Power-off protection connecting piece, single battery and battery module

Abstract

The utility model provides a power-off protection connecting piece, a single battery and a battery module, the power-off protection connecting piece comprises a tab connecting part and a pole connecting part, and the tab connecting part is connected with the pole connecting part; a fusing region is formed at the junction of the tab connecting part and the pole connecting part, the fusing region comprises a first fusing section, a fusing port and a second fusing section, the fusing port is rectangular, the first fusing section and the second fusing section are respectively positioned between two ends of the fusing port and two side edges of the fusing region, the width of the fusing port is W, and the value range of W is 4-10mm; the length of the fusing area is H1, the length of the fusing port is H, and H and H1 meet the relational expression: 1 / 2 < = H / H1; when overcurrent occurs, the power-off protection connecting sheet performs fusing protection at the fusing section to avoid fire in the single battery, and under the condition that a plurality of single batteries exist, the setting of the fusing area can prevent the fire from spreading to other single batteries to cause serious loss, so that the safety performance of the single battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a power-off protection connecting piece, a single battery and a battery module. Background Art

[0002] With the increasing maturity of battery technology, power batteries are widely used in electric vehicles, and the requirements for the use performance and safety of power batteries are increasing day by day. There are risks such as thermal runaway in power batteries. When abnormal conditions such as short circuits occur inside the battery, the gas pressure inside the battery increases. If the high-temperature flue gas inside the battery is not discharged in time, more serious safety accidents such as battery explosion may occur. In view of the above situation, in the prior art, an explosion-proof valve is arranged on the shell, and the high-temperature flue gas inside the battery is discharged through the explosion of the explosion-proof valve.

[0003] However, the explosion-proof valve is usually directly arranged on the surface of the shell, and components such as the power-off protection connecting piece arranged between the electrode group and the shell inside the battery will have a certain obstruction to the flow of gas, affecting the smoothness of exhaust. And when thermal runaway occurs, the battery is usually connected to the circuit. If the connection between the battery cell and the circuit cannot be disconnected in time, it may cause short-circuit damage to the entire circuit, further increasing the loss.

[0004] The ear of the single battery of the existing battery module is connected to the pole column through a power-off protection connecting piece. When the single battery is powered on, the current may be too large. In the prior art, a fusing port is arranged on the power-off protection connecting piece. When the current is too large, the fusing section at the fusing port fuses; however, the current fusing port is strip-shaped, and its fusing time is often greater than 35 s. When thermal runaway occurs in the single battery, the fusing time of the fusing section at the fusing port is relatively long, which is likely to cause thermal runaway, thus spreading to other single batteries and causing serious losses. Therefore, how to overcome the above existing technical problems and defects has become a key problem to be solved. Summary of the Utility Model

[0005] Aiming at the problem that the fusing time of the existing power-off protection connecting piece is too long and the single battery cannot be effectively protected, the utility model provides a power-off protection connecting piece, a single battery and a battery module.

[0006] The technical solutions adopted by the utility model to solve the above technical problems are as follows:

[0007] The present utility model provides a power-off protection connecting piece on the one hand, which includes an ear connecting part and a pole connecting part, and the ear connecting part is connected to the pole connecting part; a fusing area is formed at the connection boundary position between the ear connecting part and the pole connecting part, and the fusing area includes a first fusing section, a fusing opening and a second fusing section. The shape of the fusing opening is rectangular, the length direction of the fusing opening is consistent with the extending direction of the fusing area, the first fusing section extends from one end of the fusing opening to one end edge of the fusing area, the second fusing section extends from the other end of the fusing opening to the other end edge of the fusing area, the width of the fusing opening is W, and the value range of W is 4-10 mm; the length of the fusing area is H1, the length of the fusing opening is H, and H and H1 satisfy the relational expression: 1 / 2 ≤ H / H1.

[0008] Optionally, the side length of the fusing opening is W, and the value range of W is 6-10 mm.

[0009] Optionally, the length of the fusing area is H1, the length of the fusing opening is H, and H and H1 satisfy the relational expression: 1 / 2 ≤ H / H1 ≤ 2 / 3.

