Batteries and battery packs

Abstract

The present invention relates to the field of battery technology, and discloses a battery and a battery pack, including: a housing, which is formed with a storage space; a pole group, which is arranged in the storage space and has at least two pole groups arranged along the y direction, the pole group includes a main body and a pole ear connected and arranged, and the main body has a contact surface along the x-z direction; a heat insulation structure, which is arranged between adjacent pole groups, and the heat insulation structure covers the contact surface. The present invention arranges a heat insulation structure between adjacent pole groups to avoid heat superposition at the bonding surface caused by the bonding of adjacent pole groups, and the heat insulation structure covers the contact surface of the main body to ensure the heat insulation effect, thereby solving the problem that the pole group temperature is prone to increase sharply and improving the safety performance of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to batteries and battery packs. Background Art

[0002] Batteries, such as lithium-ion batteries, sodium-ion batteries, and solid-state batteries, have outstanding advantages such as high energy density and good cycle performance, and are widely used in portable electronic devices, electric vehicles, electric tools, drones, energy storage equipment, etc. Due to internal resistance, the internal pole group of the battery will generate a lot of heat when working for a long time. The heat accumulation between the adjacent pole groups will cause a sharp increase in the temperature rise of the pole group. This heat accumulation can easily cause battery safety problems. Summary of the invention

[0003] In view of this, the present invention provides a battery and a battery pack to solve the problem in the prior art that the battery temperature rise tends to increase sharply, resulting in reduced battery safety performance.

[0004] In a first aspect, the present invention provides a battery, comprising: a shell, which forms a accommodating space; an electrode group, which is arranged in the accommodating space and has at least two electrodes arranged along the y direction, the electrode group comprising a main body and an electrode ear connected to each other, and the main body has a contact surface along the xz direction; a heat insulation structure, which is fitted between adjacent electrode groups and covers the contact surface; the electrode group is a laminated electrode group, including a stacked negative electrode sheet; along the x direction, the length of the negative electrode sheet is a, the inner length of the shell is b, and the length of the heat insulation structure is c, satisfying (a+0.5) mm≤c≤(b-0.5) mm; or, the electrode group is a wound electrode group; along the x direction, the length of the electrode group is p, the inner length of the shell is b, the length of the heat insulation structure is c, and along the y direction, the thickness of the electrode group is q, satisfying (p-q+1.5) mm≤c≤(b-0.5) mm.

[0005] Beneficial effects: By arranging a heat insulation structure between adjacent electrode groups, it is avoided that the adjacent electrode groups are attached to each other and the heat is superimposed on the attached surface, and the heat insulation structure is arranged to cover the contact surface of the main body to ensure the heat insulation effect. Therefore, the problem that the temperature of the electrode group is prone to increase sharply is solved, and the safety performance of the battery is improved; while avoiding the heat insulation structure from damaging the electrode group, it is ensured that the electrode group and the heat insulation structure can be smoothly inserted into the shell.

[0006] In an optional embodiment, the shell includes: an enclosure structure, which is opened at both ends; a first closed structure, which is connected to the enclosure structure and blocks one of the openings; a second closed structure, which is connected to the enclosure structure and blocks the other opening, and the enclosure structure, the first closed structure and the second closed structure together form the accommodating space; wherein the first closed structure and the second closed structure are both connected to the enclosure structure by welding; or, the first closed structure is connected to the enclosure structure by welding, and the second closed structure is integrally provided with the enclosure structure.

[0007] In an optional embodiment, the first closed structure includes a cover body and an insulating member, the cover body is connected to the enclosure structure, one side of the insulating member is in contact with a side of the cover body facing the accommodating space, and the other side of the insulating member is in contact with the main body; along the z direction, the thickness of the first closed structure is f, the thickness of the cover body is j, and the thickness of the insulating member is k, satisfying f=j+k.

[0008] In an optional embodiment, the second closed structure includes a sealing plate and a bottom support plate, the sealing plate is connected to the enclosure structure, one side of the bottom support plate is in contact with a side of the sealing plate facing the accommodating space, and the other side of the bottom support plate is arranged toward the pole group; along the z direction, the thickness of the second closed structure is g, the thickness of the sealing plate is l, and the thickness of the bottom support plate is m, satisfying g=l+m.

