Soft package cylindrical battery

Abstract

The utility model 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 can be reduced, the energy density of the battery can be remarkably improved, and the service life of the battery can be prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of secondary batteries, and particularly relates to a soft-pack cylindrical battery. Background Technique

[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 various 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 model cylindrical battery has been widely used in fields such as laptop computers and power tools due to its excellent performance and moderate size.

[0003] However, existing cylindrical batteries, such as Figure 1 shown, generally use a steel shell structure for the outer shell, and there are some problems that need to be solved urgently. First, there are certain safety hazards in the use of steel shell cylindrical batteries, especially for product application fields that need to be carried around. This is mainly because the gas generated during the formation process of the steel shell battery will stay inside the battery, resulting in a relatively large internal pressure of the battery. At the same time, the shell of the steel shell cylindrical battery generally uses a relatively thick steel shell material. Once thermal runaway occurs, the battery may explode, causing serious safety hazards and lethality. Second, there are some deficiencies in the structural design of the steel shell cylindrical battery. Due to the existence of a gap of about 3 mm between the tab welding the positive electrode and the wound 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 large, 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 solve the above problems. Content of the Utility Model

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

[0006] To achieve the above purpose, the utility model provides the following technical solutions:

[0007] A soft-pack cylindrical battery includes a cylindrical wound core, an electrolyte, and a cylindrical soft-pack outer shell. The wound core includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially laminated and wound to form the wound core. The wound core and the electrolyte are jointly sealed inside the soft-pack outer shell;

[0008] The cylindrical winding core includes a first end and a second end which are oppositely arranged. The first end is connected with a positive electrode tab, and the second end is connected with a negative electrode tab; the positive electrode tab extends outward from the first end and penetrates through the soft package housing, and the negative electrode tab extends outward from the second end and penetrates through the soft package housing.

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

[0010] Preferably, the soft package housing includes a first housing and a second housing. The first housing and the second housing are connected by heat sealing and fitting. At both ends of the first housing and the second housing, there are respectively arranged first sealing edges that are mutually fitted. And the first sealing edge is bent radially along the soft package housing to form a flat folded edge, and at the corner of the flat folded edge, there is a corner bent portion formed by horizontally bending along the end plane of the soft package housing; at the two side edges of the first housing and the second housing, there are respectively arranged second sealing edges that are mutually fitted, and the second sealing edge is bent circumferentially along the soft package housing to form an arc-shaped folded edge.

[0011] Preferably, the positive electrode tab extends outward from the first end and penetrates through the soft package housing along the first sealing edge. The part of the positive electrode tab penetrating through the soft package housing is bent reversely along the edge of the flat folded edge to form a first bent section. Between the first bent section and the end plane of one end of the soft package housing, there is a first protective paper, and the first protective paper covers the corner bent portion; the thickness of the first protective paper is 0.1 - 0.5 mm.

[0012] Preferably, the negative electrode tab extends outward from the second end and penetrates through the soft package housing along the first sealing edge. The part of the negative electrode tab penetrating through the soft package housing is bent reversely along the edge of the flat folded edge to form a second bent section. Between the second bent section and the end plane of the other end of the soft package housing, there is a second protective paper, and the second protective paper covers the corner bent portion; the thickness of the second protective paper is 0.1 - 0.5 mm.

[0013] Preferably, at both ends of the soft package housing, there are respectively provided fixing adhesive tapes for fixing the first bent section and the second bent section. The fixing adhesive tapes respectively cover the surfaces of the bent portions of the first bent section and the second bent section, and both ends of the fixing adhesive tapes are respectively fixed on the circumferential side wall of the soft package housing;

[0014] A heat shrinkable film is tightly sleeved on the outer surface of the soft package housing, and the heat shrinkable film presses tightly on both ends of the fixing adhesive tape.

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

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

[0017] Preferably, the positive electrode tab includes a first section and a second section, the first section is located within 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 paper and a second heat-resistant insulating adhesive paper, and the heat-resistant temperature of the first heat-resistant insulating adhesive paper and the second heat-resistant insulating adhesive paper is ≥130°C;

[0019] In the Y direction, the first heat-resistant insulating adhesive paper extends beyond 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 adhesive paper 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] In the X direction, the second heat-resistant insulating adhesive paper extends beyond the edge of the positive electrode tab by 0 - 2.5 mm.

