Laminated battery

Abstract

The utility model provides a laminated battery which comprises a battery cell, a top cover, a positive electrode adapter piece, a negative electrode adapter piece and a shell, the battery cell comprises a plurality of negative electrode pieces, a plurality of positive electrode pieces and diaphragms, the diaphragms are folded in a Z shape in the length direction to form a plurality of insertion spaces, and the negative electrode pieces and the positive electrode pieces are sequentially and alternately inserted into the insertion spaces in the first direction; the battery cell further comprises a top surface and a bottom surface which are oppositely arranged, and the top surface is arranged close to the top cover; wherein the diaphragm comprises two free sections, and the two free sections are both bent along the first direction and extend to the bottom surface, so that the two free sections are both arranged on the bottom surface of the battery cell, namely at the position deviating from the top cover, and the free sections of the diaphragm do not interfere with the top cover and do not extend into a gap between the top cover and the shell when entering the shell; therefore, the possibility that the diaphragm goes deep into the gap between the top cover and the shell can be eliminated fundamentally, and the risk of hole explosion caused by diaphragm foreign matter during top cover welding is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to a laminated battery. BACKGROUND

[0002] According to the connection mode of the laminated body and the top cover, the single-side pole post square shell cell can be divided into two types: the laminated body is directly connected with the cell top cover, and the laminated body is indirectly connected with the cell top cover through an adapter piece. In the former type, the positive and negative tabs of the laminated body are located on the same side, and in the latter type, the positive and negative tabs of the laminated body are located on different sides.

[0003] For the laminated body with different tabs, the conventional "Z-type" laminated body design does not have a clear requirement for the end position of the separator. The end edge of some laminated bodies is located at the top of the cell. Moreover, the end length of the laminated body is not clearly defined, and the end length of the laminated body is random, which may cause the separator to extend into the gap between the top cover and the shell when entering the shell, thereby causing abnormal problems such as burst holes in the top cover welding process, and greatly reducing the yield of the cell. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the present application aims to provide a laminated battery to solve or partially solve the problems in the background art.

[0005] To achieve the above purpose, the present application provides a laminated battery, which comprises a cell, a top cover, a positive adapter piece, a negative adapter piece and a shell, the top cover and the shell form a containing space, and the cell is located in the containing space.

[0006] The cell comprises a plurality of negative plates, a plurality of positive plates and a separator, the separator is folded in a "Z" shape along the length direction to form a plurality of insertion spaces, the negative plates and the positive plates are alternately inserted in the insertion spaces along a first direction, the positive plates extend outward to form positive tabs, the negative plates extend outward to form negative tabs, the positive tabs are connected with positive poles of the top cover through the positive adapter piece, and the negative tabs are connected with negative poles of the top cover through the negative adapter piece. The cell further comprises oppositely arranged top and bottom surfaces, and the top surface is arranged close to the top cover.

[0007] The separator comprises two free sections, and the two free sections are bent along the first direction and extend to the bottom surface.

[0008] Optionally, in the first direction, the size of the free section is a, the size of the cell is b, and 1 / 2b>a>1 / 3b.

[0009] Optionally, in the first direction, the first layer and the last layer of the diaphragm are both first surfaces away from the surface of the insertion space, and the laminated battery further comprises a first adhesive, the first adhesive being connected to one of the first surfaces and extending to the other first surface, and the first adhesive covering the two free sections.

[0010] Optionally, a plurality of the first adhesives are provided, and the plurality of the first adhesives are arranged at intervals in a second direction, the distance between two adjacent first adhesives in the second direction being c, the size of the free section in the first direction being a, and 1 / 2a≦c<a, the second direction being the width direction of the diaphragm.

[0011] Optionally, at least one of the first adhesives is arranged close to the tab, and the ratio between the distance between the edge of the first adhesive arranged close to the tab and the edge of the first surface in the second direction and the size of the first surface in the second direction is 1:10-3:10.

