Soft package cylindrical battery

Abstract

The invention discloses a soft package cylindrical battery which comprises a cylindrical roll core, electrolyte and a cylindrical soft package shell, the roll core comprises a positive plate, a negative plate and a diaphragm arranged between the positive plate and the negative plate, and the positive plate, the diaphragm and the negative plate are sequentially stacked and wound to form the roll core; the roll core and the electrolyte are jointly sealed in the soft package shell; the cylindrical roll core comprises a first end part and a second end part which are oppositely arranged, the first end part is connected with a positive pole lug, and the second end part is connected with a negative pole lug; the positive pole lug extends outwards from the first end part and penetrates out of the soft package shell, and the negative pole lug extends outwards from the second end part and penetrates out of the soft package shell. Through reasonable packaging design and structural optimization, the safety performance of the battery can be effectively improved, the risks of thermal runaway and explosion are reduced, the energy density of the battery can be remarkably improved, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary batteries, and in particular relates to a soft-pack cylindrical battery. Background Art

[0002] With the rapid development of portable electronic devices, lithium-ion batteries have become the mainstream choice in various application fields due to their high energy density, long cycle life and environmental friendliness. Among the many forms of lithium-ion batteries, cylindrical batteries are widely favored due to their simple structure, low manufacturing cost and high energy density. For example, the 21700 cylindrical battery has been widely used in laptops and power tools due to its excellent performance and moderate size.

[0003] However, existing cylindrical batteries, such as Figure 1 As shown, the outer shell generally adopts a steel shell structure, and there are some problems that need to be solved urgently. First of all, there are certain safety hazards in the use of steel shell cylindrical batteries, especially for product applications that need to be carried around. This is mainly because the gas generated by the steel shell battery during the formation process will be trapped inside the battery, resulting in a large internal pressure in the battery. At the same time, the shell of the steel shell cylindrical battery generally adopts a thicker steel shell material. Once thermal runaway occurs, the battery may explode, causing serious safety hazards and lethality. Secondly, there are some shortcomings in the structural design of the steel shell cylindrical battery. Since there is a gap of about 3mm between the positive electrode of the pole ear welding and the winding core, the internal space utilization rate of the battery is low, which limits the further improvement of the battery energy density. In addition, the density of the steel shell material itself is relatively high, which also increases the overall weight of the battery to a certain extent and reduces the battery energy density.

[0004] In view of this, it is indeed necessary to provide a technical solution to the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a soft-pack cylindrical battery with good safety and high energy density in view of the shortcomings of the prior art. Through reasonable packaging design and internal structure optimization, not only the safety performance of the battery can be effectively improved and the risk of thermal runaway and explosion can be reduced, but also the energy density of the battery can be significantly improved and the service life of the battery can be extended.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A soft-pack cylindrical battery, comprising a cylindrical winding core, an electrolyte and a cylindrical soft-pack shell, wherein the winding core comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and wound to form the winding core, and the winding core and the electrolyte are sealed together inside the soft-pack shell;

[0008] The cylindrical winding core includes a first end and a second end that are arranged opposite to each other, the first end is connected to a positive electrode tab, and the second end is connected to a negative electrode tab; the positive electrode tab extends outward from the first end and passes through the soft package shell, and the negative electrode tab extends outward from the second end and passes through the soft package shell.

[0009] Preferably, the soft package shell is an aluminum-plastic film, and the thickness of the aluminum-plastic film is 0.05-0.15 mm.

[0010] Preferably, the soft package shell includes a first shell and a second shell, the first shell is heat-sealed and connected to the second shell, both ends of the first shell and the second shell are respectively provided with first sealed edges that fit each other, and the first sealed edge is bent along the radial direction of the soft package shell to form a flat folded edge, and the corners of the flat folded edge are horizontally bent along the end plane of the soft package shell to form a corner bending portion; the two side edges of the first shell and the second shell are respectively provided with second sealed edges that fit each other, and the second sealed edge is bent along the circumference of the soft package shell to form an arc folded edge.

[0011] Preferably, the positive electrode tab extends outward from the first end portion and passes through the soft-pack shell along the first sealed edge, and the portion of the positive electrode tab passing through the soft-pack shell is bent in the opposite direction along the edge of the flat folded edge to form a first bending section, and a first protective paper is arranged between the first bending section and an end plane of the soft-pack shell, and the first protective paper covers the corner bending portion; the thickness of the first protective paper is 0.1 to 0.5 mm.