[0009] In an optional embodiment, among the outer surfaces of the overall structure composed of all the electrode groups and the thermal insulation structure, at least one side facing the second closed structure is covered with an insulating film, and the insulating film is bonded to the bottom support plate; the electrode group includes a negative electrode sheet, and along the z direction, the height of the negative electrode sheet corresponding to the main body is d, the height of the outer shell is e, the thickness of the insulating film is h, and the height of the thermal insulation structure is i, satisfying (d+0.5) mm≤i≤(efgh-0.5) mm.

[0010] Beneficial effect: while avoiding damage to the electrode group caused by the heat insulation structure, the smooth assembly of the first closed structure and / or the second closed structure and the enclosure structure is ensured.

[0011] In an optional implementation, along the y direction, the thickness of the thermal insulation structure is n, satisfying 0.05 mm ≤ n ≤ 3 mm.

[0012] Beneficial effect: While ensuring the heat insulation effect, it avoids occupying too much internal space of the battery and affecting the battery energy density.

[0013] In an optional embodiment, the thermal insulation structure is a mica board, a silicone rubber board, or a ceramic silicone rubber board.

[0014] In a second aspect, the present invention further provides a battery pack, comprising the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A top view of a battery according to an embodiment of the present invention;

[0017] Figure 2 for Figure 1 Sectional view in the AA direction;

[0018] Figure 3 It is a structural schematic diagram of a laminated pole group according to an embodiment of the present invention;

[0019] Figure 4 It is a schematic projection diagram of the negative electrode sheet, the heat insulation structure and the housing space of the laminated electrode group according to an embodiment of the present invention on the xz plane;

[0020] Figure 5 It is a structural schematic diagram of a wound pole group according to an embodiment of the present invention;

[0021] Figure 6 A top view of the wound pole group and the thermal insulation structure in cooperation with each other according to an embodiment of the present invention;

[0022] Figure 7 for Figure 1 Cross-sectional view in the BB direction;

[0023] Figure 8 for Figure 7 A schematic diagram of a partial structure of one part of the battery shown;

[0024] Fig. 9 for Figure 7 A schematic diagram of the partial structure of another part of the battery is shown.

[0025] Description of reference numerals:

[0026] 1. Shell; 11. Enclosing structure; 111. First enclosure; 112. Second enclosure; 12. First closed structure; 121. Cover body; 122. Insulating member; 13. Second closed structure; 131. Sealing plate; 132. Bottom support plate; 2. Pole group; 21. Main body; 211. Negative electrode sheet; 212. Straight section; 213. Curved section; 22. Pole ear; 3. Thermal insulation structure; 4. Insulating film. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0028] Combine the following Figures 1 to 9 , describing an embodiment of the present invention.

[0029] According to an embodiment of the present invention, on the one hand, a battery is provided, comprising: a housing 1, a pole group 2 and a heat insulation structure 3. The housing 1 is formed with a receiving space, the pole group 2 is arranged in the receiving space, and at least two pole groups 2 are arranged along the y direction. The pole group 2 includes a main body 21 and a pole ear 22 connected and arranged, and the main body 21 has a contact surface along the xz direction. The heat insulation structure 3 is arranged between adjacent pole groups 2, and the heat insulation structure 3 covers the contact surface.

[0030] The battery of this embodiment, by providing a heat insulation structure 3 between adjacent electrode groups 2, avoids heat accumulation at the bonding surface caused by the adjacent electrode groups 2 being bonded together, and the heat insulation structure 3 is provided to cover the contact surface of the main body 21 to ensure the heat insulation effect, thereby solving the problem that the temperature of the electrode group 2 is prone to increase sharply, and improving the safety performance of the battery.

[0031] Specifically, Figure 7 As shown, there are two pole groups 2 arranged along the y direction. At this time, one thermal insulation structure 3 is provided, and the thermal insulation structure 3 is arranged between the two pole groups 2. One side surface of the thermal insulation structure 3 is in contact with the contact surface of one of the pole groups 2, and the other side surface of the thermal insulation structure 3 is in contact with the contact surface of the other pole group 2.

[0032] Of course, in other alternative embodiments, more electrode groups 2 may be provided, such as three, four, etc. It is understandable that as the number of electrode groups 2 increases, the number of thermal insulation structures 3 also increases. For example, when there are three electrode groups 2, there are two thermal insulation structures 3.

