Secondary battery

Abstract

The invention discloses a secondary battery, and belongs to the technical field of batteries, and the secondary battery comprises a shell provided with an accommodating cavity; the cover plate assembly comprises a cover plate body, the cover plate body is connected with the shell and covers the containing cavity, and the cover plate body is provided with a liquid injection hole; the electrode assembly is arranged in the accommodating cavity, the electrode assembly comprises an electrode body and a tab, and the tab is connected with the electrode body; the distance piece is arranged in the containing cavity and located between the cover plate body and the electrode body, the distance piece is provided with a plurality of first flow guide holes, each first flow guide hole penetrates through the distance piece in the thickness direction of the distance piece, and the first flow guide holes correspond to the liquid injection hole; the falling electrolyte is blocked by the distance piece and bears the impact force of the electrolyte, so that the electrolyte is dispersed on the distance piece and flows in from the first flow guide holes, the electrolyte is divided into a plurality of relatively small electrolyte flows, the impact force of the electrolyte is further reduced, and the possibility that the diaphragm is wrinkled is reduced.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a secondary battery. Background Art

[0002] When a battery cell is manufactured, after the electrode assembly is installed in the shell, the electrolyte needs to be injected from the injection hole of the end cover. When the electrolyte is injected, it usually carries a certain pressure to speed up the injection speed. This makes the electrolyte have a greater impact force and easily impacts the diaphragm of the battery cell, causing diaphragm wrinkles. Summary of the invention

[0003] Purpose of the invention: The embodiment of the present application provides a secondary battery, aiming to solve the current technical problem that pressurized injection of electrolyte easily impacts the diaphragm and causes diaphragm wrinkles.

[0004] Technical solution: The secondary battery described in the embodiment of the present application includes:

[0005] A housing having a receiving cavity;

[0006] A cover plate assembly, comprising a cover plate body, the cover plate body is connected to the shell and covers the accommodating cavity, and the cover plate body has a liquid injection hole;

[0007] An electrode assembly is disposed in the accommodating cavity, wherein the electrode assembly comprises an electrode body and a tab, wherein the tab is connected to the electrode body;

[0008] A spacer is arranged in the accommodating cavity and located between the cover plate body and the electrode body. The spacer has a plurality of first flow guide holes, each of which penetrates the spacer along the thickness direction of the spacer, and the plurality of first flow guide holes are arranged corresponding to the injection holes.

[0009] In some embodiments, the spacer further has a plurality of second guide holes, which are arranged at intervals on the periphery of the region where the plurality of first guide holes are located, and are arranged through the spacer along the thickness direction;

[0010] The flow area of ​​each of the first flow guide holes is S a mm 2 , the flow area of ​​each of the second flow guide holes is S c mm 2 , satisfy: S a mm 2 <S c mm 2 .

[0011] In some embodiments, the secondary battery has a first direction, and along the first direction, at least one second flow guide hole is disposed on opposite sides of a region where the plurality of first flow guide holes are located.

[0012] In some embodiments, the secondary battery has a second direction intersecting with the first direction, and each of the second flow guide holes extends along the second direction.

[0013] In some embodiments, the spacer includes a first plate and a second plate, the first guide hole and the second guide hole are both provided on the first plate, the second plate is connected to the first plate, and at least a portion of the second plate is located on a side of the first plate close to the electrode body;

[0014] The electrode tab includes a connecting portion and a folding portion, wherein the connecting portion is connected to the electrode body and is attached to a side of the second plate body facing the electrode body;

[0015] The folding portion is connected to an end of the connecting portion away from the electrode body and is attached to the first plate body.

[0016] In some embodiments, the folded portion is attached to the first plate along a surface of the first plate facing away from the second plate, and extends toward a direction where the second air guide hole is located, avoiding the first air guide hole.

[0017] In some embodiments, the injection hole has an axis, and the cover plate assembly further comprises:

[0018] The guide portion is arranged on a side of the cover plate body facing the electrode assembly, and one end of the guide portion is connected to the cover plate body and the other end of the guide portion extends in the direction of the axis.

