Individual batteries, battery packs, and electronic devices

Abstract

To provide a standalone battery, battery pack, and electronic device that can avoid safety problems caused by lithium deposition and significantly improve the safety performance of the standalone battery. [Solution] The single battery includes a case and an electrode member 20 housed within the case, the electrode member including a winding structure formed by winding a positive electrode sheet 21, a separator 22, and a negative electrode sheet 23. The first negative electrode surface of the negative electrode current collector of the negative electrode sheet is covered with a first negative electrode active material layer, and the second negative electrode surface is covered with a second negative electrode active material layer. The negative electrode sheet includes a negative electrode sheet starting end 235, a first position, a second position, and a negative electrode sheet ending end 238 along the winding direction. The group margin of the single battery is 94%-99%, and the region on the surface away from the central hole of the second negative electrode active material layer and between the first position and the second position is a setting region, in which a first insulating layer 25 is continuously installed along the winding direction.

Description

Technical Field

[0001] The present invention relates to a single battery, a battery pack, and an electronic device.

Background Art

[0002] In recent years, with the rapid development of electric vehicles, consumer electronic devices, and new energy storage systems, for electric vehicles, battery technology is an important factor related to their development.

[0003] In the development of battery technology, the method of improving the safety of batteries is an urgent technical problem to be solved in battery technology.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem to be solved by the present invention is to provide a single battery, a battery pack, and an electronic device in order to overcome the above-mentioned technical problems of the prior art.

Means for Solving the Problems

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] A single battery, comprising: a case; an electrode member accommodated in the case and including a wound structure formed by laminating and winding a positive electrode sheet, a separator, and a negative electrode sheet; the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode current collector includes a first negative electrode surface and a second negative electrode surface installed along the thickness direction, the negative electrode active material layer includes a first negative electrode active material layer and a second negative electrode active material layer, the first negative electrode active material layer covers a partial region of the first negative electrode surface, the second negative electrode active material layer covers a partial region of the second negative electrode surface, and the first negative electrode surface is installed along the radial direction of the wound structure toward the central hole of the wound structure. Along the winding direction of the winding structure, the negative electrode sheet includes, in order, the starting end of the negative electrode sheet, a first position, a second position, and the ending end of the negative electrode sheet, and the positive electrode sheet includes, in order, the starting end of the positive electrode sheet and the ending end of the positive electrode sheet, and on one side away from the central hole from the first position through the second position to the ending end of the negative electrode sheet, there is no corresponding positive electrode sheet installed, and along the radial direction of the winding structure, the first position and the second position are located on the connecting line between the ending end of the positive electrode sheet and the center point of the central hole, and on the extension of the connecting line, and both the first position and the second position are adjacent to the ending end of the positive electrode sheet, Here, the group margin of the single battery is 94%-99%, the setting region is the area on the surface of the second negative electrode active material layer away from the central hole and between the first position and the second position, and the first insulating layer is continuously installed in the setting region along the winding direction.

[0007] In this technical solution, by continuously installing the first insulating layer along the winding direction in the designated region, it is possible to prevent lithium ions from diffusing outward away from the central hole in the designated region of the negative electrode sheet, thereby avoiding lithium deposition on the surface away from the central hole of the outermost second negative electrode active material layer, thus avoiding safety problems caused by lithium deposition and significantly improving the safety performance of the individual battery.

[0008] Preferably, the first insulating layer is aligned with one side of the second negative electrode active material layer near the positive electrode tab along one side in the width direction, or extends beyond the one side of the second negative electrode active material layer near the positive electrode tab. The group margin is the ratio of the maximum diameter of the electrode member to the maximum diameter of the case when the individual battery is in a fully discharged state.

[0009] Preferably, along the height direction of the winding structure, the width of the first insulating layer is 12.5%-37.5% of the width of the set area, or The area of ​​the first insulating layer is 4%-10% of the area of ​​the set region.

[0010] Preferably, the first insulating layer is provided at least partially between the second position and the end portion of the negative electrode sheet on the surface of the second negative electrode active material layer away from the central hole.

[0011] Preferably, the first insulating layer comprises a first substrate and a first adhesive layer located on the surface of the first substrate, the material of the first substrate is PET or PI, and / or The number of the first insulating layers located in the aforementioned setting region is one.

[0012] Preferably, the outermost periphery of the electrode member further includes an insulating film, and along the radial direction of the winding structure, the insulating film does not overlap with the orthographic projection of the first insulating layer. The insulating film comprises a second substrate and a second adhesive layer located on the surface of the second substrate, wherein the material of the second substrate is PET or PI.

[0013] Preferably, the positive electrode sheet includes a positive electrode current collector, and along the height direction of the winding structure, the positive electrode current collector includes a positive electrode coated region covered with a positive electrode active material layer and a positive electrode uncoated region not covered with a positive electrode active material layer, and the negative electrode current collector includes a negative electrode coated region covered with a negative electrode active material layer and a negative electrode uncoated region not covered with a negative electrode active material layer. The positive electrode uncoated region includes a positive electrode tab and a positive electrode connection region connected between the positive electrode tab and the positive electrode coated region, and the negative electrode uncoated region includes a negative electrode tab and a negative electrode connection region connected between the negative electrode tab and the negative electrode coated region. Here, at least a portion of the positive electrode connection region is covered by a second insulating layer, and / or at least a portion of the negative electrode connection region is covered by a third insulating layer.