[0010] Optionally, a pole welding area is provided on the pole connecting part. The first fusing section is located on the side of the fusing opening away from the pole welding area, and the second fusing section is located on the side of the fusing opening close to the pole welding area. The length of the first fusing section is L1, the length of the second fusing section is L2, and L1 and L2 satisfy the relational expression: 1 ≤ L1 / L2.

[0011] Optionally, L1 and L2 satisfy the relational expression: 1 ≤ L1 / L2 ≤ 2.

[0012] Optionally, the ear connecting part includes a first ear connecting part and a second ear connecting part, the fusing area includes a first fusing area and a second fusing area, the first fusing area is located between the pole connecting part and the first ear connecting part, and the second fusing area is located between the pole connecting part and the second ear connecting part.

[0013] Optionally, the power-off protection connecting piece has a first plane, and the first plane is parallel to the thickness direction of the power-off protection connecting piece; the first ear connecting part and the second ear connecting part are respectively located on both sides of the first plane, the pole connecting part is symmetrically arranged with respect to the first plane, and the first fusing area and the second fusing area are symmetrically arranged with respect to the first plane.

[0014] On the other hand, the present utility model provides a single cell, comprising a housing, a battery cell assembly and a cover assembly; the battery cell assembly is disposed in an inner cavity formed by enclosing the housing and the cover assembly; a positive tab is provided on the battery cell assembly, a positive terminal is provided on the cover assembly, and the power-off protection connection piece as described above is further included. The tab connection portion of the power-off protection connection piece is connected to the positive tab, the terminal connection portion of the power-off protection connection piece is connected to the positive terminal, and the positive tab and the positive terminal are respectively located on both sides of the power-off protection connection piece.

[0015] Optionally, the battery cell assembly includes a plurality of battery cells, and the positive tabs of the plurality of battery cells are connected to the tab connection portion.

[0016] On yet another aspect, the present utility model provides a battery module, comprising the single cell as described above.

[0017] According to the power-off protection connection piece provided by the present utility model, a fusing zone is formed at the connection boundary position between the tab connection portion and the terminal connection portion, and a fusing opening is provided on the fusing zone. Due to the formation of the fusing opening, the resistance around the fusing opening is greater, and fusing is more likely to occur at the first fusing section and the second fusing section. When overcurrent occurs (such as short circuit), the first fusing section and the second fusing section on both sides of the fusing opening are fused, and the tab connection portion and the terminal connection portion will be spaced apart from each other and form an open circuit, thereby achieving the fusing protection effect. At the same time, the present utility model sets the fusing opening as a rectangle, and the value range of W is 4-10 mm, and H and H1 satisfy the relationship: 1 / 2 ≤ H / H1. For the single cell of the present utility model, when overcurrent occurs (such as short circuit), fusing protection can be carried out at the fusing section through the power-off protection connection piece, thereby avoiding the occurrence of fire inside the single cell. In the case of having a plurality of single cells, the spread of fire to other single cells can be avoided, causing serious losses. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of a conventional power-off protection connection piece;

[0019] Figure 2 is a schematic labeled diagram of a power-off protection connection piece provided by an embodiment of the present utility model;

[0020] Figure 3 is a schematic structural diagram of a power-off protection connection piece provided by an embodiment of the present utility model;

[0021] Figure 4 is a schematic structural diagram of a single cell provided by an embodiment of the present utility model;

[0022] Figure 5Schematic structure of the power-off protection connection piece, battery cell assembly, and cover plate assembly in a single battery provided by an embodiment of the present utility model before cell assembly Figure 1 ;

[0023] Figure 6 is Figure 5 Schematic structure from another perspective Figure 2 ;

[0024] Reference numerals in the accompanying drawings of the specification are as follows:

[0025] 100 - Power-off protection connection piece; 11 - Pole connection part; 111 - Pole welding area; 112 - First plane; 12 - Tab connection part; 121 - First tab connection part; 122 - Second tab connection part; 13 - Avoidance notch; 131 - Arc segment; 132 - Straight segment; 14 - Fusing area; 141 - First fusing area; 142 - Second fusing area; 143 - First fusing segment; 144 - Second fusing segment; 15 - Fusing opening; 151 - First fusing opening; 152 - Second fusing opening; 200 - Single battery; 21 - Housing; 22 - Battery cell assembly; 221 - Positive tab; 222 - Battery cell; 23 - Cover plate assembly; 231 - Positive pole Detailed implementation manners

[0026] In order to make the technical problems, technical solutions, and beneficial effects solved by the present utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0027] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "side", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0028] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present utility model can be understood according to specific situations.

[0029] Such as Figure 2 - Figure 3As shown, in one embodiment, the present utility model provides a power-off protection connecting piece, which includes an ear connecting portion 12 and a pole connecting portion 11. The ear connecting portion 12 is connected to the pole connecting portion 11; a fusing area 14 is formed at the connection boundary position between the ear connecting portion 12 and the pole connecting portion 11. The fusing area 14 includes a first fusing segment 143, a fusing opening 15 and a second fusing segment 144. The shape of the fusing opening 15 is rectangular, and the length direction of the fusing opening 15 is consistent with the extending direction of the fusing area 14. The first fusing segment 143 extends from one end of the fusing opening 15 to one end edge of the fusing area 14, and the second fusing segment 144 extends from the other end of the fusing opening 15 to the other end edge of the fusing area 14. The width of the fusing opening 15 is W, and the value range of W is 4-10mm; the length of the fusing area 14 is H1, and the length of the fusing opening 15 is H. H and H1 satisfy the relational expression: 1 / 2≤H / H1.

[0030] Specifically, for the sake of simplifying subsequent expressions, the first fusing segment 143 and the second fusing segment 144 are collectively referred to as fusing segments.

[0031] Specifically, a fusing area 14 is formed at the connection boundary position between the ear connecting portion 12 and the pole connecting portion 11, and a fusing opening 15 is arranged on the fusing area 14. Due to the formation of the fusing opening 15, the resistance around the fusing opening 15 is greater, and fusing is more likely to occur at the first fusing segment 143 and the second fusing segment 144. When overcurrent occurs (such as short circuit), the first fusing segment 143 and the second fusing segment 144 on both sides of the fusing opening 15 are fused, and the ear connecting portion 12 and the pole connecting portion 11 will be spaced apart from each other and form an open circuit, thereby achieving the fusing protection effect.

[0032] As Figure 1 shown, the width of the existing fusing opening 15 is within 2.5mm, and when the overcurrent area is certain and the current is 3200A, its fusing time is greater than 35s;

[0033] As Figure 2 - 3 shown, the width of the fusing opening 15 of the present utility model is 4-10mm, and when the overcurrent area is certain and the current is 3200A, its fusing time is less than 30s.

[0034] Specifically, the value range of W is any one value or a range value composed of any two point values among 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm.

[0035] Specifically, the length of the fusing area 14 can be designed according to the capacity ratio performance of the single cell 200, and the size of H1 does not affect the width W of the fusing opening 15; further, when the width W of the fusing opening 15 is equal, the greater the length H of the fusing opening 15, the faster the fusing speed; when the length H of the fusing opening 15 is much less than the length of the fusing area 14, such as when H / H1 = 0.4, the fusing area 14 cannot be fused.

[0036] In the present utility model, the fusing opening 15 is set to be rectangular, and the value range of W is 4 - 10 mm, and H and H1 satisfy the relation: 1 / 2 ≤ H / H1; for the single cell 200 of the present utility model, in case of overcurrent (such as short circuit), the power-off protection connecting piece can quickly fuse at the first fusing section 143 and the second fusing section 144, thereby avoiding the occurrence of fire inside the single cell 200. In the case of having multiple single cells 200, it can prevent the spread of fire to other single cells 200, causing serious losses.

[0037] As Figure 2 - Figure 3 shown, in a preferred embodiment, the value range of W is 6 - 10 mm.

