Battery and battery module

Abstract

The invention belongs to the technical field of batteries, and discloses a battery and a battery module, the battery comprises a pole group, a cover plate assembly and an insulating film, the cover plate assembly comprises an insulating part, the insulating film comprises a coating part and a hot melting part, the hot melting part is used for hot melting with the insulating part, and the hot melting part is coplanar with the coating part when not hot melting with the insulating part, the hot melting part comprises two first surfaces which face the insulating part and are oppositely arranged in the first direction, when the hot melting part and the insulating part are not subjected to hot melting, the length size of the two first surfaces in the first direction is L1, the length size of the insulating part in the first direction is L2, and the condition that (L1-L2) / 2 is larger than 0 mm and smaller than or equal to 1.5 mm is met. The problem that when the hot melting part of the insulating film is not subjected to hot melting with the insulating part, the gap between the hot melting part and the insulating part is too large, so that the angle of the hot melting part deviating from the insulating part is too large during hot melting is avoided, the wrinkling degree of the insulating film at the corner angle of the insulating part is small, shell entering is smoother, the strength of the hot melting part is improved, and the problem of insulation failure caused by cracking is avoided.

Description

Technical Field

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

[0002] In a battery structure, a battery top cover and a battery case form a sealed space for accommodating a battery electrode assembly. The battery electrode assembly is formed by superimposing a battery positive electrode sheet, a negative electrode sheet, and a separator. After the positive electrode sheet, the negative electrode sheet, and the separator are superimposed, an insulating film, called Mylar, is often wrapped around the superimposed electrode assembly to achieve insulation of the entire battery electrode assembly.

[0003] Among them, the insulating film is heat-melted with an insulating member on the battery top cover, thereby completing the connection between the battery top cover and the electrode assembly. Then, the connected battery top cover and electrode assembly are installed in the battery case to complete the assembly of the battery.

[0004] However, after the insulating film is heat-melted with the insulating member, the insulating film is prone to wrinkle at the corners of the insulating member. On the one hand, it affects the insertion of the electrode assembly into the case. On the other hand, after the battery is charged, the positive electrode sheet and the negative electrode sheet will expand, resulting in easy cracking at the heat-melting point, and finally leading to insulation failure of the insulating film. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery and a battery module. After the insulating film is heat-melted with the insulating member, the insulating film will be relatively flat at the corners of the insulating member, with a small degree of wrinkle, smooth insertion into the case, and good insulation.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, a battery is provided, and the battery includes:

[0008] An electrode assembly;

[0009] A cover plate assembly, the cover plate assembly includes an insulating member, and the insulating member abuts against the electrode assembly;

[0010] An insulating film, the insulating film includes a covering portion and a heat-melting portion. The covering portion surrounds the outside of the electrode assembly, and the heat-melting portion is disposed on the side of the covering portion facing the insulating member and is used for heat-melting with the insulating member. When the heat-melting portion is not heat-melted with the insulating member, it is coplanar with the covering portion.

[0011] The heat-melting portion includes two first surfaces facing the insulating member and oppositely arranged along a first direction. When the heat-melting portion is not heat-melted with the insulating member, the length dimension of the two first surfaces along the first direction is L1, and the length dimension of the insulating member along the first direction is L2, and 0mm < (L1 - L2) / 2 ≤ 1.5mm is satisfied.

[0012] Optionally, the heat fusion part includes two second surfaces facing the insulating part and oppositely arranged along the second direction. When the heat fusion part is not heat-fused with the insulating part, the length dimension of the two second surfaces along the second direction is H1, the length dimension of the insulating part along the second direction is H2, and 0mm < (H1 - H2) / 2 ≤ 1mm is satisfied.

[0013] Optionally, the battery further includes a housing body, the housing body is a hollow shell structure with an opening, and the cover plate assembly is arranged at the opening of the housing body to form a receiving cavity for accommodating the electrode group;

[0014] The covering part includes two third surfaces facing away from the insulating part and oppositely arranged along the first direction. The length dimension of the two third surfaces along the first direction is L3, the spatial dimension of the receiving cavity along the first direction is L4, and 0.2mm ≤ (L4 - L3) / 2 ≤ 1mm is satisfied.

