A single battery and electronic device

Abstract

The application discloses a single battery and an electronic device. The single battery comprises a shell, an electrode assembly, a cover plate, a pole and an electric connecting sheet. The electric connecting sheet comprises a pole connecting part, a fusing part, a boss part and a tab connecting part connected in sequence. The pole connecting part is connected with the pole, and the tab connecting part is connected with the tab. The pole connecting part and the fusing part are both double-layer structures with a first metal layer as an upper layer and a second metal layer as a lower layer. The pole connecting part and the boss part abut against the cover plate to limit the electric connecting sheet. There is a gap between the fusing part and the cover plate. The fusing part is provided with a fusing area along the width direction, and the cross-sectional area of the fusing area is smaller than that of other areas of the fusing part. The electric connecting sheet can improve the safety of the single battery and the electronic device, and the cost is low, the energy density of the battery cell or the overcurrent capacity of the battery cell is not reduced, the electric connecting sheet can avoid the reconnection after fusing, and the generation of debris is also avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lithium ion secondary batteries, in particular to a single battery and an electronic device. BACKGROUND

[0002] Lithium ion batteries have been widely used in new energy vehicles. In order to improve the safety of electric vehicles, there are generally fuses in the battery pack and the battery module. The fuse is an alloy material with high electrical conductivity and low melting point, which will quickly melt or cut off the electrical connection between the battery cells under large current. However, inside a single lithium ion battery, due to considerations of cost, space, energy density, etc., it is rare to set a fuse inside the lithium ion battery.

[0003] After the thermal runaway of the battery cell, it will trigger the thermal runaway and combustion of the adjacent battery cell until the module, and then cause a fire of the lithium ion battery. Therefore, adding a fuse at the battery cell level can disconnect the battery cell loop at the first time when the battery cell short-circuits, cut off the current, and greatly improve the safety of the lithium ion battery. The fuse of the lithium ion battery is a soft connection structure established between the pole and the tab of the battery cell, which relies on the melting of the soft connection to cut off the circuit and improve the safety of the battery cell.

[0004] At present, one existing design is to use the existing soft connection to partially melt, which still has the risk of re-contacting, cannot effectively disconnect the battery cell loop, and will produce debris falling into the battery cell when melting. For example, CN112490595A discloses placing the melting part of the soft connection in a containing cavity, and when the melting part melts, the debris generated is retained in the containing space. This scheme will also affect the manufacturing cost, increase the mass of the electrical connection sheet, and increase the temperature of the soft connection during normal operation, thereby affecting the overcurrent capacity of the battery cell and being detrimental to the performance of the battery cell.

[0005] Another design is to add a spring sheet in the soft connection, which relies on the elastic force of the spring to quickly disconnect the electrical connection sheet after the soft connection melts to avoid re-contacting, as described in CN217405653U "Lithium ion battery soft connection sheet structure with high safety performance". This design will affect the manufacturing cost of the electrical connection sheet, increase the mass of the electrical connection sheet, and affect the energy density of the battery cell.

[0006] In summary, the current battery, battery cell or electrical connection sheet cannot meet the requirements of safety and stability, and there is an urgent need to develop a single battery and an electronic device. SUMMARY

[0007] The technical problem solved by the present application is to provide a single battery and an electronic device to overcome the safety problem caused by the re-contacting of the electric connecting sheet after it is fused, and the defects of the debris generated during the fusing process and the reduction of the electrical performance caused by the increase of the electric connecting sheet.

[0008] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0009] In a first aspect, the present application provides a single battery, comprising: a shell, an electrode assembly, a cover plate and a pole; the inside of the shell is hollow as a containing cavity; the electrode assembly is arranged in the containing cavity and comprises a tab; the cover plate is arranged above the shell and is used for sealing the containing cavity; the cover plate is provided with a pole mounting hole for the pole to pass through;

[0010] The single battery further comprises an electric connecting sheet;

[0011] The electric connecting sheet comprises: a pole connecting part, a fusing part, a boss part and a tab connecting part connected in sequence; the pole connecting part is connected with the pole, and the tab connecting part is connected with the tab; the pole connecting part and the fusing part are both double-layer structures with a first metal layer as an upper layer and a second metal layer as a lower layer; wherein, α1<α2, and α1 and α2 are the metal thermal expansion coefficients of the first metal layer and the second metal layer respectively; the pole connecting part and the fusing part are integrally formed through the continuous joint of the first metal layer and the second metal layer; the pole connecting part and the boss part abut against the cover plate to limit the electric connecting sheet; there is a gap between the fusing part and the cover plate; the fusing part is provided with a fusing area along the width direction, and the cross-sectional area of the fusing area is smaller than that of other areas of the fusing part.