[0022] Preferably, the negative electrode tab includes a third section and a fourth section, the third section is located within 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 paper and a fourth heat-resistant insulating adhesive paper, and the heat-resistant temperature of the third heat-resistant insulating adhesive paper and the fourth heat-resistant insulating adhesive paper is ≥130°C;

[0024] In the Y direction, the third heat-resistant insulating adhesive paper extends beyond 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 adhesive paper 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] In the X direction, the fourth heat-resistant insulating adhesive tape extends 0 - 2.5 mm beyond the edge of the negative electrode tab.

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

[0028] 1) The soft-pack structure adopted by the utility model improves the safety performance of the battery. A cylindrical soft-pack outer shell is used to replace the traditional steel shell structure. The soft-pack outer shell is usually made of aluminum-plastic film. The aluminum-plastic film is a thin film material composed of aluminum foil and polymer materials, with 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 cells. Moreover, the thinner aluminum-plastic film shell can effectively reduce the internal pressure of the battery and reduce the explosion risk during thermal runaway. In addition, the gas generated during the formation process of the soft-pack cylindrical battery of the utility model will be removed through the second sealing process, making the inside of the battery in an approximately vacuum state. This not only further reduces the internal pressure of the battery, but also when the battery undergoes thermal runaway, the vacuum environment can effectively inhibit the rapid rise of the internal temperature of the battery and delay the occurrence and spread of thermal runaway. Even in extreme cases where the battery undergoes thermal runaway, the soft-pack outer shell can release the internal pressure through expansion and deformation, avoiding battery explosion and greatly improving the safety of the battery.

[0029] 2) The utility model improves the energy density of the battery by optimizing the structural design. The traditional steel shell cylindrical battery needs to reserve a certain gap at the ear welding position, and this part of the space cannot be effectively utilized, resulting in a reduced internal space utilization rate of the battery. However, the utility model utilizes the characteristics of the soft-pack structure and does not need to reserve too much ear welding gap. The wound core can fully fill the internal space of the soft-pack outer shell. At the same time, the positive electrode tab and the negative electrode tab are respectively led out from both ends of the wound core and pass through the soft-pack outer shell, reducing the space occupied by the tabs. This internal structural design can significantly improve the space utilization rate of the battery, thereby enhancing the energy density of the battery. In addition, the density of the aluminum-plastic film is much lower than that of the steel shell. Using the aluminum-plastic film as the soft-pack outer shell 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 energy density. Combining the advantages of high space utilization rate and lightweight outer shell, the soft-pack cylindrical battery of the utility model can achieve a significant increase in energy density.

[0030] 3) The utility model can extend the service life of the battery. The aluminum-plastic film soft package shell has excellent barrier properties, which can effectively prevent the intrusion of external moisture and oxygen, reduce the decomposition and volatilization of the electrolyte, inhibit the side reactions of 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 package shell can effectively buffer external vibration and impact, prevent the core from being damaged, and improve the reliability of battery use. At the same time, the internal pressure of the soft package cylindrical battery is smaller, reducing the influence of the volume change of the electrode material on the core structure, which is beneficial to maintaining the stability of the electrode structure and further extending the cycle life of the battery.

[0031] 4) The utility model can simplify the production process and reduce the manufacturing cost. Compared with the steel shell cylindrical battery, the production process of the soft package cylindrical battery is simpler. The steel shell battery needs to go through complex processing processes such as stretching, rolling grooves, and welding, while the shell of the soft package battery can directly use the aluminum-plastic film and complete the encapsulation through the sealing process. During the formation process, the soft package battery can also be conveniently evacuated, simplifying the process flow. This simplified production process can improve production efficiency and reduce equipment and labor costs. In addition, the price of the aluminum-plastic film is relatively low, and using the aluminum-plastic film to replace the steel shell can effectively reduce the battery manufacturing cost. Combining the advantages of the production process and manufacturing cost, the soft package cylindrical battery of the utility model can significantly reduce the manufacturing cost and enhance the market competitiveness of the product. Description of the Drawings

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

[0033] Figure 2 is a schematic structural diagram of a soft package cylindrical battery according to an embodiment of the utility model;

[0034] Figure 3 is an exploded view of the structure of a soft package cylindrical battery according to an embodiment of the utility model;