[0012] Optionally, a plurality of second adhesives are further provided, one end of at least one of the second adhesives being adhered to the first surface, and the other end covering the area where the positive tab is connected to the positive plate, and one end of at least one of the second adhesives being adhered to the first surface, and the other end covering the area where the negative tab is connected to the negative plate.

[0013] Optionally, the second adhesive does not overlap the first adhesive in the second direction.

[0014] Optionally, one end of the positive adapter plate is connected to the positive tab, the other end of the positive adapter plate is connected to the positive column of the top cover, one end of the negative adapter plate is connected to the negative tab, and the other end of the negative adapter plate is connected to the negative column of the top cover.

[0015] Optionally, the plurality of insertion spaces comprise first spaces and second spaces arranged alternately along the first direction, the first insertion space and the last insertion space in the first direction are both the first spaces, and in the cross section along the first direction, the opening end of the first space and the opening end of the second space are arranged opposite to each other, the opening end of the first space is arranged away from the top cover, the negative plate is inserted into the first space, and the positive plate is inserted into the second space.

[0016] Optionally, an insulating layer is further provided, the insulating layer being located between the shell and the electric core, and the insulating layer covering the two free sections.

[0017] Optionally, a plurality of the electric cores are provided, and the plurality of the electric cores are stacked along the first direction.

[0018] As can be seen from the above, the laminated battery provided by the application comprises a cell, a top cover, a positive electrode adapter plate, a negative electrode adapter plate and a shell. The cell comprises a plurality of negative electrode plates, a plurality of positive electrode plates and a separator. The separator is folded in a "Z" shape along a length direction to form a plurality of insertion spaces. The negative electrode plates and the positive electrode plates are alternately inserted into the insertion spaces along a first direction. The positive electrode plates extend outward to form positive electrode tabs. The negative electrode plates extend outward to form negative electrode tabs. The positive electrode tabs are connected to positive electrode posts of the top cover through the positive electrode adapter plate. The negative electrode tabs are connected to negative electrode posts of the top cover through the negative electrode adapter plate. The cell further comprises oppositely arranged top and bottom surfaces. The top surface is arranged close to the top cover. The separator comprises two free sections. Both of the two free sections are bent along the first direction and extend to the bottom surface. Thus, both of the two free sections are arranged on the bottom surface of the cell, i.e., arranged away from the top cover. The free sections of the separator will not interfere with the top cover, nor will they extend into the gap between the top cover and the shell when entering the shell. Thus, the possibility of the separator extending into the gap between the top cover and the shell can be eliminated from the root cause, and the risk of top cover welding due to separator foreign object burst holes can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] Figure 1 A first kind of schematic diagram of a single-side pole square shell cell in the related art is shown;

[0021] Figure 2 A second kind of schematic diagram of a single-side pole square shell cell in the related art is shown;

[0022] Figure 3 A cross-sectional schematic diagram of a first kind of single-side pole square shell cell in the related art is shown;

[0023] Figure 4 A first kind of cross-sectional schematic diagram of a laminated battery of an embodiment of the present application is shown;

[0024] Figure 5 A second kind of cross-sectional schematic diagram of a laminated battery of an embodiment of the present application is shown;

[0025] Figure 6 A third kind of cross-sectional schematic diagram of a laminated battery of an embodiment of the present application is shown;

[0026] Figure 7 A first kind of cross-sectional schematic diagram of a cell of an embodiment of the present application is shown.

[0027] Fig. 01, positive electrode tab; 02, negative electrode tab; 03, negative electrode post; 04, positive electrode post;

[0028] 1, battery cell; 11, separator; 111, first surface; 112, free section; 12, positive electrode sheet; 13, negative electrode sheet; 14, positive electrode tab; 15, negative electrode tab; 16, top surface; 17, bottom surface; 18, insertion space; 181, first space; 182, second space; 2, top cover; 21, positive electrode post; 22, negative electrode post; 3, shell; 4, first adhesive; 5, second adhesive; 6, positive electrode adapter sheet; 7, negative electrode adapter sheet; 8, buffer layer; 9, opening. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present application clearer, the present application is further described in detail below with reference to specific embodiments and drawings.

