Battery Pack

Abstract

The present invention discloses a battery pack, comprising a plurality of batteries, wherein the batteries comprise a shell, a cover plate, a pole, a conductive row and a battery cell, wherein the shell has an opening; the cover plate is arranged on the opening, and a through hole is formed on the cover plate; the pole is arranged in the through hole; the conductive row is electrically connected to a side of the pole facing away from the battery cell; the battery cell comprises a battery cell body and a pole ear, wherein the battery cell body is arranged in the shell, the pole ear comprises a first connecting portion, a fuse portion and a second connecting portion, and the cross-sectional areas of the first connecting portion and the second connecting portion are both larger than the cross-sectional area of ​​the fuse portion, the first connecting portion is connected to the battery cell body, the second connecting portion is connected to the end of the pole located in the shell, and the minimum cross-sectional area of ​​the fuse portion is S 1 mm², the surface area of ​​the conductive bar is S 2 mm², the thickness of the conductive bar is T 1 mm, where 9600≤S 1 *S 2 *T 1 ≤320000. The present invention can make the fuse part fuse under the originally set current threshold, thereby ensuring the safety of the battery pack.

Description

Technical Field

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

[0002] At present, since the commercialization of lithium-ion power batteries, they have been rapidly and widely used in various electrical equipment due to their many advantages such as light weight, high voltage, small size, no memory effect, high specific energy, long cycle life and environmental friendliness.

[0003] In order to ensure the safety of the battery, conventional batteries are equipped with a fuse at the tab. In the event of a short circuit, the short-circuit current is greater than the fusing current of the fuse, causing the fuse to melt and cut off the connection with the battery cell.

[0004] However, in a battery pack, since the tab is connected to the pole and the heat-conducting bar is connected to the pole, the heat at the tab will be transferred to the heat-conducting bar. Under the heat dissipation of the heat-conducting bar, the fuse part will not melt at the originally set current threshold, thereby affecting the safety of the battery pack. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery pack to ensure that the fuse part of the tab can be more accurately fused under the originally set current threshold value to ensure safety.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A battery pack includes a plurality of batteries, wherein the batteries include:

[0008] a housing having an opening;

[0009] a cover plate, the cover plate being arranged on the opening and having a through hole;

[0010] a pole, wherein the pole is at least partially disposed in the through hole;

[0011] A battery cell, the battery cell comprising a battery cell body and a tab, the battery cell body being disposed within the housing, the tab comprising a first connecting portion, a fuse portion, and a second connecting portion connected in sequence, wherein the cross-sectional areas of the first connecting portion and the second connecting portion are both larger than the cross-sectional area of ​​the fuse portion, the first connecting portion being connected to the battery cell body, and the second connecting portion being connected to the end of the pole located within the housing;

[0012] A conductive bar, the conductive bar being electrically connected to a side of the electrode facing away from the battery cell;

[0013] The minimum cross-sectional area of ​​the fuse portion is S1 mm², the surface area of ​​the conductive bar is S2 mm², and the thickness of the conductive bar is T1 mm, wherein 9600≤S1*S2*T1≤320000.

[0014] Compared with the prior art, the battery pack according to the embodiment of the present invention has the following advantages:

[0015] In the present invention, the smaller the minimum cross-sectional area of ​​the fusing part of the tab, the greater its resistance, and the greater the heat generated at the same overcurrent, so the minimum cross-sectional area of ​​the fusing part of the tab determines the fusing current threshold of the fusing part, the first connecting part of the tab is connected to the battery body, the second connecting part of the tab is welded to the end of the pole located inside the shell, and the conductive bar is connected to the end of the pole located outside the shell, so the heat of the battery body can be transferred to the conductive bar through the tab. Since the conductive bar has the function of heat dissipation and can absorb the heat at the fusing part of the tab, it will cause the fusing part to not melt within the originally set current threshold. At the same time, the larger the volume of the conductive bar, the greater the heat absorbed by the conductive bar from the fusing part, and generally the conductive bar has a fixed material, a fixed specific heat capacity and a fixed density, so the heat that the conductive bar can absorb also mainly depends on the volume of the conductive bar. Therefore, in order to ensure that the fusing part can melt within the set current threshold, the larger the volume of the conductive bar, the smaller the minimum cross-sectional area of ​​the fusing part. The smaller the area, the greater the maximum current that the fuse can withstand due to heat dissipation of the conductive bar. Therefore, the minimum cross-sectional area of ​​the fuse is set to S1mm², the surface area of ​​the conductive bar is set to S2mm², and the thickness of the conductive bar is set to T1mm. 9600≤S1*S2*T1≤320000. When the value of S1*S2*T1 is greater than 320000, it indicates that the conductive bar absorbs a large amount of heat and the minimum cross-sectional area of ​​the fuse is also large, which will cause the fuse to not blow within the set current threshold. When the value of S1*S2*T1 is less than 9600, it indicates that the conductive bar absorbs a small amount of heat and the minimum cross-sectional area of ​​the fuse is also small, which will cause the fuse to easily blow before the set current threshold is reached and the blowing time does not meet the requirements. Therefore, keeping S1*S2*T1 between 9600-320000 allows the fuse to blow within the originally set current threshold, thereby ensuring the safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a battery according to an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of a battery cell, a cover plate, and a conductive bar according to an embodiment of the present invention;

[0018] Figure 3is another schematic diagram of a battery cell, a cover plate, and a conductive bar according to an embodiment of the present invention;

[0019] Figure 4 is a front view of a battery cell according to an embodiment of the present invention;

[0020] Figure 5 is a side view of a battery cell according to an embodiment of the present invention;

[0021] Figure 6 Schematic diagram of the relationship between the battery body, tabs, poles and conductive bars of an embodiment of the present invention;

[0022] Figure 7 This is a schematic diagram of the dimensions of a battery cell body, tabs, poles, and conductive bars according to an embodiment of the present invention;

[0023] Figure 8 This is another schematic diagram of the dimensions of the battery cell body, tabs, poles, and conductive bars in an embodiment of the present invention;

[0024] Figure 9 is a top view of a conductive bar according to an embodiment of the present invention;

[0025] Figure 10 is a front view of a conductive bar according to an embodiment of the present invention;

[0026] Figure 11 is a schematic diagram of the relationship between the flexible circuit substrate and the conductive bar according to an embodiment of the present invention;

[0027] Figure 12 Schematic diagram of the relationship between the insulating film and the tab in an embodiment of the present invention.