[0014] Preferably, the case includes an annular side wall, an opening is formed at one end of the side wall, and the end of the case near the opening includes a crimped portion that is recessed toward the inside of the case. The aforementioned single battery is A cover plate attached to the opening, An insulating seal component is provided so as to surround the periphery of the cover plate and insulates and seals the cover plate and the case, A current collector plate is installed between the electrode member and the cover plate and electrically connected to the case, wherein the connecting piece of the current collector plate is located on the side of the crimped portion facing the electrode member and is welded to the crimped portion, further comprising: and / or, The aforementioned single battery is a cylindrical battery, and / or, The maximum diameter of the case is 40mm-50mm, and when the single battery is fully discharged, the minimum distance between the outer circumference of the electrode member and the inner surface of the case can be in the range of 0.2mm-0.8mm.

[0015] A battery pack characterized by including the above-mentioned individual battery.

[0016] An electronic device characterized by including the aforementioned battery pack. [Effects of the Invention]

[0017] The positive advancements of this invention are as follows: When the group margin of a single battery is 94%-99%, no positive electrode sheet is installed on one side of the outermost negative electrode sheet (the region from the first position through the second position to the end of the negative electrode sheet) away from the central hole, and no corresponding positive electrode active material layer is installed on either side. In this case, the larger group margin means that the distance from the outermost negative electrode sheet to the inner surface of the case is shorter, and during the expansion process of charging and discharging the battery, lithium ions migrate from the positive electrode active material layer of the outermost positive electrode sheet to the outside of the outermost negative electrode sheet, causing a safety problem related to lithium deposition.

[0018] Both the first position and the second position of the negative electrode sheet are located on the connecting line between the end portion of the positive electrode sheet and the central hole, and both the first position and the second position are adjacent to the end portion of the positive electrode sheet. The first position and the second position are sequentially arranged along the winding direction on the negative electrode sheet, and since the first position and the second position are respectively located on the connecting line between the end portion of the positive electrode sheet and the central hole and the extension line of the connecting line, both the first position and the second position are adjacent to the end portion of the positive electrode sheet along the radial direction. That is, the first position is located on the connecting line between the end portion of the positive electrode sheet and the center point of the central hole, and is located at a position adjacent to the side closer to the central hole of the end portion of the positive electrode sheet. The second position is located on the extension line of the connecting line between the end portion of the positive electrode sheet and the center point of the central hole, and is located at a position adjacent to the side away from the central hole of the end portion of the positive electrode sheet. The winding from the first position to the second position of the negative electrode sheet just forms one complete turn.

[0019] In the present invention, by continuously installing the first insulating layer on the surface of the second negative electrode active material layer away from the central hole and in the set region between the first position and the second position, it is possible to prevent lithium ions from diffusing to the outside away from the central hole of the set region in the negative electrode sheet, avoid lithium precipitation on the surface of the outermost second negative electrode active material layer away from the central hole, avoid safety problems caused by lithium precipitation, and greatly improve the safety performance of the single cell. Here, the second negative electrode active material layer covers a partial region of the second negative electrode surface of the negative electrode current collector, and along the radial direction of the winding structure, the second negative electrode surface is installed on the side away from the central hole of the winding structure of the negative electrode current collector.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic cross-sectional structure diagram of a single cell of a preferred embodiment of the present invention. [Figure 2] It is a partially enlarged schematic structural diagram of part A in FIG. 1. [Figure 3] It is a partially enlarged schematic structural diagram of part B in FIG. 1. [Figure 4] It is a schematic three-dimensional structure diagram of an electrode member of a single cell of a preferred embodiment of the present invention. [Figure 5]This is a schematic diagram of the cross-sectional structure of an electrode member of a single battery according to one preferred embodiment of the present invention. [Figure 6] This is a schematic diagram of a partially enlarged structure of section C in Figure 5. [Figure 7] This is a schematic diagram of a partial cross-sectional structure at a different angle of the electrode member of a single battery according to one preferred embodiment of the present invention. [Figure 8] This is a schematic diagram of a partially enlarged structure of part E in Figure 7. [Figure 9] This is a schematic diagram of a partially enlarged structure of part F in Figure 7. [Figure 10] This is a schematic diagram of a partial cross-sectional structure of a single-winding positive electrode sheet of a single battery according to one preferred embodiment of the present invention. [Figure 11] This is a schematic diagram of a partial cross-sectional structure of a single-winding negative electrode sheet of a single battery according to one preferred embodiment of the present invention. [Figure 12] This is a schematic diagram of a partial structure of the negative electrode sheet of a single battery in one preferred embodiment of the present invention when it is unfolded. [Figure 13] This is a schematic diagram of the structure of a battery pack according to one preferred embodiment of the present invention. [Figure 14] This is a schematic diagram of the structure of an electronic device according to one preferred embodiment of the present invention. [Modes for carrying out the invention]

[0021] The present invention will be described more clearly and completely below, with reference to preferred embodiments and in conjunction with the accompanying drawings.

[0022] As shown in Figures 1 to 3, this embodiment provides a standalone battery 1. The standalone battery 1 includes a case 10 and an electrode member 20, the electrode member 20 being housed within the case 10.

[0023] As shown in Figures 4 to 12, the electrode member 20 is a wound structure 201 formed by stacking and winding a positive electrode sheet 21, a separator 22, and a negative electrode sheet 23.

[0024] The negative electrode sheet 23 includes a negative electrode current collector 231 and a negative electrode active material layer 2311. The negative electrode current collector 231 includes a first negative electrode surface 23101 and a second negative electrode surface 23102 arranged along the thickness direction. The negative electrode active material layer 2311 includes a first negative electrode active material layer 23111 and a second negative electrode active material layer 23112. The first negative electrode active material layer 23111 covers a portion of the first negative electrode surface 23101, and the second negative electrode active material layer 23112 covers a portion of the second negative electrode surface 23102. The first negative electrode surface 23101 is positioned along the radial direction R of the winding structure 201 toward the central hole 201 of the winding structure 201, and the second negative electrode surface 23102 is positioned away from the central hole 2011.

