Secondary battery

Abstract

The embodiment of the utility model discloses a secondary battery, which comprises at least one battery cell, at least two tabs extending along a second direction are arranged on one side of the battery cell; the protection plate comprises a circuit board, one side of the circuit board is provided with connecting pieces which are sequentially arranged in the first direction and are equal to the tabs in number, and the connecting pieces are electrically connected with the tabs corresponding to the connecting pieces in position respectively; wherein in the second direction, the width of at least one connecting sheet is equal to the width of the tab correspondingly connected with the connecting sheet, and the width of the other connecting sheets is greater than the width of the tab correspondingly connected with the connecting sheets. According to the utility model, the tabs and the connecting sheets which have the same width and are connected are used for connecting and positioning between the protective plate and the battery cell, and the rest of connecting sheets are subjected to redundant design for possible offset tolerance, so that the width of the connecting sheets is greater than the width of the rest tabs, and the redundant design required by at least one connecting sheet is omitted; the purpose of reducing the overall length of the protection plate is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a secondary battery. Background Art

[0002] Electronic devices, such as mobile phones or laptops, are equipped with lithium batteries to power them. Among them, the lithium battery is also equipped with a battery protection board, which mainly protects the charging and discharging of the lithium battery to extend its service life.

[0003] In related technologies, in order to meet the battery life and fast charging performance of electronic products, the space utilization rate of lithium batteries needs to be continuously improved. In order to improve the fast charging performance of lithium batteries, reducing the space occupied by battery protection boards has become an inevitable choice.

[0004] However, the battery protection board in the prior art is affected by the offset tolerance of the tab position. To ensure that the tab of the battery cell can be completely welded on the tab, the length of the connecting piece on the battery protection board is increased, which in turn increases the overall length of the battery protection board. Utility Model Content

[0005] An embodiment of the utility model provides a secondary battery, in which a first connecting piece and a first pole ear are used as the connection positioning between a protection plate and a battery cell, and a second connecting piece is redundantly designed for a possible offset tolerance so that its width is greater than the width of the second pole ear, thereby eliminating the redundant design required for the first connecting piece, thereby achieving the purpose of reducing the overall length of the protection plate.

[0006] In order to solve the above technical problems, the embodiments of the present utility model disclose the following technical solutions:

[0007] In one aspect, a secondary battery is provided, comprising:

[0008] At least one battery cell having a first direction, a second direction and a third direction that intersect and are perpendicular to each other, and at least two tabs extending along the second direction are provided on one side of the battery cell;

[0009] A protection plate, comprising a circuit board, on one side of which connection plates are arranged in sequence along the first direction and are equal in number to the pole tabs, and each of the connection plates is electrically connected to a pole tab corresponding to its position;

[0010] Wherein, in the second direction, the width of at least one of the connecting sheets is equal to the width of the corresponding pole lug connected thereto, and the widths of the remaining connecting sheets are greater than the widths of the corresponding pole lugs connected thereto.

[0011] In addition to one or more of the features disclosed above, or as an alternative, a connecting piece having a width equal to a width of a correspondingly connected pole lug is a first connecting piece, and a pole lug connected to the first connecting piece is a first pole lug;

[0012] The connecting piece whose width is greater than the width of the corresponding pole lug connected thereto is the second connecting piece, and the pole lug connected to the second connecting piece is the second pole lug;

[0013] The number of the first pole tabs and the first connecting sheets is equal to the number of the battery cells, and the number of the second pole tabs and the second connecting sheets is greater than or equal to the number of the battery cells.

[0014] In addition to one or more features disclosed above, or as an alternative, when the first pole lug and the second pole lug do not have an offset tolerance with respect to the battery cell about the first direction, the second pole lug has a first centerline extending along the second direction, the second connecting piece has a second centerline extending along the second direction, and the first centerline and the second centerline are collinear.

[0015] In addition to or as an alternative to one or more features disclosed above, in the first direction, the second pole tab has a second width w2, and the second connecting piece has a fourth width w4, wherein w2=2 mm, and w4=4 mm.