[0015] Optionally, the covering part includes two fourth surfaces facing away from the insulating part and oppositely arranged along the second direction. The length dimension of the two fourth surfaces along the second direction is H3, the length dimension of the receiving cavity along the second direction is H4, and 89.2% ≤ H3 / H4 ≤ 93.3% is satisfied.

[0016] Optionally, when the heat fusion part is not heat-fused with the insulating part, the overlapping dimension with the insulating part along the third direction is W, and W ≥ 3mm is satisfied.

[0017] Optionally, the insulating part includes two first wall surfaces oppositely arranged along the first direction and two second wall surfaces arranged along the second direction. The first wall surface and the adjacent second wall surface are connected through a first arc angle transition.

[0018] Optionally, the battery further includes a housing body, the housing body includes a first side plate and a second side plate. The first side plate is located on the side of the first wall surface away from the insulating part, and the second side plate is located on the side of the second wall surface away from the insulating part. The first side plate and the adjacent second side plate are connected through a second arc angle transition.

[0019] Optionally, the radius dimension of the first arc angle is R1, the radius dimension of the second arc angle is R2, and R2 > R1 is satisfied.

[0020] Optionally, the insulating film is a polypropylene film or a polycarbonate film.

[0021] On the other hand, a battery module is also provided, and the battery module includes a plurality of batteries as described in any one of the above.

[0022] Advantages of the present invention:

[0023] The present invention provides a battery. By setting the length dimension between two first surfaces oppositely arranged along a first direction on the heat-melt part of the insulating film as L1, and setting the length dimension of the insulating part along the first direction as L2, such that 0 mm < (L1 - L2) / 2 ≤ 1.5 mm, it is avoided that when the heat-melt part of the insulating film is not heat-melted with the insulating part, the gap between the two is too large, resulting in an excessive angle of the heat-melt part of the insulating film deviating towards the insulating part during heat melting. After the heat-melt part of the insulating film is heat-melted with the insulating part, the insulating film is relatively flat at the corners of the insulating part and has a small degree of wrinkling. On the one hand, it makes the cover plate assembly enter the shell more smoothly after being heat-melted and connected to the electrode group. On the other hand, because the heat-melt part of the insulating film is relatively flat and has a small deflection angle when being heat-melted with the insulating part, there is a large contact area between the heat-melt part and the insulating part, thus having a high heat-melt strength, and avoiding the problem that the heat-melt point cracks and causes insulation failure after the positive electrode plate and the negative electrode plate expand.

[0024] The present invention also provides a battery module. By applying the above battery, on the one hand, due to the relatively smooth entry into the shell, the assembly efficiency is improved. On the other hand, because the probability of insulation failure is reduced, the yield of the product is improved and the quality of the product is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is an exploded view of the structure of the battery provided by the present invention;

[0026] Figure 2 is a front sectional view of the battery provided by the present invention;

[0027] Figure 3 is Figure 2 an enlarged view of the structure of part A in

[0028] Figure 4 is a side sectional view of the battery provided by the present invention;

[0029] Figure 5 is Figure 4 an enlarged view of the structure of part B in

[0030] Figure 6 is a partial structural schematic diagram of the cover plate assembly in the battery provided by the present invention.

[0031] In the figure:

[0032] 1. Electrode group;

[0033] 2. Cover plate assembly; 21. Insulating part; 211. First wall surface; 212. Second wall surface; 213. First arc angle; 22. Cover plate body;

[0034] 3. Insulating film; 31. Wrapping part; 311. Third surface; 312. Fourth surface; 32. Heat-melting part; 321. First surface; 322. Second surface;

[0035] 4. Housing body; 41. First side plate; 42. Second side plate; 43. Second arc corner. Detailed implementation manners

[0036] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the convenience of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0037] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; 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 or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0038] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below", and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is lower than that of the second feature.