[0025] Along the winding direction P of the winding structure 201, the negative electrode sheet 23 includes, in order, the negative electrode sheet starting end 235, the first position 236, the second position 237, and the negative electrode sheet ending end 238, while the positive electrode sheet 21 includes, in order, the positive electrode sheet starting end 217 and the positive electrode sheet ending end 218. On one side away from the central hole 2011, from the first position 236 through the second position 237 to the negative electrode sheet ending end 238, there is no corresponding positive electrode sheet 21 installed. Along the radial direction R of the winding structure 201, the first position 236 and the second position 237 are located on the connection line between the positive electrode sheet ending end 218 and the center point of the central hole 2011, and on the extension of the connection line, respectively, and both the first position 236 and the second position 237 are adjacent to the positive electrode sheet ending end 218.

[0026] Here, the group margin of the single battery 1 is 94%-99%, and the setting region K is the area on the surface away from the central hole 2011 of the second negative electrode active material layer 23112, and between the first position 236 and the second position 237, and the first insulating layer 25 is continuously installed in the setting region K along the winding direction P.

[0027] One point that needs explanation is that when the group margin of a single battery 1 is 94%-99%, the positive electrode sheet 21 is not installed on either side of the outermost negative electrode sheet 23 (the region from the first position 236 through the second position 237 to the end portion 238 of the negative electrode sheet 23) away from the central hole 2011, and the corresponding positive electrode active material layer 2111 is also not installed. In this case, because the group margin is larger, the distance from the outermost negative electrode sheet 23 to the inner surface of the case 10 is shorter, and during the expansion process of charging and discharging the battery, lithium ions migrate from the positive electrode active material layer 2111 of the outermost positive electrode sheet 21 to the outside of the outermost negative electrode sheet 23, causing a safety problem of lithium deposition. Furthermore, the first position 236 and the second position 237 are sequentially positioned on the negative electrode sheet 23 along the winding direction P, and the first position 236 and the second position 237 are located on the connection line between the positive electrode sheet end portion 218 and the central hole 2011, and on the extension of the connection line, respectively. Therefore, both the first position 236 and the second position 237 are adjacent to the positive electrode sheet end portion 218 along the radial direction R. That is, the first position 236 is located on the connection line between the positive electrode sheet end portion 218 and the center point of the central hole 2011, and is adjacent to one side of the positive electrode sheet end portion 218 that is closer to the central hole 2011. The second position 237 is located on the extension of the connection line between the positive electrode sheet end portion 218 and the center point of the central hole 2011, and is adjacent to one side of the positive electrode sheet end portion 218 that is further away from the central hole 2011. The winding of the negative electrode sheet 23 from the first position 236 to the second position 237 forms exactly one full turn.

[0028] In this embodiment, by continuously installing the first insulating layer 25 along the winding direction P in the setting region K, it is possible to prevent lithium ions from diffusing outward away from the central hole 2011 in the setting region K, thereby avoiding lithium deposition on the surface of the outermost second negative electrode active material layer 23112 away from the central hole 2011, thus avoiding safety problems caused by lithium deposition and significantly improving the safety performance of the single battery 1. Here, the area between the first position 236 and the second position 237 of the negative electrode sheet 23 refers to including the first position 236, the second position 237, and all positions located between the first position 236 and the second position 237. The second negative electrode surface 23102 of the negative electrode current collector 231 is installed away from the central hole 2011. That is, the second negative electrode surface 23102 is installed facing the case 10.

[0029] Further explanation is needed regarding the outermost negative electrode sheet 23, which may consist of one or multiple turns. Whether it consists of one or multiple turns, as long as the first insulating layer 25 is continuously installed along the winding direction P in the setting region K closest to the positive electrode sheet end 218, the effect of preventing lithium ions from diffusing outward away from the central hole 2011 in the setting region K can be achieved. For turns relatively farther from the positive electrode sheet end 218, the probability of lithium ions migrating is lower due to the greater distance. In addition, regardless of whether the first insulating layer 25 is installed in the setting region K at an intermediate position along the height direction of the second negative electrode active material layer 23112, or at a position close to the edge of the second negative electrode active material layer 23112, as long as the first insulating layer 25 is continuously installed along the winding direction P in the setting region K, an insulating structure continuously installed along the winding direction P can be formed, thereby achieving the effect of preventing lithium ions from diffusing outward away from the central hole 2011 in the setting region K.

[0030] Furthermore, on the surface of the second negative electrode active material layer 23112 away from the central hole 2011, the first insulating layer 25 is at least partially installed between the second position 237 and the negative electrode sheet end portion 238, thereby preventing lithium ions from diffusing outward away from the central hole 2011 in the region between the second position 237 and the negative electrode sheet end portion 238 of the negative electrode sheet 23, and further demonstrating the beneficial technical effect of reducing the amount of lithium delithion of the positive electrode sheet 21 in the corresponding region. Here, the space between the second position 237 and the negative electrode sheet end portion 238 includes the second position 237, the negative electrode sheet end portion 238, and all positions located between the second position 237 and the negative electrode sheet end portion 238.