[0038] Specifically, when the width of the fusing opening 15 is between 6 - 10 mm, with a certain overcurrent area and a current of 3200 A, the fusing time of the fusing section is less than 30 s, avoiding serious losses caused by fire.

[0039] As Figure 2 - Figure 3 shown, in a preferred embodiment, H and H1 satisfy the relation: 1 / 2 ≤ H / H1 ≤ 2 / 3.

[0040] Specifically, the length of the fusing area 14 can be designed according to the capacity rate performance of the single cell 200, and the size of H does not affect the width W of the fusing opening 15; further, when the width W of the fusing opening 15 is equal, the larger the length H of the fusing opening 15, the faster the fusing speed.

[0041] When the set fusing time is constant, the difference between H1 - H has a corresponding relationship with W, that is, the smaller the difference between H1 - H (overcurrent cross-section), the smaller W; that is, the larger the difference between H1 - H (overcurrent cross-section), the larger W.

[0042] When H and H1 satisfy the relation: 1 / 2 ≤ H / H1 ≤ 2 / 3, when the current flowing through the fusing area 14 is greater than or equal to the fusing current, the fusing area 14 will quickly fuse accordingly, disconnecting the connection between the tab connection part 12 and the terminal connection part 11, avoiding the occurrence of fire inside; when H and H1 satisfy the relation: 1 / 2 ≤ H / H1 ≤ 2 / 3, when the current flowing through the fusing area 14 is less than the fusing current, it can indicate that the connection between the tab connection part 12 and the terminal connection part 11 of the single cell 200 is normally energized, and it will not cause the fusing section to be too short due to the too large fusing opening 15, avoiding the too short fusing section causing the temperature of the single cell 200 to rise when the current is normal, thereby affecting the service life of the single cell, and even causing a fusing phenomenon when the current is normal, affecting the normal operation of the single cell 200.

[0043] As Figure 2 - Figure 3As shown, in one embodiment, a pole welding area 111 is provided on the pole connection part 11. The first fusing section 143 is located on the side of the fusing opening 15 away from the pole welding area 111, and the second fusing section 144 is located on the side of the fusing opening 15 close to the pole welding area 111. The length of the first fusing section 143 is L1, and the length of the second fusing section 144 is L2. L1 and L2 satisfy the relational expression: 1 ≤ L1 / L2.

[0044] Specifically, when the ratio of the length of the first fusing section 143 to the length of the second fusing section 144 is less than 1, the fusing time is longer. When the ratio of the length of the first fusing section 143 to the length of the second fusing section 144 is greater than 1, the fusing speed is faster.

[0045] As Figure 2 - Figure 3 shown, in one embodiment, L1 and L2 satisfy the relational expression: 1 ≤ L1 / L2 ≤ 2.

[0046] Specifically, the ratio range of the length of the first fusing section 143 to the length of the second fusing section 144 is any point value or the range value composed of any two point values among 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2; in a preferred embodiment, the ratio range of the length of the first fusing section 143 to the length of the second fusing section 144 is 1.5.

[0047] When the ratio of the length of the first fusing section 143 to the length of the second fusing section 144 is less than 1, the fusing time is longer; when the ratio of the length of the first fusing section 143 to the length of the second fusing section 144 is greater than 2, the fusing time is longer, and the strength of the power-off protection connecting piece becomes weak and is prone to deformation, affecting the welding between the pole welding area 111 and the pole, resulting in poor welding reliability.

[0048] As Figure 2 - Figure 3 shown, in one embodiment, the tab connection part 12 includes a first tab connection part 121 and a second tab connection part 122. The fusing area 14 includes a first fusing area 141 and a second fusing area 142. The first fusing area 141 is located between the pole connection part 11 and the first tab connection part 121, and the second fusing area 142 is located between the pole connection part 11 and the second tab connection part 122.