[0012] In a second aspect, the present application provides an electronic device comprising the single battery as described above.

[0013] On the basis of the common sense in the art, the above-mentioned preferred conditions can be combined arbitrarily, that is, to obtain each preferred example of the present application.

[0014] The reagents and raw materials used in the present application are commercially available.

[0015] The positive progress effect of the present application is that:

[0016] The safety of the single battery of the present application is improved after the electric connecting piece is arranged, and the cost is low, and the energy density or overcurrent capacity of the battery is not reduced. The electric connecting piece can avoid the situation of reconnection after melting, and ensure the safety of the battery; meanwhile, the generation of debris is avoided, so that additional parts such as a melting debris accommodating cavity are not needed. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structure schematic view of the electric connecting piece of the embodiment 1 of the present application.

[0018] Figure 2 It is a front view of the electric connecting piece of the embodiment 1 of the present application.

[0019] Figure 3 It is a schematic view of the cover plate of the embodiment 1 of the present application.

[0020] Figure 4 It is a schematic view of the electric connecting piece of the embodiment 1 of the present application.

[0021] Figure 5 It is a schematic view of the position relationship between the electric connecting piece and the cover plate of the embodiment 1 of the present application.

[0022] BRIEF DESCRIPTION OF DRAWINGS:

[0023] Electric connecting piece 1

[0024] Pole connecting part 101

[0025] Melting part 102

[0026] Melting area 1021

[0027] First melting groove 1022

[0028] Second melting groove 1023

[0029] Boss part 103

[0030] Tab connecting part 104

[0031] First metal layer 105

[0032] Second metal layer 106

[0033] Transition area 107

[0034] Cover plate 2. DETAILED DESCRIPTION

[0035] In the single battery of the first aspect of the present application:

[0036] Preferably, the boss part protrudes upward along the thickness direction of the first metal layer.

[0037] Preferably, the thickness ratio of the first metal layer to the second metal layer is x:(1-x), 1 / 3≤x≤2 / 3.

[0038] In some preferred embodiments of the present application, the thickness ratio of the first metal layer to the second metal layer is 1:2, 1:1 or 2:1.

[0039] Preferably, when the material of the first metal layer is copper, the material of the second metal layer is aluminum or aluminum alloy.

[0040] Preferably, when the material of the first metal layer is stainless steel, the material of the second metal layer is aluminum or aluminum alloy.

[0041] Preferably, the first metal layer and the second metal layer have different coefficients of thermal expansion, and as the temperature rises, they will produce different bending stresses and different degrees of expansion deformation.

[0042] In the present application, in the melting section, due to the cross-sectional area of the melting zone being smaller than that of other areas, the local temperature is higher, that is, the temperature of the melting zone is higher than that of other areas.

[0043] Preferably, the melting zone satisfies one or both of the following conditions:

[0044] a. The melting zone is a region symmetrically provided with a pair of grooves on both sides of the melting section, and the opening part of the groove penetrates the first metal layer and the second metal layer in the thickness direction of the melting zone;

[0045] b. The melting zone is located at one end of the melting section close to the boss section.

[0046] Preferably, a slotted region is added to the electrical connection sheet to control the melting position of the electrical connection sheet and ensure that the electrical connection sheet can be reliably disconnected when the battery cell is short-circuited.

[0047] Preferably, the pole connecting section and the boss section are located in the same plane along the height direction of the electrical connection sheet, the melting section is parallel to and lower than the plane, forming a concave structure.

[0048] Preferably, the length ratio of the pole connecting section to the melting section is (0.5-2):1.

[0049] Preferably, the boss section and the tab connecting section are single-layer structures or double-layer structures.

[0050] In some preferred embodiments of the present application, when the boss section and the tab connecting section are both single-layer structures, the boss section and the tab connecting section are the first metal layer or the second metal layer.