[0039] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, 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 to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meanings.

[0040] At present, after the insulating film and the insulating part are heat-melted, the insulating film is prone to wrinkle at the edges and corners of the insulating part. On the one hand, it affects the insertion of the electrode group into the shell. On the other hand, after the battery is charged, the positive electrode plate and the negative electrode plate will expand, resulting in easy cracking at the heat-melting points, and ultimately leading to the insulation failure of the insulating film.

[0041] Therefore, in order to reduce the degree of wrinkles at the edges and corners of the insulating member after the insulating film and the insulating member are heat-melted, improve the smoothness of shell insertion, increase the strength of the heat-melted portion, and improve insulation, the present embodiment provides a battery.

[0042] As Figures 1 to 6 shown, the battery includes a pole group 1, a cover plate assembly 2, and an insulating film 3. The cover plate assembly 2 includes an insulating member 21. The insulating member 21 abuts against the pole group 1. The insulating film 3 includes a covering portion 31 and a heat-melted portion 32. The covering portion 31 surrounds the outside of the pole group 1. The heat-melted portion 32 is provided on the side of the covering portion 31 facing the insulating member 21 and is used for heat-melting with the insulating member 21. When the heat-melted portion 32 is not heat-melted with the insulating member 21, it is coplanar with the covering portion 31.

[0043] The heat-melted portion 32 includes two first surfaces 321 facing the insulating member 21 and oppositely arranged in a first direction. When the heat-melted portion 32 is not heat-melted with the insulating member 21, the length dimension of the two first surfaces 321 in the first direction is L1, and the length dimension of the insulating member 21 in the first direction is L2, and 0 mm < (L1 - L2) / 2 ≤ 1.5 mm is satisfied.

[0044] By setting the length dimension between the two first surfaces 321 oppositely arranged in the first direction on the heat-melted portion 32 of the insulating film 3 as L1 and setting the length dimension of the insulating member 21 in the first direction as L2, so that 0 mm < (L1 - L2) / 2 ≤ 1.5 mm is satisfied, it is thus avoided that when the heat-melted portion 32 of the insulating film 3 is not heat-melted with the insulating member 21, the gap between the two is too large, resulting in too large an angle at which the heat-melted portion 32 of the insulating film 3 deflects towards the insulating member 21 when heat-melting. After the heat-melted portion 32 of the insulating film 3 is heat-melted with the insulating member 21, the insulating film 3 is relatively flat at the edges and corners of the insulating member 21 and has a small degree of wrinkles. On the one hand, it makes the cover plate assembly 2 more smoothly inserted into the shell after being heat-melted and connected to the pole group 1. On the other hand, since the heat-melted portion 32 of the insulating film 3 is relatively flat and has a small deflection angle when heat-melting with the insulating member 21, there is a large contact area between the heat-melted portion 32 and the insulating member 21, so that there is a high heat-melt strength, avoiding the problem that the heat-melting point fails to insulate due to cracking after the positive and negative electrode plates expand.

[0045] In this embodiment, the insulating film 3 is a planar structure before wrapping the electrode group 1, and is wrapped around the electrode group 1 by winding. Since the insulating film 3 needs to be heat-melted and connected to the insulating part 21, a part of the insulating film 3 will exceed the surface of the electrode group 1 where the tab is provided. The part of the insulating film 3 that exceeds the surface of the electrode group 1 where the tab is provided constitutes the heat-melting part 32, and the part that fits the electrode group 1 constitutes the wrapping part 31. At this time, after the insulating film 3 is wrapped outside the electrode group 1, the heat-melting part 32 and the wrapping part 31 are coplanar. In this embodiment, the cover plate assembly 2 further includes a cover plate body 22. The insulating part 21 is connected to one side of the cover plate body 22 facing the electrode group 1. The cover plate body 22 is arranged at the open mouth of the housing body 4 to seal the housing body 4.