[0049] Specifically, to increase the capacity, multiple battery cells 222 are usually provided in the single battery cell 200. The first tab connection part 121 and the second tab connection part 122 are provided. The tabs of some battery cells 22 are connected to the first tab connection part 121 (such as by welding), and the tabs of some battery cells 222 are connected to the second tab connection part 122 (such as by welding), which is beneficial to reducing the tab length of the battery cells 222 and facilitating the welding of the tabs to the tab connection part 12. Specifically, the first tab connection part 121 and the second tab connection part 122 can respectively weld the tabs of the corresponding battery cells 222. When a fire breaks out inside the single battery cell 200, the first fuse segments 143 and the second fuse segments 144 on both sides of the first fuse area 141 are fused. The first tab connection part 121 and the second tab connection part 122 will be spaced apart from the pole connection part 11 and form an open circuit, thereby achieving the fuse protection effect, preventing the single battery cell from catching fire, and preventing a fire in one single battery cell 200 from spreading to other single battery cells 200 in the battery module.

[0050] Such as Figure 2 - Figure 3 As shown, in one embodiment, the power-off protection connecting piece 100 has a first plane 112, and the first plane 112 is parallel to the thickness direction of the power-off protection connecting piece 100; the first tab connection part 121 and the second tab connection part 122 are respectively located on both sides of the first plane 112, the pole connection part 11 is symmetrically arranged with respect to the first plane 112, the fuse opening 15 on the first fuse area 141 is the first fuse opening 151, the fuse opening 15 on the second fuse area 142 is the second fuse opening 152, and the first fuse area 141 and the second fuse area 142 are symmetrically arranged with respect to the first plane 112, so that the first fuse opening 151 and the second fuse opening 152 are also symmetrically arranged with respect to the first plane 112. This is convenient for the processing of the power-off protection connecting piece 100, facilitates the connection of the power-off protection connecting piece 100 to the tabs and poles of the single battery cell 200, and can also ensure the consistency of the fuse times of the first fuse area 141 and the second fuse area 142.

[0051] Specifically, a pole welding area 111 is provided on the pole connection part 11. The pole welding area 111 is circular, and the center of the circle of the pole welding area 111 is located on the first plane 112.

[0052] Such as Figure 2 - 3 As shown, in one embodiment, it further includes an avoidance notch 13 for avoiding the liquid injection hole. The avoidance notch 13 is directly opposite to the liquid injection hole. At least part of the avoidance notch 13 is configured as an arc-shaped notch and the radius is greater than the size of the liquid injection hole to improve the stability of the battery cell during the electrolyte injection process. Specifically, the arc-shaped notch is located on the tab connection part 12 and the pole connection part 11.

[0053] Specifically, the avoidance notch 13 is located between the first tab connection portion 121, the pole connection portion 11, and the second tab connection portion 122; the avoidance notch 13 includes an arc segment 131 and two straight segments 132. The arc segment 131 is arranged on the pole connection portion 11 and is recessed in the direction of the pole connection portion 11. The two straight segments 132 are respectively arranged at both ends of the arc segment 131, and the two straight segments 132 respectively coincide with the side surfaces of the first tab connection portion 121 and the second tab connection portion 122 that are close to each other. Both ends of the arc segment 131 are connected to the two straight segments 132 to form a "U" shape. The first tab connection portion 121, the pole connection portion 11, and the second tab connection portion 122 jointly define the avoidance notch 13. The straight segments 132 are arranged on the first tab connection portion 121 and the second tab connection portion 122, and the arc segment 131 is arranged on the pole connection portion 11. The first tab connection portion 121 and the second tab connection portion 122 can also be constructed as straight lines or curves. Both ends of the arc segment 131 are respectively connected to one end of the straight segment 132, so that the avoidance notch 13 forms a complete notch structure. The straight segments 132 of the two tab connection portions 12 are parallel to each other and arranged at intervals to be separated from the liquid injection hole, avoiding contact between the liquid injection hole and the tab connection portion 12.