[0030] It should be noted that, unless otherwise defined, technical or scientific terms used in the embodiments of the present application should be understood as their common meanings to those of ordinary skill in the art to which the present application belongs. The terms "first", "second", and similar terms used in the present application do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like only represent relative positional relationships, which can change when the absolute positions of the described objects change.

[0031] Single-sided electrode post stack square shell battery is one of the main packaging forms of lithium ion battery cells, and has been widely used in the fields of energy storage and power battery cells.

[0032] Figure 1 A first kind of schematic diagram of a single-sided electrode post square shell battery in the related art is shown, Figure 2 A second kind of schematic diagram of a single-sided electrode post square shell battery in the related art is shown, Figure 3 A cross-sectional schematic diagram of the first kind of single-sided electrode post square shell battery in the related art is shown.

[0033] Single-sided electrode post square shell batteries can be further divided into batteries in which the stack body is directly connected to the top cover of the battery cell (as shown in Figure 1 ), and batteries in which the stack body is indirectly connected to the top cover of the battery cell through an adapter sheet (as shown in Figure 2As shown in FIG. 1 and FIG. 2, the positive and negative tabs of the former are located on the same side, and the positive and negative tabs of the latter are located on different sides.

[0034] In order to facilitate the assembly of the cell module, the prismatic cell is usually designed in a cuboid shape, and the internal stack is also in a cuboid shape. In this case, as shown by the folding stroke of the isolation film "Z", the stack efficiency of the stack with different side tabs is significantly higher than that of the stack with the same side tabs. Therefore, the stack of the prismatic cell with single side pole usually adopts the design of different side tabs.

[0035] For the stack with different side tabs, the conventional "Z" stack design does not have a clear requirement for the end position of the isolation film 11. The end of some stacks is located at the top of the cell (close to the tab side, such as Figure 3 As shown). Moreover, the end length of the stack is not clearly defined, and the end length of the stack is random.

[0036] When the design of the end isolation film 11 slightly exceeds the stack, and the end of the isolation film 11 is just on the side of the top cover of the cell, the interval arrangement of the stack binding tape and the melting point of the insulating layer and the lower plastic cannot completely bind the isolation film 11 on the side of the stack. When the stack enters the shell, the isolation film 11 exceeding the stack is easily stretched into the gap between the top cover and the shell (as shown in Figure 3 ), which further causes abnormal problems such as burst holes in the top cover welding process, and greatly reduces the yield of the cell.

[0037] When the design of the end isolation film 11 wraps the outer surface of the stack, there are problems such as large amount of isolation film 11 and complex stack tooling design, which produces high cost.

[0038] Therefore, how to limit the end position of the isolation film 11 to avoid the end of the isolation film 11 from stretching into the gap between the top cover and the shell, while also avoiding increasing the manufacturing cost is a problem to be solved.

[0039] Based on this, the application provides a stack battery.

[0040] Figure 4 A first cross-sectional schematic view of the stack battery of the embodiment of the application is shown, Figure 5 A second cross-sectional schematic view of the stack battery of the embodiment of the application is shown.

[0041] Referring to Figure 4 and Figure 5 As shown, the stack battery comprises a cell 1, a top cover 2, a positive tab adapter 6, a negative tab adapter 7, and a shell 3. The top cover 2 and the shell 3 form a containing space, and the cell 1 is located in the containing space.

[0042] The electric core 1 comprises a plurality of negative pole pieces 13, a plurality of positive pole pieces 12 and a diaphragm 11, the diaphragm 11 is folded in a "Z" shape along the length direction to form a plurality of insertion spaces 18, the negative pole pieces 13 and the positive pole pieces 12 are alternately inserted in the insertion spaces 18 in a first direction, the positive pole pieces 12 extend outwardly to form positive pole tabs 14, the negative pole pieces 13 extend outwardly to form negative pole tabs 15, the positive pole tabs 14 are connected with the positive pole posts 21 of the top cover 2 through positive pole adapter pieces 6, the negative pole tabs 15 are connected with the negative pole posts 22 of the top cover 2 through negative pole adapter pieces 7; the electric core 1 further comprises oppositely arranged top surfaces 16 and bottom surfaces 17, the top surfaces 16 are arranged close to the top cover 2.