[0028] In the figure, 100, housing; 200, cover plate; 300, first weld mark; 400, second weld mark; 500, third weld mark;

[0029] 1. Battery cell body;

[0030] 2. Tab; 21. First connection portion; 22. Fusing portion; 23. Second connection portion;

[0031] 3. Pole;

[0032] 4. Conductive bar; 41. Buffer tank;

[0033] 5. Flexible circuit substrate; 51. Circuit trace; 52. Fuse; 53. Cantilever portion;

[0034] 6. Temperature collection unit;

[0035] 7. Conductive connecting piece;

[0036] 8. Insulating film. DETAILED DESCRIPTION

[0037] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0038] In the description of the present invention, it should be understood that the term "comprising" as used in the present specification refers to the presence of the stated features, integers, steps, operations, parts / components, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts / components, components, and / or groups thereof. It should be understood that when we refer to a part / component as being "connected" to another part / component, it can be directly connected to the other part / component, or there can be intermediate parts / components. The term "and / or" as used herein includes all or any one of the associated listed items and all combinations thereof.

[0039] like Figures 1 to 12 As shown, the present invention relates to a battery pack, including a plurality of batteries, wherein the battery includes: a shell 100, a cover plate 200, a pole 3, a conductive bar 4 and a battery cell.

[0040] The shell 100 has an opening; the cover 200 is covered on the opening, and a through hole is formed on the cover 200; the pole 3 is at least partially disposed in the through hole; and the conductive bar 4 is electrically connected to a side of the pole 3 facing away from the battery cell.

[0041] The battery cell includes a battery cell body 1 and a tab 2. The battery cell body 1 is arranged in the housing 100. The tab 2 includes a first connecting portion 21, a fuse portion 22, and a second connecting portion 23 connected in sequence. The cross-sectional areas of the first connecting portion 21 and the second connecting portion 23 are both larger than the cross-sectional area of ​​the fuse portion 22. The first connecting portion 21 is connected to the battery cell body 1, and the second connecting portion 23 is connected to the end of the pole 3 located in the housing 100. The minimum cross-sectional area of ​​the fuse portion is S1 mm², where S1=[4, 20]. mm², S1 can be 6mm², 8mm², 10mm², 12mm², 14mm², 16mm² or 18mm², the surface area of ​​the conductive bar is S2mm², S2=[1200, 4000]mm², S2 can be 1600mm², 2000mm², 2400mm², 2800mm², 3200mm² or 3600mm², the thickness of the conductive bar is T1mm, T1=[2,4]mm, T1 can be 2.5mm, 3mm or 3.5mm, wherein 9600≤S1*S2*T1≤320000.

[0042] In the present invention, the smaller the minimum cross-sectional area of ​​the fuse portion 22 of the tab 2, the greater its resistance, and the greater the heat generated at the same overcurrent. Therefore, the minimum cross-sectional area of ​​the fuse portion 22 of the tab 2 determines the melting current threshold of the fuse portion 22. The first connecting portion 21 of the tab 2 is connected to the battery body 1, the second connecting portion 23 of the tab 2 is welded to the end of the pole 3 located inside the shell 100, and the conductive bar 4 is connected to the end of the pole 3 located outside the shell 100, so the heat of the battery body 1 can be transferred to the conductive bar 4 through the tab 2. At the conductive bar 4, since the conductive bar 4 has the function of heat dissipation and can absorb the heat at the fuse part 22 of the tab 2, the fuse part 22 will not be melted within the originally set current threshold. At the same time, the larger the volume of the conductive bar 4, the greater the heat absorbed by the conductive bar 4 from the fuse part 22. In general, the conductive bar 4 has a fixed material, a fixed specific heat capacity and a fixed density, so the heat that the conductive bar 4 can absorb also mainly depends on the volume of the conductive bar 4. Therefore, in order to ensure that the fuse part 22 can be melted within the set current threshold, the volume of the conductive bar 4 is When the value of S1*S2*T1 is greater than 320000, it means that the heat absorption of the conductive bar 4 is large and the minimum cross-sectional area of ​​the fuse part 22 is large. The cross-sectional area is also large, which will cause the fuse part 22 to not melt within the set current threshold. When the value of S1*S2*T1 is less than 9600, it means that the heat absorption of the conductive bar 4 is small, and the minimum cross-sectional area of ​​the fuse part 22 is also small, which will cause the fuse part 22 to easily melt before reaching the set current threshold, and the melting time does not meet the requirements. Therefore, keeping S1*S2*T1 between 9600-320000 can make the fuse part 22 melt at the original set current threshold, thereby ensuring the safety of the battery pack.

[0043] It should be noted that, since the thickness of the conductive bar 4 is relatively small, and the ratio of the conductive bar 4 to the surface area of ​​the conductive bar 4 is also relatively small, the volume of the conductive bar 4 can be S2*T1.

[0044] In this embodiment, on the heat transfer path from the battery cell to the conductive bar 4 , the distance between the fuse 22 and the conductive bar 4 is L1 mm, where 6 mm ≤ L1 ≤ 18 mm, and L1 can be 8 mm, 10 mm, 12 mm, 14 mm, or 16 mm.

[0045] When the fuse part 22 is too close to the conductive bar 4, the heat transfer path between the two is short, so the conductive bar 4 absorbs more heat from the fuse part 22, making the heat dissipation efficiency higher. In addition, when the conductive bar 4 vibrates, it is easy to transfer the vibration energy to the fuse part 22, causing the fuse part 22 to easily break. When the fuse part 22 is too far from the conductive bar 4, the distance between the fuse part 22 and the battery body 1 is even closer, and the heat from the fuse part 22 is likely to damage the battery body 1. Therefore, maintaining L1 at 6-18mm can ensure the stability of the fuse part 22 structure itself and avoid affecting the battery body 1.

[0046] In this embodiment, the minimum cross-sectional area of ​​the conductive bar 4 is S3 mm², where S3=[60, 150] mm², and S3 can be 80 mm², 100 mm², 120 mm², or 140 mm², wherein 3≤S3 / S1≤37.5.

[0047] When S3 / S1 is less than 3, that is, the ratio of the minimum cross-sectional area of ​​the conductive bar 4 to the minimum cross-sectional area of ​​the fuse 22 is too small, the conductive bar 4 may easily blow before the fuse 22, rendering the fuse 22 ineffective and the battery pack unprotected.