[0046] Among them, the gap value in the first direction between the first surface 321 on the heat-melting part 32 and the insulating part 21 can be any value between 0 mm and 1.5 mm or the range between any two values, but does not include 0 mm. For example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc.

[0047] In this solution, when the heat-melting part 32 of the insulating film 3 is not heat-melted with the insulating part 21, the dimension limitation of the length dimension L1 between the two first surfaces 321 arranged oppositely in the first direction on the heat-melting part 32 and the length dimension L2 of the insulating part 21 in the first direction can be adapted to different types of battery designs. In this embodiment, it is mainly adapted to blade batteries.

[0048] Optionally, as Figure 5 shown, the heat-melting part 32 includes two second surfaces 322 arranged oppositely in the second direction facing the insulating part 21. When the heat-melting part 32 is not heat-melted with the insulating part 21, the length dimension in the second direction of the two second surfaces 322 is H1, and the length dimension of the insulating part 21 in the second direction is H2, and 0 mm < (H1 - H2) / 2 ≤ 1 mm is satisfied. By setting the length dimension between the two second surfaces 322 arranged oppositely in the second direction on the heat-melting part 32 of the insulating film 3 as H1, and setting the length dimension of the insulating part 21 in the second direction as H2, so that the two satisfy 0 mm < (H1 - H2) / 2 ≤ 1 mm, thereby avoiding the gap between the heat-melting part 32 of the insulating film 3 and the insulating part 21 in the second direction from being too large when the heat-melting part 32 is not heat-melted with the insulating part 21, and cooperating with the dimension limitation between the length dimension L1 between the two first surfaces 321 arranged oppositely in the first direction on the heat-melting part 32 and the length dimension L2 of the insulating part 21 in the first direction, the gap values of the heat-melting part 32 of the insulating film 3 and the insulating part 21 in the first direction and the second direction can be effectively controlled, thereby further improving the degree of wrinkles and the heat-melting strength after the insulating film 3 and the insulating part 21 are heat-melted.

[0049] Among them, the clearance value in the second direction between the second surface 322 of the hot-melt part 32 and the insulating part 21 can be any value between 0 mm and 1 mm or the range between any two values, but does not include 0 mm, such as 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0050] Optionally, as Figure 1 , Figure 2 shown, the battery further includes a housing body 4. The housing body 4 is a hollow shell structure with an opening, and the cover plate assembly 2 is arranged at the opening of the housing body 4 to form a receiving cavity for receiving the electrode group 1;

[0051] The covering part 31 includes two third surfaces 311 that face away from the insulating part 21 and are arranged opposite to each other in the first direction. The length dimension of the two third surfaces 311 in the first direction is L3, and the spatial dimension of the receiving cavity in the first direction is L4, and 0.2 mm ≤ (L4 - L3) / 2 ≤ 1 mm is satisfied.

[0052] By defining the relationship between the length dimension L3 of the two third surfaces 311 of the covering part 31 in the first direction and the spatial dimension L4 of the receiving cavity in the first direction, making the two satisfy 0.2 mm ≤ (L4 - L3) / 2 ≤ 1 mm, it is ensured that after the insulating film 3 is wrapped outside the electrode group 1, there is still enough clearance between it and the receiving cavity in the first direction. On the one hand, it avoids the difficulty of inserting the electrode group 1 into the shell due to too small a clearance, and on the other hand, it avoids too large a clearance, which may cause the electrode group 1 to shake in the receiving cavity and cause the pole ear to be strained.