[0035] Figure 4 is a schematic structural diagram of a soft package cylindrical battery according to another embodiment of the utility model;

[0036] Figure 5 is a schematic structural diagram of a soft package cylindrical battery according to another embodiment of the utility model;

[0037] Figure 6 is an exploded view of the structure of a soft package cylindrical battery according to another embodiment of the utility model;

[0038] Figure 7 is a schematic structural diagram of a soft package cylindrical battery according to yet another embodiment of the utility model;

[0039] Figure 8Structural decomposition diagram of a soft-pack cylindrical battery according to another embodiment of the present utility model;

[0040] Figure 9 Schematic structural diagram of the positive electrode sheet of a soft-pack cylindrical battery according to an embodiment of the present utility model;

[0041] Figure 10 Schematic structural diagram of the negative electrode sheet of a soft-pack cylindrical battery according to an embodiment of the present utility model.

[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-pack outer shell; 21, first shell; 22, second shell; 23, first sealing edge; 24, second sealing edge; 25, corner bending part; 3, first protective paper; 4, second protective paper; 5, fixing adhesive tape; 6, heat-shrinkable film; 10, positive current collector; 101, positive active material layer; 102, first empty foil area; 103, first heat-resistant insulating adhesive tape; 104, second heat-resistant insulating adhesive tape; 20, negative current collector; 201, negative active material layer; 202, second empty foil area; 203, third heat-resistant insulating adhesive tape; 204, fourth heat-resistant insulating adhesive tape. Detailed implementation manners

[0043] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0044] In the description of the present application, unless otherwise clearly defined and limited, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; the term "plurality" means two or more; unless otherwise specified or stated, the terms "connection", "fixation", etc. shall be understood in a broad sense. For example, "connection" may be a fixed connection, a detachable connection, an integral connection, or an electrical connection; "connection" may be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0045] Please refer to the attached Figures 2 - 3 , a soft-pack cylindrical battery provided by the present application includes a cylindrical winding core 1, an electrolyte, and a cylindrical soft-pack outer shell 2. The winding core 1 includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and wound to form the winding core 1. The winding core 1 and the electrolyte are jointly sealed inside the soft-pack outer shell 2;

[0046] The cylindrical winding core 1 includes a first end portion and a second end portion which are oppositely arranged. A positive electrode tab 11 is connected to the first end portion, and a negative electrode tab 12 is connected to the second end portion. The positive electrode tab 11 extends outward from the first end portion and penetrates through the soft package housing 2, and the negative electrode tab 12 extends outward from the second end portion and penetrates through the soft package housing 2.

[0047] Among them, the soft package cylindrical battery of the present application has the following advantages:

[0048] 1) Compared with the traditional steel shell structure, the cylindrical battery of the present application adopts a soft package structure. The relatively thin aluminum-plastic film housing can effectively reduce the internal pressure of the battery and reduce the explosion risk during thermal runaway. In addition, the gas generated during the formation process of the soft package cylindrical battery will be removed through the second sealing process, making the inside of the battery in an approximately vacuum state, further reducing the internal pressure of the battery. When the battery undergoes thermal runaway, the vacuum environment can effectively inhibit the rapid rise of the internal temperature of the battery and delay the occurrence and spread of thermal runaway. The soft package housing 2 can also release the internal pressure through expansion deformation, avoiding violent explosion and greatly improving the safety of the battery.

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

[0050] In an embodiment according to the present application, the soft package housing 2 is an aluminum-plastic film, and the thickness of the aluminum-plastic film is 0.05 - 0.15 mm. Using the aluminum-plastic film as the material of the soft package housing 2 and controlling the thickness of the aluminum-plastic film within the range of 0.05 - 0.15 mm is much smaller than the housing thickness of the traditional steel shell cylindrical battery. The relatively thin aluminum-plastic film housing can effectively reduce the internal pressure of the battery and reduce the explosion risk during thermal runaway.

