Battery

Abstract

The utility model provides a battery. The battery comprises a shell; the top cover and the shell are encircled to form an accommodating space; a liquid injection through hole communicated with the accommodating space is formed in the top cover; the at least one naked battery cell is positioned in the accommodating space, and the naked battery cell comprises a top surface close to the top cover; each naked battery cell comprises a plurality of positive plates and a plurality of negative plates which are alternately arranged along a first direction, and a diaphragm for isolating the positive plates from the negative plates; a diaphragm opening for exposing the positive plate and / or the negative plate is formed in the top surface of the diaphragm; the protection layer is connected to the naked battery core; along the axial direction of the liquid injection through hole, the orthographic projection of the liquid injection through hole on the top surface is at least partially overlapped with the orthographic projection of the protective layer on the top surface. According to the battery provided by the invention, through the protection layer which is connected to the naked battery cell and corresponds to the liquid injection through hole, the electrolyte injected through the liquid injection through hole can be blocked, so that the problems that the diaphragm of the naked battery cell is wrinkled and shrunk, active substances of a pole piece fall off, an interface is poor and the like due to the fact that the electrolyte directly impacts the diaphragm opening of the naked battery cell are avoided.

Description

TECHNICAL FIELD

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

[0002] The battery comprises a shell, a top cover and a bare cell, the bare cell is arranged in a space formed by the top cover and the shell, and the top cover is further provided with a liquid injection through hole for pouring electrolyte into the space.

[0003] In the related art, the diaphragm of the bare cell can have a diaphragm opening on the side surface facing the liquid injection through hole, so that the electrolyte injected from the liquid injection through hole can enter the inside of the bare cell through the diaphragm opening more quickly, thereby better wetting the bare cell. However, in order to pursue the injection efficiency of the electrolyte, the injection pressure is usually large. If the electrolyte with large pressure directly flushes the diaphragm opening of the bare cell, the diaphragm will wrinkle and shrink, thereby causing the positive plate and the negative plate located on the two sides of the diaphragm to contact at the position where the diaphragm shrinks, and further causing internal short circuit. At the same time, under the flushing of the electrolyte, the active material coated on the positive plate or the negative plate is also likely to fall off, thereby adversely affecting the electrical performance of the battery. In addition, the direct flushing of the electrolyte to the diaphragm opening of the bare cell will also cause the positive plate, the negative plate and the diaphragm to separate from each other, that is, the bare cell is flushed and layered, thereby causing interface failure. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the purpose of the present application is to provide a battery to at least partially solve the problem of the bare cell caused by the direct flushing of the electrolyte to the diaphragm opening of the bare cell.

[0005] In order to achieve the above purpose, the present application provides a battery, comprising: a shell; a top cover, which forms a containing space together with the shell; the top cover is provided with a liquid injection through hole communicating with the containing space; at least one bare cell located in the containing space, the bare cell comprises a top surface close to the top cover; each of the bare cells comprises a plurality of positive plates and a plurality of negative plates arranged alternately along a first direction, and a diaphragm separating the positive plates and the negative plates; the diaphragm forms a diaphragm opening on the top surface, which exposes the positive plate and / or the negative plate; a protective layer connected to the bare cell; along the axial direction of the liquid injection through hole, the top surface of the liquid injection through hole is a hole projection, the top surface of the protective layer is a layer projection, and the hole projection and the layer projection at least partially overlap.

[0006] Optionally, the hole projection is located in the layer projection.

[0007] Optionally, the minimum distance between the edge of the hole projection and the edge of the layer projection is L, and L is greater than or equal to 10 mm.

[0008] Optionally, the protection layer comprises a substrate connected to the bare battery cell through an adhesive layer; the bare battery cell comprises two side surfaces oppositely arranged along a first direction, and each of the two side surfaces is connected to the top surface; the protection layer extends along the first direction, and comprises a first region corresponding to the top surface and a second region located at least one side of the first region along the first direction.

[0009] Optionally, the second region has a dimension m along the extension direction of the protection layer, and m≥20mm.

[0010] Optionally, the protection layer is in a relaxed state, and the first region has a convex portion relative to the top surface.