[0043] The diaphragm 11 comprises two free sections 112, the two free sections 112 are both folded in the first direction and extend to the bottom surfaces 17.

[0044] Specifically, the first direction is Figure 5 the direction shown in FIG. 1C.

[0045] The top cover 2 comprises the positive pole posts 21 and the negative pole posts 22 on the same side, the positive pole tabs 14 and the negative pole tabs 15 are respectively led out from the two sides of the electric core 1, the positive pole tabs 14 are connected with the positive pole posts 21 of the top cover 2 through the positive pole adapter pieces 6, the negative pole tabs 15 are connected with the negative pole posts 22 of the top cover 2 through the negative pole adapter pieces 7. Specifically, one end of the positive pole adapter piece 6 is connected with the positive pole tab 14 on the side of the electric core 1, the other end of the positive pole adapter piece 6 is connected with the positive pole post 21 of the top cover 2 on the top surface 16 of the electric core 1, one end of the negative pole adapter piece 7 is connected with the negative pole tab 15 on the side of the electric core 1, the other end of the negative pole adapter piece 7 is connected with the negative pole post 22 of the top cover 2 on the top surface 16 of the electric core 1.

[0046] In this way, the laminated battery in the present application adopts a "Z-type" lamination mode of single-side positive pole post and opposite-side negative pole tab, and in this mode, the folding stroke of the diaphragm 11 is shorter when the pole pieces are manufactured, and the cutting and lamination efficiency is higher.

[0047] The diaphragm 11 comprises two free sections 112, the free sections 112 are the starting section and the ending section of the diaphragm 11. The two free sections 112 are both folded in the first direction and extend to the bottom surfaces 17, in this way, the two free sections 112 are arranged on the bottom surfaces 17 of the electric core 1, i.e. arranged at positions away from the top cover 2, the free sections 112 of the diaphragm 11 will not interfere with the top cover 2, and will not stretch into the gap between the top cover 2 and the shell 3 when entering the shell, in this way, the possibility of the diaphragm 11 deeply entering the gap between the top cover 2 and the shell 3 can be eliminated from the root, and the risk of the top cover 2 welding caused by the foreign matter burst hole of the diaphragm 11 is avoided.

[0048] Further, each free section 112 includes a free end, and an opening 9 is left between the free ends of the two free sections 112, so that the opening 9 is beneficial for the electrolyte to enter the inside of the battery cell 1 to better soak the battery cell 1 and is also beneficial for the gas to quickly overflow in the thermal runaway; meanwhile, the opening 9 is beneficial for the two free sections 112 not to contact each other to avoid mutual interference of the two free sections to affect the subsequent gluing process; and the two free sections 112 not contacting each other can reduce the amount of the separator 11 under the premise of ensuring that the free section 112 does not warp, thereby reducing the cost.

[0049] In some embodiments, continuing to refer to Figure 5 As shown in the first direction, the size of the free section 112 is a, the size of the battery cell 1 is b, and 1 / 2b>a>1 / 3b.

[0050] Specifically, when the size of the free section 112 and the size of the battery cell 1 satisfy 1 / 2b>a>1 / 3b, the size of the free section 112 is moderate, which can not only reduce the probability of the outermost separator 11 warping, but also avoid mutual interference of the two free sections 112 when the bundling tape is glued, and can reduce the amount of the separator 11 under the premise of ensuring that the free section 112 does not warp, thereby reducing the cost.

[0051] When the size of the free section 112 is less than 1 / 3b, the size of the free section 112 is too small, and the separator 11 is prone to warping; when the size of the free section 112 is greater than 1 / 2b, the size of the free section 112 is too large, and the two free sections 112 will interfere with each other when the bundling tape is glued, which is not conducive to the gluing process, and the amount of the separator 11 is too large, and the cost is high.