[0012] Preferably, the negative electrode tab extends outward from the second end and passes through the soft-pack shell along the first sealed edge, and the part of the negative electrode tab passing through the soft-pack shell is reversely bent along the edge of the flat folded edge to form a second bending section, and a second protective paper is arranged between the second bending section and the other end plane of the soft-pack shell, and the second protective paper covers the corner bending portion; the thickness of the second protective paper is 0.1 to 0.5 mm.

[0013] Preferably, fixing tapes for fixing the first bending section and the second bending section are respectively provided at the two ends of the soft package shell, the fixing tapes respectively cover the bending surface of the first bending section and the bending surface of the second bending section, and the two ends of the fixing tapes are respectively fixed to the circumferential side walls of the soft package shell;

[0014] The outer surface of the soft package shell is tightly covered with a heat shrink film, and the heat shrink film is tightly pressed against the two ends of the fixing tape.

[0015] Preferably, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector; a first empty foil area is arranged in the middle position of the positive electrode sheet, and the positive electrode tab is arranged in the first empty foil area; the middle position of the positive electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the positive electrode sheet.

[0016] Preferably, the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector; a second empty foil area is arranged in the middle position of the negative electrode sheet, and the negative electrode tab is arranged in the second empty foil area; the middle position of the negative electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the negative electrode sheet.

[0017] Preferably, the positive electrode tab comprises a first section and a second section, the first section is located in the first empty foil area, and the second section is located outside the first empty foil area;

[0018] The first empty foil area is covered with a first heat-resistant insulating adhesive tape and a second heat-resistant insulating adhesive tape, and the heat-resistant temperature of the first heat-resistant insulating adhesive tape and the second heat-resistant insulating adhesive tape is ≥130°C;

[0019] Along the Y direction, the first heat-resistant insulating tape exceeds the edge of the positive electrode current collector by 0-2.5 mm and completely covers the surface of the first section of the positive electrode tab;

[0020] The second heat-resistant insulating tape completely covers the surface of the first section of the positive electrode tab, and partially covers the surface of the second section of the positive electrode tab;

[0021] Along the X direction, the second heat-resistant insulating tape exceeds the edge of the positive electrode tab by 0-2.5 mm.

[0022] Preferably, the negative electrode tab comprises a third section and a fourth section, the third section is located in the second empty foil area, and the fourth section is located outside the second empty foil area;

[0023] The second empty foil area is covered with a third heat-resistant insulating adhesive tape and a fourth heat-resistant insulating adhesive tape, and the heat-resistant temperature of the third heat-resistant insulating adhesive tape and the fourth heat-resistant insulating adhesive tape is ≥130°C;

[0024] Along the Y direction, the third heat-resistant insulating tape exceeds the edge of the negative electrode current collector by 0-2.5 mm and completely covers the surface of the third section of the negative electrode tab;

[0025] The fourth heat-resistant insulating tape completely covers the surface of the third section of the negative electrode tab, and partially covers the surface of the fourth section of the negative electrode tab;

[0026] Along the X direction, the fourth heat-resistant insulating tape exceeds the edge of the negative electrode tab by 0-2.5 mm.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] 1) The present invention adopts a soft-pack structure to improve the safety performance of the battery. A cylindrical soft-pack shell is used to replace the traditional steel shell structure, and the soft-pack shell is usually made of aluminum-plastic film. Aluminum-plastic film is a thin film material composed of aluminum foil and polymer materials, which has good barrier properties, mechanical strength and flexibility. Compared with the steel shell, the aluminum-plastic film is thinner, but it can still provide sufficient mechanical strength to protect the internal battery core. And the thinner aluminum-plastic film shell can effectively reduce the internal pressure of the battery and reduce the risk of explosion during thermal runaway. In addition, the gas generated by the soft-pack cylindrical battery of the present invention during the formation process will be extracted through the second sealing process, so that the inside of the battery is in a state of near vacuum. This not only further reduces the internal pressure of the battery, but also when the battery has thermal runaway, the vacuum environment can effectively suppress the rapid rise of the internal temperature of the battery, delaying the occurrence and propagation of thermal runaway. Even in extreme cases where the battery has thermal runaway, the soft-pack shell can release the internal pressure by expansion and deformation to avoid battery explosion, greatly improving the safety of the battery.