[0048] In this embodiment, the conductive bar 4 and the pole 3 are welded to form a first weld mark 300 . The area of ​​the first weld mark 300 is S4 mm², where S4=[60,150] mm². S4 can be 80 mm², 100 mm², 120 mm², or 140 mm², where 240≤S4*S1≤3000.

[0049] The conductive bar 4 is welded to the terminal 3, forming a first weld mark 300 therebetween. Because heat transfer is more efficient at the weld between the conductive bar 4 and the terminal 3, a larger area of ​​the first weld mark 300 increases the heat absorption efficiency of the conductive bar 4 and reduces the minimum cross-sectional area of ​​the fuse 22. Otherwise, the fuse 22 will not easily open at the set current threshold. Therefore, maintaining S4*S1 between 240 and 3000 ensures that the fuse 22 opens at the set current threshold, thus ensuring battery pack safety.

[0050] In this embodiment, the contact area between the conductive bar 4 and the pole 3 is S5 mm², S5=[100,500] mm², S5 can be 150 mm², 200 mm², 250 mm², 300 mm², 350 mm², 400 mm² or 450 mm², wherein 400≤S5*S1≤10000.

[0051] Since the contact surfaces of the conductive bar 4 and the pole 3 both transfer heat, and the larger the contact area between the two, the larger the cross-sectional area of ​​the heat transfer path, and the higher the heat transfer efficiency, in order to ensure that the fuse 22 melts at the originally set current threshold, the minimum cross-sectional area of ​​the fuse 22 should be designed to be smaller. Therefore, S5*S1 is maintained between 400-10000 to ensure the safety of the battery pack.

[0052] In this embodiment, the conductive bar 4 is connected to the plurality of poles 3 , and a buffer groove 41 is provided on the conductive bar 4 and in an area between two adjacent poles 3 . The width of the buffer groove 41 is W1 mm, and the depth of the buffer groove 41 is D mm, where W1*D=[6,12] mm², and 0.3≤(W1*D) / S1≤3.

[0053] By providing a buffer slot 41 on the conductive bar 4, and positioning the buffer slot 41 between two adjacent poles 3, that is, between two adjacent battery cells, the buffer slot 41 can act as a buffer when the battery cells vibrate. This reduces the vibration transmitted to the tab 2, making the fuse 22 less susceptible to vibration and thus less likely to break. Since the smaller the minimum cross-sectional area of ​​the fuse 22, the more fragile it is, the greater the buffering capacity required for the fuse 22. Furthermore, the buffering capacity of the buffer slot 41 is related to its width and depth: the wider and deeper the buffer slot 41, the greater the buffering capacity. Therefore, the ratio (W1*D) / S1 is maintained between 0.3 and 3 to ensure that the fuse 22 is less likely to break.

[0054] In this embodiment, the battery pack further includes a flexible circuit substrate 5 and a temperature acquisition unit 6 disposed on the conductive bar 4. The temperature acquisition unit 6 is electrically connected to the flexible circuit substrate 5. Along the heat transfer path from the battery cell to the temperature acquisition unit 6, the distance between the temperature acquisition unit 6 and the fuse 22 is L2 mm, where 6.5 mm ≤ L2 ≤ 20 mm. L2 can be 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, or 18 mm.

[0055] By setting the temperature acquisition unit 6, the temperature of the conductive bar 4 can be collected. In addition, on the heat transfer path from the battery cell to the temperature acquisition unit 6, the distance between the temperature acquisition unit 6 and the fuse part 22 is set to 6.5mm≤L2≤20mm, so that the temperature acquisition unit 6 is closer to the fuse part 22, so that the temperature monitored by the temperature acquisition unit 6 is closer to the temperature of the fuse part 22, so as to facilitate timely control by the battery management system. The temperature acquisition unit 6 can be a thermistor sensor.

[0056] Preferably, on the path of heat transfer from the battery cell to the temperature acquisition unit 6, the distance between the temperature acquisition unit 6 and the pole 3 is L3 mm, wherein 0.5 mm ≤ L3 ≤ 12 mm. L3 can be 2 mm, 4 mm, 6 mm, 8 mm or 10 mm.

[0057] On the heat transfer path from the battery cell to the temperature acquisition unit 6, the distance between the temperature acquisition unit 6 and the pole 3 is set to 0.5 mm ≤ L3 ≤ 12 mm to prevent the temperature acquisition unit 6 and the pole 3 from being too close, thereby preventing the conductive bar 4 and the pole 3 from interfering during assembly. It also prevents the temperature acquisition unit 6 and the pole 3 from being too far away, which affects the accuracy of temperature acquisition.

[0058] Furthermore, the battery pack includes a conductive connecting piece 7 connected to the conductive bar 4. The flexible circuit substrate 5 is provided with a circuit trace 51, the conductive connecting piece 7 is connected to the circuit trace 51, and the circuit trace 51 is provided with a fuse 52. In the heat transfer path from the battery cell to the flexible circuit substrate 5, the distance between the fuse 52 and the fuse portion 22 is L4 mm, where 6.5 mm ≤ L4 ≤ 20 mm. L4 can be 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, or 18 mm.

[0059] Because the heat from the fuse 22 is transferred through the terminal 3, the conductive bar 4, the conductive connecting piece 7, and the circuit trace 51, and thus to the flexible circuit substrate 5, if the fuse 52 is too close to the fuse 22 along the heat transfer path from the battery cell to the flexible circuit substrate 5, the fuse 52 on the flexible circuit substrate 5 may be heated and melted first. If the fuse 52 is too far from the fuse 22, the heat transfer path between the fuse 22 and the fuse 52 is too long, and the heat from the fuse 22 is dissipated significantly along the heat transfer path, which may affect the melting of the fuse 52. Therefore, the distance L4 between the fuse 52 and the fuse 22 is maintained between 6.5 and 20 mm to ensure the normal operation of the fuse 52. The conductive connecting piece 7 may be a nickel sheet.

[0060] Furthermore, the flexible circuit substrate 5 has a cantilever portion 53 extending outward, the circuit trace 51 extends to the cantilever portion 53, one end of the conductive connecting piece 7 is attached to the conductive bar 4, and the other end is provided on the cantilever portion 53 and connected to the circuit trace 51 on the cantilever portion 53, and the fuse 52 is provided on the circuit trace 51 of the cantilever portion 53.