[0011] Optionally, the battery comprises a plurality of bare battery cells stacked along the first direction; each of the bare battery cells is connected to the protection layer, and the protection layer extends from one of the side surfaces of one of the bare battery cells to the other side surface along the first direction; along the first direction, the protection layer of adjacent two bare battery cells has a gap between the projections of the two protection layers, and the hole projection at least partially overlaps with the gap.

[0012] Optionally, the battery comprises a plurality of bare battery cells stacked along the first direction; along the first direction, a first bare battery cell has a first side surface away from an adjacent bare battery cell, and a last bare battery cell has a second side surface away from an adjacent bare battery cell; the protection layer extends from the first side surface to the second side surface.

[0013] Optionally, the top surface of the bare battery cell is connected to a fixing layer; along the width direction of the protection layer, the fixing layer is arranged at least one side of the protection layer with a spacing distance, and the spacing distance between the fixing layer and the protection layer is not less than 3mm.

[0014] Optionally, the bare battery cell has a laminated structure, and the separator is folded in a “Z” shape to form a plurality of insertion spaces; the plurality of insertion spaces comprise first spaces and second spaces alternately arranged along the first direction, the positive electrode plates are inserted into the first spaces, and the negative electrode plates are inserted into the second spaces; the first spaces and / or the second spaces form the separator openings at the openings of the top surface; or, the bare battery cell has a wound structure, the separator comprises a first surface and a second surface oppositely arranged, a plurality of the positive electrode plates are connected to the first surface, and a plurality of the negative electrode plates are connected to the second surface; the separator is wound to form the wound structure; the end of the wound structure along the winding axis forms the top surface, and the openings between the adjacent two turns of the separator of the top surface form the separator openings.

[0015] As can be seen from the above, the battery provided by the application connects the protection layer on the top surface of the bare battery cell with the diaphragm opening. Since the orthographic projection of the protection layer and the liquid injection through hole on the top surface at least partially overlaps, after the electrolyte is injected into the accommodation space through the liquid injection through hole, at least part of the electrolyte will be blocked by the protection layer before contacting the diaphragm, so that the flow rate of the electrolyte is reduced. After the electrolyte bypasses the protection layer, since the flow rate of the electrolyte is low, the diaphragm will not be damaged even if it contacts the diaphragm, thereby avoiding problems such as diaphragm folding and shrinking, active material falling off of the pole piece, and poor interface of the bare battery cell caused by direct impact of the electrolyte on the diaphragm opening of the bare battery cell. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 Part of the schematic diagram of the battery of the first structure of the embodiment of the application;

[0018] Figure 2 Part of the schematic diagram of the battery of the second structure of the embodiment of the application;

[0019] Figure 3 Part of the schematic diagram of the battery of the second structure of the embodiment of the application;

[0020] Figure 4 Part of the schematic diagram of the battery of the third structure of the embodiment of the application;

[0021] Figure 5 Part of the schematic diagram of the battery of the fourth structure of the embodiment of the application;

[0022] Figure 6 Part of the schematic diagram of the battery of the fifth structure of the embodiment of the application.

[0023] Explanation of reference signs:

[0024] 100, bare battery cell; 110, diaphragm; 111, first surface; 112, second surface; 120, diaphragm opening; 130, side surface; 130a, first side surface; 130b, second side surface; 140, top surface; 150, side end surface; 160, negative pole piece; 170, positive pole piece; 180, first space; 190, second space;

[0025] 200, top cover; 210, liquid injection through hole;

[0026] 300, top cover plastic; 310, baffle;

[0027] 410, positive tab; 420, negative tab;

[0028] 500, protective layer; 510, first region; 520, second region;

[0029] 600, gap; 700, hole projection; 800, fixed layer;

[0030] 900, shell; 910, containing space. DETAILED DESCRIPTION

[0031] To make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with reference to the embodiments and the accompanying drawings.

[0032] It should be noted that the relative arrangement of the components, numerical expressions and values set forth in these embodiments do not limit the scope of the present application unless otherwise specified.