[0031] There is only one first insulating layer 25 located in the setting region K. That is, there is only one first insulating layer 25 installed on the surface away from the central hole 2011 of the second negative electrode active material layer 23112, and within the region between the first position 236 and the second position 237. As a result, the first insulating layer 25 forms a single continuous, integrated structure, guaranteeing a single continuous insulating performance along the winding direction P.

[0032] Furthermore, in this embodiment, the first insulating layer 25 installed between the second position 237 and the negative electrode sheet end portion 238 is a continuous structure and is connected to the first insulating layer 25 installed within the set region K, thereby forming a single continuous integrated structure. This continuous integrated structure starts from the first position 236, passes through the second position 237, and reaches the end position before the negative electrode sheet end portion 238. In other embodiments, there is only one first insulating layer 25. This integrated structure is wound at least once from the first position 236 to the negative electrode sheet end portion 238. In other embodiments, the end position of the first insulating layer 25 may overlap with the negative electrode sheet end portion 238.

[0033] However, it is not limited to this, and in other embodiments, a multi-stage structure may be in which the first insulating layer 25, which is installed only between the second position 237 and the negative electrode sheet end portion 238, is installed at intervals.

[0034] Preferably, one side of the first insulating layer 25 in the width direction (referred to as the first side 251) aligns with the side of the second negative electrode active material layer 23112 closest to the positive electrode tab 2131, or extends beyond the side of the second negative electrode active material layer 23112 closest to the positive electrode tab 2131, while the other side of the first insulating layer 25 in the width direction (referred to as the second side 252) extends toward the other side of the second negative electrode active material layer 23112, thereby better preventing lithium ions from diffusing outward away from the central hole 2011 in the set region K, thereby reducing the amount of lithium delithiation from the positive electrode sheet 21 in the corresponding region, avoiding safety problems caused by lithium deposition, and significantly improving the safety performance of the single battery. The width direction of the first insulating layer 25 is in the same direction as the height direction H of the winding structure 201. Similarly, with respect to the first insulating layer 25 installed between the second position 237 and the negative electrode sheet end portion 238, the first side 251 is aligned with one side of the second negative electrode active material layer 23112 that is close to the positive electrode tab 2131, or extends beyond one side of the second negative electrode active material layer 23112 that is close to the positive electrode tab 2131, while the second side 252 extends toward the other side of the second negative electrode active material layer 23112.

[0035] Referring again to Figure 5, the outermost periphery of the electrode member 20 further includes an insulating film 28, and along the radial direction R of the winding structure 201, the insulating film 28 does not overlap with the orthographic projection of the first insulating layer 25. That is, along the height direction H of the winding structure 201, a portion of the winding structure 201 is covered with the insulating film 28, and the insulating film 28 and the first insulating layer 25 are staggered to avoid overlapping thickness of the electrode member 20 and avoid affecting the diameter of the electrode member 20, thereby improving the energy density. The insulating film 28 also serves to fix the outer separator 22, preventing the separator 22 from loosening. The insulating film 28 can be synthesized from PP, PE, PET, PVC, PI, or other polymer materials. The separator 22 includes a separator start end 221 and a separator end end 222. The insulating film 28 is not limited to an end tape for fixing the end end of the separator 22. In other words, the insulating film 28 may be a termination tape, or it may be another insulating structure, such as a Mylar film. Regardless of the structure of the insulating film 28, it does not overlap with the orthographic projection of the first insulating layer 25 along the radial R of the winding structure 201.

[0036] Referring again to Figure 12, specifically, along the height direction H of the winding structure 201, the width h1 of the first insulating layer 25 is 5 mm to 15 mm, and may be, for example, 5 mm, 7 mm, 10 mm, 13.5 mm, or 15 mm. By setting a range of possible values ​​for the width h1 of the first insulating layer 25 in this way, on the one hand, we avoid the width h1 of the first insulating layer 25 becoming excessively large, thus avoiding an impact on the energy density of the battery, and on the other hand, we avoid the width h1 of the first insulating layer 25 becoming excessively small, thus avoiding a situation where it fails to perform its function of preventing lithium ion diffusion.

[0037] Along the height direction H of the wound structure 201, the width h1 of the first insulating layer 25 is 12.5%-37.5% of the width h2 of the set region K, and may be, for example, 12.5%, 17.5%, 25%, 30%, or 37.5%. By setting the relationship between the width h1 of the first insulating layer 25 and the width h2 of the set region K in this way, on the one hand, it is possible to avoid the width h1 of the first insulating layer 25 becoming excessively large, thereby avoiding an impact on the energy density of the battery, and on the other hand, it is possible to avoid the width h1 of the first insulating layer 25 becoming excessively small, thereby avoiding a loss of its function in preventing the diffusion of lithium ions.

[0038] The area of ​​the first insulating layer 25 is 4%-10% of the area of ​​the set region K. By setting the relationship between the area of ​​the first insulating layer 25 and the area of ​​the second negative electrode surface 23102 in this way, on the one hand, it is possible to avoid the area of ​​the first insulating layer 25 becoming excessively large, thereby avoiding an impact on the energy density of the battery, and on the other hand, it is possible to avoid the area of ​​the first insulating layer 25 becoming excessively small, thereby avoiding a situation where it fails to perform its function of preventing lithium ion diffusion.

[0039] The thickness t of the first insulating layer 25 is 10 μm to 65 μm, and may be, for example, 10 μm, 25 μm, 37.5 μm, 53.5 μm, or 65 μm. By setting a range of possible values ​​for the thickness t of the first insulating layer 25 in this way, on the one hand, it is possible to avoid the thickness t of the first insulating layer 25 becoming excessively large, thereby avoiding an impact on the energy density of the battery, and on the other hand, it is possible to avoid the thickness t of the first insulating layer 25 becoming excessively small, thereby avoiding a loss of its function in preventing the diffusion of lithium ions.