[0033] In the first embodiment, if Figure 3 and Figure 4 As shown, the electrode group is a laminated electrode group, including a stacked negative electrode sheet 211. Along the x direction, the length of the negative electrode sheet 211 is a, the inner length of the shell 1 is b, and the length of the thermal insulation structure 3 is c, satisfying (a+0.5) mm≤c≤(b-0.5) mm. This arrangement prevents the thermal insulation structure 3 from damaging the electrode group 2 while ensuring that the electrode group 2 and the thermal insulation structure 3 can be smoothly inserted into the shell.

[0034] It should be noted that if the value of c is too small, not only will the coverage of the electrode group 2 be too small, resulting in poor insulation effect, but also the edge of the insulation structure 3 ( Figure 4 The left and right edges shown in the figure fall within the range of the negative electrode sheet 211. During the use of the battery, the edge of the thermal insulation structure 3 exerts a shear force on the electrode group 2, which is likely to damage the electrode group 2 and even cause lithium deposition in the battery. If the value of c is too large, when the electrode group 2 and the thermal insulation structure 3 are assembled into the shell, they are likely to interfere with part of the shell 1, affecting the assembly efficiency.

[0035] It is worth noting that the laminated electrode group also includes a positive electrode sheet and a separator. The negative electrode sheets 211 and the positive electrode sheets are alternately stacked in sequence, and the separator is stacked between adjacent positive electrode sheets and negative electrode sheets 211 .

[0036] In the second embodiment, if Figure 5 and Figure 6 As shown, the pole group is a wound pole group. Along the x direction, the length of the pole group is p, the inner length of the shell is b, the length of the insulation structure is c, and along the y direction, the thickness of the pole group is q, satisfying (p-q+1.5) mm≤c≤(b-0.5) mm. This arrangement prevents the insulation structure 3 from damaging the pole group 2 while ensuring that the pole group 2 and the insulation structure 3 can be smoothly inserted into the shell.

[0037] It should be noted that if the value of c is too small, not only will the coverage of the electrode group 2 be too small, resulting in poor insulation effect, but also the edge of the insulation structure 3 ( Figure 6 The left and right edges shown in the figure fall within the range of the negative electrode sheet 211. During the use of the battery, the edge of the thermal insulation structure 3 exerts a shear force on the electrode group 2, which is likely to damage the electrode group 2 and even cause lithium deposition in the battery. If the value of c is too large, when the electrode group 2 and the thermal insulation structure 3 are assembled into the shell, they are likely to interfere with part of the shell 1, affecting the assembly efficiency.

[0038] It is worth noting that, for the wound electrode group, the positive electrode sheet, the separator and the negative electrode sheet 211 stacked in layers are wound together, such as Figure 5 As shown, the main body 21 includes a straight section 212 and curved sections 213 connected to opposite sides of the straight section 212. Figure 6If the value of c is (pq) mm<c<(p-q+1.5) mm, the distance that the thermal insulation structure extends out of the straight section is too small. Since the thermal insulation structure has a certain thickness, the edge of the thermal insulation structure is likely to come into contact with the curved section. The edge of the thermal insulation structure 3 will exert a shear force on the curved section, which may easily cause damage to the electrode group 2 and even lead to lithium deposition in the battery.

[0039] Specifically, in one embodiment, Figure 1 , Figure 2 and Figure 7 As shown, the housing 1 includes an enclosure structure 11, a first closed structure 12, and a second closed structure 13. The enclosure structure 11 is provided with openings at both ends, the first closed structure 12 is connected to the enclosure structure 11 and blocks one opening, the second closed structure 13 is connected to the enclosure structure 11 and blocks the other opening, and the enclosure structure 11, the first closed structure 12, and the second closed structure 13 are enclosed to form a receiving space. The first closed structure and the second closed structure are both connected to the enclosure structure by welding; or the first closed structure is connected to the enclosure structure by welding, and the second closed structure is integrally provided with the enclosure structure.

[0040] Further, such as Figure 2 and Figure 7 As shown, the enclosure structure 11 includes a first enclosure plate 111 and a second enclosure plate 112. The first enclosure plate 111 and the second enclosure plate 112 are each provided with two. Figure 2 As shown, the two first enclosure plates 111 are arranged relatively spaced apart along the x direction, as shown in FIG. Figure 7 As shown, the two second panels 112 are arranged relatively spaced apart along the y direction. The two first panels 111 and the two second panels 112 are sequentially connected and arranged along the circumferential direction, so that the two first panels 111 and the two second panels 112 are enclosed at both ends along the z direction to form two openings.