[0029] 2) The present invention improves the energy density of the battery by optimizing the structural design. Traditional steel shell cylindrical batteries need to reserve a certain gap at the pole ear welding point, and this part of the space cannot be effectively utilized, resulting in a decrease in the internal space utilization of the battery. The present invention utilizes the characteristics of the soft-pack structure, and there is no need to reserve too much pole ear welding gap, and the winding core can fully fill the internal space of the soft-pack shell. At the same time, the positive pole ear and the negative pole ear are respectively led out from the two ends of the winding core and pass through the soft-pack shell, reducing the space occupied by the pole ear. This internal structure design can significantly improve the space utilization of the battery, thereby improving the energy density of the battery. In addition, the density of the aluminum-plastic film is much lower than that of the steel shell, and the use of the aluminum-plastic film as the soft-pack shell can effectively reduce the overall weight of the battery. At the same mass, the soft-pack cylindrical battery can accommodate more active materials and further improve the energy density. Combining the advantages of space utilization and lightweight shell, the soft-pack cylindrical battery of the present invention can achieve a significant increase in energy density.

[0030] 3) The present invention can extend the service life of the battery. The aluminum-plastic film soft-pack shell has excellent barrier properties, which can effectively prevent the intrusion of external moisture and oxygen, reduce the decomposition and volatilization of the electrolyte, and inhibit the side reactions of the battery materials, thereby delaying the attenuation of battery performance and extending the service life of the battery. In addition, the good flexibility of the soft-pack shell can effectively buffer external vibrations and impacts, prevent damage to the battery core, and improve the reliability of the battery. At the same time, the internal pressure of the soft-pack cylindrical battery is smaller, which reduces the impact of the volume change of the electrode material on the battery core structure, is conducive to maintaining the stability of the electrode structure, and further extends the cycle life of the battery.

[0031] 4) The present invention can simplify the production process and reduce manufacturing costs. Compared with steel shell cylindrical batteries, the production process of soft-pack cylindrical batteries is simpler. Steel shell batteries need to go through complex processing processes such as stretching, grooving, and welding, while the outer shell of the soft-pack battery can directly adopt aluminum-plastic film and complete the packaging through a sealing process. During the formation process, the soft-pack battery can also be easily evacuated, which simplifies the process flow. This simplified production process can improve production efficiency and reduce equipment and labor costs. In addition, the price of aluminum-plastic film is relatively low, and the use of aluminum-plastic film instead of steel shell can effectively reduce the production cost of the battery. Combining the advantages of production process and manufacturing cost, the soft-pack cylindrical battery of the present invention can achieve a significant reduction in manufacturing cost and enhance the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a steel shell cylindrical battery in the prior art;

[0033] Figure 2 This is a schematic structural diagram of a soft-pack cylindrical battery according to an embodiment of the present invention;

[0034] Figure 3 This is a structural exploded view of a soft-pack cylindrical battery according to an embodiment of the present invention;

[0035] Figure 4 A schematic structural diagram of a soft-pack cylindrical battery according to another embodiment of the present invention;

[0036] Figure 5 A schematic structural diagram of a soft-pack cylindrical battery according to another embodiment of the present invention;

[0037] Figure 6 This is a structural exploded view of a soft-pack cylindrical battery according to another embodiment of the present invention;

[0038] Figure 7 A schematic diagram of the structure of a soft-pack cylindrical battery according to another embodiment of the present invention;

[0039] Figure 8 This is a structural exploded view of a soft-pack cylindrical battery according to another embodiment of the present invention;

[0040] Fig. 9 A schematic structural diagram of a positive electrode sheet of a soft-pack cylindrical battery according to an embodiment of the present invention;

[0041] Fig.10 The figure is a schematic structural diagram of the negative electrode sheet of a soft-pack cylindrical battery according to an embodiment of the present invention.

[0042] In the figure: 1. winding core; 11. positive electrode tab; 12. negative electrode tab; 13. first tab glue; 14. second tab glue; 2. soft package shell; 21. first shell; 22. second shell; 23. first edge seal; 24. second edge seal; 25. corner bending part; 3. first protective paper; 4. second protective paper; 5. fixing tape; 6. heat shrink film; 10. positive electrode collector; 101. positive electrode active material layer; 102. first empty foil area; 103. first heat-resistant insulating tape; 104. second heat-resistant insulating tape; 20. negative electrode collector; 201. negative electrode active material layer; 202. second empty foil area; 203. third heat-resistant insulating tape; 204. fourth heat-resistant insulating tape. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of this application, unless otherwise clearly specified and limited, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more; unless otherwise specified or explained, the terms "connected", "fixed", etc. should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0045] Please see attached Figures 2-3 The present application provides a soft-pack cylindrical battery, comprising a cylindrical winding core 1, an electrolyte and a cylindrical soft-pack shell 2, wherein the winding core 1 comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and wound to form the winding core 1, and the winding core 1 and the electrolyte are sealed together inside the soft-pack shell 2;

[0046] The cylindrical winding core 1 includes a first end and a second end that are arranged opposite to each other, the first end is connected to a positive electrode tab 11, and the second end is connected to a negative electrode tab 12; the positive electrode tab 11 extends outward from the first end and passes through the soft package shell 2, and the negative electrode tab 12 extends outward from the second end and passes through the soft package shell 2.