[0061] That is, the fuse 52 is disposed on the cantilever portion 53 , which can prevent the fuse 52 from contacting the heated conductive bar 4 and the pole 3 , thereby minimizing heat transfer to the fuse 52 .

[0062] In this embodiment, the number of the battery cell bodies 1 is n, and the conductive bars 4 are connected to the poles 3 corresponding to the n battery cell bodies 1 , wherein n=[2,400], 24≤((S2*T1) / n)*S1≤160000.

[0063] Since the conductive bar 4 is electrically connected to the poles 3 corresponding to n battery cell bodies 1, one conductive bar 4 simultaneously absorbs the heat transferred from the fuse parts 22 of the tabs 2 corresponding to n battery cell bodies 1. Therefore, the volume of the conductive bar 4 can be divided into multiple parts according to the number of battery cell bodies 1. Therefore, to ensure that the fuse part 22 can melt at the originally set current threshold, it is necessary to set 24≤S1*(V1 / n)≤160000.

[0064] In one embodiment, the battery cell is a wound battery cell, and the tab 2 includes a plurality of tab sheets stacked together, and the tab sheet includes a first sub-connection portion, a sub-fuse portion and a second sub-connection portion connected in sequence. All the first sub-connection portions of the tab 2 are stacked together to form the first connection portion 21, and all the second sub-connection portions of the tab 2 are stacked together to form the second connection portion 23. All the sub-fuse portions of the tab 2 are welded together to form the fuse portion 22, and a second weld mark 400 is formed on the side of the tab 2.

[0065] Since the tab 2 includes multiple tab sheets stacked together, each tab sheet includes a first sub-connection portion, a sub-fuse portion, and a second sub-connection portion connected in sequence, the first sub-connection portion is connected to the cell body 1, and the second sub-connection portion is welded to the electrode 3. The second sub-connection portions of multiple tab sheets are welded together and welded to the electrode 3, and then the multiple sub-fuse portions of the multiple tab sheets are welded together. Therefore, when a set current threshold is reached, the multiple sub-fuse portions can be ensured to melt simultaneously, thereby smoothly severing the electrical connection between the cell body 1 and the electrode 3. If the sub-fuse portions of the multiple tab sheets are separated from each other, then when the fuse 22 melts, some sub-fuse portions may not melt, and the already melted sub-fuse portions may re-attach to the tab sheets that have not melted, which means that the electrical connection between the cell body 1 and the electrode 3 is still not severed, and the high-current protection function of the fuse 22 cannot be achieved.

[0066] In one embodiment, all sub-fuse portions of the tab 2 are partially welded together, and the area of ​​the second weld mark 400 is smaller than the area of ​​the side surface of the fusing portion 22. This can also prevent overlapping and adhesion between the fused and unfused sub-fuse portions.

[0067] In another embodiment, the entire area of ​​all sub-fuse portions of the tab 2 is welded together, and the area of ​​the second weld mark 400 is equal to the area of ​​the side surface of the fusing portion 22. This can also prevent overlapping and adhesion between the fusing and unfusing sub-fuse portions.

[0068] In other embodiments, the entire area of ​​all sub-fusible portions of the tab 2 is welded together, the area of ​​the second weld mark 400 is larger than the area of ​​the side surface of the fusible portion 22, and the second weld mark 400 completely covers the fusible portion 22. This can also prevent overlapping and adhesion between fused and unfused sub-fusible portions.

[0069] Specifically, the area of ​​the electrode tab located between the first sub-connection portion and the second sub-connection portion can be welded together first, and then the welded area can be cut or punched to reduce the cross-sectional area of ​​the welded area, thereby forming the fuse portion 22 at the position of the smallest cross-sectional area, so as to improve assembly efficiency and avoid the need to cut multiple electrode tabs individually.

[0070] Preferably, the second weld mark 400 is formed on the side of the outermost tab. Along the heat transfer path from the battery cell to the conductive bar 4, the distance between the end of the second weld mark 400 near the second sub-connection portion and the end of the sub-fuse portion of the tab near the second sub-connection portion is L5 mm, where 1 mm ≤ L5 ≤ 8 mm. L5 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or 7 mm.

[0071] On the path of heat transfer from the battery cell to the conductive bar 4, if the distance between the end of the second weld mark 400 close to the second sub-connection portion and the end of the sub-fuse portion of the tab close to the second sub-connection portion is too large, it means that the second weld mark 400 is too close to the weld mark between the tab 2 and the pole 3, and due to assembly tolerances, the two weld marks may overlap, resulting in a second repeated welding. The strength of the part welded twice will decrease, making the tab 2 prone to breakage, and it will also cause a deviation in the maximum current threshold of the fuse 22. If the distance between the end of the second weld mark 400 near the second sub-connection portion and the end of the sub-fuse portion of the tab near the second sub-connection portion is too small, the multiple sub-fuse portions of multiple tabs located away from the welding equipment area may not be completely welded together, resulting in partial separation. As a result, when the multiple sub-fuse portions of multiple tabs reach the originally set current threshold and fuse, adhesion may still occur between the multiple sub-fuse portions. This is equivalent to not severing the electrical connection between the battery cell body 1 and the terminal 3, and the high-current protection function of the fuse portion 22 cannot be achieved. Therefore, maintaining the distance L5 between the end of the second weld mark 400 near the second sub-connection portion and the end of the sub-fuse portion of the tab near the second sub-connection portion between 1-8 mm is beneficial to ensuring the safety of the battery pack.

[0072] Furthermore, a second weld mark 400 is formed on the side of the outermost tab. Along the heat transfer path from the battery cell to the conductive bar 4, the distance between the end of the second weld mark 400 near the first sub-connection portion and the end of the sub-fuse portion of the tab near the first sub-connection portion is L6 mm, where 1 mm ≤ L6 ≤ 8 mm. L6 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or 7 mm.