[0019] In some embodiments, the secondary battery has a third direction, which corresponds to the thickness direction of the cover body. The cover assembly also includes an insulating part, which is connected to the cover body and is located on a side of the cover body close to the electrode assembly. The insulating part has a through hole, which is arranged corresponding to the injection hole along the third direction, and the guide part is connected to the insulating part.

[0020] In some embodiments, there are multiple guide portions, and the multiple guide portions are arranged at intervals along the circumferential direction of the through hole.

[0021] In some embodiments, the injection hole has a minimum radius R 1 mm, the length of the portion of the guide portion corresponding to the injection hole in the third direction is N mm, satisfying: 0.2≤N / R 1 ≤0.8.

[0022] In some embodiments, the guide portion has a guide surface arranged toward the injection hole, and an angle α is formed between the guide surface and the third direction, satisfying: 90°≤α≤110°.

[0023] In some embodiments, along the third direction, there is a minimum spacing dimension Lmm between the guide portion and the injection hole, satisfying: 2≤L≤5.

[0024] In some embodiments, the cover body includes a first surface, the first surface is disposed toward the electrode assembly, and the area enclosed by the opening end of the injection hole on the first surface is S mm 2 , each of the guide portions has an orthographic projection on the first surface along the third direction, and the sum of the areas of the orthographic projections that cross the edge of the injection hole and are located inside the injection hole is S 1 mm 2 , satisfying: 0.2≤S 1 / S≤0.5.

[0025] In some embodiments, the sum of the areas enclosed by the first guide holes on the surface of the spacer facing the cover plate assembly is S. 2 mm 2 , satisfying: 1.2≤S 2 / S≤3.

[0026] In some embodiments, the injection hole has a minimum radius R 1 mm, the first guide hole has an aperture D mm, satisfying: 0.2≤D / R 1 ≤1.

[0027] Beneficial effect: The secondary battery of the embodiment of the present application blocks the falling electrolyte and withstands the impact force of the electrolyte through the spacer. The electrolyte is dispersed on the spacer and flows in from each first guide hole, thereby being divided into multiple relatively small electrolyte flows, further reducing the impact force of the electrolyte, allowing the diaphragm to remain flat under the flushing of the electrolyte, reducing the possibility of wrinkles on the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic diagram of the three-dimensional structure of a secondary battery provided in an embodiment of the present application;

[0030] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0031] Figure 3 A schematic diagram of the three-dimensional structure of a spacer provided in an embodiment of the present application;

[0032] Figure 4 A schematic diagram of the three-dimensional structure of the cover plate assembly provided in an embodiment of the present application;

[0033] Figure 5 A bottom view of the guide portion provided in an embodiment of the present application;

[0034] Figure 6 A cross-sectional view of a secondary battery provided in an embodiment of the present application;

[0035] Figure 7 for Figure 6 A partial enlarged view of point B in the middle;

[0036] Figure numerals: 1. Shell; 10. Accommodating cavity; 2. Cover plate assembly; 20. Liquid injection hole; 201. Injection groove; 202. Liquid outlet hole; 21. Cover plate body; 211. First surface; 22. Insulating portion; 221. Through hole; 23. Guide portion; 231. Guide surface; 24. Pole; 3. Electrode assembly; 31. Electrode body; 32. Ear; 321. Connecting portion; 322. Folding portion; 4. Spacer; 41. First plate body; 411. First guide hole; 412. Second guide hole; 42. Second plate body; 5. Adapter; 51. Notch. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0038] In the description of the present application, it should be understood that the terms "height", "thickness", "up", "down", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined. In the description of the present application, "vertical" means completely vertical at 90° or almost completely vertical, for example, an angle in the range of 85° to 95° is considered vertical.

[0039] It should also be noted that, in the drawings of the embodiments of the present application, the arrow marked with X indicates the first direction X of the secondary battery, the arrow marked with Y indicates the second direction Y of the secondary battery, and the arrow marked with Z indicates the third direction Z of the secondary battery. The first direction X, the second direction Y and the third direction Z are introduced to more clearly describe the structure and relative position relationship of each component in the secondary battery. In actual applications, the introduction of the first direction X, the second direction Y and the third direction Z may change according to different placement methods of the secondary battery.