[0033] It should be understood that the sizes of the various parts shown in the drawings are not necessarily drawn to scale for the sake of convenience of description.

[0034] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the scope of the application or its application or uses.

[0035] It should be noted that unless otherwise defined, technical terms or scientific terms used in the embodiments of the present application should be understood as their common meanings to those skilled in the art to which the present application belongs. The terms "first", "second" and similar terms used in the embodiments of the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude 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 "up", "down", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0036] In order to avoid direct impact of electrolyte on the bare battery cell 100, the bare battery cell 100 can be covered and protected.

[0037] As Figure 1 , Figure 1A partial schematic diagram of a battery of the first structure is shown. In some embodiments, the top cover 200 is provided with a liquid injection hole 210 extending through the top cover 200 along its thickness direction. The bottom of the liquid injection hole 210 is connected to the top cover plastic 300 (or lower plastic part). The top cover plastic 300 includes a blocking piece 310 for blocking the liquid injection hole 210.

[0038] The stopper 310 of the plastic cover 300 shields the injection hole 210 on the top cover 200. When electrolyte is injected through the injection hole 210, it is first blocked by the stopper 310, reducing the impact force. By the time the electrolyte bypasses the stopper 310 and contacts the bare cell 100, the flow rate of the electrolyte has slowed down, and it will no longer impact the bare cell 100.

[0039] However, the applicant's research found that since the injection hole 210 needs to be sealed with a sealing nail after the injection is completed, in order to avoid interference between the baffle 310 and the sealing nail, the baffle 310 needs to be separated from the bottom of the top cover 200 to form a clearance space. Due to the existence of this clearance space, the bare battery cell 100 needs to be lowered accordingly, which will cause the energy density of the battery to decrease. At the same time, since the baffle 310 is close to the top cover 200, although it can block the electrolyte, it will also create a large resistance to the injection, which greatly reduces the injection speed of the electrolyte, thereby affecting the injection efficiency.

[0040] In order to solve the above problems, Figure 2 A schematic diagram showing the front view of a battery with the second structure. Figure 3 A schematic diagram of a top view of a battery with the second structure is shown. Figure 2 and Figure 3 The embodiment of the present application provides a battery, comprising: a housing 900; a top cover 200, which forms a receiving space 910 together with the housing 900; the top cover 200 is provided with a liquid injection through hole 210 connected to the receiving space 910; at least one bare cell 100, located in the receiving space 910, the bare cell 100 including a top surface 140 close to the top cover 200; each bare cell 100 includes a first direction (such as Figure 3 A plurality of positive electrode sheets 170 and a plurality of negative electrode sheets 160 are alternately arranged (in the Y direction in the figure), and a diaphragm 110 isolating the positive electrode sheets 170 and the negative electrode sheets 160; the diaphragm 110 is formed with a diaphragm opening 120 on the top surface 140 to expose the positive electrode sheets 170 and / or the negative electrode sheets 160; a protective layer 500 is connected to the bare battery cell 100; along the axial direction of the liquid injection through hole 210, the orthographic projection of the liquid injection through hole 210 on the top surface 140 is a hole projection 700, and the orthographic projection of the protective layer 500 on the top surface 140 is a layer projection, and the hole projection 700 at least partially overlaps with the layer projection.

[0041] For example, Figure 3The bare battery cell 100 can be a stacked structure; or, as shown in FIG. 1C, the bare battery cell 100 can be a jelly-roll structure. Figure 4 , Figure 4 A top view of a third structure of the battery is shown in FIG. 1D. The bare battery cell 100 can also be a jelly-roll structure.

[0042] The protective layer 500 can be connected to the bare battery cell 100 by adhesion, hot melt connection or the like.

[0043] It should be noted that in the embodiments of the present application, the separator 110 is in a spiral winding structure or a Z-shaped (or serpentine) folding structure on the top surface 140 of the bare battery cell 100. There is a space between two adjacent sections of the separator 110 in the first direction, and the space contains the positive plate 170 or the negative plate 160. The space forms a separator opening 120 on the top surface 140, and the positive plate 170 or the negative plate 160 in the space is exposed through the separator opening 120.