[0047] Among them, the soft-pack cylindrical battery of this application has the following advantages:

[0048] 1) Compared with the traditional steel shell structure, the cylindrical battery of the present application adopts a soft-pack structure, and the thinner aluminum-plastic film shell can effectively reduce the internal pressure of the battery and reduce the risk of explosion during thermal runaway. In addition, the gas generated by the soft-pack cylindrical battery during the formation process will be extracted through the second sealing process, so that the interior of the battery is in a state of near vacuum, further reducing the internal pressure of the battery. When the battery has thermal runaway, the vacuum environment can effectively suppress the rapid rise in the internal temperature of the battery and delay the occurrence and spread of thermal runaway. The soft-pack shell 2 can also release internal pressure by expansion and deformation, avoiding violent explosions, greatly improving the safety of the battery.

[0049] 2) The soft-pack cylindrical battery of the present application does not need to reserve too much gap at the welding point of the pole ear, and the winding core 1 can fully fill the internal space of the soft-pack shell 2. This internal structure design significantly improves the space utilization of the battery, accommodates more active materials under the same volume, and greatly improves the energy density of the battery. In addition, the density of aluminum-plastic film is much lower than that of steel shell. Using aluminum-plastic film as the soft-pack shell 2 can effectively reduce the overall weight of the battery. Under the same mass, the soft-pack cylindrical battery can accommodate more active materials, further improving the battery energy density.

[0050] In one embodiment of the present application, the soft-pack shell 2 is an aluminum-plastic film, and the thickness of the aluminum-plastic film is 0.05 to 0.15 mm. The aluminum-plastic film is used as the material of the soft-pack shell 2, and the thickness of the aluminum-plastic film is controlled within the range of 0.05 to 0.15 mm, which is much smaller than the shell thickness of the traditional steel-shell cylindrical battery. The thinner aluminum-plastic film shell can effectively reduce the internal pressure of the battery and reduce the risk of explosion during thermal runaway.

[0051] In one embodiment according to the present application, Figures 3-4As shown, the soft-pack shell 2 includes a first shell 21 and a second shell 22, the first shell 21 and the second shell 22 are heat-sealed and connected, and the first shell 21 and the second shell 22 are respectively provided with first sealing edges 23 that fit each other, and the first sealing edges 23 are bent along the radial direction of the soft-pack shell 2 to form a flat folded edge, and the corners of the flat folded edge are horizontally bent along the end plane of the soft-pack shell 2 to form a corner bending portion 25; the edges of the first shell 21 and the second shell 22 are respectively provided with second sealing edges 24 that fit each other, and the second sealing edges 24 are bent along the circumference of the soft-pack shell 2 to form an arc folded edge. Among them, the first sealing edges 23 are provided at both ends of the soft-pack shell 2, the first sealing edges 23 are bent along the radial direction of the soft-pack shell 2 to form a flat folded edge, and the corners of the flat folded edge are horizontally bent along the end plane of the soft-pack shell 2 to form a corner bending portion 25. This multiple folding edge structure can effectively increase the sealing edge path, improve the sealing performance of the battery, and improve the packaging efficiency. Second edge seals 24 are provided on both side edges of the soft-pack shell 2. The second edge seals 24 are bent along the circumference of the soft-pack shell 2 to form arc-shaped edges, which are adapted to the shape of the cylindrical battery and improve the structural reliability of the battery.

[0052] In one embodiment according to the present application, Figures 5-6 As shown, the positive electrode tab 11 extends outward from the first end and passes through the soft-pack shell 2 along the first sealing edge 23. The portion of the positive electrode tab 11 passing through the soft-pack shell 2 is reversely bent along the edge of the flat folded edge to form a first bending section. A first protective paper 3 is arranged between the first bending section and an end plane of the soft-pack shell 2, and the first protective paper 3 covers the corner bending portion 25; the thickness of the first protective paper 3 is 0.1 to 0.5 mm.