[0051] In an embodiment according to the present application, as Figures 3 - 4As shown in the figure, the soft package housing 2 includes a first housing 21 and a second housing 22. The first housing 21 and the second housing 22 are heat-sealed and bonded together. At both ends of the first housing 21 and the second housing 22, there are respectively provided first sealing edges 23 that are fitted to each other. The first sealing edges 23 are bent radially along the soft package housing 2 to form flat folded edges, and at the corners of the flat folded edges, there are horizontally bent corner bending portions 25 within the end plane of the soft package housing 2. On both side edges of the first housing 21 and the second housing 22, there are respectively provided second sealing edges 24 that are fitted to each other. The second sealing edges 24 are bent circumferentially along the soft package housing 2 to form arc-shaped folded edges. Among them, at both ends of the soft package housing 2, there are first sealing edges 23. The first sealing edges 23 are bent radially along the soft package housing 2 to form flat folded edges, and at the corners of the flat folded edges, there are horizontally bent corner bending portions 25 within the end plane of the soft package housing 2. This multi-folded edge structure can effectively increase the sealing path, improve the sealing performance of the battery, and improve the packaging efficiency. On both side edges of the soft package housing 2, there are second sealing edges 24. The second sealing edges 24 are bent circumferentially along the soft package housing 2 to form arc-shaped folded edges, which are adapted to the shape of the cylindrical battery and improve the structural reliability of the battery.

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

[0053] In an embodiment according to the present application, the negative electrode tab 12 extends outward from the second end and passes through the soft package housing 2 along the first sealing edge 23. The part of the negative electrode tab 12 passing through the soft package housing 2 is reversely bent along the edge of the flat folded edge to form a second bending section. Between the second bending section and the end plane of the other end of the soft package housing 2, there is a second protective paper 4, and the second protective paper 4 covers the corner bending portion 25. The thickness of the second protective paper 4 is 0.1 - 0.5 mm.

[0054] Among them, the positive electrode tab 11 and the negative electrode tab 12 are respectively led out from both ends of the winding core 1 and pass through the soft package housing 2. The parts of the tabs passing through the soft package housing 2 are reversely bent along the edges of the flat folded edges to form the first bending section and the second bending section. Between the first bending section / the second bending section and the end plane of the soft package housing 2, there is a first protective paper 3 / a second protective paper 4. The protective paper covers the corner bending portion 25, which can effectively prevent the burrs of the tabs from scratching the soft package housing 2. At the same time, it buffers the contact stress between the tabs and the soft package housing 2, prevents the short-circuit risk caused by tab damage, and improves 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, Figure 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, Figure 10As shown in the figure, the negative electrode sheet includes a negative electrode current collector 20 and a negative electrode active material layer 201 provided on at least one surface of the negative electrode current collector 20; a second empty foil area 202 is provided at the middle position of the negative electrode sheet, and a negative electrode tab 12 is provided in the second empty foil area 202; the middle position of the negative electrode sheet is between 3 / 8 and 5 / 8 in the length direction of the negative electrode sheet. Among them, setting 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, thereby improving the safety of the battery cell.

[0060] In an embodiment according to the present application, as Figure 9 shown, the positive electrode tab 11 includes a first section and a second section, the first section is located within 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 adhered 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 ≥ 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 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 generally needs to be higher than the heat shrinkage temperature of the separator;

[0062] In the Y direction, the first heat-resistant insulating adhesive 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 adhesive 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] In the X direction, the second heat-resistant insulating adhesive tape 104 extends beyond the edge of the positive electrode tab 11 by 0 - 2.5 mm.

[0065] Among them, on the one hand, by providing the first heat-resistant insulating adhesive tape 103 and the second heat-resistant insulating adhesive tape 104 on the positive electrode sheet of the present application, it can not only prevent the direct contact between the positive and negative electrodes caused by the thermal shrinkage of the separator, but also effectively cover the burrs on the edge of the current collector and the tab, prevent the occurrence of short circuit of the battery cell, and improve the use safety of the battery cell; on the other hand, by simultaneously providing the first heat-resistant insulating adhesive tape 103 and the second heat-resistant insulating adhesive tape 104 on the positive electrode sheet of the present application and controlling the sizes of the first heat-resistant insulating adhesive tape 103 and the second heat-resistant insulating adhesive tape 104, it is avoided that the insulating adhesive tape is too large and does not affect the top sealing of the aluminum-plastic film, thereby improving the stability and reliability of the battery cell performance.

[0066] In an embodiment according to the present application, a first tab glue 13 is provided on the second section of the positive tab 11, and the first tab glue 13 is located between the first sealing edge 23 where the first housing 21 and the second housing 22 are mutually attached; in 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 - 2.5 mm.

