1.3; CMC should be baked at 120 ° C for 2 ~ 3 hours, graphite should be baked at 300 ° C ~ 500 ° C for 4 ~ 8 hours; S B R can be replaced by P T F E; the anode material is screened by 300 mesh vibration, the remaining ones on the Internet are generally not suitable for use; add CM C to water and stir for about After 3 ~ 4 hours, add S B R (or P T F E) to it and stir for about 0. 5 to 1 hour. Finally, add graphite after baking and sieve through 3 2 5 mesh. Stir for about 3-4 hours to form a thick paste. The particle size of the positive electrode material can be selected in the range of 2 μm to 12 μm, and the optimal particle size should be 5 μm to 8 μm; the particle size distribution of the positive electrode material is too fine or too coarse The sum of the powders usually does not exceed 40%; for fine powders below 2 μm, the solid-liquid ratio should be increased by 20 ° / based on the original solid-liquid ratio. ~ 50%, the solid-liquid ratio of coarser powders larger than 12 μm should be reduced by 10% to 30% based on the original solid-liquid ratio; in the preparation of the positive electrode, the particle size of the conductive material used must be equal to Or smaller than the particle size of the positive electrode material; (2) Coating: Coat the stirred positive or negative electrode slurry onto the metal foil current collector, pull it out through a roller knife into the oven and bake it. After baking, it becomes a semi-finished current collector sheet; The cloth must be careful not to have scratches, exposed substrates, lightness and weight in the vertical and horizontal directions; whether it is the positive or negative electrode, the prepared slurry must enter the coating machine from the preheating section after coating on the metal foil. The drying tunnel must not be inverted; the temperature of the preheating zone is usually 90 ° C or below, and the temperature of the medium temperature zone is 1 1 0. C ~ 1 3 0 ° C, ± 10 ° C, the temperature in the high-temperature section is 1 1 0 ° C ~ 1 40. Between C, ± 10 ° C; under the aforementioned temperature conditions, the temperature of the negative electrode slurry can be slightly higher than the temperature of the positive electrode slurry by 10 ° C ~ 15 ° C during coating and baking, using water as a medium The temperature of the slurry can be slightly higher than the temperature of the slurry with NM P as the medium. The temperature of the coating can be adjusted within the range of 8 0 mm to 5 0 0 mm per minute. The best linear speed is 1 200 mm-3 5 0 mm per minute; the density of the active material of the coated positive electrode (1 3) per square centimeter is 0.0 2 ₈ ~ 0.06 ₈ , most The best density per square centimeter is 0, 0 3 2 g ~ 0. 0 4 2 g; the density of the active material of the negative electrode (1 2) after coating is about 0. 0 1 g ~ 0. 0 3 g , Optimum density per square centimeter is 0. 0 1 4 g to 0. 0 2 1 g; both can be coated on one side, can be coated on both sides at the same time; the active material is coated on one side. The back of the pole pieces are pasted to form a current collector with active materials on both sides; the thickness of the metal foil used for single-sided coating must be thinner than the thickness of the aforementioned metal foil;  (3) Production: the positive electrode (1 3) is cut into a rectangular piece with large leaf monopole or large leaf multipole and scrapes off the slurry at the pole (1 1); the negative electrode (1 2) 0); the best aspect ratio of the positive and negative electrode sheet is 6.2: 3.8 or 6: 4; the shape of the positive and negative electrode sheet can be made into a circle or other shapes besides rectangular shape. Shape; in addition to cutting, the pole pieces can be directly processed by rolling or shear punching; large leaf ears can also be made separately and welded to the positive and negative poles after being rolled On the pole piece; the maximum width of the large leaf pole ear is smaller than the pole ear The half of the long side (1/2) of the large leaf pole ears drawn from the two ends of the pole piece or in different directions can have a maximum width equal to the side of the pole ear; the maximum height of the large leaf pole ears Not more than its own width, preferably less than its width; The minimum width should not be less than its