[0053] In one embodiment of the present application, the negative electrode tab 12 extends outward from the second end and passes through the soft-pack shell 2 along the first sealing edge 23. The part of the negative electrode tab 12 that passes through the soft-pack shell 2 is bent in the opposite direction along the edge of the flat folded edge to form a second bending section. A second protective paper 4 is arranged between the second bending section and the other end plane of the soft-pack shell 2, and the second protective paper 4 covers the corner bending portion 25. The thickness of the second protective paper 4 is 0.1 to 0.5 mm.

[0054] Among them, the positive electrode tab 11 and the negative electrode tab 12 are respectively led out from the two ends of the winding core 1 and pass through the soft-package shell 2. The part of the tab passing through the soft-package shell 2 is bent in the opposite direction along the edge of the flat folded edge to form a first bending section and a second bending section. A first protective paper 3 / second protective paper 4 is arranged between the first bending section / second bending section and the end plane of the soft-package shell 2. The protective paper covers the corner bending part 25, which can effectively prevent the tab burrs from scratching the soft-package shell 2, and at the same time buffer the contact stress between the tab and the soft-package shell 2, prevent the risk of short circuit caused by tab damage, and improve the safety of the battery.

[0055] In one embodiment of the present application, one surface of the first protective paper 3 and the second protective paper 4 are respectively coated with an adhesive layer, and the adhesive layer is an acrylic adhesive, a silicone adhesive, a vinyl acrylate adhesive, a nitrile rubber adhesive or a chloroprene rubber adhesive, so as to fix the first protective paper 3 and the second protective paper 4 to the end of the soft package shell 2.

[0056] In one embodiment of the present application, the first protective paper 3 is red barley paper, and the second protective paper 4 is green barley paper; wherein, both red barley paper and green barley paper have good insulation protection effects; in addition, the positive electrode tab 11 and the negative electrode tab 12 are respectively provided with protective papers of different colors, which can facilitate the distinction and identification of the positive and negative electrodes.

[0057] In one embodiment according to the present application, Figures 7-8 As shown, the two ends of the soft package shell 2 are respectively provided with fixing tape 5 for fixing the first bending section and the second bending section, the fixing tape 5 covers the bending surface of the first bending section and the bending surface of the second bending section respectively, and the two ends of the fixing tape 5 are respectively fixed to the circumferential side wall of the soft package shell 2; the outer surface of the soft package shell 2 is tightly covered with a heat shrink film 6, and the heat shrink film 6 is tightly pressed against the two ends of the fixing tape 5. Among them, the fixing tape 5 is respectively provided at the two ends of the soft package shell 2 for fixing the first bending section and the second bending section, and the heat shrink film 6 is tightly covered on the outer surface of the soft package shell 2, and the two ends of the fixing tape 5 are tightly pressed, which further improves the reliability and stability of the tab lead-out structure.

[0058] In one embodiment according to the present application, Fig. 9 As shown, the positive electrode sheet includes a positive electrode current collector 10 and a positive electrode active material layer 101 disposed on at least one surface of the positive electrode current collector 10; a first empty foil area 102 is disposed in the middle of the positive electrode sheet, and a positive electrode tab 11 is disposed in the first empty foil area 102; the middle of the positive electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the positive electrode sheet. Among them, arranging the positive electrode tab in the middle of the positive electrode sheet can effectively reduce the resistance inside the battery cell, thereby improving the output power and energy density of the battery cell; in addition, it can also effectively disperse the current and temperature inside the battery cell, reduce the risk of thermal runaway and explosion inside the battery cell, and thus improve the safety of the battery cell.

[0059] In one embodiment according to the present application, Fig.10As shown, the negative electrode sheet includes a negative electrode current collector 20 and a negative electrode active material layer 201 disposed on at least one surface of the negative electrode current collector 20; a second empty foil area 202 is disposed in the middle of the negative electrode sheet, and a negative electrode tab 12 is disposed in the second empty foil area 202; the middle of the negative electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the negative electrode sheet. Among them, arranging the negative electrode tab in the middle of the negative electrode sheet can effectively reduce the resistance inside the battery cell, thereby improving the output power and energy density of the battery cell; in addition, it can also effectively disperse the current and temperature inside the battery cell, reduce the risk of thermal runaway and explosion inside the battery cell, and thus improve the safety of the battery cell.