[0067] In an embodiment according to the present application, the area of the first heat-resistant insulating tape 103 is larger than the area of the second heat-resistant insulating tape 104. Preferably, the area ratio of the first heat-resistant insulating tape 103 to the second heat-resistant insulating tape 104 is 1:(0.8 - 0.1). Among them, the second heat-resistant insulating tape 104 is usually attached along the length direction (Y direction) of the positive tab 11, and the attached area should cover the positive tab 11, so that not only can the burrs on the edge of the positive tab 11 be covered, but also the influence of the over-sized tape on the top sealing of the aluminum-plastic film can be avoided, and the waste of the tape can be reduced.

[0068] In an embodiment according to 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, so that better insulation effect and safety performance can be achieved.

[0069] In an embodiment according to the present application, as Figure 10 shown, the negative tab 12 includes a third section and a fourth section. The third section is located within 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 attached with a third heat-resistant insulating tape 203 and a fourth heat-resistant insulating tape 204. The heat-resistant temperatures of the third heat-resistant insulating tape 203 and the fourth heat-resistant insulating tape 204 are ≥ 130°C; preferably, the heat-resistant temperatures of the third heat-resistant insulating tape 203 and the fourth heat-resistant insulating tape 204 are both 130°C - 500°C. Generally speaking, the higher the heat-resistant temperature of the heat-resistant insulating 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 separator film;

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

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

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

[0074] On the one hand, by providing the third heat-resistant insulating adhesive tape 203 and the fourth heat-resistant insulating adhesive tape 204, the negative electrode sheet of the present application can not only prevent the positive and negative electrodes from coming into direct contact due to the heat shrinkage of the separator, but also effectively cover the burrs on the edge of the current collector and the tab, preventing the occurrence of short circuit of the battery cell and improving the safety of use of the battery cell. On the other hand, by simultaneously providing the third heat-resistant insulating adhesive tape 203 and the fourth heat-resistant insulating adhesive tape 204 and controlling the sizes of the third heat-resistant insulating adhesive tape 203 and the fourth heat-resistant insulating adhesive tape 204, the negative electrode sheet of the present application can avoid the excessive size of the insulating adhesive tape and will not affect the top sealing of the aluminum-plastic film, improving the stability and reliability of the performance of the battery cell.

[0075] In an embodiment according to the present application, a second tab adhesive 14 is provided on the fourth section of the negative tab 12, and the second tab adhesive 14 is located between the first sealing edge 23 where the first housing 21 and the second housing 22 are mutually adhered; in the Y direction, the distance between the upper edge of the fourth heat-resistant insulating adhesive tape 204 and the lower edge of the second tab adhesive 14 is 0.5 - 2.5 mm.

[0076] In an embodiment according to the present application, the area of the third heat-resistant insulating adhesive tape 203 is larger 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). Among them, the fourth heat-resistant insulating adhesive tape 204 is usually attached along the length direction (Y direction) of the negative tab 12, and the attached area should cover the negative tab 12, so that it can not only cover the burrs on the edge of the negative tab 12, but also avoid the excessive size of the adhesive tape affecting the top sealing of the aluminum-plastic film, and can also reduce the waste of the adhesive tape.

[0077] In an embodiment according to the present application, the area of the third heat-resistant insulating adhesive 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 adhesive tape 203 accounts for 100 - 120% of the area of the second empty foil area 202, so as to have better insulating effect and safety performance.

[0078] In an embodiment according to 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 base material and an adhesive layer provided on the surface of the base material; the base material is PP, PET, PI, PE, PTFE, PA, PU or acrylic, and the adhesive layer is acrylic adhesive, silicone adhesive, vinyl acetate adhesive, nitrile rubber adhesive or chloroprene rubber adhesive. Among them, the heat-resistant insulating adhesive tapes of the above materials all have good high-temperature resistance and insulating properties; 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 temperature resistance and insulation requirements.

[0079] It should be noted that the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art and will not be elaborated here.

[0080] Based on the disclosure and teachings of the above specification, those skilled in the art of the present utility model can also make changes and modifications to the above embodiments. Therefore, the present utility model is not limited to the above specific embodiments, and any obvious improvements, substitutions or variations made by those skilled in the art on the basis of the present utility model fall within the protection scope of the present utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present utility model.