[0044] In the present embodiment, since the layer projection at least partially overlaps with the hole projection 700 (hereinafter referred to as overlapping part), after the electrolyte is injected through the liquid injection through hole 210, the above-mentioned overlapping part of the protective layer 500 can block the injected electrolyte, that is, at least part of the electrolyte will directly contact the protective layer 500 after entering the accommodation space 910, and under the blocking action of the protective layer 500, the flow rate of the electrolyte will be reduced, and then the electrolyte will flow to the inside of the bare battery cell 100 at a lower flow rate to soak the bare battery cell 100.

[0045] It should be noted that in the present embodiment, the top cover plastic 300 connected to the bottom of the top cover 200 is provided with a through hole corresponding to the liquid injection through hole 210, and the electrolyte can be smoothly injected into the shell through the liquid injection through hole 210 and the through hole.

[0046] The battery provided in the present embodiment is connected with the protective layer 500 on the top surface 140 of the bare battery cell 100 having the separator opening 120. Since the orthogonal projection of the protective layer 500 and the liquid injection through hole 210 on the top surface 140 at least partially overlaps, after the electrolyte is injected into the accommodation space 910 through the liquid injection through hole 210, at least part of the electrolyte will be blocked by the protective layer 500 before contacting the separator 110, thereby reducing the flow rate of the electrolyte. After bypassing the protective layer 500, the electrolyte will not damage the separator 110 due to its low flow rate, even if it contacts the separator 110. This avoids problems such as separator crease shrinkage, active material falling off of the plate and interface failure of the bare battery cell 100 caused by direct impact of the electrolyte on the separator opening 120 of the bare battery cell 100.

[0047] As shown in FIG. 1A, Figure 2 In some embodiments, the hole projection 700 is located within the layer projection.

[0048] In the embodiment, since the layer projection completely covers the hole projection 700, the protective layer 500 can more comprehensively shield the electrolyte entering the accommodation space 910 through the liquid injection through hole 210, that is, most of the electrolyte entering the accommodation space 910 is blocked by the protective layer 500, so as to further improve the protection effect of the protective layer 500 on the bare battery cell 100.

[0049] For example, Figure 2 In some embodiments, the minimum distance between the edge of the hole projection 700 and the edge of the layer projection is L, and L≥10mm.

[0050] For example, the hole projection 700 is aligned with the center of the layer projection.

[0051] For example, when the layer projection has two along the first direction, the center of the hole projection 700 is aligned with the center of the gap 600 between the two layer projections.

[0052] Generally, the minimum distance between the edge of the hole projection 700 and the edge of the layer projection is the distance between them along the second direction (such as the X direction in the figure) Figure 2 , which is perpendicular to the first direction.

[0053] Since the electrolyte will be scattered into the accommodation space 910 after flowing out of the liquid injection through hole 210, if L is small, the protective layer 500 may not be able to fully block the electrolyte, and a part of the electrolyte may directly impact the separator opening 120. Therefore, the embodiment limits L to ensure that the protective layer 500 can more comprehensively shield the electrolyte injected through the liquid injection through hole 210, thereby further improving the protection effect of the protective layer 500 on the bare battery cell 100.

[0054] For example, Figure 2 and Figure 3 In some embodiments, the protective layer 500 includes a substrate connected to the bare battery cell 100 through an adhesive layer; the bare battery cell 100 has two side surfaces 130 oppositely arranged along a first direction, and the two side surfaces 130 are respectively connected to the top surface 140; the protective layer 500 extends along the first direction, and the protective layer 500 includes a first region 510 and a second region 520 located on at least one side of the first region 510 along the first direction; the first region 510 corresponds to the top surface 140, and the second region 520 is connected to the side surface 130.

[0055] For example, the protective layer 500 can be an insulating tape.

[0056] For example, the first region 510 of the protective layer 500 can have a gap with the top surface 140.

[0057] Exemplarily, the first region 510 and the second region 520 of the protective layer 500 are continuous and integrally formed.