[0060] In one embodiment according to the present application, Fig. 9 As shown, the positive electrode tab 11 includes a first section and a second section, the first section is located in the first empty foil area 102, and the second section is located outside the first empty foil area 102;

[0061] The first empty foil area 102 is covered with a first heat-resistant insulating adhesive tape 103 and a second heat-resistant insulating adhesive tape 104, and the heat-resistant temperature of the first heat-resistant insulating adhesive tape 103 and the second heat-resistant insulating adhesive tape 104 is ≥130°C; preferably, the heat-resistant temperature of the first heat-resistant insulating adhesive tape 103 and the second heat-resistant insulating adhesive tape 104 are both 130°C to 500°C. Generally speaking, the higher the heat-resistant temperature of the heat-resistant insulating adhesive tape, the better, and in order to improve the safety of the battery cell, it is generally required to be higher than the heat shrinkage temperature of the isolation film;

[0062] Along the Y direction, the first heat-resistant insulating tape 103 extends beyond the edge of the positive electrode current collector 10 by 0-2.5 mm and completely covers the surface of the first section of the positive electrode tab 11;

[0063] The second heat-resistant insulating tape 104 completely covers the surface of the first section of the positive electrode tab 11, and partially covers the surface of the second section of the positive electrode tab 11;

[0064] Along the X direction, the second heat-resistant insulating tape 104 extends beyond the edge of the positive electrode tab 11 by 0-2.5 mm.

[0065] Among them, on the one hand, the positive electrode sheet of the present application can not only avoid direct contact between the positive and negative electrodes caused by thermal shrinkage of the isolation membrane by setting the first heat-resistant insulating tape 103 and the second heat-resistant insulating tape 104, but also effectively cover the burrs on the edge of the current collector and the pole ear, prevent the occurrence of short circuit in the battery cell, and improve the safety of the battery cell; on the other hand, the positive electrode sheet of the present application can avoid the insulating tape from being too large by setting the first heat-resistant insulating tape 103 and the second heat-resistant insulating tape 104 at the same time, and controlling the sizes of the first heat-resistant insulating tape 103 and the second heat-resistant insulating tape 104, so as not to affect the top seal of the aluminum-plastic film, thereby improving the stability and reliability of the battery cell performance.

[0066] In one embodiment of the present application, the second section of the positive electrode tab 11 is provided with a first tab glue 13, and the first tab glue 13 is located between the first sealing edge 23 where the first shell 21 and the second shell 22 are bonded to each other; along the Y direction, the distance between the upper edge of the second heat-resistant insulating tape 104 and the lower edge of the first tab glue 13 is 0.5 to 2.5 mm.

[0067] In one embodiment of the present application, the area of ​​the first heat-resistant insulating adhesive tape 103 is greater than the area of ​​the second heat-resistant insulating adhesive tape 104. Preferably, the area ratio of the first heat-resistant insulating adhesive tape 103 to the second heat-resistant insulating adhesive tape 104 is 1:(0.8-0.1). The second heat-resistant insulating adhesive tape 104 is usually pasted along the length direction (Y direction) of the positive electrode tab 11, and the pasted area should cover the positive electrode tab 11, so that the burrs on the edge of the positive electrode tab 11 can be covered, and the adhesive tape size can be prevented from being too large to affect the top seal of the aluminum-plastic film, and the waste of adhesive tape can also be reduced.

[0068] In one embodiment of the present application, the area of ​​the first heat-resistant insulating tape 103 accounts for 50-120% of the area of ​​the first empty foil area 102; preferably, the area of ​​the first heat-resistant insulating tape 103 accounts for 100-120% of the area of ​​the first empty foil area 102, which has better insulation effect and safety performance.

[0069] In one embodiment according to the present application, Fig.10 As shown, the negative electrode tab 12 includes a third section and a fourth section, the third section is located in the second empty foil area 202, and the fourth section is located outside the second empty foil area 202;

[0070] The second empty foil area 202 is covered with a third heat-resistant insulating adhesive tape 203 and a fourth heat-resistant insulating adhesive tape 204, and the heat-resistant temperature of the third heat-resistant insulating adhesive tape 203 and the fourth heat-resistant insulating adhesive tape 204 is ≥130°C; preferably, the heat-resistant temperature of the third heat-resistant insulating adhesive tape 203 and the fourth heat-resistant insulating adhesive tape 204 is 130°C to 500°C. Generally speaking, the higher the heat-resistant temperature of the heat-resistant insulating adhesive tape, the better, and in order to improve the safety of the battery cell, it is generally required to be higher than the heat shrinkage temperature of the isolation film;

[0071] Along the Y direction, the third heat-resistant insulating adhesive tape 203 exceeds the edge of the negative electrode current collector 20 by 0-2.5 mm and completely covers the surface of the third section of the negative electrode tab 12;

[0072] The fourth heat-resistant insulating adhesive tape 204 completely covers the surface of the third section of the negative electrode tab 12, and partially covers the surface of the fourth section of the negative electrode tab 12;

[0073] Along the X direction, the fourth heat-resistant insulating tape 204 extends beyond the edge of the negative electrode tab 12 by 0-2.5 mm.