[0016] In addition to or as an alternative to one or more features disclosed above, in the first direction, the first pole tab has a first width w1, and the first connecting piece has a third width w3, wherein w1=w3=2 mm.

[0017] In addition to or as an alternative to one or more of the features disclosed above, in the first direction, there is a third distance L3 between adjacent connecting pieces, wherein L3=4 mm.

[0018] In addition to one or more of the features disclosed above, or as an alternative, the circuit board includes a first bending portion, which is arranged on a side of the circuit board close to the connecting piece and separated from the connecting piece, and the first bending portion is a flexible structure so that the circuit board can be bent with the first bending portion as a fold line.

[0019] In addition to or as an alternative to one or more of the features disclosed above, a terminal is provided at one end of the circuit board away from the tab.

[0020] In addition to one or more of the features disclosed above, or as an alternative, the circuit board includes a plurality of equally spaced second bending portions, the second bending portions being arranged on a side of the circuit board close to the terminal, and the second bending portions being flexible structures so that the circuit board can be bent along the second bending portions as fold lines.

[0021] In addition to or as an alternative to one or more of the features disclosed above, the circuit board includes a device-free area arranged around the periphery of the connecting piece, and the electronic components arranged on the circuit board (100) are arranged in an area outside the device-free area.

[0022] One of the above technical solutions has the following advantages or beneficial effects: the present application uses pole ears and connecting sheets with equal width and connected as the connection positioning between the protection plate and the battery cell, and makes redundant design for the possible offset tolerance of the remaining connecting sheets so that their width is greater than the width of the remaining pole ears, thereby eliminating the redundant design required for at least one connecting sheet, so as to achieve the purpose of shortening the overall length of the protection plate, reduce the space occupied by the protection plate in the secondary battery, and then improve the space utilization in the secondary battery, thereby improving the energy density of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The technical solutions and other beneficial effects of the present invention will be made apparent by describing in detail the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0024] Figure 1 It is a structural schematic diagram of a battery cell and a protection board in a secondary battery provided according to an embodiment of the utility model;

[0025] Figure 2 It is a structural schematic diagram of a battery cell and a protection board in a secondary battery provided according to an embodiment of the utility model;

[0026] In the figure: 10 - battery cell; 11 - first pole ear; 12 - second pole ear;

[0027] 100 - circuit board; 101 - first connecting piece; 102 - second connecting piece; 110 - first area; 120 - second area; 131 - first bending portion; 132 - second bending portion; 200 - terminal. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and beneficial effects of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described in this specification are only for explaining the utility model, and are not intended to limit the utility model.

[0029] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are 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 cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, the meaning of "multiple" refers to two or more, unless otherwise clearly and specifically defined.

[0030] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0031] In the present utility model, unless otherwise clearly stipulated and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0032] Reference Figure 1 , Figure 2 As shown, Figure 1 , Figure 2The schematic diagram of the structure of a battery cell and a protection board in a secondary battery provided according to an embodiment of the utility model is shown. In this embodiment, the secondary battery includes a battery cell 10 and a protection board. The battery cell 10 is a bare battery cell 10. The battery cell 10 is in the shape of a rectangular parallelepiped structure. The battery cell 10 has a first direction x, a second direction y and a third direction z that intersect and are perpendicular. The battery cell 10 is provided with a first pole tab 11 and a second pole tab 12 drawn from the battery cell 10 at one end of the second direction y. The first pole tab 11 and the second pole tab 12 are arranged side by side and extend in a direction away from the battery cell 10. The extension directions of the first pole tab 11 and the second pole tab 12 are parallel. One of the first pole tab 11 and the second pole tab 12 is a positive pole tab, which is electrically connected to the positive pole piece in the battery cell 10, and the other is a negative pole tab, which is electrically connected to the negative pole piece inside the battery cell 10. In this embodiment, the first pole tab 11 and the second pole tab 12 are of equal size. The first pole tab 11 has a first width w1 parallel to the first direction x and a first length l1 parallel to the second direction y. The second pole tab 12 has a second width w2 parallel to the first direction x and a second length l2 parallel to the second direction y, wherein w1=w2, l1=l2. In the first direction x, there is a first distance L1 between the first pole tab 11 and the second pole tab 12. In this embodiment, w1=w2=2mm, l1=l2=3mm, and L1=5mm.