[0040] The secondary battery in the present application includes but is not limited to lithium-ion single battery, lithium-sulfur battery, sodium-lithium-ion battery, sodium-ion battery or magnesium-ion battery, etc.

[0041] Please combine Figure 1 and Figure 2 The secondary battery of the embodiment of the present application includes a shell 1, a cover assembly 2, an electrode assembly 3 and a spacer 4. The shell 1 is provided with a receiving cavity 10. The cover assembly 2 includes a cover body 21, which is connected to the shell 1 and covers the receiving cavity 10 to close the receiving cavity 10; the cover body 21 has an injection hole 20, which is arranged through the thickness direction of the cover body 21, and the injection hole 20 connects the receiving cavity 10 with the outside for electrolyte injection. The electrode assembly 3 is arranged in the receiving cavity 10, and the electrode assembly 3 includes an electrode body 31 and a pole ear 32. The electrode body 31 is formed by winding a stacked pole sheet and a diaphragm or by laminating a pole sheet and a diaphragm, and the pole ear 32 is connected to the electrode body 31. The spacer 4 is arranged in the accommodating cavity 10 and is located between the cover plate assembly 2 and the electrode body 31. The spacer 4 is arranged opposite to the cover plate assembly 2. The spacer 4 has a plurality of first guide holes 411. Each first guide hole 411 penetrates the spacer 4 along the thickness direction of the spacer 4. The plurality of first guide holes 411 are arranged corresponding to the injection holes 20.

[0042] During the injection, the electrolyte is injected from the injection hole 20 and then falls onto the spacer 4. The electrolyte is blocked by the spacer 4 and dispersed. After passing through the plurality of first flow guide holes 411, the electrolyte flows into a plurality of streams and then falls onto the electrode body 31. Since the spacer 4 absorbs most of the impact force of the electrolyte, the flow rate of the electrolyte is reduced. After the electrolyte flows into a plurality of streams, the power of the fluid is further reduced, thereby reducing the effect of scouring the diaphragm and reducing the possibility of wrinkles on the diaphragm.

[0043] Please combine Figure 2 and Figure 3In some embodiments, the spacer 4 further has a plurality of second flow guide holes 412, each of which penetrates the spacer 4 along the thickness direction of the spacer 4, and the plurality of second flow guide holes 412 are arranged at intervals on the periphery of the first flow guide hole 411. The flow area of ​​each first flow guide hole 411 is S a mm 2 , the flow area of ​​each second flow guide hole 412 is S c mm 2 , satisfy: S a mm 2 <S c mm 2 . Multiple first guide holes 411 are concentrated in one area of ​​the spacer 4, and multiple second guide holes 412 are arranged at intervals around the periphery of the first guide holes 411, that is, multiple second guide holes 412 are arranged at intervals around the periphery of the multiple first guide holes 411 area. When the electrolyte is blocked by the spacer 4 and dispersed everywhere, part of the electrolyte will not have time to pass through the first guide holes 411 and flow outside the area of ​​the multiple first guide holes 411. The second guide holes 412 prevent the electrolyte from flowing in the direction in which it is located, so that the electrolyte flows from the second guide holes 412, shortening the flow path of the electrolyte to reduce the retention of the electrolyte on the spacer 4. The flow area mentioned here refers to the cross-sectional area when the electrolyte flows through a first flow guide hole 411 in a full flow state or the cross-sectional area when the electrolyte flows through a second flow guide hole 412 in a full flow state. The flow areas of the first flow guide hole 411 and the second flow guide hole 412 can be measured optically. An optical measuring device, such as a laser scanner or a projector, is used to measure the geometric shapes of the first flow guide hole 411 and the second flow guide hole 412. The flow area of ​​the hole can be calculated by analyzing the shape and size of the hole. If it is a regular shape, such as the first flow guide hole 411 is a circular hole, the flow area of ​​the first flow guide hole 411 can be obtained by multiplying the square of the radius of the first flow guide hole 411 by π. The flow area of ​​the second flow guide hole 412 can also be calculated according to the same calculation idea.