[0073] On the path of heat transfer from the battery cell to the conductive bar 4, if the distance between the end of the second weld mark 400 close to the first sub-connection portion and the end of the sub-fuse portion of the electrode tab close to the first sub-connection portion is too large, it means that the second weld mark 400 is too close to the battery cell body 1, which is equivalent to when the sub-fuse portions of multiple electrode tabs are welded together. The high temperature generated by the welding may burn the battery cell body 1, causing loss of electrical performance of the battery cell body 1 or thermal safety risks; if the distance between the end of the second weld mark 400 close to the first sub-connection portion and the end of the sub-fuse portion of the electrode tab close to the first sub-connection portion is too small, the multiple sub-fuse portions of multiple electrode tabs in the electrode 2 away from the welding equipment area may not be completely welded together, resulting in partial separation. As a result, when the multiple sub-fuse portions of the multiple electrode tabs reach the originally set current threshold and fuse, the multiple sub-fuse portions may still be bonded to each other, which is equivalent to the battery cell body 1 and the pole 3 still not being electrically connected, and the high-current protection function of the fuse 22 cannot be achieved. Therefore, maintaining the distance L6 between the end of the second weld mark 400 close to the first sub-connection portion and the end of the sub-fuse portion of the tab close to the first sub-connection portion between 1-8 mm is beneficial to ensuring the safety of the battery pack.

[0074] The second connecting portion 23 is welded to the end of the electrode 3 located within the housing 100, forming a third weld mark 500. Along the heat transfer path from the battery cell to the conductive bar 4, the distance between the second weld mark 400 and the third weld mark 500 is L7 mm, where 1 mm ≤ L7 ≤ 5 mm. L7 can be 2 mm, 3 mm, or 4 mm.

[0075] That is, a distance is maintained between the third weld mark 500 formed by the connection between the second connecting portion 23 of the tab 2 and the terminal post 3 and the second weld mark 400 on the tab 2. This allows the multiple tab pieces of the tab 2 located between the second weld mark 400 and the third weld mark 500 to be dispersed, thereby providing a buffering effect. This prevents vibration from being transmitted through the terminal post 3 to the fuse 22 of the tab 2, thus preventing the fuse 22 from breaking. Furthermore, the distance L7 between the second weld mark 400 and the third weld mark 500 is maintained between 1 and 5 mm to prevent the third weld mark 500 from being too close to the second weld mark 400, thereby providing a buffering effect. Furthermore, the second weld mark 400 is also kept away from the battery cell body 1 to prevent the welding temperature from affecting the battery cell body 1.

[0076] Preferably, on the path of heat transfer from the battery cell to the conductive bar 4, the distance between the end of the fuse 22 away from the first connection part 21 and the end of the fuse 22 close to the first connection part 21 is L8 mm, L8=[2,8] mm, L8 can be 3 mm, 5 mm or 7 mm, wherein 0.4≤L8 / L7≤8.

[0077] On the heat transfer path from the tab 2 to the conductive bar 4, if the ratio of the distance L8 between the end of the fuse 22 away from the first connection portion 21 and the end of the fuse 22 close to the first connection portion 21 to the distance L7 between the second weld mark 400 and the third weld mark 500 is too large, it means that the fuse 22 is too long and easily breaks due to vibration, while the distance between the second weld mark 400 and the third weld mark 500 is short, and the buffering capacity provided is weak, which easily causes the fuse 22 to break; if the ratio of the distance L8 between the end of the fuse 22 away from the first connection portion 21 and the end of the fuse 22 close to the first connection portion 21 to the distance L7 between the second weld mark 400 and the third weld mark 500 is too small, it means that the length of the fuse 22 is too short, and the distance between the second weld mark 400 and the third weld mark 500 is too long, which will cause the fuse 22 to fail to meet the melting time requirement. Therefore, maintaining L8 / L7 between 0.4 and 8 can ensure smooth use of the fuse part 22.

[0078] In other embodiments, the second connection portion 23 is welded to the end of the pole 3 located inside the housing 100 to form a third weld mark 500 , and the second weld mark 400 and the third weld mark 500 are connected together.

[0079] That is, a line is welded directly on the tab 2 , a long strip is welded when welding the tab 2 and the pole 3 , and then the welded area is cut to form the fuse portion 22 , which can improve assembly efficiency.

[0080] In other embodiments, the battery cell is a laminated battery cell, the tab 2 includes a plurality of tab sheets stacked together, the tab sheet includes a first sub-connection portion, a sub-fuse portion, and a second sub-connection portion connected in sequence, and the sub-fuse portions of the plurality of tab sheets are spaced apart from each other.

[0081] Since the multiple tabs of the laminated battery cell are individually connected to the pole pieces in the multiple battery cell bodies 1, the sub-fuse parts of the multiple tabs can be separately provided, and the tabs on the problematic pole pieces can be individually fused.

[0082] In this embodiment, the second connecting portion 23 is welded to the end of the electrode 3 located within the housing 100, forming a third weld mark 500. Along the heat transfer path from the battery cell to the conductive bar 4, the distance between the fuse 22 and the third weld mark 500 is L9 mm, where 1 mm ≤ L9 ≤ 10 mm. L9 can be 2 mm, 4 mm, 6 mm, or 8 mm.

[0083] If the distance between the fuse 22 and the third weld mark 500 is too small along the heat transfer path from the tab 2 to the conductive bar 4, the heat from the welding of the tab 2 to the terminal post 3 may affect the fuse 22, causing partial melting. Furthermore, if the fuse 22 is too close to the terminal post 3, it may be easily pulled or vibrated and break, affecting the performance of the fuse 22. If the distance between the fuse 22 and the third weld mark 500 is too large, the fuse 22 is far from the terminal post 3 and close to the battery cell body 1, which can easily affect the performance of the battery cell body 1. Therefore, the distance L9 between the fuse 22 and the third weld mark 500 is maintained between 1 and 10 mm to ensure the performance of the battery pack.

[0084] In this embodiment, the second connecting portion 23 is welded to the end of the pole 3 located inside the housing 100 to form a third weld mark 500. The area of ​​the third weld mark 500 is S6 mm², where S6=[10,80] mm². S6 can be 20 mm², 40 mm², or 60 mm², where 0.00062≤S6 / (S2*T1)≤0.033.

[0085] When the tab 2 and the pole 3 are welded, in order to prevent more heat from being transferred to the fuse part 22 and causing the fuse part 22 to melt, the heat can be dissipated through the conductive bar 4. The volume of the conductive bar 4 is related to the heat dissipation efficiency. Therefore, the ratio of the area of ​​the third weld mark 500 of the tab 2 and the pole 3 to the volume of the conductive bar 4 is set between 0.00062 and 0.033. In this way, under the premise that the volume of the conductive bar 4 meets the assembly conditions, the volume of the conductive bar 4 is increased to achieve a better heat dissipation effect, thereby reducing the impact on the fuse part 22.