[0033] Continue to refer to Figure 1The protection board is electrically connected to the first pole ear 11 and the second pole ear 12 of the battery cell 10, wherein the protection board includes: a circuit board 100, on which a first connecting piece 101 and a second connecting piece 102 are provided, and the first connecting piece 101 and the second connecting piece 102 are electrically connected to the first pole ear 11 and the second pole ear 12 respectively. The first connecting piece 101 and the second connecting piece 102 are arranged on the same side of the circuit board 100. In the third direction z, the orthographic projection of the first pole lug 11 on the circuit board 100 overlaps with the first connecting piece 101, wherein the orthographic projection of the first pole lug 11 on the circuit board 100 overlaps with the orthographic projection of the first pole lug 11 on the circuit board 100 on both sides of the first direction x, and the orthographic projection of the second pole lug 12 on the circuit board 100 overlaps with the second connecting piece 102, and the orthographic projection of the second pole lug 12 on the circuit board 100 on both sides of the first direction x are both accommodated in the second connecting piece 102, the width of the second connecting piece 102 is greater than the width of the second pole lug 12, and the first center line of the second pole lug 12 extending along the second direction y is collinear with the second center line of the second connecting piece 102 extending along the second direction y. It should be understood that the first connecting piece 101 has a third width w3 parallel to the first width w1, satisfying that w1=w3; the second connecting piece 102 has a fourth width w4 parallel to the second width w2, satisfying that w4>w2. In this embodiment, the first connecting piece 101 has a third width w3, w3=2 mm; the second connecting piece 102 has a fourth width w4, w4=4 mm. There is a third distance L3 between the first connecting piece 101 and the second connecting piece 102, satisfying that L3=4 mm.

[0034] Further, the process of electrically connecting the first connecting sheet 101 and the second connecting sheet 102 to the first pole tab 11 and the second pole tab 12 respectively includes a welding process. Further, the first connecting sheet 101 and the second connecting sheet 102 are nickel sheets, which have good plasticity and good corrosion resistance, and the surface of the nickel sheet is easy to polish for welding.

[0035] It should be noted that in the process of producing the battery cell 10, the actual position of the first pole ear 11 and the second pole ear 12 may be affected by the process and may produce a certain offset relative to its design position in the first direction x, and the offset is the first offset tolerance T1. The production line will screen the offset of the actual position of the first pole ear 11 and the second pole ear 12 relative to the design position. Only when the absolute value of the first offset tolerance T1 is less than or equal to 1, the battery cell 10 can enter the next production stage and perform the connection process with the protection board on the battery cell 10. When the absolute value of the first offset tolerance T1 is greater than 1, the battery cell 10 will be screened as a defective product and cannot enter the next production stage. It should be understood that the battery cell 10 electrically connected to the protection board has a first offset tolerance T1 of the first pole ear 11 and the second pole ear 12, which satisfies -1mm≤T1≤1mm.

[0036] Furthermore, in the process of producing the battery cell 10, the actual distance between the first pole ear 11 and the second pole ear 12 will also be screened. The distance between the first pole ear 11 and the second pole ear 12 is affected by the offset tolerance of the first pole ear 11 and the second pole ear 12 to form a second distance L2 with a second offset tolerance T2, L1+T2=L2. When the absolute value of the second offset tolerance T2 is less than or equal to 1, the battery cell 10 can enter the next production stage and perform the protection board connection process on the battery cell 10. When the absolute value of the second offset tolerance T2 is greater than 1, the battery cell 10 will be screened as a defective product and cannot enter the next production stage. It should be understood that the battery cell 10 electrically connected to the protection board has a second offset tolerance T2 between the first section and the second pole ear 12, which satisfies -1mm≤T2≤1mm.