[0053] Among them, the clearance value in the first direction between the third surface 311 of the covering part 31 and the inner wall of the receiving cavity can be any value between 0.2 mm and 1 mm or the range between any two values, such as 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0054] Optionally, as Figure 4 , Figure 5As shown, the covering portion 31 includes two fourth surfaces 312 that face away from the insulating member 21 and are oppositely arranged in the second direction. The length dimension of the two fourth surfaces 312 in the second direction is H3, the length dimension of the accommodating cavity in the second direction is H4, and 89.2% ≤ H3 / H4 ≤ 93.3% is satisfied. By defining the relationship between the length dimension H3 of the two second surfaces 322 on the covering portion 31 in the second direction and the length dimension H4 of the accommodating cavity in the second direction, so that 89.2% ≤ H3 / H4 ≤ 93.3% is satisfied, thus ensuring that after the insulating film 3 is covered outside the electrode group 1, there is still enough clearance between it and the accommodating cavity in the second direction. On the one hand, it avoids the difficulty of inserting the electrode group 1 into the shell due to too small a clearance. On the other hand, it avoids too large a clearance, which may cause the electrode group 1 to shake in the accommodating cavity and cause the pole ear to be strained.

[0055] In this embodiment, in order to detect the relationship between the length dimension L1 between the two first surfaces 321 oppositely arranged in the first direction on the heat-melted portion 32 of the insulating film 3 and the length dimension L2 of the insulating member 21 in the first direction, the relationship between the length dimension H1 between the two second surfaces 322 oppositely arranged in the second direction on the heat-melted portion 32 of the insulating film 3 and the length dimension H2 of the insulating member 21 in the second direction, the relationship between the length dimension L3 of the two third surfaces 311 on the covering portion 31 in the first direction and the spatial dimension L4 of the accommodating cavity in the first direction, and the relationship between the length dimension H3 of the two second surfaces 322 on the covering portion 31 in the second direction and the length dimension H4 of the accommodating cavity in the second direction, and their influence on the insertion of the electrode group 1 into the shell and the heat melting of the insulating film 3, twelve sets of examples are provided in Table 1 and eight sets of comparative examples are provided in Table 2 for testing.

[0056] Table 1

[0057]

[0058] As shown in Table 1, when the relationship between the length dimension L1 between the two first surfaces 321 oppositely arranged in the first direction on the heat-melted portion 32 of the insulating film 3 and the length dimension L2 of the insulating member 21 in the first direction satisfies the range of 0 mm < (L1 - L2) / 2 ≤ 1.5 mm, and the relationship between the length dimension H1 between the two second surfaces 322 oppositely arranged in the second direction on the heat-melted portion 32 of the insulating film 3 and the length dimension H2 of the insulating member 21 in the second direction satisfies the range of 0 mm < (H1 - H2) / 2 ≤ 1 mm, at this time, after the insulating film 3 and the insulating member 21 are heat-melted, there are no problems such as edge wrinkles and affecting the assembly of the electrode group 1 into the shell; after the battery is fully charged and disassembled, there are no problems such as heat-melting point cracking;

[0059] When the relationship between the length dimension L3 of the two third surfaces 311 on the covering part 31 in the first direction and the spatial dimension L4 of the accommodation cavity in the first direction satisfies the range of 0.2 mm ≤ (L4 - L3) / 2 ≤ 1 mm, and the relationship between the length dimension H3 of the two second surfaces 322 on the covering part 31 in the second direction and the length dimension H4 of the accommodation cavity in the second direction satisfies the range of 89.2% ≤ H3 / H4 ≤ 93.3%, during the battery assembly production, it is difficult for the electrode group 1 to enter the shell, and there are no abnormal problems such as scratches on the electrode group 1; after the battery is fully charged, there is no obvious swelling of the battery and no problems such as shaking of the internal electrode group 1.

[0060] Table 2

[0061]

[0062] As can be seen from Comparative Example 01 in Table 2, when the assembly allowance dimension (L4 - L3) / 2 is not within the range of 0.2 mm - 1 mm and is lower than the lower limit value, the gap is too small, and it is difficult for the battery electrode group 1 to enter the shell during the battery assembly production.

[0063] As can be seen from Comparative Example 02 in Table 2, when the assembly allowance dimension (L4 - L3) / 2 is not within the range of 0.2 mm - 1 mm and is higher than the upper limit value, the gap is too large, resulting in the problem that the internal electrode group 1 still shakes after the battery is fully charged.