[0040] In this embodiment, the first insulating layer 25 includes a first substrate and a first adhesive layer located on the surface of the first substrate, and the material of the first substrate is PET (polyethylene terephthalate). However, it is not limited to this, and in other embodiments, the material of the first substrate of the first insulating layer 25 may be another insulating material, for example, PI (polyimide). The insulating film 28 includes a second substrate and a second adhesive layer located on the surface of the second substrate, and the material of the second substrate is PET or PI.

[0041] When a single battery 1 is in a fully discharged state, the group margin is the ratio of the maximum diameter of the electrode member 20 to the maximum inner diameter of the case 10, and the inner diameter of the case is the diameter of the cavity inside the case 10. Here, the fully discharged state is the state when the SOC of a single battery is close to 0%SOC, where SOC (State of Charge) refers to the charge state of the battery, and SOC is the percentage of the available capacity that can be released according to the specified discharge conditions in the current storage battery. The available capacity refers to the maximum amount of electricity that the battery can release under the specified charge and discharge conditions, i.e., the remaining amount of electricity in the battery. When single battery 1 is at 0%SOC, that is, single battery 1 is in a fully discharged state, however, in some batteries, when fully discharged, the SOC may slightly exceed 0%, and in this case, the charge state slightly above 0%SOC is the fully discharged state of the single battery at that time. For batteries already manufactured as complete units, the discharged state is the rated capacity obtained from the nameplate of the battery unit at the time of shipment. Subsequently, the battery, including the battery unit, is first charged to a fully charged state with a charge ratio of 0.33C. When the charging current decreases to 0.01C, charging is considered complete, and the battery is already in a fully charged state (for example, the fully charged state corresponds to the state when the battery unit can be charged to its rated capacity). The fully discharged state is the state when the battery unit has already released the capacity indicated as its rated capacity, and a discharge ratio of 0.33C can be selected. For example, in a 42Ah cylindrical battery, charging is performed by selecting a current of 0.33C, and the battery is fully charged by cutting off the current (i.e., charging is considered complete when the charging current decreases to 0.01C). After that, the battery is discharged to the outside, a charge ratio of 0.33C is selected, and when the 42Ah capacity is released, the state at this time is the fully discharged state. In some specific experiments, to quickly determine the state of static electricity, a cutoff voltage of 2.5V can be used to define static electricity for a single battery containing a silicon negative electrode, and a cutoff voltage of 2.75V can be used to define static electricity for a negative electrode made solely of carbon material.

[0042] Preferably, the positive electrode sheet 21 includes a positive electrode current collector 211, and along the height direction H of the winding structure 201, the positive electrode current collector 211 includes a positive electrode coated region 212 covered by a positive electrode active material layer 2111 and a positive electrode uncoated region 213 not covered by the positive electrode active material layer 2111, and the negative electrode current collector 231 includes a negative electrode coated region 232 covered by a negative electrode active material layer 2311 and a negative electrode uncoated region 233 not covered by the negative electrode active material layer 2311. The positive electrode uncoated region 213 includes a positive electrode tab 2131 and a positive electrode connection region 2132 connected between the positive electrode tab 2131 and the positive electrode coated region 212, and the negative electrode uncoated region 233 includes a negative electrode tab 2331 and a negative electrode connection region 2332 connected between the negative electrode tab 2331 and the negative electrode coated region 232. Here, at least a portion of the positive electrode connection region 2132 is covered by the second insulating layer 26, and at least a portion of the negative electrode connection region 2332 is covered by the third insulating layer 27.

[0043] In this way, by installing the second insulating layer 26, the risk of deformation of the positive electrode connection region 2132 can be reduced, and the insulation performance of the positive electrode connection region 2132 can be improved, thereby significantly improving the safety and reliability of the battery performance. By installing the third insulating layer 27, the risk of deformation of the negative electrode connection region 2332 can be reduced, and the insulation performance of the negative electrode connection region 2332 can be improved, thereby significantly improving the safety and reliability of the battery performance. The second insulating layer 26 and the first insulating layer 25 overlap at least partially at the corresponding radial R position, making the region more closely aligned, which prevents displacement of the positive electrode sheet 21 and the negative electrode sheet 23 during the vibration operation of the battery, prevents the positive electrode sheet 21 and the negative electrode sheet 23 from coming into contact with each other, prevents short circuits, and improves safety.

[0044] In other embodiments, at least a portion of the positive electrode connection region 2132 may be covered by the second insulating layer 26, or at least a portion of the negative electrode connection region 2332 may be covered by the third insulating layer 27.

[0045] Specifically, the positive electrode connection region 2132 includes a first side surface that moves away from the central hole 2011 along the radial direction R of the winding structure 201 and a second side surface that moves toward the central hole 2011, where at least a portion of both the first and second side surfaces is covered by the second insulating layer 26. By covering at least a portion of both the first and second side surfaces of the positive electrode connection region 2132 with the second insulating layer 26 in this way, the risk of deformation of the positive electrode connection region 2132 can be effectively reduced, and the insulating performance of the positive electrode connection region 2132 can be improved, thereby significantly improving the safety and reliability of the battery performance. The main composition of the second insulating layer 26 is boehmite and PVDF (polyvinylidene difluoride). The occupancy rate of boehmite is 80%, and the occupancy rate of PVDF is 20%. The thickness of the second insulating layer 26 is 1.5 μm to 2.5 μm, and may be, for example, 1.5 μm, 1.7 μm, 2 μm, 2.1 μm, 2.3 μm, or 2.5 μm. By setting a thickness range for the second insulating layer 26, it is possible to avoid the coating thickness of the second insulating layer 26 becoming excessively thin, making it difficult to obtain the necessary electrical insulation and support strength. At the same time, it is possible to avoid the possibility of the second insulating layer 26 becoming excessively thick, resulting in a longer curing time for the coating layer and an increase in the overall thickness of the structure. Preferably, the thickness of the second insulating layer 26 is 2 μm.