[0058] In the embodiment, the first region 510 can shield the liquid injection through hole 210, thereby covering and protecting the bare battery cell 100; and the second region 520 is bonded with the side surface 130 of the bare battery cell 100 with a large area, so that the protective layer 500 and the bare battery cell 100 have a large bonding area, thereby ensuring the connection reliability between the two.

[0059] As shown in FIG. 1, the protective layer 500 is arranged on the bare battery cell 100, and the protective layer 500 covers the liquid injection through hole 210 and the side surface 130 of the bare battery cell 100. Figure 2 In some embodiments, the dimension of the second region 520 along the extension direction of the protective layer 500 (hereinafter referred to as the extension length of the second region 520) is m, and m≥20 mm.

[0060] When the protective layer 500 is connected with the bare battery cell 100 only through the second region 520, if m is small, in order to make the bonding area of the protective layer 500 and the bare battery cell 100 meet the process requirements, the overall width of the protective layer 500 (i.e. the dimension of the protective layer 500 along the second direction) needs to be large. If the width of the protective layer 500 is too large, on the one hand, it will increase the material consumption of the protective layer 500, thereby increasing the cost of setting the protective layer 500; on the other hand, it will also make the protective layer 500 cover too large an area of the diaphragm opening 120, thereby making it difficult for the electrolyte to enter the inside of the bare battery cell 100, affecting the infiltration rate of the electrolyte.

[0061] Therefore, the extension length m of the second region 520 is limited in the embodiment, which can further ensure that the bonding area between the protective layer 500 and the bare battery cell 100 meets the process requirements and guarantees the connection reliability between the two; and can also avoid the adverse effects on the infiltration rate of the electrolyte due to the too large width of the protective layer 500.

[0062] As shown in FIG. 1, the protective layer 500 is arranged on the bare battery cell 100, and the protective layer 500 covers the liquid injection through hole 210 and the side surface 130 of the bare battery cell 100. Figure 3 In some embodiments, the protective layer 500 is in a relaxed state, and the first region 510 has an arch part relative to the top surface 140.

[0063] If the protective layer 500 is in a tight state, the bare battery cell 100 will expand to a certain extent during the process of the electrolyte infiltrating the bare battery cell 100 and the battery charging process. The protective layer 500 in the tight state will generate a large binding force on the bare battery cell 100, which is easy to cause the protective layer 500 to break or cause the protective layer 500 to separate from the bare battery cell 100. At the same time, the protective layer 500 in the tight state will also make the positive plate 170, the negative plate 160 and the diaphragm 110 of the bare battery cell 100 too close, compressing the flow space of the electrolyte inside the bare battery cell 100, thereby making it difficult for the electrolyte to enter the inside of the bare battery cell 100.

[0064] To solve the above problems, in the embodiment, the protective layer 500 is in a relaxed state, and the first area 510 has a certain amount of redundancy, thereby forming an arch part relative to the top surface 140. When the bare battery cell 100 expands, the arch part of the first area 510 can ensure that the protective layer 500 does not generate a large binding force on the bare battery cell 100, which can avoid the protective layer 500 being broken by tension on one hand, and can ensure that the positive plate 170, the negative plate 160, and the separator 110 in the bare battery cell 100 have a certain gap, so that the electrolyte can more smoothly enter the inside of the bare battery cell 100.

[0065] It should be noted that the length (dimension along the first direction) of the arch part of the first area 510 needs to be limited within a certain range. If the length is too large, the protective layer 500 cannot play a certain limiting role on the separator opening 120, and the bare battery cell 100 still has the risk of delamination. At the same time, when the injection hole 210 is subjected to negative pressure, if the length of the arch part is too long, it can also be close to or adhere to the hole of the injection hole 210, thereby blocking the injection hole 210.

[0066] As shown in FIG. 1, the protective layer 500 is connected to the bare battery cell 100, and the protective layer 500 extends along the first direction from one side surface 130 of the bare battery cell 100 to the other side surface 130 of the bare battery cell 100. Figure 5 , Figure 5 As shown in FIG. 1, the protective layer 500 is connected to the bare battery cell 100, and the protective layer 500 extends along the first direction from one side surface 130 of the bare battery cell 100 to the other side surface 130 of the bare battery cell 100.