[0041] Therefore, please refer to Figure 2 , the inner length of the housing 1 is the inner length of the enclosure structure 11, that is, the distance between the two opposite sides of the two first enclosure panels 111. Furthermore, if the value of c is too large, when the pole group 2 and the thermal insulation structure 3 are assembled into the housing (that is, assembled from the opening into the enclosure structure 11), the thermal insulation structure 3 is likely to interfere with the first enclosure panels 111.

[0042] Specifically, in one embodiment, Figure 8 As shown, the first closed structure 12 includes a cover body 121 and an insulating member 122. The cover body 121 is connected to the enclosure structure 11, one side of the insulating member 122 is in contact with a side of the cover body 121 facing the accommodating space, and the other side of the insulating member 122 is in contact with the main body 21. Along the z direction, the thickness of the first closed structure 12 is f, the thickness of the cover body 121 is j, and the thickness of the insulating member 122 is k, satisfying f=j+k.

[0043] Please note that Figure 8 The first closed structure 12 is inserted into the enclosure structure 11 from the upper end opening of the enclosure structure 11, the upper surface of the cover body 121 is flush with the upper end surface of the enclosure structure 11, the upper surface of the insulating member 122 is in contact with the lower surface of the cover body 121, and the lower surface of the insulating member 122 is in contact with the upper surface of the main body 21.

[0044] Specifically, in one embodiment, Fig. 9 As shown, the second closed structure 13 includes a sealing plate 131 and a bottom supporting plate 132, the sealing plate 131 is connected to the enclosure structure 11, one side of the bottom supporting plate 132 is in contact with the side of the sealing plate 131 facing the accommodating space, and the other side of the bottom supporting plate 132 is arranged toward the pole group 2; along the z direction, the thickness of the second closed structure 13 is g, the thickness of the sealing plate 131 is l, and the thickness of the bottom supporting plate 132 is m, satisfying g=l+m.

[0045] Please note that Fig. 9 The sealing plate 131 is connected to the lower end surface of the enclosure structure 11, and the bottom supporting plate 132 is arranged at the upper surface of the sealing plate 131. Further, the enclosure structure 11 and the sealing plate 131 are arranged as one body.

[0046] Therefore, in this embodiment, during the actual processing, the sealing plate 131 and the enclosure structure 11 are integrally formed, so that during the processing, the sealing plate 131 can block the opening at one end of the enclosure structure 11, and the opening formed at the other end opposite to the sealing plate 131 is used as the installation opening of the electrode group 2 (that is, the electrode group 2 is installed in the accommodation space through the installation opening), and the installation opening is further blocked by the cover body 121. As an alternative embodiment, during the actual processing, the enclosure structure 11 can also be formed separately by processing, that is, the enclosure structure 11 with openings at both ends is first processed, and the openings at both ends are blocked by the first closing structure 12 and the second closing structure 13 respectively during the battery assembly process.

[0047] Of course, in other alternative embodiments, the second enclosing structure 13 may also be configured similarly to the first enclosing structure 12 , that is, the second enclosing structure 13 includes a cover body 121 and an insulating member 122 .

[0048] In one embodiment, Fig. 9 As shown, in the outer surface of the integral structure composed of all the electrode groups 2 and the heat insulation structure 3, at least one side facing the second closed structure 13 is covered with an insulating film 4, and the insulating film 4 is in contact with the bottom support plate 132; Figures 4 to 9As shown, the electrode group includes a negative electrode sheet 211. Along the z direction, the height of the negative electrode sheet 211 corresponding to the main body is d, the height of the shell 1 is e, the thickness of the first closed structure 12 is f, the thickness of the second closed structure 13 is g, the thickness of the insulating film 4 is h, and the height of the heat insulation structure 3 is i, satisfying (d+0.5) mm≤i≤(efgh-0.5) mm. In this way, while avoiding damage to the electrode group 2 by the heat insulation structure 3, the smooth assembly of the first closed structure 12 and / or the second closed structure 13 and the enclosure structure 11 is ensured.