[0051] In some preferred embodiments of the present application, when the boss portion and the tab connecting portion are both double-layer structures, the boss portion and the tab connecting portion are double-layer structures with the first metal layer as the upper layer and the second metal layer as the lower layer, which are arranged extending from the fuse portion.

[0052] Preferably, the length of the boss portion in the horizontal direction is 5-10 mm.

[0053] Preferably, the length of the boss portion in the horizontal direction is 3-10 times the thickness of the electric connecting sheet.

[0054] Preferably, the size of the boss portion on the electric connecting sheet is designed to ensure that the electric connecting sheet can be reliably disconnected when the electric cell is short-circuited.

[0055] Preferably, the electric connecting sheet is L-shaped, the tab connecting portion, the fuse portion and the boss portion are arranged in the horizontal direction, and the tab connecting portion includes a round corner transition zone extending downward from the end of the boss portion perpendicular to the fuse portion.

[0056] In the present application, when the electric cell is short-circuited, a large current is generated, which significantly increases the temperature of the connecting sheet. In the entire electric connecting sheet, the temperature of the groove area is the highest and the strength is the weakest. The tab connecting portion and the boss portion abut against the battery cover plate. Since the metal thermal expansion coefficient of the second metal layer in the lower layer is larger, the area that expands will move upward. The tab connecting portion and the boss portion are constrained by the cover plate and cannot move upward. The fuse portion, which has a gap between the cover plate, will expand upward. The higher the temperature, the more obvious the bending deformation. Taking the material of the first metal layer as copper and the material of the second metal layer as aluminum as an example, when the temperature reaches 550℃, the metal strength of aluminum will decrease rapidly. At this time, the bending stress caused by the expansion of aluminum is greater than the metal strength of aluminum, and the electric connecting sheet will be quickly broken under stress. The temperature of 550℃ does not reach the melting point temperature of aluminum of 660℃, so there will be no debris.

[0057] The present application will be described in more detail below with reference to a preferred embodiment and the accompanying drawings.

[0058] Embodiment 1

[0059] Figure 1 FIG. 1 is a structural schematic diagram of the electric connecting sheet of the present embodiment; Figure 2 FIG. 2 is a front view of the electric connecting sheet of the present embodiment. Figure 3 FIG. 3 is a schematic diagram of the cover plate of the present embodiment. Figure 4 FIG. 4 is a schematic diagram of the electric connecting sheet of the present embodiment. Figure 5 FIG. 5 is a schematic diagram of the positional relationship between the electric connecting sheet and the cover plate of the present embodiment.

[0060] The electric connecting sheet 1 of the embodiment comprises: a pole connecting part 101, a fusing part 102, a boss part 103 and a tab connecting part 104 connected in sequence; the pole connecting part 101 and the fusing part 102 are both double-layer structures with the first metal layer 105 as the upper layer and the second metal layer 106 as the lower layer, and the thickness ratio of the first metal layer 105 to the second metal layer 106 is 1:1; the material of the first metal layer 105 is copper, and the material of the second metal layer 106 is aluminum, and the metal thermal expansion coefficient of copper is less than that of aluminum.

[0061] The pole connecting part 101 and the fusing part 102 are integrally formed through the continuous joint of the first metal layer 105 and the second metal layer 106; the pole connecting part 101 and the boss part 103 abut against the cover plate 2, and there is a gap between the fusing part 102 and the cover plate 2 for limiting the electric connecting sheet 1; the fusing part 102 is provided with a fusing area 1021 in the width direction, and the cross-sectional area of the fusing area 1021 is less than that of other areas of the fusing part 102.

[0062] The fusing area 1021 is a region with a pair of grooves symmetrically formed on both sides of the fusing part 102, and the opening part of the groove penetrates the first metal layer and the second metal layer in the thickness direction of the fusing area to form a first fusing groove 1022 and a second fusing groove 1023; the fusing area 1021 is located at one end of the fusing part 102 close to the tab connecting part 104; the pole connecting part 101 and the boss part 103 are located in the same plane along the height direction of the electric connecting sheet 1, and the fusing part 102 is parallel to and lower than the plane to form a concave structure; the length ratio of the pole connecting part 101 to the fusing part 102 is 1:1; when the tab connecting part 104 is a single-layer structure, the tab connecting part is the first metal layer or the second metal layer.