Claims

1. A soft-pack cylindrical battery, characterized in that: It includes a cylindrical winding core, an electrolyte, and a cylindrical soft package housing. The winding core includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially laminated and wound to form the winding core. The winding core and the electrolyte are jointly sealed inside the soft package housing; The cylindrical winding core includes a first end portion and a second end portion disposed opposite to each other. The first end portion is connected with a positive electrode tab, and the second end portion is connected with a negative electrode tab. The positive electrode tab extends outward from the first end portion and penetrates through the soft package housing, and the negative electrode tab extends outward from the second end portion and penetrates through the soft package housing.

2. The soft-pack cylindrical battery according to claim 1, characterized in that: The soft package housing 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 housing includes a first housing and a second housing. The first housing and the second housing are heat-sealed and adhesively connected. The two ends of the first housing and the second housing are respectively provided with mutually-adhered first sealing edges, and the first sealing edges are bent radially along the soft package housing to form flat folded edges, and at the corners of the flat folded edges, there are horizontally bent corner bent portions along the end plane of the soft package housing. The two side edges of the first housing and the second housing are respectively provided with mutually-adhered second sealing edges, and the second sealing edges are bent circumferentially along the soft package housing to form arc-shaped folded edges.

4. The soft-pack cylindrical battery according to claim 3, wherein: The positive electrode tab extends outward from the first end portion and penetrates through the soft package housing along the first sealing edge. The part of the positive electrode tab penetrating through the soft package housing is reversely bent along the edge of the flat folded edge to form a first bent section. A first protective paper is disposed between the first bent section and the end plane of one end of the soft package housing, and the first protective paper covers the corner bent portion. The thickness of the first protective paper is 0.1 - 0.5 mm.

5. The soft-pack cylindrical battery according to claim 4, wherein: The negative electrode tab extends outward from the second end portion and penetrates through the soft package housing along the first sealing edge. The part of the negative electrode tab penetrating through the soft package housing is reversely bent along the edge of the flat folded edge to form a second bent section. A second protective paper is disposed between the second bent section and the end plane of the other end of the soft package housing, and the second protective paper covers the corner bent portion. The thickness of the second protective paper is 0.1 - 0.5 mm.

6. The soft-pack cylindrical battery according to claim 5, wherein: Fixing adhesive tapes for fixing the first bent section and the second bent section are respectively disposed at the two end portions of the soft package housing. The fixing adhesive tapes respectively cover the surfaces of the bent portions of the first bent section and the second bent section, and the two ends of the fixing adhesive tapes are respectively fixed to the circumferential side wall of the soft package housing; A heat-shrinkable film is tightly sleeved on the outer surface of the soft package housing, and the heat-shrinkable film tightly presses the two ends of the fixing adhesive tape.

7. The soft-pack cylindrical battery according to claim 1, wherein: The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. A first empty foil area is disposed at the middle position of the positive electrode sheet, and the positive electrode tab is disposed 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.

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

9. The soft-pack cylindrical battery according to claim 7, wherein: The positive electrode tab includes a first section and a second section, the first section is located within 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 paper and a second heat-resistant insulating adhesive paper, and the heat-resistant temperatures of the first heat-resistant insulating adhesive paper and the second heat-resistant insulating adhesive paper are ≥130 °C; In the Y direction, the first heat-resistant insulating adhesive paper extends 0 - 2.5 mm beyond the edge of the positive electrode current collector and completely covers the surface of the first section of the positive electrode tab; The second heat-resistant insulating adhesive paper 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; In the X direction, the second heat-resistant insulating adhesive paper extends 0 - 2.5 mm beyond the edge of the positive electrode tab.

10. The soft-pack cylindrical battery according to claim 8, characterized in that: The negative electrode tab includes a third section and a fourth section, the third section is located within 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 paper and a fourth heat-resistant insulating adhesive paper, and the heat-resistant temperatures of the third heat-resistant insulating adhesive paper and the fourth heat-resistant insulating adhesive paper are ≥130 °C; In the Y direction, the third heat-resistant insulating adhesive paper extends 0 - 2.5 mm beyond the edge of the negative electrode current collector and completely covers the surface of the third section of the negative electrode tab; The fourth heat-resistant insulating adhesive paper 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; In the X direction, the fourth heat-resistant insulating adhesive paper extends 0 - 2.5 mm beyond the edge of the negative electrode tab.

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