[0049] It should be noted that if the value of i is too small, not only will the coverage of the electrode group 2 be too small, resulting in poor insulation effect, but also the edge of the insulation structure 3 ( Figure 4 The upper edge shown in the figure) falls within the range of the negative electrode sheet 211. During the use of the battery, the edge of the thermal insulation structure 3 applies a shear force to the electrode group 2, which is likely to damage the electrode group 2 and even cause lithium deposition in the battery. If the value of i is too large, when the first closed structure 12 and / or the second closed structure 13 are assembled to the enclosure structure 11, they are likely to interfere with the thermal insulation structure 3, affecting the assembly efficiency.

[0050] It can be understood that the negative electrode sheet 211 corresponding to the main body is the remaining portion of the negative electrode sheet 211 after removing the tab.

[0051] It is worth noting that, in some embodiments, a pole is provided on the first closed structure 12 and / or the second closed structure 13, and the pole is used to be electrically connected to the pole ear 22 to lead out the electricity of the main body 21. In this embodiment, the height e of the housing 1, the thickness f of the first closed structure 12, and the thickness g of the second closed structure 13 do not include the thickness of the pole along the z direction.

[0052] Based on the above, in this embodiment, please refer to Figures 7 to 9 , the height i of the thermal insulation structure 3 satisfies (d+0.5) mm≤i≤(ejklmh-0.5) mm.

[0053] In one embodiment, Figure 7 As shown, along the y direction, the thickness of the heat insulation structure 3 is n, which satisfies 0.05mm≤n≤3mm. This arrangement ensures the heat insulation effect while avoiding excessive occupation of the internal space of the battery and affecting the battery energy density.

[0054] It is worth noting that if the value of n is too small, the insulation effect of the thermal insulation structure 3 is poor, and it is still easy to cause heat to accumulate between adjacent electrode groups 2, thereby causing the temperature rise of the battery to increase. If the value of n is too large, the thermal insulation structure 3 occupies too much space inside the battery, resulting in a decrease in the space utilization of the battery and affecting the energy density of the battery.

[0055] In one embodiment, the heat insulation structure 3 is a mica board, a silicone rubber board, or a ceramic silicone rubber board. Of course, the heat insulation structure 3 can also be made of other materials that can achieve heat insulation.

[0056] The following temperature detection and thermal runaway test were performed on the battery without the thermal insulation structure 3 and the battery with the thermal insulation structure 3 of different thicknesses, and the test results of the embodiment battery and the comparative example battery are shown in Table 1. Among them, the embodiment battery refers to the battery with the thermal insulation structure 3, and the comparative example battery refers to the battery without the thermal insulation structure 3.

[0057] It should be noted that temperature detection refers to the detection of the middle temperature of the two-pole group 2 when the battery is normally charged, and the detection result in Table 1 is the maximum value of the detected temperature. Specifically, for a battery without a heat insulation structure 3, a temperature sensor is set in the middle position of the two-pole group 2; for a battery with a heat insulation structure 3, a temperature sensor is preset in the middle position inside the heat insulation structure 3.

[0058] Table 1 Test results of example batteries and comparative example batteries

[0059]

[0060] It can be seen from Table 1 that the battery of Comparative Example 1 is not provided with a heat insulation structure 3 (that is, the thickness of the heat insulation structure 3 is 0), and the middle temperature of the two-pole group 2 is relatively high; the batteries of Examples 1 to 12 are provided with a heat insulation structure 3, and compared with the battery of Comparative Example 1, the middle temperature of the two-pole group 2 is reduced, and, in the batteries of Examples 1 to 12, as the thickness of the heat insulation structure 3 increases, the middle temperature of the two-pole group 2 also decreases. At the same time, it can also be seen from Table 1 that the triggering time of thermal runaway of the batteries of Examples 1 to 12 is extended compared with the battery of Comparative Example 1, and, in the batteries of Examples 1 to 12, as the thickness of the heat insulation structure 3 increases, the extended time of triggering thermal runaway increases accordingly.

[0061] The following observations were made on the assembly process and disassembly of batteries with different sizes of housing, laminated electrode group and thermal insulation structure, and the observation results of the example battery and the comparative example battery are shown in Table 2. Among them, the example battery refers to a battery whose sizes of housing, electrode group and thermal insulation structure meet the requirements of this example, and the comparative example battery refers to a battery whose sizes of housing, electrode group or thermal insulation structure do not meet the requirements of this example.