[0052] Figure 6 Fig. 3 shows a third cross-sectional schematic view of the laminated battery of the embodiment of the present application, Figure 7 Fig. 1 shows a first cross-sectional schematic view of the battery cell 1 of the embodiment of the present application.

[0053] In some embodiments, referring to Figure 6 and Figure 7 As shown in the first direction, the first layer and the last layer of the separator 11 are both the first surface 111 away from the insertion space 18, and the laminated battery further includes a first adhesive 4, the first adhesive 4 is connected with one of the first surfaces 111 and extends to the other first surface 111, and the first adhesive 4 covers the two free sections 112.

[0054] Specifically, the first bonding member 4 is connected to one of the first surfaces 111 and extends to the other first surface 111. In this way, the first bonding member 4 can bond the first surface 111 and the second surface of the battery cell 1 to achieve the bundling and restraint of each battery cell 1, ensuring that the positive electrode plate 12, the negative electrode plate 13, and the separator 11 will not be misaligned. At the same time, it can also prevent the separator 11 on the first surface 111 from warping, so as to expose the electrode plate, resulting in black leakage.

[0055] At the same time, the first bonding member 4 covers the two free segments 112. In this way, the first bonding member 4 can also restrain the two free segments 112, preventing the free segments 112 from warping and affecting the subsequent assembly process.

[0056] In some embodiments, continue to refer to Figure 4 and Figure 5 As shown, there are multiple first bonding members 4. The multiple first bonding members 4 are arranged at intervals along the second direction (i.e., Figure 4 the A direction in

[0057] Specifically, the distance c between two adjacent first bonding members 4 in the second direction is very crucial. If c is too large, the free segment 112 that is not restrained between two adjacent first bonding members 4 is very likely to warp. If c is too small, although it can ensure that the free segment 112 will not warp, it will also result in an excessive amount of the first bonding member 4, increasing the manufacturing cost.

[0058] Therefore, in this application, when 1 / 2a ≤ c < a, the size of the distance c between two adjacent first bonding members 4 in the second direction is appropriate, which can not only effectively restrain the free segment 112 and prevent the free segment 112 from warping, but also save costs.

[0059] In some embodiments, continue to refer to Figure 4 As shown, at least one first bonding member 4 is arranged close to the tab. In the second direction, the ratio of the distance between the edge of the first bonding member 4 arranged close to the tab and the edge of the first surface 111 (i.e., Figure 4 the distance d shown in Figure 4 to the size of the first surface 111 in the second direction (i.e.,

[0060] Specifically, at least one first bonding member 4 is arranged close to the tab, that is, at least one first bonding member 4 is arranged close to the edge of the first surface 111. In this way, the first bonding member 4 can also restrain the edge of the first surface 111, preventing the edge of the first surface 111 from warping, so as to expose the electrode plate, resulting in black leakage.

[0061] When the ratio between the distance between the edge of the first adhesive 4 arranged near the tab and the edge of the first surface 111 and the size of the first surface 111 in the second direction is 1:10-3:10, the adhesive position of the first adhesive 4 is appropriate, which ensures that the first adhesive 4 can fix the edge area of the first surface 111 and prevent the edge of the first surface 111 from being folded.

[0062] When the ratio between the distance between the edge of the first adhesive 4 arranged near the tab and the edge of the first surface 111 and the size of the first surface 111 in the second direction is less than 1:10, the adhesive position of the first adhesive 4 is too close to the edge of the first surface 111, which requires very fine adhesive process of the first adhesive 4 and is not conducive to the actual manufacturing process.

[0063] When the ratio between the distance between the edge of the first adhesive 4 arranged near the tab and the edge of the first surface 111 and the size of the first surface 111 in the second direction is greater than 3:10, the adhesive position of the first adhesive 4 is too far away from the edge of the first surface 111, which makes the first adhesive 4 unable to effectively fix the edge area of the first surface 111, so that the edge of the first surface 111 may still be folded, thereby causing the black leakage phenomenon.