[0044] Please combine Figure 1 , Figure 2 and Figure 3In some embodiments, the secondary battery has a first direction X, and the first direction X passes vertically through the two large surfaces of the shell 1; along the first direction X, at least one second flow guide hole 412 is provided on each of the opposite sides of the area where the multiple first flow guide holes 411 are located. The secondary battery in the present application is a square shell battery, which corresponds to the diaphragm on the outside of the electrode body 31 in the first direction X. The diaphragm on the outside has a relatively low mutual support force with the pole piece due to the relatively small number of layers wound, and the length of the diaphragm makes its own tension more susceptible to influence. By cutting off the electrolyte through the second flow guide hole 412, the scouring of the outer diaphragm after the electrolyte overflows from the spacer 4 can be reduced, and the possibility of the outer diaphragm being scour and folding is reduced. At the same time, the second flow guide holes 412 are arranged on opposite sides of the first direction X, which can also effectively ensure the structural strength of the spacer 4.

[0045] Please combine Figure 2 and Figure 3 In some embodiments, the secondary battery has a second direction Y intersecting with the first direction X, and each second flow guide hole 412 extends along the second direction Y, so that the length of the second flow guide hole 412 is increased, and the interception range of the electrolyte is expanded. In some other embodiments, the area where each first flow guide hole 411 is located can be circular, that is, all the first flow guide holes 411 are located in this circular area, and the second flow guide holes 412 are arranged at intervals around the periphery of the circular area and extend along the peripheral direction of the circular area. At this time, the second flow guide hole 412 is arc-shaped, its own length is increased, and the fit with the outer contour of the area where each first flow guide hole 411 is located is improved, which is conducive to increasing the blocking effect on the electrolyte. In some other embodiments, along the second direction Y, the second flow guide holes 412 are arranged on one side of the area where the multiple first flow guide holes 411 are located, the area where the multiple first flow guide holes 411 are located is arranged at one end of the spacer 4 along the second direction Y, and the second flow guide holes 412 are located between the area where the multiple first flow guide holes 411 are located and the other end of the spacer 4 along the second direction Y to limit the flow path of the electrolyte. In some other embodiments, the multiple second flow guide holes 412 are arranged on the periphery of the area where the multiple first flow guide holes 411 are located, the second flow guide holes 412 in the first direction X extend along the second direction Y, and the second flow guide holes 412 in the second direction Y extend along the first direction X, further increasing the enclosure range of the area where the multiple first flow guide holes 411 are located, and at the same time, the second flow guide holes 412 are arranged at intervals, which can ensure the strength of the spacer 4.

[0046] Please combine Figure 2 and Figure 3In some embodiments, the spacer 4 includes a first plate body 41 and a second plate body 42. The first plate body 41 is arranged opposite to the cover plate assembly 2. The first guide hole 411 and the second guide hole 412 are both arranged on the first plate body 41 and penetrate along the thickness direction of the first plate body 41. The second plate body 42 is connected to the first plate body 41, and at least part of the second plate body 42 is located on the side of the first plate body 41 close to the electrode body 31. An angle is formed between the second plate body 42 and the first plate body 41, and the degree of the angle is less than 60°.

[0047] The pole lug 32 includes a connecting portion 321 and a folding portion 322, wherein the connecting portion 321 is connected to the electrode body 31 and is attached to the side of the second plate 42 facing the electrode body 31, and the folding portion 322 is connected to the end of the connecting portion 321 away from the electrode body 31 and is attached to the side of the first plate 41 away from the electrode body 31, so that the connection position of the folding portion 322 and the connecting portion 321 corresponds to one side of the first plate 41 along the first direction X. The pole lug 32 is folded onto the second plate 42 along the second plate 42, which guides the bending direction of the pole lug 32 and integrates the pole lug 32, so that the stress distribution of the pole lug 32 is uniform, especially in the case of multiple pole lugs 32, so that the pole lugs 32 can be attached to each other, reduce the gaps between each other, and reduce the possibility of uneven thickness of the pole lug 32 affecting the internal resistance and conductive performance.