[0074] Among them, on the one hand, the negative electrode sheet of the present application is provided with a third heat-resistant insulating tape 203 and a fourth heat-resistant insulating tape 204, which can not only avoid direct contact between the positive and negative electrodes caused by thermal shrinkage of the isolation membrane, but also effectively cover the burrs on the edge of the current collector and the pole ear, prevent the occurrence of short circuit in the battery cell, and improve the safety of the battery cell; on the other hand, the negative electrode sheet of the present application is provided with a third heat-resistant insulating tape 203 and a fourth heat-resistant insulating tape 204 at the same time, and the sizes of the third heat-resistant insulating tape 203 and the fourth heat-resistant insulating tape 204 are controlled to avoid the insulating tape being too large, and will not affect the top seal of the aluminum-plastic film, thereby improving the stability and reliability of the battery cell performance.

[0075] In one embodiment of the present application, the fourth section of the negative electrode tab 12 is provided with a second tab glue 14, and the second tab glue 14 is located between the first sealing edge 23 where the first shell 21 and the second shell 22 are bonded to each other; along the Y direction, the distance between the upper edge of the fourth heat-resistant insulating tape 204 and the lower edge of the second tab glue 14 is 0.5 to 2.5 mm.

[0076] In one embodiment of the present application, the area of ​​the third heat-resistant insulating adhesive tape 203 is greater than the area of ​​the fourth heat-resistant insulating adhesive tape 204. Preferably, the area ratio of the third heat-resistant insulating adhesive tape 203 to the fourth heat-resistant insulating adhesive tape 204 is 1:(0.8-0.1). The fourth heat-resistant insulating adhesive tape 204 is usually applied along the length direction (Y direction) of the negative electrode tab 12, and the applied area should cover the negative electrode tab 12, so that the burrs on the edge of the negative electrode tab 12 can be covered, and the adhesive tape size can be prevented from being too large to affect the top seal of the aluminum-plastic film, and the waste of adhesive tape can also be reduced.

[0077] In one embodiment of the present application, the area of ​​the third heat-resistant insulating tape 203 accounts for 50-120% of the area of ​​the second empty foil area 202; preferably, the area of ​​the third heat-resistant insulating tape 203 accounts for 100-120% of the area of ​​the second empty foil area 202, which has better insulation effect and safety performance.

[0078] In one embodiment of the present application, the first heat-resistant insulating adhesive tape 103, the second heat-resistant insulating adhesive tape 104, the third heat-resistant insulating adhesive tape 203 and the fourth heat-resistant insulating adhesive tape 204 all include a substrate and an adhesive layer provided on the surface of the substrate; the substrate is PP, PET, PI, PE, PTFE, PA, PU or acrylic, and the adhesive layer is an acrylic adhesive, a silicone adhesive, a vinyl ester adhesive, a nitrile rubber adhesive or a chloroprene rubber adhesive. The heat-resistant insulating adhesive tapes of the above materials all have good high temperature resistance and insulation performance; in addition, it should be noted that heat-resistant insulating adhesive tapes of other materials can also be used as long as they can meet the corresponding heat resistance and insulation requirements.

[0079] It should be noted that the contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field and will not be repeated here.

[0080] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs can also change and modify the above embodiment. Therefore, the present invention is not limited to the above specific embodiment, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the present invention belongs to the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A soft-pack cylindrical battery, characterized in that: The invention comprises a cylindrical winding core, an electrolyte and a cylindrical soft-package shell, wherein the winding core comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and wound to form the winding core, and the winding core and the electrolyte are sealed together inside the soft-package shell; The cylindrical winding core includes a first end and a second end that are arranged opposite to each other, the first end is connected to a positive electrode tab, and the second end is connected to a negative electrode tab; the positive electrode tab extends outward from the first end and passes through the soft package shell, and the negative electrode tab extends outward from the second end and passes through the soft package shell.

2. The soft-pack cylindrical battery according to claim 1, characterized in that: The soft package shell is an aluminum-plastic film, and the thickness of the aluminum-plastic film is 0.05-0.15 mm.