[0062] Table 2 Observation results of the example battery and the comparative example battery

[0063]

[0064] After calculation, for the batteries in Examples 13 to 18, 100.5 mm ≤ c ≤ 104.5 mm and 100.5 mm ≤ i ≤ 104.5 mm must be satisfied. As can be seen from Table 2, in Examples 13 to 18, the values ​​of c and i all meet the above requirements. Therefore, the batteries in Examples 13 to 18 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0065] After calculation, for the battery of Example 19, 80.5mm≤c≤84.5mm, 60.5mm≤i≤64.5mm must be satisfied. As can be seen from Table 2, in Example 19, the values ​​of c and i both meet the above requirements. Therefore, the battery of Example 19 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0066] After calculation, for the battery of Example 20, 200.5mm≤c≤204.5mm and 200.5mm≤i≤204.5mm must be satisfied. As can be seen from Table 2, in Example 20, the values ​​of c and i both meet the above requirements. Therefore, the battery of Example 20 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0067] After calculation, for the battery of Example 21, 300.5mm≤c≤304.5mm, 300.5mm≤i≤304.5mm must be satisfied. As can be seen from Table 2, in Example 21, the values ​​of c and i both meet the above requirements. Therefore, the battery of Example 21 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0068] After calculation, for the battery of Example 22, 600.5mm≤c≤604.5mm, 120.5mm≤i≤124.5mm must be satisfied. As can be seen from Table 2, in Example 22, the values ​​of c and i both meet the above requirements. Therefore, the battery of Example 22 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0069] After calculation, for the batteries in Comparative Examples 2 to 5, 100.5 mm ≤ c ≤ 104.5 mm and 100.5 mm ≤ i ≤ 104.5 mm must be satisfied.

[0070] It can be seen from Table 2 that in Comparative Example 2, c=98mm, which does not meet the above requirements, and c<100.5mm, resulting in the edge of the thermal insulation structure 3 applying shear force to the electrode group 2, causing lithium deposition problems in the electrode.

[0071] It can be seen from Table 2 that in Comparative Example 3, i=98mm, which does not meet the above requirements, and i<100.5mm, resulting in the edge of the thermal insulation structure 3 applying shear force to the electrode group 2, causing lithium deposition problems on the electrode sheet.

[0072] It can be seen from Table 2 that in Comparative Example 4, c=105 mm, which does not meet the above requirements, and c>104.5 mm, resulting in interference between the thermal insulation structure 3 and the housing 1, and the battery cannot be assembled normally.

[0073] It can be seen from Table 2 that in Comparative Example 5, i=105 mm, which does not meet the above requirements, and i>104.5 mm, resulting in interference between the thermal insulation structure 3 and the housing 1, and the battery cannot be assembled normally.

[0074] The following observations were made on the assembly process and disassembly of batteries with different sizes of housing, wound electrode group and thermal insulation structure, and the observation results of the example battery and the comparative example battery are shown in Table 3. Among them, the example battery refers to a battery whose sizes of housing, electrode group and thermal insulation structure meet the requirements of this example, and the comparative example battery refers to a battery whose sizes of housing, electrode group or thermal insulation structure do not meet the requirements of this example.

[0075] Table 3 Observation results of the battery of the embodiment and the battery of the comparative example

[0076]

[0077] After calculation, for the batteries in Examples 23 to 28, 181.5 mm ≤ c ≤ 204.5 mm and 80.5 mm ≤ i ≤ 84.5 mm must be satisfied. As can be seen from Table 3, in Examples 23 to 28, the values ​​of c and i all meet the above requirements. Therefore, the batteries in Examples 23 to 28 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0078] After calculation, for the battery of Example 29, 291.5mm≤c≤304.5mm, 60.5mm≤i≤64.5mm must be satisfied. As can be seen from Table 3, in Example 29, the values ​​of c and i both meet the above requirements, so the battery of Example 29 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0079] After calculation, for the battery of Example 30, 91.5mm≤c≤154.5mm, 200.5mm≤i≤204.5mm must be satisfied. As can be seen from Table 3, in Example 30, the values ​​of c and i both meet the above requirements. Therefore, the battery of Example 30 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0080] After calculation, for the battery of Example 31, 61.5mm≤c≤84.5mm, 300.5mm≤i≤304.5mm must be satisfied. As can be seen from Table 3, in Example 31, the values ​​of c and i both meet the above requirements. Therefore, the battery of Example 31 can be assembled normally during the assembly process, the electrode group 2 can be normally inserted into the shell, and after the battery is disassembled, the electrode sheet does not have lithium deposition problems.