[0048] Please refer to Figure 3 In some embodiments, the folding portion 322 is attached to the first plate body 41 along the surface of the first plate body 41 facing away from the second plate body 42, and extends toward the second guide hole 412 and avoids the first guide hole 411, that is, the folding portion 322 is located on the side of the second guide hole 412 away from the plurality of first guide holes 411 to avoid blocking the first guide holes 411.

[0049] Please combine Figure 1 , Figure 4 , Figure 5 and Figure 7 In some embodiments, the injection hole 20 has an axis P, and the cover assembly 2 further includes a pole 24 and a guide 23, the pole 24 is connected to the cover body 21, and is electrically connected to the pole ear 32. The guide 23 is arranged on the side of the cover body 21 facing the electrode assembly 3, and one end is connected to the cover body 21, and the other end extends in the direction of the axis P. The guide 23 blocks the electrolyte falling from the injection hole 20, so that the impact force of a part of the electrolyte is alleviated, and most of the electrolyte injection positions are concentrated to correspond to the spacer 4. The spacer 4 resists the impact of the remaining electrolyte and diverts the electrolyte, thereby avoiding the electrolyte directly impacting the diaphragm and the pole piece and causing damage. In addition, part of the electrolyte blocked by the guide 23 falls to the surroundings, which can increase the distribution range of the electrolyte landing point, so that the electrolyte is quickly and evenly distributed.

[0050] In some other embodiments, the secondary battery further includes a transfer plate 5, the pole ear 32 is attached to the spacer 4, the transfer plate 5 is located on the side of the pole ear 32 facing the cover body 21, and is connected to the pole ear 32, the transfer plate 5 is connected to the pole column 24, and the transfer plate 5 has a notch 51, so that the first guide hole 411 is exposed, so that the electrolyte can pass and fall onto the spacer 4 and enter the first guide hole 411. Specifically, the connection between the pole ear 32, the transfer plate 5 and the pole column 24 can be ultrasonic welding, laser welding, resistance welding, etc. The transfer plate 5 plays the role of current conduction to ensure the effective transmission of current.

[0051] Please combine Figure 4 and Figure 5 In some embodiments, the secondary battery has a third direction Z, which corresponds to the thickness direction of the cover body 21, and the third direction Z is perpendicular to the first direction X and the second direction Y. The cover assembly 2 also includes an insulating portion 22, which is connected to the cover body 21 and is located on the side of the cover body 21 close to the electrode body 31. The insulating portion 22 has a through hole 221, and the through hole 221 is arranged corresponding to the injection hole 20 along the third direction Z; the guide portion 23 is connected to the insulating portion 22 to form a structure indirectly connected to the cover body 21, and the positive projection of the guide portion 23 on the insulating portion 22 along the third direction Z at least partially falls into the through hole 221. The insulating portion 22 is located in the accommodating cavity 10 and is connected to the inner wall of the shell 1 to seal the cover body 21 and the shell 1, prevent electrolyte leakage or external impurities from entering the shell 1, and protect the internal structure and chemical substances of the battery from the influence of the external environment. The electrolyte flows through the injection hole 20 and the through hole 221 and contacts the guide part 23. In the embodiment of the present application, the guide part 23 can be integrally formed with the insulating part 22 by injection molding, which is convenient for processing.

[0052] Please refer to Figure 5 In some embodiments, the number of the guide portions 23 is multiple, and the multiple guide portions 23 are arranged at intervals along the circumferential direction of the through hole 221. The multiple guide portions 23 improve the effect of alleviating the impact force of the electrolyte, and also increase the path for the electrolyte to fall to the surroundings through the guide portions 23, further accelerating the speed of the electrolyte being evenly distributed in the accommodating cavity 10.

[0053] Please combine Figure 5 , Figure 6 and Figure 7 In some embodiments, the injection hole 20 has a minimum radius R 1 mm, the length of the guide portion 23 corresponding to the injection hole 20 in the third direction Z is N mm, satisfying: 0.2≤N / R 1 ≤0.8.