3. The soft-pack cylindrical battery according to claim 1, characterized in that: The soft package shell includes a first shell and a second shell, the first shell is heat-sealed and connected to the second shell, both ends of the first shell and the second shell are respectively provided with first sealed edges that fit each other, and the first sealed edges are bent along the radial direction of the soft package shell to form a flat folded edge, and the corners of the flat folded edge are horizontally bent along the end plane of the soft package shell to form a corner bending portion; the two side edges of the first shell and the second shell are respectively provided with second sealed edges that fit each other, and the second sealed edges are bent along the circumference of the soft package shell to form an arc-shaped folded edge.

4. The soft-pack cylindrical battery according to claim 3, characterized in that: The positive electrode tab extends outward from the first end portion and passes through the soft-pack shell along the first sealed edge. The portion of the positive electrode tab that passes through the soft-pack shell is bent in the opposite direction along the edge of the flat folded edge to form a first bending section. A first protective paper is arranged between the first bending section and an end plane of the soft-pack shell, and the first protective paper covers the corner bending portion. The thickness of the first protective paper is 0.1 to 0.5 mm.

5. The soft-pack cylindrical battery according to claim 4, characterized in that: The negative electrode tab extends outward from the second end and passes through the soft-pack shell along the first sealed edge. The part of the negative electrode tab that passes through the soft-pack shell is bent in the opposite direction along the edge of the flat folded edge to form a second bending section. A second protective paper is arranged between the second bending section and the other end plane of the soft-pack shell, and the second protective paper covers the corner bending portion; the thickness of the second protective paper is 0.1 to 0.5 mm.

6. The soft-pack cylindrical battery according to claim 5, characterized in that: The two ends of the soft package shell are respectively provided with fixing adhesive tapes for fixing the first bending section and the second bending section, the fixing adhesive tapes respectively cover the bending surface of the first bending section and the bending surface of the second bending section, and the two ends of the fixing adhesive tapes are respectively fixed to the circumferential side walls of the soft package shell; The outer surface of the soft package shell is tightly covered with a heat shrink film, and the heat shrink film is tightly pressed against the two ends of the fixing tape.

7. The soft-pack cylindrical battery according to claim 1, characterized in that: The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector; a first empty foil area is arranged in the middle of the positive electrode sheet, and the positive electrode tab is arranged in the first empty foil area; the middle of the positive electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the positive electrode sheet.

8. The soft-pack cylindrical battery according to claim 1 or 7, characterized in that: The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector; a second empty foil area is arranged in the middle of the negative electrode sheet, and the negative electrode tab is arranged in the second empty foil area; the middle of the negative electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the negative electrode sheet.

9. The soft-pack cylindrical battery according to claim 7, characterized in that: The positive electrode tab comprises a first section and a second section, the first section is located in the first empty foil area, and the second section is located outside the first empty foil area; The first empty foil area is covered with a first heat-resistant insulating adhesive tape and a second heat-resistant insulating adhesive tape, and the heat-resistant temperature of the first heat-resistant insulating adhesive tape and the second heat-resistant insulating adhesive tape is ≥130°C; Along the Y direction, the first heat-resistant insulating tape exceeds the edge of the positive electrode current collector by 0-2.5 mm and completely covers the surface of the first section of the positive electrode tab; The second heat-resistant insulating tape completely covers the surface of the first section of the positive electrode tab, and partially covers the surface of the second section of the positive electrode tab; Along the X direction, the second heat-resistant insulating tape exceeds the edge of the positive electrode tab by 0-2.5 mm.

10. The soft-pack cylindrical battery according to claim 8, characterized in that: The negative electrode tab comprises a third section and a fourth section, wherein the third section is located in the second empty foil area, and the fourth section is located outside the second empty foil area; The second empty foil area is covered with a third heat-resistant insulating adhesive tape and a fourth heat-resistant insulating adhesive tape, and the heat-resistant temperature of the third heat-resistant insulating adhesive tape and the fourth heat-resistant insulating adhesive tape is ≥130°C; Along the Y direction, the third heat-resistant insulating tape exceeds the edge of the negative electrode current collector by 0-2.5 mm and completely covers the surface of the third section of the negative electrode tab; The fourth heat-resistant insulating tape completely covers the surface of the third section of the negative electrode tab, and partially covers the surface of the fourth section of the negative electrode tab; Along the X direction, the fourth heat-resistant insulating tape exceeds the edge of the negative electrode tab by 0-2.5 mm.

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