[0086] In this embodiment, the battery pack further includes an insulating film 8 , and the insulating film 8 is provided on at least one side of the tab 2 in the first direction, thereby protecting the tab 2 .

[0087] Preferably, the insulating film 8 covers the region of the fuse portion 22 of the tab 2 , thereby protecting the fuse portion 22 from corrosion by the electrolyte or other impurities, and ensuring the accuracy of the fuse threshold of the fuse portion 22 .

[0088] Furthermore, the insulating film 8 extends to the region of the first connecting portion 21 , that is, the insulating film 8 extends to the root of the tab 2 , thereby further preventing the tab 2 from being torn.

[0089] Furthermore, the insulating film 8 extends to the area of ​​the second connecting portion 23 , that is, the insulating film 8 extends to the area where the tab 2 and the pole 3 are welded, so as to provide corrosion protection for the third weld mark 500 .

[0090] In this embodiment, the distance between the two sides of the insulating film 8 in the second direction is W2mm, that is, the width of the insulating film 8 is W2mm, and the distance between the two sides of the pole ear 2 in the second direction is W3mm, that is, the width of the pole ear 2 is W3mm, wherein 1.1≤W2 / W3≤1.5, and the second direction is perpendicular to the first direction.

[0091] That is, the ratio of the width of the insulating film 8 to the width of the tab 2 is between 1.1-1.5, so the width of the insulating film 8 can be greater than the width of the tab 2, so that the insulating film 8 can fully protect the tab 2 and prevent the tab 2 from breaking and being corroded. At the same time, the width of the insulating film 8 will not be too large to occupy too much space.

[0092] In one embodiment, two opposite sides of the tab 2 are covered with the insulating film 8 to more comprehensively protect the tab 2 and prevent the tab 2 from being torn and corroded.

[0093] Preferably, one side of the tab 2 in the first direction is a welding surface, a welding area is provided on the welding surface, and the area corresponding to the welding area on the other side of the tab 2 in the first direction is not covered with the insulating film 8 .

[0094] At present, when the insulating film 8 is assembled, a layer of insulating film 8 is first pasted on the side of the pole tab 2 away from the welding surface, and then the pole tab 2 is welded. After the welding is completed, another layer of insulating film 8 is pasted on the welding surface of the pole tab 2, thereby completing the attachment of the insulating film 8 on both sides of the pole tab 2 in the first direction. However, since the insulating film 8 is pasted on the side of the pole tab 2 away from the welding surface, it is easy to explode during welding, resulting in poor welding of the pole tab 2. Therefore, the insulating film 8 located on the side of the pole tab 2 away from the welding surface and corresponding to the welding area needs to be hollowed out.

[0095] In this embodiment, the distance between the two sides of the pole tab 2 in the first direction is T2mm, that is, the thickness of the pole tab 2 is T2mm, 0.004mm≤T2≤0.02mm, T2 can be 0.008mm, 0.012mm or 0.016mm, the resistivity of the pole tab 2 is ρΩ·m, 1.5*10^-8Ω·m≤ρ≤3*10^-8Ω·m, and on the connection path between the pole tab 2 and the battery body 1, the distance between the end of the fuse 22 close to the first connection portion 21 and the end away from the first connection portion 21 is L 10 mm, that is, the length of the fuse part 22 is L 10 mm, 2mm≤L 10 ≤8mm. L 10 It can be 3mm, 5mm or 7mm.

[0096] In this embodiment, the distance between the fuse part 22 and the battery body 1 on the connection path between the tab 2 and the battery body 1 is L 11 mm, where 5 mm ≤ L 11 ≤20mm. L 11 It can be 7mm, 9mm, 11mm, 13mm, 15mm, 17mm or 19mm.

[0097] On the connection path between the tab 2 and the battery body 1, the distance L between the fuse part 22 and the battery body 1 is 11 The distance between the fuse part 22 and the battery body 1 is kept between 5-20 mm, so that the distance between the fuse part 22 and the battery body 1 will not be too close, thereby preventing the heat of the fuse part 22 from damaging the battery body 1, and the distance between the fuse part 22 and the pole 3 will not be too close, thereby preventing the pole 3 from vibrating and easily pulling the fuse part 22, thereby causing the fuse part 22 to tear.

[0098] Preferably, the battery cell body 1 has an active material layer inside, and on the connection path between the tab 2 and the battery cell body 1, the distance between the fuse part 22 and the active material layer inside the battery cell body 1 is L 12 mm, where 6.5 mm ≤ L 12 ≤21.5mm. L 12It can be 9mm, 12mm, 15mm or 18mm.

[0099] On the connection path between the tab 2 and the cell body 1, the distance L between the fuse part 22 and the active material layer in the cell body 1 is 12 Maintained between 6.5-21.5mm, on the one hand, the fuse part 22 will not be too close to the active material layer of the battery body 1, and the temperature difference between the active material layer near the fuse part 22 and the active material layer not near the fuse part 22 will not be too large, thereby not causing differences in the local resistance of the battery body 1, resulting in uneven lithium insertion, differences in aging status and other problems. It also prevents the fuse part 22 from overheating and causing partial inactivation of the active material, that is, losing the ability to insert and remove lithium ions, thereby causing lithium precipitation, black spots and other problems; on the other hand, the distance between the fuse part 22 and the pole 3 will not be too close, so as to avoid the pole 3 from easily involving the fuse part 22 when vibrating, causing the fuse part 22 to tear.

[0100] Furthermore, the battery cell body 1 has a tab glue inside, and on the connection path between the tab 2 and the battery cell body 1, the distance between the fuse part 22 and the tab glue inside the battery cell body 1 is L 13 mm, where 7 mm ≤ L 13 ≤22mm. L 13 It can be 9mm, 11mm, 13mm, 15mm, 17mm, 19mm or 21mm.

[0101] The ear glue is made of PVDF and Al2O3, so the ear glue also has a certain high temperature resistance. However, the instantaneous temperature when the fuse part 22 melts is also high, and the melting point can reach 660 degrees. Therefore, on the connection path between the ear 2 and the battery body 1, when the fuse part 22 is too close to the ear glue, the ear glue will be burned and fail, causing a short circuit between the positive electrode foil and the negative electrode material area, and the risk of thermal runaway of the battery body 1 will be greatly increased. When the distance between the fuse part 22 and the pole 3 is too close, the vibration of the pole 3 is likely to involve the fuse part 22, causing the fuse part 22 to tear. Therefore, the distance L between the fuse part 22 and the ear glue in the battery body 1 is set to 1. 13 Maintain between 7-22 mm to ensure the performance of the battery cell body 1.