[0067] In the embodiment, the protective layer 500 has two second areas 520, and the two second areas 520 are respectively located on opposite sides of the first area 510 along the first direction. The two second areas 520 are connected to the opposite two side surfaces 130 of the bare battery cell 100 one by one, and the first area 510 between the two second areas 520 corresponds to the top surface 140 between the two side surfaces 130.

[0068] When the plurality of bare battery cells 100 are stacked, if the second areas 520 of the adjacent two protective layers 500 are close, the flow of the electrolyte will be hindered. To avoid the above problem, the embodiment makes the protective layers 500 on the adjacent two bare battery cells 100 spaced along the first direction, so as to form a gap 600 between the protective layers 500 of the adjacent bare battery cells 100. When the electrolyte is injected through the injection hole 210, the electrolyte can quickly spread to each angle inside the bare battery cell 100 through the gap 600 between the two protective layers 500 and the gap 600 between the two side surfaces 130, which helps to improve the infiltration speed.

[0069] Meanwhile, it should be noted that the diaphragm 110, the positive electrode sheet 170 and the negative electrode sheet 160 do not exist in the gap 600, and thus the electrolyte entering the gap 600 will not cause damage to the bare battery cell 100.

[0070] As shown in Figure 6 , Figure 6 A top view of a battery of the fifth structure is shown. In some embodiments, the battery includes a plurality of bare battery cells 100 stacked along a first direction; along the first direction, a first bare battery cell 100 has a first side surface 130a away from an adjacent bare battery cell 100, and a last bare battery cell 100 has a second side surface 130b away from an adjacent bare battery cell 100; the protective layer 500 extends from the first side surface 130a to the second side surface 130b.

[0071] For example, as shown in the structure and direction, Figure 6 , Figure 6 In the embodiment, three bare battery cells 100 are arranged along the first direction, which are referred to as upper bare battery cell, middle bare battery cell and lower bare battery cell. The side surface 130a of the upper bare battery cell away from the middle bare battery cell is the first side surface 130a, and the side surface 130b of the lower bare battery cell away from the middle bare battery cell is the second side surface 130b. The protective layer 500 extends from the first side surface 130a to the second side surface 130b, thereby protecting the diaphragm opening 120 of the top surface 140 of the upper, middle and lower bare battery cells 100.

[0072] Compared with arranging the protective layer 500 for each bare battery cell 100, the plurality of bare battery cells 100 are covered by the same protective layer 500. Since the second region 520 of the plurality of protective layers 500 is omitted, the amount of material of the protective layer 500 can be reduced, which helps to reduce the manufacturing cost of the battery. Meanwhile, the protective layer 500 of the embodiment can easily cover the injection hole 210, and can ensure that the protective layer 500 reliably covers the bare battery cell 100.

[0073] As shown in Figure 2 , in some embodiments, the top surface 140 of the bare battery cell 100 is connected with a fixing layer 800. Along the width direction of the protective layer 500 (for example, the X direction in Figure 2 , the fixing layer 800 is arranged at least on one side of the protective layer 500, and the distance d between the fixing layer 800 and the protective layer 500 is not less than 3 mm, i.e., d≥3 mm.

[0074] For example, the fixing layer 800 can be a fixing tape.

[0075] The embodiment limits the distance between the protective layer 500 and the fixing layer 800. If the distance is too large, a large area of the diaphragm opening 120 cannot be protected by the fixing layer 800 or the protective layer 500. When the electrolyte injection rate is unstable (for example, at the beginning and end of injection) or too fast, the diaphragm 110 at the diaphragm opening 120 position is prone to wrinkle shrinkage or the bare battery cell 100 at the diaphragm opening 120 position is prone to delamination, thereby reducing the adhesion between the positive plate 170, the negative plate 160, and the diaphragm 110.

[0076] If the distance between the protective layer 500 and the fixing layer 800 is too small, a large area of the diaphragm opening 120 is covered by the protective layer 500 and the fixing layer 800. It is difficult for the electrolyte to enter between the adjacent bare battery cells 100. The local binding force of the fixing layer 800 and the protective layer 500 on the bare battery cell 100 is too large, which affects the uniformity of the bare battery cell 100 and may increase the risk of lithium precipitation.