[0081] After calculation, for the batteries in Comparative Examples 6 to 9, 181.5 mm ≤ c ≤ 204.5 mm and 80.5 mm ≤ i ≤ 84.5 mm must be satisfied.

[0082] It can be seen from Table 3 that in Comparative Example 6, c=178 mm, which does not meet the above requirements, and c<181.5 mm, resulting in the edge of the thermal insulation structure 3 applying shear force to the electrode group 2, causing lithium deposition problems in the electrode.

[0083] It can be seen from Table 3 that in Comparative Example 7, i=78mm, which does not meet the above requirements, and i<80.5mm, resulting in the edge of the thermal insulation structure 3 applying shear force to the electrode group 2, causing lithium deposition problems on the electrode sheet.

[0084] It can be seen from Table 3 that in Comparative Example 8, c=205 mm, which does not meet the above requirements, and c>204.5 mm, resulting in interference between the thermal insulation structure 3 and the housing 1, and the battery cannot be assembled normally.

[0085] It can be seen from Table 3 that in Comparative Example 9, i=88mm, which does not meet the above requirements, and i>84.5mm, resulting in interference between the thermal insulation structure 3 and the housing 1, and the battery cannot be assembled normally.

[0086] According to another aspect of an embodiment of the present invention, a battery pack is provided, comprising the above-mentioned battery.

[0087] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: include: A housing is formed with a receiving space; A pole group is arranged in the accommodation space, and at least two pole groups are arranged along the y direction, the pole group comprises a main body and pole ears which are connected, and the main body has a contact surface along the xz direction; A heat-insulating structure is arranged between adjacent electrode groups, and the heat-insulating structure covers the contact surface; The electrode group is a laminated electrode group, including stacked negative electrode sheets; along the x direction, the length of the negative electrode sheet is a, the inner length of the shell is b, and the length of the thermal insulation structure is c, satisfying (a+0.5) mm≤c≤(b-0.5) mm; or, The pole group is a wound pole group; along the x direction, the length of the pole group is p, the inner length of the shell is b, the length of the thermal insulation structure is c, and along the y direction, the thickness of the pole group is q, satisfying (p-q+1.5) mm≤c≤(b-0.5) mm; The housing comprises: An enclosure structure, wherein both ends of the enclosure structure are open; A first closing structure connected to the enclosing structure and blocking one of the openings; a second closed structure connected to the enclosing structure and blocking the other opening, wherein the enclosing structure, the first enclosing structure and the second enclosing structure together form the accommodation space; Wherein, the first closed structure and the second closed structure are both connected to the enclosed structure by welding; or, the first closed structure is connected to the enclosed structure by welding, and the second closed structure is integrally arranged with the enclosed structure; The first closed structure comprises a cover body and an insulating member, wherein the cover body is connected to the enclosure structure, one side of the insulating member is in contact with a side of the cover body facing the accommodation space, and the other side of the insulating member is in contact with the main body; Along the z direction, the thickness of the first closed structure is f, the thickness of the cover body is j, and the thickness of the insulating member is k, satisfying f=j+k; The second closed structure comprises a sealing plate and a bottom supporting plate, wherein the sealing plate is connected to the enclosure structure, one side of the bottom supporting plate is in contact with one side of the sealing plate facing the accommodation space, and the other side of the bottom supporting plate is arranged toward the electrode group; Along the z direction, the thickness of the second closed structure is g, the thickness of the sealing plate is l, and the thickness of the bottom supporting plate is m, satisfying g=l+m; Among the outer surfaces of the integral structure composed of all the electrode groups and the heat insulation structure, at least one side facing the second closed structure is covered with an insulating film, and the insulating film is attached to the bottom support plate; The electrode group includes a negative electrode sheet. Along the z direction, the height of the negative electrode sheet corresponding to the main body is d, the height of the shell is e, the thickness of the insulating film is h, and the height of the thermal insulation structure is i, satisfying (d+0.5) mm≤i≤(efgh-0.5) mm.

2. The battery according to claim 1, characterized in that Along the y direction, the thickness of the thermal insulation structure is n, satisfying 0.05 mm ≤ n ≤ 3 mm.

3. The battery according to claim 1, characterized in that The heat insulation structure is a mica board, a silicone rubber board, or a ceramic silicone rubber board.

4. A battery pack, characterized in that: A battery comprising the battery according to any one of claims 1 to 3.

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