[0054] As Figure 4 - Figure 6 shown, in an embodiment, on the other hand, the present utility model provides a single cell 200, including a housing 21, a battery cell assembly 22, and a cover plate assembly 23; the battery cell assembly 22 is arranged in the inner cavity formed by enclosing the housing 21 and the cover plate assembly 23; a positive tab 221 is arranged on the battery cell assembly 22, and a positive pole 231 is arranged on the cover plate assembly 23; the single cell 200 further includes the above-mentioned power-off protection connection piece 100. The tab connection portion 12 of the power-off protection connection piece 100 is connected to the positive tab 221, and the pole connection portion 11 of the power-off protection connection piece 100 is connected to the positive pole 231. The positive tab 221 and the positive pole 231 are respectively located on both sides of the power-off protection connection piece 100. Figure 4 Among them, the positive tab 221 is located on the lower side of the power-off protection connection piece 100, and the positive pole 231 is respectively located on the upper side of the power-off protection connection piece 100.

[0055] Specifically, the power-off protection connection piece 100 is constructed as a metal thin sheet, such as an aluminum sheet.

[0056] The power-off protection connection piece 100 is connected to the battery cell assembly 22 because a fuse opening 15 is arranged on the power-off protection connection piece 100. The shape of the fuse opening 15 is rectangular, the width of the fuse opening 15 is 4 - 10 mm, the length of the fuse area 14 is H1, the length of the fuse opening 15 is H, and H and H1 satisfy the relationship: 1 / 2 ≤ H / H1 ； When overcurrent occurs (such as a short circuit), fuse protection can be carried out at the fuse section through the power-off protection connection piece 100, thereby avoiding internal ignition of the single cell 200.

[0057] The present application places no particular limitation on the shape of the single cell 200, which may be cylindrical, square, or any other shape.

[0058] As Figure 4 - Figure 6 shown, in one embodiment, the battery cell assembly 22 includes a plurality of battery cells 222, and the positive electrode tabs 221 of the plurality of battery cells 222 are connected to the tab connection portion 12.

[0059] Specifically, the positive electrode tabs 221 of some battery cells are connected to the first tab connection portion 121 (such as by welding), and the positive electrode tabs 221 of the remaining battery cells are connected to the second tab connection portion 122 (such as by welding). Compared with the positive electrode tabs 221 of all battery cells being connected to the same tab connection portion 12, it is more conducive to reducing the tab length of the battery cells and facilitating the welding of the positive electrode tabs to the tab connection portion.

[0060] Preferably, the single cell 200 has an even number of battery cells 222 (such as 2, 4, 6, etc.). The positive electrode tabs 221 of half of the battery cells 222 are connected to the first tab connection portion 121, and the positive electrode tabs 221 of the other half of the battery cells 222 are connected to the second tab connection portion 122.

[0061] Another aspect of the present utility model provides a battery module, including the above-mentioned single cell 200.

[0062] The number of single cells 200 included in the battery module of the present application is multiple, effectively expanding the capacity of the battery module and the application range of the battery module. Those skilled in the art can select an appropriate number according to the application and capacity of the battery module. Moreover, inside the single cell 200, one or more battery cells 222 can be connected through the power-off protection connection piece 100. When overcurrent occurs (such as short circuit) in the power-off protection connection piece 100 of the present application, the power-off protection connection piece 100 can perform fusing protection at the fusing section, thereby avoiding the internal fire of the single cell 200. In the case of having multiple single cells 200, it can prevent the fire from spreading to other single cells 200, causing serious losses, and improving the safety during the operation of the battery module.

[0063] The battery module disclosed in the embodiments of the present application can be but is not limited to being used in electrical equipment such as vehicles, ships, or aircraft. The power supply system of the electrical equipment can be composed of the battery module disclosed in the present application.

[0064] The preferred embodiments of the present utility model will be described in more detail below. Although the preferred embodiments of the present utility model are described below, it should be understood that the present utility model can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present utility model more thorough and complete, and to fully convey the scope of the present utility model to those skilled in the art.

[0065] Table 1 Design parameters and test results of examples and comparative examples of a power-off protection connecting piece:

[0066] Table 1

[0067]

[0068]

[0069] Example 1

[0070] This example provides a power-off protection connecting piece, including a tab connecting portion, a terminal connecting portion, and a fusing port. The shape of the fusing port is rectangular, the length of the fusing port is 11.5 mm, the width of the fusing port is 4 mm, the length of the fusing area is 23 mm, the length of the first fusing section is 6.9 mm, and the length of the second fusing section is 4.6 mm.