[0064] As can be seen from Comparative Examples 03 to 04 in Table 2, when the hot-melt allowance dimension (L1 - L2) / 2 is not within the range of 0 mm - 1.5 mm, after the insulating film 3 and the insulating part 21 in the electrode group 1 are hot-melted, there are problems such as edge wrinkles and affecting the assembly of the electrode group 1 into the shell; after the battery is fully charged and disassembled, the hot-melt points all have cracking problems.

[0065] As can be seen from Comparative Example 05 in Table 2, when the assembly ratio H3 / H4 is not within the range of 89.2% - 93.3% and is lower than the lower limit value, the gap is too large, and it is relatively easy for the electrode group 1 to enter the shell during the battery assembly production; when the battery is fully charged, the internal electrode group 1 shakes significantly.

[0066] As can be seen from Comparative Example 06 in Table 2, when the assembly ratio H3 / H4 is not within the range of 89.2% - 93.3% and is higher than the upper limit value, the gap is too small, and it is difficult for the battery electrode group 1 to enter the shell.

[0067] As can be seen from Comparative Examples 07 to 08 in Table 2, when the hot-melt allowance dimension (H1 - H2) / 2 is not within the range of 0 mm - 1 mm, after the insulating film 3 and the insulating part 21 in the electrode group 1 are hot-melted, there are problems such as edge wrinkles and affecting the assembly of the electrode group 1 into the shell; after the battery is fully charged and disassembled, the hot-melt points all crack.

[0068] Optionally, as Figure 3As shown, the overlapping dimension W between the hot-melt portion 32 and the insulating member 21 along the third direction when the hot-melt portion 32 is not hot-melted with the insulating member 21 is satisfied, and W≥3mm. By limiting the overlapping dimension W between the hot-melt portion 32 and the insulating member 21 along the third direction when the hot-melt portion 32 is not hot-melted with the insulating member 21, so that it satisfies W≥3mm, it is avoided that the overlapping dimension W between the hot-melt portion 32 and the insulating member 21 along the second direction is too small, which results in too small contact area when the hot-melt portion 32 approaches the insulating member 21 for hot-melting, and then the structural strength after hot-melting is too low, resulting in the expansion of the positive and negative pole pieces after the battery is charged, and cracking at the hot-melt point, and finally the insulation failure of the insulating film 3.

[0069] Alternatively, if Figure 6 As shown, the insulating member 21 includes two first walls 211 arranged opposite to each other along the first direction and two second walls 212 arranged along the second direction, and the first wall 211 and the adjacent second wall 212 are transitionally connected via a first arc angle 213. By transitionally connecting the first wall 211 and the adjacent second wall 212 via the first arc angle 213, it is avoided that the junction between the first wall 211 and the second wall 212 of the insulating member 21 is an edge, which causes scratches on the insulating film 3 and causes insulation failure of the insulating film 3.

[0070] Furthermore, if Figure 1 , Figure 6 As shown, the battery further includes a shell body 4, and the shell body 4 includes a first side plate 41 and a second side plate 42. The first side plate 41 is located on the side of the first wall 211 away from the insulating member 21, and the second side plate 42 is located on the side of the second wall 212 away from the insulating member 21. The first side plate 41 and the adjacent second side plate 42 are transitionally connected via a second arc angle 43. Since the first wall 211 and the adjacent second wall 212 are transitionally connected via the first arc angle 213, an arc bulge will be formed at the junction between the first wall 211 and the adjacent second wall 212 after the insulating film 3 and the insulating member 21 are hot-melted. Therefore, by making the first side plate 41 and the adjacent second side plate 42 transitionally connected via the second arc angle 43, the arc bulge formed after the insulating film 3 and the insulating member 21 are hot-melted is avoided, thereby ensuring that the electrode group 1 is smoothly inserted into the shell.