height; In special needs, the minimum width of the large leaf tabs can be less than its height; If the tabs on the positive and negative electrodes are drawn from the same direction, the The centerline position of the leaf monopole should be about 1/4 or 3/4 on the side length of the laminated pole piece; the inner edge line of the large leaf monopole should be close to the center line of the pole piece; The ears can be either raised or hidden heads. The raised or hidden large leaf pole ears can be on either the long side or the short side of the rectangular plate. Under normal circumstances, the horizontal type should be used as much as possible. Generally, the width of the large leaf tabs on the positive and negative plates is the same width; but under special requirements, the width of the large leaf tabs on the positive and negative plates can also be unequal. In the case of fast high-power charging without high-power discharge, the negative The width of the large leaf tab of the pole can be greater than the width of the large leaf tab of the positive pole. In the case of high power discharge without fast high power charging, the width of the large leaf tab of the positive pole can be larger than that of the negative pole. Wide leaf monopole ears for the positive electrode and large leaf monopole ears for the negative electrode; large leaf multipole ears for the negative electrode; large leaf multipole ears for the negative electrode; when high-speed charging is required, high-power charging is not required. In the case of a large-leaf multipole ear for the negative electrode, and a large-leaf monopole ear for the positive electrode; in the case of high-power discharge without fast high-power charging, the large-leaf multipole ear can be used for the positive electrode, and the negative electrode can be Large-leaf monopole ears can be used; the shape of the large-leaf pole ears can be square, rectangular, semi-circular, trapezoidal, or other shapes that facilitate flow and heat dissipation. The best shape of the ear ears is a trapezoid with R rounded corners. Tabs; the connection between the root of the large leaf tab and the pole piece can be a clear angle connection or a smooth arc connection; the large leaf tab can be processed into a raised head (1 0/1 1), or Hidetou (17/18); () Rolling: In the rolling process, the linear pressure of the positive electrode is 100 ~ 180 kg / CM, the linear pressure of the negative electrode is 80 ~ 160 kg / CM; the positive electrode (1 3) before rolling The thickness is about 170 μ m to 2 70 μ m, and the thickness after rolling is about 110 μ μm to 1 6 5 μ m. The optimal thickness before the positive electrode rolling is 195 μ m ~ 2 3 5 μ m, the optimal thickness after rolling is 1 3 5 μ m to 1 5 5 μ m; the thickness of the negative electrode (1 2) before rolling is about 1 8 5 μ m to 2 7 5 μ m, After rolling 1 110 μm ~ 16 5 μm, Optimum thickness before negative electrode rolling 2 2 0 μ m ~ 2 5 0 μ m, the optimal thickness after rolling is 1 3 5 μ m ~ 1 5 5 μ m;  (5) Assembly: Usually only one positive pole and one negative pole are assembled on the casing (9); a large-capacity lithium ion power battery can be installed with several pole posts, and the number of positive and negative poles may be equal or different. In the case of fast high-power charging and discharging, the number of positive and negative poles should be equal; In the case of fast high-power charging without high-power discharge, the number of negative poles can be equal to the number of positive poles or Greater than the number of positive poles; in the case of high power discharge without fast high power charging, the number of positive poles can be equal to or greater than the number of negative poles; the diameter of the poles can also be adjusted To meet the above requirements, the diameter of the positive and negative poles should be equal when fast high-power charging and discharging are required. In the case of fast high-power charging without high-power discharging, the diameter of the negative pole can be the same as that of the positive pole The diameter is equal to or greater than the diameter of the positive pole; when high power discharge is required without fast high power charging , The diameter of the positive pole may be equal to or greater than the diameter