[0071] Examples 2 - 11

[0072] Examples 2 - 11 are used to illustrate a power-off protection connecting piece disclosed by the present utility model, including most of the operation steps in Example 1. The differences are as follows:

[0073] The lengths of the fusing port, the widths of the fusing port, the lengths of the fusing area, the lengths of the first fusing section, and the lengths of the second fusing section used in Examples 2 - 11 are shown in Table 1.

[0074] Comparative Examples 1 - 5

[0075] Comparative Examples 1 - 5 are used to comparatively illustrate a power-off protection connecting piece disclosed by the present utility model, including most of the operation steps in Example 1. The differences are as follows:

[0076] The lengths of the fusing port, the widths of the fusing port, the lengths of the fusing area, the lengths of the first fusing section, and the lengths of the second fusing section used in Comparative Examples 1 - 5 are shown in Table 1.

[0077] Performance test:

[0078] Perform a fusing test on the power-off protection connecting pieces of Examples 1 - 11 and Comparative Examples 1 - 5 and the battery modules prepared with single cells:

[0079] Test methods and steps:

[0080] a. Adjust the resistance of the test device between the center position of the connection between the short - circuit test device and the positive electrode of the single - cell battery and the center position of the connection between the short - circuit test device and the negative electrode of the single - cell battery to 0.8 - 1.0 mΩ, and record the resistance of the test device.

[0081] b. Connect the single - cell battery that has completed the initial charging to the short - circuit test device.

[0082] c. Connect the voltage and temperature sampling lines of the short - circuit test device to the single - cell battery.

[0083] d. Measure the contact resistance between the center points of the positive and negative electrodes of the single - cell battery and the positive and negative electrodes of the short - circuit test device respectively, and adjust the contact resistance of the connection state between the short - circuit test device and the positive and negative electrodes of the single - cell battery to be less than or equal to 0.1 mΩ respectively. Record the contact resistance, and at the same time calculate the external line resistance (test device resistance + positive electrode contact resistance + negative electrode contact resistance).

[0084] e. Start the test device to form a current loop between the positive and negative electrodes of the single - cell battery. Keep the current for 10 min, then disconnect the current loop, observe for 1 h, and record the current, time, voltage, and temperature; including recording test phenomena such as: swelling, leakage, smoking, fire, explosion, shell rupture and rupture position.

[0085] f. Record the fusing time of the power - off protection connecting piece. If there is no fire, explosion, or leakage phenomenon in the single - cell battery, and the performance of the single - cell battery meets the requirements of GB36276 - 2023, it is determined that the short - circuit test passes.

[0086] As can be seen from the test results in Table 1, in Examples 1 - 11, Comparative Example 1, and Comparative Examples 3 - 5, a rectangular fusing port is used, and the fusing port of Comparative Example 2 is a strip - shaped fusing port. The fusing time of the fusing ports in Examples 1 - 11 is less than 30 s, which can meet the safety use standard.

[0087] The widths of the fusing ports in Comparative Example 1 and Comparative Example 2 are both less than 4 mm, and their fusing times are both above 30 s.

[0088] The ratio of the length of the fusing port in Comparative Example 3 to the length of the fusing area is less than 1 / 2, and no fusing can occur.

[0089] When the length of the first fusing section in Comparative Example 4 is smaller than the length of the second fusing section, its fusing time is above 30 s.

[0090] When the ratio of the length of the first fusing section to the length of the second fusing section in Comparative Example 5 is greater than 2, its fusing time is above 30 s.