[0102] Furthermore, the cell body 1 has a diaphragm inside, and on the connection path between the tab 2 and the cell body 1, the distance between the fuse part 22 and the diaphragm inside the cell body 1 is L 14 mm, where 5 mm ≤ L 14 ≤20mm. L 14 It can be 7mm, 9mm, 11mm, 13mm, 15mm, 17mm or 19mm.

[0103] Since the diaphragm in the battery cell body 1 is not heat-resistant, when the distance between the fuse part 22 and the diaphragm is close on the connection path between the tab 2 and the battery cell body 1, it is easy to cause the diaphragm to burn, thereby causing a short circuit between the positive electrode foil and the negative electrode material area, and the risk of thermal runaway of the battery cell body 1 is greatly increased. When the distance between the fuse part 22 and the pole 3 is too close on the connection path between the tab 2 and the battery cell body 1, the vibration of the pole 3 is easy to involve the fuse part 22, causing the fuse part 22 to tear. Therefore, the distance L between the fuse part 22 and the tab glue in the battery cell body 1 is 14 Maintain between 5-20 to ensure the performance of the battery cell body 1.

[0104] It should be noted that, since the present invention is intended to reduce the impact of the heat of the fuse part 22 on the performance of the battery cell body 1, the connection path between the tab 2 and the battery cell body 1 can also be considered as the heat transfer path between the tab 2 and the battery cell body 1.

[0105] It should be emphasized that, in the present invention, the minimum cross-sectional area of ​​the fuse portion is the area of ​​the cross-section formed by breaking the fuse portion at a position of minimum size along a direction perpendicular to the fuse portion; the surface area of ​​the conductive bar is the sum of the areas of the outer sides of the conductive bar; the volume of the conductive bar refers to the size of the space it occupies; the minimum cross-sectional area of ​​the conductive bar is the area of ​​the cross-section formed by breaking the conductive bar at a position of minimum size along a direction perpendicular to the conductive bar; the areas of the first weld mark, the second weld mark and the third weld mark refer to the area of ​​the welding area.

[0106] The following are the relevant test methods:

[0107] Provide a test method to determine whether the fuse part of the tab meets the requirements of the fusing time:

[0108] The electrode ear includes a first connection part, a fuse part and a second connection part connected in sequence. The first connection part is a free end, the second connection part is welded to one end of the pole, and the other end of the pole is welded to the conductive bar. One electrical connection end of the current source test equipment is connected to the conductive bar, and the other electrical connection end of the current source test equipment is connected to the first connection part. The current source test equipment is energized with a current of 800A, and the fuse part blows within 10 minutes, which meets the product safety standards.

[0109] If the current is less than 800A and the fuse blows within 10 minutes, it means that the fuse does not meet the overcurrent requirement and is judged as unqualified;

[0110] If the current is greater than 800A and the fuse blows after 10 minutes, it means that the fuse does not meet the fusing requirements and is judged as unqualified.

[0111] Using the above test method, the results are shown in the following table:

[0112]

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A battery pack, characterized in that: A plurality of batteries are included, the batteries comprising: a housing having an opening; A cover plate, the cover plate is arranged on the opening, and a through hole is formed on the cover plate; A pole, wherein the pole is at least partially disposed in the through hole; A battery cell, wherein the battery cell comprises a battery cell body and a pole ear, wherein the battery cell body is arranged in the shell, and the pole ear comprises a first connection part, a fuse part and a second connection part which are connected in sequence, and the cross-sectional areas of the first connection part and the second connection part are both larger than the cross-sectional area of ​​the fuse part, the first connection part is connected to the battery cell body, and the second connection part is connected to the end of the pole located in the shell; A conductive bar, the conductive bar being electrically connected to a side of the pole facing away from the battery cell; The minimum cross-sectional area of ​​the fuse portion is S1mm², the surface area of ​​the conductive bar is S2mm², and the thickness of the conductive bar is T1mm, wherein S1=[4, 20]mm², S2=[1200, 4000]mm², T1=[2, 4]mm, and 9600≤S1*S2*T1≤320000.

2. The battery pack according to claim 1, characterized in that: On the path of heat transfer from the battery cell to the conductive bar, the distance between the fuse part and the conductive bar is L1 mm, wherein 6 mm ≤ L1 ≤ 18 mm.

3. The battery pack according to claim 1, characterized in that: The minimum cross-sectional area of ​​the conductive bar is S3 mm², where 3≤S3 / S1≤37.

5.

4. The battery pack according to claim 1, characterized in that: The conductive bar and the pole are welded to form a first weld mark, and the area of ​​the first weld mark is S4 mm², wherein 240≤S4*S1≤3000.

5. The battery pack according to claim 1, characterized in that: The contact area between the conductive bar and the pole is S5 mm², wherein 400≤S5*S1≤10000.

6. The battery pack according to claim 1, characterized in that: The conductive bar is connected to the plurality of poles, and a buffer groove is provided on the conductive bar and in an area between two adjacent poles. The width of the buffer groove is W1 mm, and the depth of the buffer groove is D mm, wherein 0.3≤(W1*D) / S1≤3.

7. The battery pack according to claim 1, characterized in that: It also includes a flexible circuit substrate and a temperature collection unit arranged on the conductive bar, the temperature collection unit is electrically connected to the flexible circuit substrate, and on the path of heat transfer from the battery cell to the temperature collection unit, the distance between the temperature collection unit and the fuse part is L2mm, wherein 6.5mm≤L2≤20mm.

8. The battery pack according to claim 7, characterized in that: On the path of heat transfer from the battery cell to the temperature collection unit, the distance between the temperature collection unit and the pole is L3 mm, wherein 0.5 mm≤L3≤12 mm.

9. The battery pack according to claim 7, characterized in that: It also includes a conductive connecting piece, which is connected to the conductive row. The flexible circuit substrate is provided with a circuit trace. The conductive connecting piece is connected to the circuit trace. A fuse is provided on the circuit trace. On the path of heat transfer from the battery cell to the flexible circuit substrate, the distance between the fuse and the fuse part is L4mm, wherein 6.5mm≤L4≤20mm.