of the negative pole and the negative pole diameter;  The diaphragm (1 9) is made of a polyethylene or polypropylene material with a microporous structure and a low current cut-off temperature of 15 μ m to 80 μ m. The bag shape (1 9) or book shape (1 9- 1), so that the positive electrode (1 3) can be installed or clamped, and the bag-shaped separator (1 9) can be heat-sealed from three sides, or only the adjacent two sides can be heat-sealed, so as to load or clamp the positive electrode sheet 13 . When the charge and discharge requirements are 1 C to 2 C, the optimal thickness of the separator (19 or 19-1) is 20 μm to 40 μm; when the charge and discharge requirements are 3 C or more, the optimal thickness of the separator 40 μ ιη or more; except for the ears, the separator (1 9) must have the positive electrode (1 3) or the negative electrode (1 2) completely shield the surroundings, and do not expose the edges to prevent short circuits; the immersed positive electrode (1 3) can be immersed in a slurry of a polyolefin-based material containing a reasonable amount of pore-forming agent, and then The positive electrode (1 3) is put into a specific solvent to extract a pore-forming agent to form a separator integrated with the positive electrode sheet; a slurry of a polyolefin-based material containing a reasonable amount of a pore-forming agent may also be directly coated after the rolling Positive (1 3) on the surface, and then put the positive electrode (1 3) into a specific solvent to extract the pore-forming agent to form a separator (1 9) integrated with the positive electrode sheet; When assembling, the positive electrode sheet should first be put into the clip of a bag-shaped separator (1 9) or a book-shaped separator (1 9-1), and the positive electrode sheet (1 3) and the negative electrode sheet (1 2) It must be stacked at intervals, that is, a negative electrode sheet and a positive electrode sheet, and then a negative electrode sheet, and so on; and then the positive electrode tabs must be arranged in parallel to one end of the inner body 7, It is clamped with a current collector plywood, and the negative electrode tabs are neatly arranged in parallel to the other end of the inner body. It is also clamped with a current collector plywood; the inner body (7) must be tightly wrapped with a diaphragm or clamped with a polyethylene or polypropylene frame; assembly A good inner body (7), excluding the thickness of the separator (1 9), and the gap distance between the positive electrode (1 3) and the negative electrode (1 2) should not be greater than 2 5 μm;  (6) Liquid injection: Before the liquid injection, the normal air in the inner cavity of the lithium ion power battery must be extracted, and then an appropriate amount of electrolyte is injected from the liquid injection hole in the safety valve (3); the liquid injection amount is usually 0.1. 5 Ah / g ~ 0.6 Ah / g adjustment; the best injection volume is 0.2 Ah / g ~ 0.3 5 Ah / g; using a multi-electrolyte that can adapt to wider temperature changes: LIPF 6 / EC: DMC: DEC, with a solvent ratio of 0.9 5 to 1. 0 5: 0.9 5 to 1. 0 5: 0.9 5-1. 1.0 5; or LIPF 6 / EC: EMC: DEC, the solvent ratio is 0.9 5 to 1. 0 5: 0.9 5 to 1. 0 5: 0.9 5 to 1. 0 5; or LIPF 6 / EC: DMC: EMC, the solvent ratio is 0. 9 5-1. 0 5: 0. 9 5-1. 0 5: 0. 9 5-1. 0 5; or LIPF 6 / EC: DMC: EMC: DEC with a solvent ratio of 0.9 5-1. 0 5: 0. 9 5-1. 0 5: 0. 9 5-1. 0 5: 0. 9 5-1. 0 5;  (7) Formation: The formation principle must be low current and low voltage, and no large current can be formed. Higher voltage formation can fully activate the active material on the positive and negative current collector substrates. The formation process must be completed without interruption at one time. Do not stop or stop arbitrarily in the middle, the formation curve should be smoothly connected, and the current should be controlled at 0. 0 1 C / 10 hours — → 0. 0 2 C / 5 hours-→ 0. 0 5 C / 5 hours a → 0. 1 C / 4 hours-→ 0.2 C / 1 hour, after the constant current is full, it will be converted to constant pressure to continue charging, so as to ensure sufficient one time;  (8) Capacity division: Put batteries with electrical performance indicators that meet process requirements and batteries with electrical performance indicators that do not meet process requirements, respectively.