[0064] Exemplarily, in the second direction, the ratio between the distance between the edge of the first adhesive 4 arranged near the tab and the edge of the first surface 111 and the size of the first surface 111 in the second direction can be 1:10, 1.5:10, 2:10, 2.5:10, 3:10, etc.

[0065] Further, the distance between the edge of the first adhesive 4 arranged near the positive tab 14 and the first surface 111 and the distance between the edge of the first adhesive 4 arranged near the negative tab 15 and the first surface 111 can be the same or different.

[0066] In some embodiments, continuing to refer to Figure 4 As shown, further comprising a plurality of second adhesives 5, one end of at least one second adhesive 5 is adhered to the first surface 111, and the other end covers the area where the positive tab 14 is connected to the positive plate 12, one end of at least one second adhesive 5 is adhered to the first surface 111, and the other end covers the area where the negative tab 15 is connected to the negative plate 13, so that the second adhesive 5 can protect the positive tab 14 and the negative tab 15 from being damaged due to pulling or scratching.

[0067] Specifically, in the third direction (i.e. Figure 4The size of the second adhesive 5 is greater than the size of the positive and negative tabs 14 and 15 in the third direction (the direction indicated by arrow B), so that the tabs are completely covered by the second adhesive 5 in the third direction.

[0068] For each battery cell 1, four second adhesives 5 can be provided, two of which correspond to the positive tabs 14 and the other two correspond to the negative tabs 15. Of the two second adhesives 5 corresponding to one tab, one is arranged on one first surface 111 of the separator 11 and the other is arranged on the other first surface 111 of the separator 11 to bind the tab from both sides.

[0069] In some embodiments, the orthogonal projection of the second adhesive 5 in the second direction does not overlap the orthogonal projection of the first adhesive 4 in the second direction, so that the first adhesive 4 and the second adhesive 5 do not overlap on the battery cell 1, thereby avoiding the problem of the thickness of the laminated body being greater in the overlapping area due to overlapping, and improving the uniformity of the thickness of the laminated body.

[0070] In some embodiments, continuing to refer to Figure 5 As shown, the plurality of insertion spaces 18 includes first spaces 181 and second spaces 182 arranged alternately along the first direction, the first and last insertion spaces 18 in the first direction are both first spaces 181, and the opening end of the first space 181 and the opening end of the second space 182 are arranged opposite each other in the cross section in the first direction. The opening end of the first space 181 is arranged away from the top cover 2, and the negative tab 13 is inserted into the first space 181, and the positive tab 12 is inserted into the second space 182.

[0071] Specifically, the opening end of the first space 181 is arranged away from the top cover 2, and the negative tab 13 is inserted into the first space 181, so that when liquid is injected into the casing 3 from the liquid injection hole on the top cover 2, the injected liquid will not directly impact the opening end of the first space 181, and will not directly impact the negative tab 13 located in the first space 181, so that the active material on the negative tab 13 can be prevented from falling off, and the negative tab 13 can be protected.

[0072] Since the negative tab 13 is more likely to cause active material to fall off than the positive tab 12, in the present application, the negative tab 13 is inserted into the first space 181, and the opening end of the first space 181 is arranged away from the top cover 2 to protect the negative tab 13 located in the first space 181 from falling off due to the impact of the liquid injection liquid.

[0073] In some embodiments, an insulating layer is further included between the casing 3 and the battery cell 1, and the insulating layer covers the two free sections 112.

[0074] Specifically, the insulation layer can isolate the shell 3 from the battery cell 1 on one hand, and cover the two free sections 112 on the other hand, so as to further limit and bind the free sections 112, and ensure that the free sections 112 will not be warped and affect the assembly process of the battery cell 1.

[0075] In some embodiments, the battery cell can be provided with one or multiple, and the multiple battery cells 1 are stacked along the first direction. The specific number of the battery cells 1 is determined according to the actual demand for the thickness of the battery cell 1, which is not limited herein.