[0071] Specifically, the radius of the first arc angle 213 is R1, and the radius of the second arc angle 43 is R2, and R2>R1 is satisfied, so that there is a space between the first arc angle 213 and the second arc angle 43 to accommodate the arc protrusion.

[0072] Optionally, the insulating film 3 is a polypropylene film or a polycarbonate film. By using polypropylene to make the insulating film 3, it has better chemical stability, reducing the performance degradation and failure risk caused by material corrosion; by using polycarbonate to make the insulating film 3, it has excellent mechanical properties, with high strength and toughness, providing reliable physical protection for the electrode group 1.

[0073] In this embodiment, a battery module is further provided, and the battery module includes a plurality of the above-mentioned batteries. By applying the above-mentioned battery, on the one hand, the assembly efficiency is improved due to the relatively smooth insertion into the shell, and on the other hand, the product yield is improved and the product quality is improved because the probability of insulation failure is reduced.

[0074] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A battery, characterized in that The battery comprises: Pole group; A cover plate assembly, the cover plate assembly comprising an insulating member, the insulating member abutting against the pole group; An insulating film, the insulating film comprising a covering portion and a hot-melt portion, the covering portion surrounding the outer side of the electrode group, the hot-melt portion being arranged on a side of the covering portion facing the insulating member and used for hot-melting with the insulating member, and the hot-melt portion being coplanar with the covering portion when not hot-melting with the insulating member; The hot melt portion includes two first surfaces facing the insulating part and arranged opposite to each other along the first direction. When the hot melt portion is not hot-melted with the insulating part, the length dimension of the two first surfaces along the first direction is L1, the length dimension of the insulating part along the first direction is L2, and 0mm<(L1-L2) / 2≤1.5mm is satisfied.

2. The battery according to claim 1, characterized in that The hot melt portion includes two second surfaces facing the insulating member and arranged opposite to each other along the second direction. When the hot melt portion is not hot-melted with the insulating member, the length dimension of the two second surfaces along the second direction is H1, the length dimension of the insulating member along the second direction is H2, and 0mm<(H1-H2) / 2≤1mm is satisfied.

3. The battery according to claim 1, characterized in that The battery further comprises a shell body, which is a hollow shell structure with an opening, and the cover plate assembly is arranged at the opening of the shell body to form a receiving cavity for accommodating the electrode group; The covering portion includes two third surfaces that are away from the insulating member and are arranged opposite to each other along the first direction. The length dimension of the two third surfaces along the first direction is L3. The spatial dimension of the accommodating cavity along the first direction is L4, and 0.2mm≤(L4-L3) / 2≤1mm is satisfied.

4. The battery according to claim 3, characterized in that The covering portion includes two fourth surfaces away from the insulating member and arranged opposite to each other along the second direction, the length dimension of the two fourth surfaces along the second direction is H3, the length dimension of the accommodating cavity along the second direction is H4, and 89.2%≤H3 / H4≤93.3% is satisfied.

5. The battery according to claim 1, characterized in that When the heat-melting portion is not heat-melted with the insulating member, an overlapping dimension between the heat-melting portion and the insulating member along the third direction is W, and W≥3 mm.

6. The battery according to claim 1, characterized in that The insulating member includes two first walls arranged opposite to each other along the first direction and two second walls arranged along the second direction, and the first wall is transitionally connected to the adjacent second wall via a first arc angle.

7. The battery according to claim 6, characterized in that The battery also includes a shell body, which includes a first side plate and a second side plate, the first side plate is located on the side of the first wall facing away from the insulating member, the second side plate is located on the side of the second wall facing away from the insulating member, and the first side plate is connected to the adjacent second side plate via a second arc angle transition.

8. The battery according to claim 7, characterized in that The radius of the first arc angle is R1, the radius of the second arc angle is R2, and R2>R1 is satisfied.

9. The battery according to claim 1, characterized in that The insulating film is a polypropylene film or a polycarbonate film.

10. A battery module, characterized in that: The battery module comprises a plurality of batteries as described in any one of claims 1 to 9.

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