[0063] The length of the boss part 103 in the horizontal direction is 5-10 mm, and the length of the boss part 103 in the horizontal direction is 3-10 times the thickness of the electric connecting sheet 1; the electric connecting sheet is L-shaped, the pole connecting part 101, the fusing part 102 and the boss part 103 are arranged in the horizontal direction, and the tab connecting part 104 is vertically downwardly extended from the end of the boss part 103 through a round corner transition area 107 to the fusing part 102.

[0064] The single battery of the embodiment comprises: a shell, an electrode assembly, a cover plate 2, a pole and an electric connecting sheet 1.

[0065] The inside of the shell is hollow as a containing cavity; the electrode assembly is arranged in the containing cavity and comprises a tab; the cover plate 2 is arranged above the shell for sealing the containing cavity; the cover plate 2 is provided with a pole mounting hole for the pole to pass through; the pole connecting part 101 is connected with the pole, and the tab connecting part 104 is connected with the tab.

[0066] The safety of the monomer battery is improved after the electric connecting piece 1 is arranged, the cost is low, and the energy density or overcurrent capacity of the battery cell is not reduced. The electric connecting piece 1 can avoid the situation that the electric connecting piece 1 is reconnected after being fused, and the safety of the battery cell is ensured. Meanwhile, the generation of the debris is avoided, so that additional parts such as a fuse debris accommodating cavity need not to be additionally increased.

Claims

1. A monobloc battery comprising: The shell, the electrode assembly, the cover plate and the pole; The shell is internally hollow as a receiving cavity; The electrode assembly is arranged in the receiving cavity and comprises a tab; The cover plate is arranged above the shell and is used for sealing the receiving cavity; The cover plate is provided with a pole mounting hole for the pole to pass through; The single battery further comprises an electric connection sheet; The electric connection sheet comprises a pole connecting portion, a fuse portion, a boss portion and a tab connecting portion connected in sequence; the pole connecting portion is connected with the pole, and the tab connecting portion is connected with the tab; the pole connecting portion, the fuse portion, the boss portion and the tab connecting portion are all double-layer structures with a first metal layer as an upper layer and a second metal layer as a lower layer; α1<α2, and α1 and α2 are the metal thermal expansion coefficients of the first metal layer and the second metal layer respectively; the pole connecting portion and the fuse portion are integrally formed through continuous jointing of the first metal layer and the second metal layer; The pole connecting portion and the boss portion abut against the cover plate to limit the electric connection sheet; There is a gap between the fuse portion and the cover plate; the fuse portion is provided with a fuse area along the width direction, and the cross-sectional area of the fuse area is smaller than that of other areas of the fuse portion; the fuse area is a region provided with a pair of grooves symmetrically on both sides of the fuse portion, and the opening part of the groove penetrates through the first metal layer and the second metal layer in the thickness direction of the fuse area. The thickness ratio of the first metal layer to the second metal layer is x:(1-x), and 1 / 3≤x≤2 / 3.

2. The unit cell of claim 1, wherein, When the material of the first metal layer is copper, the material of the second metal layer is aluminum or aluminum alloy.

3. The unit cell of claim 1, wherein, When the material of the first metal layer is stainless steel, the material of the second metal layer is aluminum alloy.

4. The cell of claim 1 wherein, The fuse area is located at one end of the fuse portion close to the boss portion.

5. The cell of claim 1 wherein, The pole connecting portion and the boss portion are arranged in the same plane along the height direction of the electric connection sheet, the fuse portion is parallel to and lower than the plane, forming a concave structure; 6. The cell of claim 1 wherein, The length ratio of the pole connecting portion to the fuse portion is (0.5-2):

1. The boss portion and the tab connecting portion are double-layer structures with the first metal layer as an upper layer and the second metal layer as a lower layer, which are arranged from the fuse portion.

7. The cell of claim 1 wherein, The length of the boss portion along the horizontal direction is 5-10 mm; 8. The cell of claim 1 wherein, Or, the length of the boss portion along the horizontal direction is 3-10 times the thickness of the electric connection sheet. The electric connection sheet is L-shaped, the pole connecting portion, the fuse portion and the boss portion are arranged along the horizontal direction, and the tab connecting portion comprises a round corner transition area extending downward from the end of the boss portion and perpendicular to the fuse portion.

9. The cell of claim 1 wherein, The single battery comprises the single battery according to any one of claims 1-9.

10. An electronic device, comprising: ​

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