[0077] For example, Figure 2 and Figure 3 In some embodiments, the bare battery cell 100 is a stacked structure, the diaphragm 110 is folded in a “Z” shape to form a plurality of insertion spaces, the plurality of insertion spaces include first spaces 180 and second spaces 190 arranged alternately along a first direction, the positive plate 170 is inserted into the first space 180, and the negative plate 160 is inserted into the second space 190. The opening of the first space 180 and / or the second space 190 at the top surface 140 forms the diaphragm opening 120.

[0078] For example, along the second direction, the bare battery cell 100 further includes a side end surface 150. When the bare battery cell 100 is a stacked structure, part of each positive plate 170 extends from the opening of the first space 180 at the side end surface 150, and the extended parts of the plurality of positive plates 170 are connected in layers to form the positive tab 410. Similarly, part of each negative plate 160 extends from the opening of the second space 190 at the side end surface 150, and the extended parts of the plurality of negative plates 160 are connected in layers to form the negative tab 420.

[0079] When the bare battery cell 100 is a stacked structure, the first region 510 of the protective layer 500 can cover and protect the diaphragm opening 120 of the stacked structure at the top surface 140, so as to avoid the electrolyte directly impacting the diaphragm opening 120, thereby causing the diaphragm 110 to wrinkle and shrink downward (i.e., away from the top cover 200). It can also avoid the electrolyte entering the first space 180 and the second space 190 at a high flow rate, thereby forcing the positive plate 170, the negative plate 160, and the diaphragm 110 to separate from each other, resulting in delamination.

[0080] For example,Figure 2 and Figure 4 In some embodiments, the bare battery cell 100 is a jelly-roll structure, the separator 110 includes a first surface 111 and a second surface 112 oppositely arranged, the plurality of positive electrode tabs 170 are connected to the first surface 111, the plurality of negative electrode tabs 160 are connected to the second surface 112, and the separator 110 is wound to form the jelly-roll structure; the end of the jelly-roll structure along the winding axis (the winding axis extends in the Z direction in the figure) forms a top surface 140, and the opening between the adjacent two turns of the separator 110 of the top surface 140 forms a separator opening 120. Figure 2 In some embodiments, the plurality of positive electrode tabs 170 on the first surface 111 are arranged in a single direction (for example, the second direction) and are integrally formed. The plurality of negative electrode tabs 160 on the second surface 112 are arranged in the same direction and are integrally formed.

[0081] In some embodiments, the plurality of positive electrode tabs 170 on the first surface 111 are arranged in a single direction (for example, the second direction) and are integrally formed. The plurality of negative electrode tabs 160 on the second surface 112 are arranged in the same direction and are integrally formed.

[0082] When the bare battery cell 100 is a jelly-roll structure, the first region 510 of the protective layer 500 can cover and protect the separator opening 120 of the jelly-roll structure located at the top surface 140, so as to avoid the direct impact of the electrolyte on the separator opening 120, thereby causing the separator 110 to wrinkle and shrink downward (i.e., in the direction away from the top cover 200 along the winding axis). It can also avoid the electrolyte entering between the positive electrode tab 170 and the separator 110 and between the negative electrode tab 160 and the separator 110 at a high flow rate, thereby forcing the positive electrode tab 170, the negative electrode tab 160, and the separator 110 to separate from each other, resulting in delamination.

[0083] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims can be performed in a different order than those described above and still achieve desirable results. Also, the process depicted in the figures does not necessarily require the particular order shown, or sequential order, to achieve the desired results. In some implementations, multitasking and parallel processing can be advantageous.

[0084] Each of the embodiments in the present application is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be mutually referred to.

[0085] The description of the present application is given for the purpose of illustration and description, and is not exhaustive or limiting to the forms disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are chosen and described in order to better illustrate the principles and practical application of the present application, and to enable those of ordinary skill in the art to understand the present application in order to design various embodiments with various modifications for specific use.