10. The battery pack according to claim 9, characterized in that: The flexible circuit substrate has a cantilever portion extending outward, the circuit trace extends to the cantilever portion, one end of the conductive connecting piece is attached to the conductive row, and the other end is arranged on the cantilever portion and connected to the circuit trace on the cantilever portion, and the fuse is arranged on the circuit trace of the cantilever portion.

11. The battery pack according to claim 1, characterized in that: The number of the battery cell bodies is n, and the conductive bar is connected to the poles corresponding to the n battery cell bodies, wherein 24≤((S2*T1) / n)*S1≤160000.

12. The battery pack according to any one of claims 1 to 11, characterized in that: The battery cell is a wound battery cell, and the pole lug includes a plurality of pole lug sheets stacked together, and the pole lug sheets include a first sub-connection portion, a sub-fuse portion, and a second sub-connection portion connected in sequence, all the first sub-connection portions of the pole lug are stacked together to form the first connection portion, all the second sub-connection portions of the pole lug are stacked together to form the second connection portion, all the sub-fuse portions of the pole lug are welded together to form the fuse portion, and a second weld mark is formed on the side of the pole lug.

13. The battery pack according to claim 12, characterized in that: Partial regions of all the sub-fuse portions of the tab are welded together.

14. The battery pack according to claim 12, characterized in that: The entire regions of all the sub-fuse portions of the tab are welded together, and the area of ​​the second weld mark is equal to or greater than the area of ​​the side surface of the fusing portion.

15. The battery pack according to claim 14, characterized in that: The second weld mark is formed on the side of the outermost pole tab sheet, and on the path of heat transfer from the battery cell to the conductive bar, the distance between one end of the second weld mark close to the second sub-connection portion and one end of the sub-fuse portion of the pole tab sheet close to the second sub-connection portion is L5mm, wherein 1mm≤L5≤8mm.

16. The battery pack according to claim 14, characterized in that: The second weld mark is formed on the side of the outermost pole tab sheet, and on the path of heat transfer from the battery cell to the conductive bar, the distance between one end of the second weld mark close to the first sub-connection part and one end of the sub-fuse part of the pole tab sheet close to the first sub-connection part is L6mm, wherein 1mm≤L6≤8mm.

17. The battery pack according to claim 12, characterized in that: The second connecting portion is welded to the end of the pole located in the shell to form a third weld mark. On the path of heat transfer from the battery cell to the conductive bar, the distance between the second weld mark and the third weld mark is L7mm, wherein 1mm≤L7≤5mm.

18. The battery pack according to claim 17, characterized in that: On the path of heat transfer from the battery cell to the conductive bar, the distance between an end of the fuse away from the first connection portion and an end of the fuse close to the first connection portion is L8 mm, wherein 0.4≤L8 / L7≤8.

19. The battery pack according to claim 12, characterized in that: The second connection portion is welded to the end of the pole located in the shell to form a third weld mark, and the second weld mark and the third weld mark are connected together.

20. The battery pack according to any one of claims 1 to 11, characterized in that: The battery cell is a laminated battery cell, the pole tab comprises a plurality of pole tab sheets stacked together, the pole tab sheet comprises a first sub-connection portion, a sub-fuse portion and a second sub-connection portion connected in sequence, and the sub-fuse portions of the plurality of pole tab sheets are spaced apart from each other.

21. The battery pack according to any one of claims 1 to 11, characterized in that: The second connecting portion is welded to the end of the pole located in the shell to form a third weld mark. On the path of heat transfer from the battery cell to the conductive bar, the distance between the fuse portion and the third weld mark is L9mm, wherein 1mm≤L9≤10mm.

22. The battery pack according to any one of claims 1 to 11, characterized in that: The second connecting portion is welded to the end of the pole located in the shell to form a third weld mark, and the area of ​​the third weld mark is S6 mm², wherein 0.00062≤S6 / (S2*T1)≤0.

033.

23. The battery pack according to any one of claims 1 to 11, characterized in that: It also includes an insulating film, and the insulating film is provided on at least one side of the electrode tab in the first direction.

24. The battery pack according to claim 23, characterized in that: The insulating film covers a region of the fusing portion of the tab.

25. The battery pack according to claim 24, characterized in that: The insulating film extends to a region of the first connecting portion and / or a region of the second connecting portion.

26. The battery pack according to claim 23, characterized in that: The distance between the two sides of the insulating film in the second direction is W2 mm, and the distance between the two sides of the tab in the second direction is W3 mm, wherein 1.1≤W2 / W3≤1.5, and the second direction is perpendicular to the first direction.

27. The battery pack according to claim 23, characterized in that: One side of the electrode tab in the first direction is a welding surface, a welding area is provided on the welding surface, and a region corresponding to the welding area on the other side of the electrode tab in the first direction is not covered with the insulating film.

28. The battery pack according to any one of claims 1 to 11, characterized in that: The distance between the two sides of the pole ear in the first direction is T2mm, 0.004mm≤T2≤0.02mm, the resistivity of the pole ear is ρΩ·m, 1.5*10^-8Ω·m≤ρ≤3*10^-8Ω·m, and on the connection path between the pole ear and the battery body, the distance between the end of the fuse part close to the first connection part and the end away from the first connection part is L 10 mm, 2mm≤L 10 ≤8mm.

29. The battery pack according to any one of claims 1 to 11, characterized in that: On the connection path between the tab and the battery body, the distance between the fuse part and the battery body is L 11 mm, where 5 mm ≤ L 11 ≤20mm.

30. The battery pack according to any one of claims 1 to 11, characterized in that: The battery body has an active material layer inside. On the connection path between the tab and the battery body, the distance between the fuse part and the active material layer is L. 12 mm, where 6.5 mm ≤ L 12 ≤21.5mm.

31. The battery pack according to any one of claims 1 to 11, characterized in that: The battery body has a tab glue inside, and the distance between the tab and the battery body is L. 13 mm, where 7 mm ≤ L 13 ≤22mm.

32. The battery pack according to any one of claims 1 to 11, characterized in that: The battery cell body has a diaphragm inside, and the distance between the fuse part and the diaphragm on the connection path between the tab and the battery cell body is L. 14 mm, where 5 mm ≤ L 14 ≤20mm.

Images