[0046] Referring again to Figure 10, in this embodiment, both the first and second sides of the positive electrode connection region 2132 are covered by the second insulating layer 26. However, it is not limited to this, and in other embodiments, only the first side of the positive electrode connection region 2132 may be covered by the second insulating layer 26, or only the second side of the positive electrode connection region 2132 may be covered by the second insulating layer 26. This can be adjusted according to design requirements.

[0047] The second insulating layer 26 contains a coloring agent, and the coloring action of the coloring agent distinguishes whether the side to which the second insulating layer 26 is applied is the front or back surface of the positive electrode sheet 21, but this does not include cases where it is not limited to distinguishing the surface density and other conditions of the front and back surfaces of the positive electrode sheet 21. The main component of the coloring agent is bismuth vanadate, and it exhibits a yellow color.

[0048] In this embodiment, the second side surface of the positive electrode connection region 2132 is covered with a second insulating layer 26 containing a color-developing agent, which exhibits a yellow color, while the first side surface of the positive electrode connection region 2132 is covered with a second insulating layer 26 that does not contain a color-developing agent, which exhibits a white color. By making the front and back surfaces of the positive electrode sheet 21 different in color, the front and back surfaces of the positive electrode sheet 21 can be quickly distinguished by utilizing the color-developing effect of the indicator agent in the second insulating layer 26.

[0049] Furthermore, since the first insulating layer 25 is a color other than the usual white, such as blue, yellow, or green, it can form a good color difference with the second insulating layer 26, which contains a yellow-colored colorant located at the end portion 218 of the positive electrode sheet. This facilitates the CCD (Charge-Coupled Device) to accurately identify the edge of the first insulating layer 25, effectively preventing the risk of the first insulating layer 25 not being properly attached, thereby ensuring a good yield.

[0050] Referring again to Figures 1 to 3, in this embodiment, the case 10 includes an annular side wall 11, with an opening 12 formed at one end of the side wall 11. The end of the case 10 closest to the opening 12 includes a crimped portion 30 recessed into the interior of the case 10. The individual battery 1 further includes a cover plate 40, an insulating seal component 50, and a current collector plate. The cover plate 40 is attached to the opening 12. The insulating seal component 50 is provided so as to surround the periphery of the cover plate 40, insulating and sealing the cover plate 40 from the case 10. The current collector plate is installed between the electrode member 20 and the cover plate 40 and is electrically connected to the case 10, with a connecting piece of the current collector plate located on one side of the crimped portion 30 facing the electrode member 20 and welded to the crimped portion 30. In this way, by positioning the connecting piece of the current collector plate on one side of the crimping portion 30 facing the electrode member 20, and welding it to the crimping portion 30, that is, by positioning the welding area between the current collector plate and the tab at an end closer to the electrode member 20 compared to the crimping portion 30, it is possible to prevent the crimping portion 30 from influencing the welding area between the tab and the current collector plate, thereby improving the welding strength between the tab and the current collector plate.

[0051] Furthermore, the case 10 further includes an end wall 13, and the side wall 11 is installed to surround the end wall 13 and is located at one end away from the opening 12 of the side wall 11. A housing chamber 14 is formed within the case 10 by being enclosed by the end wall 13 and the side wall 11, and is used to house the electrode member 20, electrolyte, and other necessary battery components. The connection between the end wall 13 and the side wall 11 can be achieved by various methods, such as integral press molding, integral casting, or segmented welding.

[0052] The single battery 1 further includes a pole 70, the pole 70 penetrates the end wall 13 and is insulated from the end wall 13 through an insulating component 80.

[0053] The current collector plate includes a first current collector plate 61 and a second current collector plate 62, where the first current collector plate 61 is installed between the electrode member 20 and the end wall 13. The second current collector plate 62 is installed between the electrode member 20 and the cover plate 40. In this embodiment, the first current collector plate 61 corresponds to the positive electrode tab 2131, and the positive electrode tab 2131 is electrically connected to the pole pole 70 via the first current collector plate 61. The second current collector plate 62 corresponds to the negative electrode tab 2331, and the negative electrode tab 2331 is electrically connected to the case 10 via the second current collector plate 62. However, the embodiment is not limited thereto, and in other embodiments, the first current collector plate 61 may correspond to the negative electrode tab 2331 and the second current collector plate 62 may correspond to the positive electrode tab 2131.

[0054] In this embodiment, the sequence for welding the first current collector plate 61 and the second current collector plate 62 of the single battery 1 to the electrode member 20 is as follows: First, the first current collector plate 61 is placed. Next, the electrode member 20 is pressed together on both the positive and negative sides (the pressing process increases contact between the current collector plate and the electrode member 20, thus avoiding welding defects). The first current collector plate 61 is welded using linear welding instead of spot welding. This is because the negative electrode tab 2331 is relatively soft, and after two pressing welds, the distance between the second current collector plate 62 and the electrode member 20 becomes closer. Using spot welding would concentrate the heat, causing burns to the separator 22. However, using linear welding generates less heat, avoiding short circuits between the positive and negative electrodes caused by burns to the separator 22. Subsequently, the second current collector plate 62 is placed again. The electrode member 20 is pressed together again on both the positive and negative sides. Finally, the second current collector plate 62 is welded.