[0037] In the prior art, in the process of electrically connecting the battery cell 10 with the protection board, the edge of one side of the battery cell 10 is usually used as a positioning reference. Due to the existence of the first offset tolerance T1 of the first pole ear 11 and the second pole ear 12, the width of the first connecting piece 101 and the second connecting piece 102 is greater than the width of the first pole ear 11 and the second pole ear 12, so as to ensure that the first connecting piece 101 and the second connecting piece 102 can be fully fitted and connected with the first pole ear 11 and the second pole ear 12 respectively. In the secondary battery of the present application, the first pole ear 11 on one side is used as the positioning reference, the width of the first pole ear 11 is equal to the width of the first connecting piece 101, and the width of the second connecting piece 102 is greater than the width of the second pole ear 12 to ensure that the second pole ear 12 is fully fitted and connected with the second connecting piece 102. The protection board in the secondary battery of the present application omits the redundant design of the second connecting piece 102 regarding the offset tolerance, reduces the size of the circuit board 100 in the protection board, reduces the space occupied by the protection board in the secondary battery, and thus improves the space utilization rate in the secondary battery, thereby improving the energy density of the secondary battery.

[0038] It should be noted that, in this embodiment, the battery cell 10 has two pole tabs, a first pole tab 11 and a second pole tab 12. In other embodiments, the battery cell has three pole tabs for fast charging and discharging, and the three pole tabs include one positive pole tab and two negative pole tabs, or two positive pole tabs and one negative pole tab. In the embodiment with three pole tabs, one of the pole tabs is the first pole tab 11, and the other two pole tabs are the second pole tabs 12. The three pole tabs are arranged in sequence, and the first pole tab 11 can be set in any order. Correspondingly, the protection plate is provided with a connecting piece corresponding to the total number of pole tabs, and the connecting piece includes a first connecting piece 101 corresponding to the first pole tab 11 and a second connecting piece 102 corresponding to the second pole tab 12. In the process of connecting the battery cell 10 with the protection package, the first pole tab 11 and the first connecting piece 101 are first connected to play a positioning role. Because the width of the second connecting piece 102 is greater than the width of the second pole tab 12, even if there is a displacement deviation in the position of the second pole tab 12, the second pole tab 12 and the second connecting piece 102 can be fully fitted and connected. In other embodiments, the number of the tabs and the connecting pieces is greater than three, and the number of the tabs and the connecting pieces is equal. The tabs include a first tab 11, and the remaining tabs are second tabs 12, and the connecting pieces include a first connecting piece 101, and the remaining connecting pieces are second connecting pieces 102. The number of the tabs and the connecting pieces is not specifically limited herein.

[0039] It should also be noted that in some other embodiments, a protective plate is connected to multiple battery cells, and each battery cell has at least two pole ears. Among them, the pole ears of each battery cell include a first pole ear 11 and at least one second pole ear 12. The protective plate is provided with a number of first connecting pieces 101 corresponding to the number of battery cells and a number of second connecting pieces 102 corresponding to the total number of second pole ears 12. In the process of connecting the battery cell to the protective plate, the first pole ear 11 is first connected to the first protective plate between each battery cell and the protective plate to play a positioning role, and then the second pole ear 12 is connected to the second connecting piece 102. Because the width of the second connecting piece 102 is greater than the width of the second pole ear 12, even if there is a displacement deviation in the position of the second pole ear 12, the second pole ear 12 and the second connecting piece 102 can be fully fitted and connected. The number of battery cells is not specifically limited here.

[0040] Continue to refer to Figure 1, the circuit board 100 includes a device-free area, which includes a first area 110 surrounding the periphery of the first connecting piece 101, and a second area 120 surrounding the periphery of the second connecting piece 102. It is prohibited to set electronic components on the surface of the circuit board 100 in the first area 110 and the second area 120 to avoid damage to the electronic components in the first area 110 and the second area 120 during the process of welding the first pole ear 11 and the second pole ear 12 to the first connecting piece 101 and the second connecting piece 102 respectively. In this embodiment, the first area 110 and the second area 120 are connected. In other embodiments, the first area 110 and the second area 120 are separated.