[0091] In summary, the present utility model sets the fusing port as a rectangle and meets the following conditions:

[0092] The width of the fusing port is W, and the value range of W is 4 - 10 mm;

[0093] The length of the fusing area is H1, and the length of the fusing port is H. H and H1 satisfy the relationship: 1 / 2H1 ≤ H ≤ 2 / 3H1;

[0094] The length of the first fusing section is L1, and the length of the second fusing section is L2. L1 and L2 satisfy the relationship: 1 ≤ L1 / L2 ≤ 2;

[0095] When the current of the power-off protection connecting piece of the present utility model is 3200 A, the fusing time is less than 30 s, which can meet the safe use standard. This is because when overcurrent occurs (such as short circuit), the overcurrent capacity of the fusing area of the power-off protection connecting piece of the present utility model is relatively good, and the heat accumulation time during overcurrent is short, so the fusing speed is fast. Furthermore, it can avoid the occurrence of fire inside the single battery. In the case of multiple single batteries, it can avoid the spread of fire to other single batteries, causing serious losses; when any of the above conditions is not met, it will lead to too long fusing time.

[0096] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A power-off protection connecting piece, characterized in that: It includes a pole lug connection part and a pole column connection part, the pole lug connection part is connected to the pole column connection part; a fuse zone is formed at the connection junction between the pole lug connection part and the pole column connection part, the fuse zone includes a first fuse section, a fuse opening and a second fuse section, the fuse opening is in the shape of a rectangle, the length direction of the fuse opening is consistent with the extension direction of the fuse zone, the first fuse section extends from one end of the fuse opening to the edge of one end of the fuse zone, the second fuse section extends from the other end of the fuse opening to the edge of the other end of the fuse zone, the width of the fuse opening is W, and the value range of W is 4-10mm; the length of the fuse zone is H1, the length of the fuse opening is H, and H and H1 satisfy the relationship: 1 / 2≤H / H1.

2. The power-off protection connecting piece according to claim 1, characterized in that: The width of the fuse opening is W, and the value range of W is 6-10 mm.

3. The power-off protection connecting piece according to claim 1, characterized in that: The length of the fuse zone is H1, the length of the fuse opening is H, and H and H1 satisfy the relationship: 1 / 2≤H / H1≤2 / 3.

4. The power-off protection connecting piece according to claim 1, characterized in that: A pole welding area is provided on the pole connecting portion, the first fuse section is located on a side of the fuse opening away from the pole welding area, and the second fuse section is located on a side of the fuse opening close to the pole welding area; the length of the first fuse section is L1, the length of the second fuse section is L2, and L1 and L2 satisfy the relationship: 1≤L1 / L2.

5. The power-off protection connecting piece according to claim 4, characterized in that: L1 and L2 satisfy the relationship: 1≤L1 / L2≤2.

6. The power-off protection connecting piece according to claim 1, characterized in that: The pole tab connection portion includes a first pole tab connection portion and a second pole tab connection portion, the fuse zone includes a first fuse zone and a second fuse zone, the first fuse zone is located between the pole connection portion and the first pole tab connection portion, and the second fuse zone is located between the pole connection portion and the second pole tab connection portion.

7. The power-off protection connecting piece according to claim 6, characterized in that: The power-off protection connecting piece has a first plane, which is parallel to the thickness direction of the power-off protection connecting piece; the first pole ear connecting portion and the second pole ear connecting portion are respectively located on both sides of the first plane, the pole connecting portion is symmetrically arranged relative to the first plane, and the first fuse zone and the second fuse zone are symmetrically arranged relative to the first plane.

8. A single battery, comprising a shell, a cell assembly and a cover assembly; the cell assembly is arranged in an inner cavity enclosed by the shell and the cover assembly; the cell assembly is provided with a positive electrode ear, and the cover assembly is provided with a positive electrode column, characterized in that: It also includes the power-off protection connecting piece described in any one of claims 1-7, wherein the pole ear connecting portion of the power-off protection connecting piece is connected to the positive pole ear, the pole column connecting portion of the power-off protection connecting piece is connected to the positive pole column, and the positive pole ear and the positive pole column are respectively located on both sides of the power-off protection connecting piece.

9. A single cell according to claim 8, characterized in that: The battery cell assembly includes a plurality of battery cells, and the positive tabs of the plurality of battery cells are connected to the tab connecting portion.

10. A battery module, characterized in that: Comprising the single cell as claimed in claim 8 or 9.

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