[0055] In this embodiment, the single battery 1 is a cylindrical battery. Cylindrical batteries have advantages such as high energy density, long cycle life, and good safety performance. However, they are not limited to this, and in other embodiments, the single battery 1 may be a battery of other shapes, such as a prismatic battery.

[0056] By applying the specific structure of the first insulating layer 25 in this embodiment to a cylindrical battery, it is possible to prevent lithium ions from diffusing outward away from the central hole 2011 in the set region K of the negative electrode sheet 23. This reduces the amount of lithium removed from the corresponding region of the positive electrode sheet 21, avoids safety problems caused by lithium deposition, and significantly improves the safety performance of the battery.

[0057] In particular, the cylindrical electrode members 20 of a cylindrical battery undergo some expansion in the electrode sheets to pursue the ultimate energy density, which reduces the interlayer distance between the electrode sheets. Furthermore, the case 10 of a cylindrical battery usually uses a high-strength steel shell, and compared to cases 10 made of other materials, the cylindrical steel shell is more restrictive to the electrode members 20, further reducing the interlayer distance between the electrode sheets, which makes lithium deposition more likely to occur. The design of the first insulating layer 25 in this embodiment prevents lithium ions from diffusing outward away from the central hole 2011 in the set region K of the negative electrode sheet 23, better addressing the problem of lithium deposition that is likely to occur due to the excessively small interlayer distance between the electrode sheets of a cylindrical battery, and improving its safety.

[0058] Specifically, the maximum diameter of case 10 is 40mm-50mm, and when a single battery 1 is fully discharged, the minimum distance between the outer circumference of the electrode member 20 and the inner surface of case 10 can be in the range of 0.2mm-0.8mm. As mentioned above, on the one hand, the cylindrical electrode member 20 of a cylindrical battery pursues the ultimate energy density, so the assembly gap cannot be made excessively large. Therefore, under the condition that the maximum diameter of case 10 is 40mm-50mm, the minimum distance between the outer circumference of the electrode member 20 and the inner surface of case 10 is controlled to 0.8mm or less to avoid the size of the electrode member 20 becoming excessively small and affecting the energy density of the single battery. On the other hand, if the minimum distance between the outer circumference of the electrode member 20 and the inner surface of case 10 is less than 0.2mm, not only does lithium deposition on the outermost negative electrode sheet 23 become more severe, but during the assembly process, the small assembly gap and the high diameter requirement for inserting the electrode member 20 into the case make it easy to cause case insertion failure. As can be seen from the above, by controlling the range of possible values ​​for the minimum distance between the outer circumference of the electrode member 20 and the inner surface of the case 10 to 0.2 mm - 0.8 mm, the requirements for assembly clearance can be satisfied while simultaneously enabling the individual battery 1 to reach an optimal energy density.

[0059] As shown in Figure 13, the present invention further provides a battery pack 100, which includes the above-described individual battery 1. In one embodiment of the battery pack 100 of the present invention, the battery pack 100 includes a box 310, a lid 320, and a plurality of individual batteries 1, which are arranged in the box 310 and connected to each other in series, parallel, or a combination of series and parallel. The lid 320 is sealed on the box 310 to provide protection for the plurality of individual batteries 1. It should be noted that the battery pack 100 may include parts other than the individual batteries 1 of the present invention, such as a battery pack 100 thermal management system and a circuit board. The battery pack 100 may be a battery module, a battery pack, or a power storage cabinet. These will not be explained in detail here.

[0060] As shown in Figure 14, the present invention further provides an electronic device 1000, which includes the battery pack 100 described above. The actuation unit 300 is electrically connected to the battery pack 100 to obtain power support. As an example, the electronic device 1000 is a vehicle, which may be a fuel-powered vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be, but is not limited to, a battery-powered electric vehicle, a hybrid vehicle, or a range-extender vehicle. The actuation unit 300 is the vehicle body, and the battery pack 100 is installed at the bottom of the vehicle body to provide power support for the vehicle's operation or the operation of in-vehicle electrical components. However, in some other embodiments, the electronic device 1000 may further be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, and a power tool, etc. Spacecraft include aircraft, rockets, space shuttles, and spacecraft, etc. The actuation unit 300 may be a unit component that can obtain power from the battery pack 100 and performs a corresponding task, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric aircraft toys. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers. The embodiments of this application do not impose any special limitations on the electronic devices 1000 described above.

[0061] Although specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative descriptions and that the scope of protection of the present invention is limited by the appended claims. Those skilled in the art can make numerous changes or modifications to these embodiments without departing from the principles and substance of the present invention, and all such changes and modifications are within the scope of protection of the present invention. [Industrial applicability]

[0062] The individual battery, battery pack, and electronic device of this application can be applied in the field of battery technology. [Explanation of Symbols]