[0076] Those skilled in the art should understand that the above discussion of any of the embodiments is only exemplary, and is not intended to imply that the scope (including claims) of the present application is limited to these examples; the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of the different aspects of the present application as described above. In order to be brief, they are not provided in details.

[0077] Embodiments of the present application are intended to cover all such alternatives, modifications and variations as fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, improvement, etc. made in the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A stacked battery, characterized in that, Comprising: a battery cell, a top cover, a positive current collector tab, a negative current collector tab and a housing, wherein the top cover and the housing enclose a receiving space, and the battery cell is located in the receiving space; the battery cell includes a plurality of negative electrode sheets, a plurality of positive electrode sheets and a separator, the separator is folded in a "Z" shape along the length direction to form a plurality of insertion spaces, the negative electrode sheets and the positive electrode sheets are alternately inserted into the insertion spaces in sequence along a first direction, the positive electrode sheets extend out positive electrode tabs, the negative electrode sheets extend out negative electrode tabs, the positive electrode tabs are connected to the positive electrode column of the top cover through the positive current collector tab, and the negative electrode tabs are connected to the negative electrode column of the top cover through the negative current collector tab; the battery cell further includes a top surface and a bottom surface arranged opposite to each other, and the top surface is close to the top cover; wherein, the separator includes two free segments, and both of the two free segments are bent along the first direction and extend to the bottom surface.

2. The stacked battery of claim 1, wherein In the first direction, the size of the free segment is a, the size of the battery cell is b, and 1 / 2b > a > 1 / 3b.

3. The stacked battery of claim 1, wherein In the first direction, the surfaces of the first layer and the last layer of the separator facing away from the insertion spaces are both first surfaces, and the laminated battery further includes a first bonding member, the first bonding member is connected to one of the first surfaces and extends to the other first surface, and the first bonding member covers the two free segments.

4. The stacked battery of claim 3, wherein There are a plurality of the first bonding members, and the plurality of first bonding members are arranged at intervals along a second direction, the distance between two adjacent first bonding members in the second direction is c, the size of the free segment in the first direction is a, and 1 / 2a ≤ c < a, and the second direction is the width direction of the separator.

5. The stacked battery of claim 4, wherein, At least one of the first bonding members is arranged close to the electrode tab, and in the second direction, the ratio of the distance between the edge of the first bonding member arranged close to the electrode tab and the edge of the first surface to the size of the first surface in the second direction is 1:10 to 3:

10.

6. The stacked battery of claim 4, wherein, It further includes a plurality of second bonding members, one end of at least one of the second bonding members is bonded to the first surface, and the other end covers the area where the positive electrode tab is connected to the positive electrode sheet, and one end of at least one of the second bonding members is bonded to the first surface, and the other end covers the area where the negative electrode tab is connected to the negative electrode sheet.

7. The stacked battery of claim 6, wherein, The orthographic projection of the second bonding member in the second direction does not overlap with the orthographic projection of the first bonding member in the second direction.

8. The stacked battery of claim 1, wherein, One end of the positive current collector tab is connected to the positive electrode tab, the other end of the positive current collector tab is connected to the positive electrode column of the top cover, one end of the negative current collector tab is connected to the negative electrode tab, and the other end of the negative current collector tab is connected to the negative electrode column of the top cover.

9. The stacked battery of claim 1, wherein, The plurality of insertion spaces include first spaces and second spaces alternately arranged along the first direction, the first insertion space and the last insertion space in the first direction are both the first spaces, in the cross-section in the first direction, the open ends of the first spaces and the open ends of the second spaces are arranged opposite to each other, the open ends of the first spaces face away from the top cover, the negative electrode sheets are inserted into the first spaces, and the positive electrode sheets are inserted into the second spaces.

10. The stacked battery of claim 1, wherein, Further comprising an insulating layer between the shell and the battery cell, the insulating layer covering the two free sections.

11. The stacked battery of claim 1, wherein, The battery cell is provided in plurality, and the plurality of battery cells are stacked along the first direction.

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