[0086] Those skilled in the art will understand that the above-mentioned discussion of any of the embodiments is merely exemplary in nature and is not intended to suggest the scope of the application, as it is contemplated that the application that out to include any of the embodiments, or their equivalents, in conjunction with the specifics of the above-mentioned embodiments. Numerous modifications, variations, and adaptations will be apparent to those skilled in the art in light of the above description.

[0087] Although the present application has been described in connection with certain specific embodiments thereof, many modifications, changes, variations and substitutions will now occur to those skilled in the art to which the application pertains.

[0088] It is intended that the application embrace all such alternatives, modifications, and variations as fall within the scope of the broadest possible interpretation of the appended claims. Accordingly, any and all modifications, variations or equivalent arrangement and operations will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the protection sought by the present application.

Claims

1. A battery, characterized by, The battery comprises: a shell; a top cover which cooperates with the shell to form a containing space; the top cover is provided with a liquid injection through hole which communicates with the containing space; at least one bare cell located in the containing space, the bare cell comprising a top surface close to the top cover; each bare cell comprises a plurality of positive electrode sheets and a plurality of negative electrode sheets which are alternately arranged along a first direction, and a diaphragm which separates the positive electrode sheets and the negative electrode sheets; the diaphragm is formed with diaphragm openings on the top surface, which expose the positive electrode sheets and / or the negative electrode sheets; a protective layer connected to the bare cell; along the axial direction of the liquid injection through hole, the top surface of the bare cell is projected onto a hole projection, and the protective layer is projected onto a layer projection; the hole projection and the layer projection at least partially overlap.

2. The battery of claim 1, wherein, The hole projection is located within the layer projection.

3. The battery of claim 2, wherein, The minimum distance between the edge of the hole projection and the edge of the layer projection is L, and L≥10mm.

4. The battery of claim 1, wherein, The protective layer comprises a substrate connected to the bare cell through an adhesive layer; the bare cell comprises two side surfaces which are oppositely arranged along the first direction, and the two side surfaces are respectively connected to the top surface; the protective layer extends along the first direction, and the protective layer comprises a first region corresponding to the top surface and a second region located on at least one side of the first region along the first direction; the second region is connected to the side surface.

5. The battery of claim 4, wherein, The size of the second region along the extension direction of the protective layer is m, and m≥20mm.

6. The battery of claim 4, wherein, The protective layer is in a relaxed state, and the first region has a bulge relative to the top surface.

7. The battery of claim 4, wherein, The battery comprises a plurality of bare cells stacked along the first direction; each bare cell is connected to the protective layer, and the protective layer extends from one side surface of one bare cell to the other side surface of the same bare cell along the first direction; along the first direction, the layer projections of two adjacent protective layers have a gap, and the hole projection at least partially overlaps with the gap.

8. The battery of claim 4, wherein, The battery comprises a plurality of bare cells stacked along the first direction; along the first direction, the first bare cell has a first side surface away from the adjacent bare cell, and the last bare cell has a second side surface away from the adjacent bare cell; the protective layer extends from the first side surface to the second side surface.

9. The battery of claim 1, wherein, The top surface of the bare cell is connected to a fixing layer; along the width direction of the protective layer, the fixing layer is arranged on at least one side of the protective layer, and the spacing distance between the fixing layer and the protective layer is not less than 3mm.

10. The battery of claim 1, wherein, The bare cell has a laminated structure, and the diaphragm is folded in a "Z" shape to form a plurality of insertion spaces; the plurality of insertion spaces comprise first spaces and second spaces which are alternately arranged along the first direction; the positive electrode sheets are inserted into the first spaces, and the negative electrode sheets are inserted into the second spaces; the openings of the first spaces and / or the second spaces on the top surface form the diaphragm openings; or The bare battery cell is in a winding structure, the separator includes a first surface and a second surface arranged oppositely, a plurality of the positive electrode sheets are connected to the first surface, a plurality of the negative electrode sheets are connected to the second surface, and the separator is wound to form the winding structure; the end of the winding structure along the winding axis forms the top surface, and the opening between the adjacent two turns of the separator of the top surface forms the separator opening.

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