[0063] 1000:Electronic equipment 100: Battery pack 300: Operating part 310: Box body 320: Lid 1: Single battery 10: Case 11: Side wall 12:Aperture 13: End wall 14: Confinement Room 20: Electrode material 201: Winding structure 2011: Center hole 21: Positive electrode sheet 211: Positive electrode current collector 2111: Positive electrode active material layer 212: Positive electrode coating area 213: Positive electrode uncoated area 2131: Positive Tab 2132: Positive electrode connection area 217: Positive electrode sheet starting end 218: Positive electrode sheet end 22: Separator 221: Separator start end 222: Separator end 23: Negative electrode sheet 231: Negative electrode current collector 23101: First negative electrode surface 23102: Second negative electrode surface 2311: Negative electrode active material layer 23111: First negative electrode active material layer 23112: Second negative electrode active material layer 232: Negative electrode coating area 233: Negative electrode uncoated area 2331: Negative electrode tab 2332: Negative electrode connection area 235: Negative electrode sheet starting end 236: First position 237:Second position 238: Negative electrode sheet termination 25: First insulating layer 251: First side 252:Second side 26: Second insulating layer 27: Third insulating layer 28: Insulating film 30: Crimping section 40: Cover plate 50: Insulating seal parts 61:First current collector plate 62:Second current collector plate 70: Polar pillar 80: Insulating components K: Setting area P: Winding direction of the winding structure R: Radial direction of the winding structure

Claims

1. The case and, An electrode member, housed within the aforementioned case, includes a winding structure formed by stacking and winding a positive electrode sheet, a separator, and a negative electrode sheet; A single battery containing, The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode current collector includes a first negative electrode surface and a second negative electrode surface arranged along the thickness direction, the negative electrode active material layer includes a first negative electrode active material layer and a second negative electrode active material layer, the first negative electrode active material layer covers a portion of the first negative electrode surface, the second negative electrode active material layer covers a portion of the second negative electrode surface, and the first negative electrode surface is arranged along the radial direction of the winding structure toward the central hole of the winding structure. Along the winding direction of the winding structure, the negative electrode sheet includes, in order, the starting end of the negative electrode sheet, a first position, a second position, and the ending end of the negative electrode sheet, and the positive electrode sheet includes, in order, the starting end of the positive electrode sheet and the ending end of the positive electrode sheet, and on one side away from the central hole from the first position through the second position to the ending end of the negative electrode sheet, there is no corresponding positive electrode sheet installed, and along the radial direction of the winding structure, the first position and the second position are located on the connecting line between the ending end of the positive electrode sheet and the center point of the central hole, and on the extension of the connecting line, and both the first position and the second position are adjacent to the ending end of the positive electrode sheet, Here, the group margin of the single battery is 94%-99%, the setting region is the surface of the second negative electrode active material layer away from the central hole and the region between the first position and the second position, and the first insulating layer is continuously installed in the setting region along the winding direction. A standalone battery characterized by the following features.

2. The first insulating layer is aligned with one side of the second negative electrode active material layer near the positive electrode tab along one side in the width direction, or extends beyond one side of the second negative electrode active material layer near the positive electrode tab. The single battery according to claim 1, characterized in that the group margin is the ratio of the maximum diameter of the electrode member to the maximum diameter of the case when the single battery is in a fully discharged state.

3. Along the height direction of the winding structure, the width of the first insulating layer is 12.5% ​​to 37.5% of the width of the set area, or The single battery according to claim 2, characterized in that the area of ​​the first insulating layer is 4% to 10% of the area of ​​the set region.

4. The single battery according to claim 2, characterized in that the first insulating layer is at least partially installed between the second position and the end portion of the negative electrode sheet on the surface of the second negative electrode active material layer away from the central hole.

5. The first insulating layer comprises a first substrate and a first adhesive layer located on the surface of the first substrate, wherein the material of the first substrate is PET or PI, and / or The single battery according to claim 1, characterized in that the number of first insulating layers located in the setting region is one.

6. The outermost periphery of the electrode member further includes an insulating film, and along the radial direction of the winding structure, the insulating film does not overlap with the orthographic projection of the first insulating layer. The single battery according to claim 1, characterized in that the insulating film comprises a second substrate and a second adhesive layer located on the surface of the second substrate, and the material of the second substrate is PET or PI.

7. The positive electrode sheet includes a positive electrode current collector, and along the height direction of the winding structure, the positive electrode current collector includes a positive electrode coated region covered with a positive electrode active material layer and a positive electrode uncoated region not covered with a positive electrode active material layer, and the negative electrode current collector includes a negative electrode coated region covered with a negative electrode active material layer and a negative electrode uncoated region not covered with a negative electrode active material layer. The positive electrode uncoated region includes a positive electrode tab and a positive electrode connection region connected between the positive electrode tab and the positive electrode coated region, and the negative electrode uncoated region includes a negative electrode tab and a negative electrode connection region connected between the negative electrode tab and the negative electrode coated region. The single battery according to claim 1, characterized in that at least a portion of the positive electrode connection region is covered by a second insulating layer, and / or at least a portion of the negative electrode connection region is covered by a third insulating layer.

8. The case includes an annular side wall, an opening is formed at one end of the side wall, and the end of the case near the opening includes a crimped portion that is recessed toward the inside of the case. The aforementioned single battery is A cover plate attached to the opening, An insulating seal component is provided so as to surround the periphery of the cover plate and insulates and seals the cover plate and the case, A current collector plate is installed between the electrode member and the cover plate and electrically connected to the case, wherein the connecting piece of the current collector plate is located on the side of the crimped portion facing the electrode member and the current collector plate is welded to the crimped portion, and / or, The aforementioned single battery is a cylindrical battery, and / or, The single battery according to claim 1, characterized in that the maximum diameter of the case is 40 mm to 50 mm, and when the single battery is in a fully discharged state, the range of possible minimum distances between the outer circumference of the electrode member and the inner surface of the case is 0.2 mm to 0.8 mm.

9. A battery pack characterized by including a single battery as described in any one of claims 1 to 8.

10. An electronic device characterized by including the battery pack described in claim 9.

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