[0041] In this embodiment, the circuit board 100 is an L-shaped structure as a whole. The circuit board 100 includes a main body extending along a first direction x and a vertical part extending along a second direction y. The main body and the vertical part are connected. A terminal 200 is provided at the end of the vertical part. The terminal 200 is used for the electrical connection between the circuit board 100 and an external circuit. The main body includes a first bending portion 131 separated from the first connecting piece 101 and the second connecting piece 102. The first bending portion 131 is a flexible structure so that the first bending portion 131 is a folding line for bending. The vertical part includes a plurality of second bending portions 132. The second bending portions 132 are flexible structures so that the vertical part can be bent with the second bending portion 132 as a folding line. The second bending portions 132 are close to the terminal 200, and the plurality of second bending portions 132 are sequentially spaced along the second direction y. The plurality of spaced second bending portions 132 facilitate the portion of the circuit board 100 carrying the terminal 200 to bend at a large angle.

[0042] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A secondary battery, characterized in that: include: At least one battery cell (10) having a first direction, a second direction and a third direction that intersect and are perpendicular to each other, and at least two tabs extending along the second direction are provided on one side of the battery cell (10); A protection plate, comprising a circuit board (100), wherein one side of the circuit board (100) is provided with connection plates arranged in sequence along the first direction and having a number equal to the number of the pole tabs, and each of the connection plates is electrically connected to a pole tab corresponding to its position; Wherein, in the second direction, the width of at least one of the connecting sheets is equal to the width of the corresponding pole lug connected thereto, and the widths of the remaining connecting sheets are greater than the widths of the corresponding pole lugs connected thereto.

2. The secondary battery according to claim 1, wherein: A connecting piece having a width equal to the width of a correspondingly connected pole lug is a first connecting piece (101), and a pole lug connected to the first connecting piece is a first pole lug (11); A connecting piece having a width greater than a width of a correspondingly connected pole lug is a second connecting piece (102), and a pole lug connected to the second connecting piece is a second pole lug (12); The number of the first pole lugs (11) and the first connecting sheets (101) is equal to the number of the battery cells, and the number of the second pole lugs (12) and the second connecting sheets (102) is greater than or equal to the number of the battery cells.

3. The secondary battery according to claim 2, characterized in that: When the first pole lug (11) and the second pole lug (12) have no offset tolerance with respect to the first direction relative to the battery cell (10), the second pole lug (12) has a first center line extending along the second direction, the second connecting piece (102) has a second center line extending along the second direction, and the first center line and the second center line are collinear.

4. The secondary battery according to claim 2, characterized in that: In the first direction, the second pole tab (12) has a second width w2, and the second connecting piece (102) has a fourth width w4, wherein w2=2 mm, and w4=4 mm.

5. The secondary battery according to claim 2, characterized in that: In the first direction, the first pole tab (11) has a first width w1, and the first connecting piece (101) has a third width w3, wherein w1=w3=2 mm.

6. The secondary battery according to claim 1, wherein: In the first direction, there is a third distance L3 between adjacent connecting sheets, wherein L3=4 mm.

7. The secondary battery according to claim 1, wherein: The circuit board (100) comprises a first bending portion (131), the first bending portion (131) being arranged on a side of the circuit board (100) close to the connecting sheet and being arranged apart from the connecting sheet, the first bending portion (131) being a flexible structure so that the circuit board (100) can be bent with the first bending portion (131) as a folding line.

8. The secondary battery according to claim 1, wherein: A terminal (200) is provided at one end of the circuit board (100) away from the tab.

9. The secondary battery according to claim 8, characterized in that The circuit board (100) comprises a plurality of second bending portions (132) arranged at equal intervals, wherein the second bending portions (132) are arranged on a side of the circuit board (100) close to the terminal (200), and the second bending portions (132) are flexible structures so that the circuit board (100) can be bent with the second bending portions (132) as a folding line.

10. The secondary battery according to claim 1, wherein: The circuit board (100) comprises a device-free area arranged around the periphery of the connecting piece, and the electronic components arranged on the circuit board (100) are arranged in an area outside the device-free area.

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