[0054] The injection hole 20 includes an injection groove 201 and a liquid outlet hole 202 which are connected to each other. In the third direction Z, the liquid outlet hole 202 penetrates the cover plate body 21 from the bottom of the injection groove 201. The inner diameter of the liquid outlet hole 202 is smaller than the inner diameter of the injection groove 201. The liquid outlet hole 202 is arranged corresponding to the guide portion 23. 1 That is, the radius of the liquid outlet 202. The length of the portion of the guide portion 23 corresponding to the liquid injection hole 20 in the third direction Z can be understood as the length of the positive projection of the guide portion 23 on the insulating portion 22 in the third direction Z beyond the edge of the liquid outlet 202. After the electrolyte is injected, it is necessary to insert a sealing nail into the liquid injection hole 20 to seal it. The injection groove 201 and the liquid outlet 202 are designed with different apertures to match the shape of the sealing nail, which can meet the plug-in requirements of the sealing nail.

[0055] R 1 The measurement can be done by using a vernier caliper to measure the diameter of the outlet hole 202. When measuring, open the two measuring claws of the vernier caliper and fit them tightly against the wall of the outlet hole 202. Read the scale of the vernier caliper at this time to get the diameter value of the outlet hole 202. Calculate half of this value to get R. 1 In addition, the diameter of the liquid outlet 202 can also be measured by measuring tools such as an inner diameter caliper and an inner diameter gauge, and then R can be calculated. 1 .

[0056] The value of N can be obtained by measuring the image size of the guide portion 23 using a projection measurement device (such as an optical projector and a profile projector), or by using a three-coordinate measuring machine.

[0057] N / R 1 It can be any value among 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or a range between any two values. Within this range, the flow guide 23 can meet the requirements of fully alleviating the impact of the electrolyte and supporting the sealing nail.

[0058] Please refer to Figure 7 In some embodiments, the guide portion 23 has a guide surface 231 disposed toward the injection hole 20, and an angle α is formed between the guide surface 231 and the third direction Z, satisfying: 90°≤α≤110°. Specifically, the value of α can be any value among 90°, 95°, 100°, 105°, 110°, or a range value between any two values. The value of α can be obtained using a three-coordinate measuring instrument or an optical projector. By setting the inclination angle of the guide portion 23, on the one hand, the possibility of overflow caused by the guide surface 231 being tilted too much toward the injection hole 20 during injection can be reduced, and the effect of guiding the electrolyte to the surroundings after being blocked by the guide portion 23 can be fully guaranteed. On the other hand, the risk of interference between the guide portion 23 and the structural parts below it is avoided.

[0059] Please refer to Figure 5 In some embodiments, the cover body 21 includes a first surface 211, the first surface 211 is disposed toward the electrode body 31, and the area enclosed by the opening end of the injection hole 20 on the first surface 211 is Smm 2 , that is, the area enclosed by the liquid outlet 202 on the first surface 211, each guide portion 23 has an orthographic projection on the first surface 211 along the third direction Z, and the sum of the areas of the orthographic projections that cross the edge of the liquid injection hole 20 and are located inside the liquid injection hole 20 is S 1 mm 2 , satisfying: 0.2≤S 1 / S≤0.5, specific, S 1 The ratio of / S can be any value among 0.2, 0.3, 0.4, 0.5, or a range between any two values.

[0060] For the injection hole 20, a specific method for measuring the area S can be selected according to its shape. When the injection hole 20 is circular, square, rectangular, etc., a vernier caliper, micrometer or other measuring tool can be used to measure the corresponding size of the injection hole 20, and the area S can be calculated using a geometric formula. For the injection hole 20 with an irregular hole structure, it can also be measured by image processing. For example, an image of the injection hole 20 in the secondary battery can be obtained, and the image can be loaded using image processing software and S can be measured using the software. Alternatively, it can also be measured by projection, using a projection measurement device (such as a digital microscope or an image measuring instrument) to measure the image area of ​​the injection hole 20, and then obtain the area S. Accordingly, for the area S 1 It can be obtained directly through projection measurement or through image processing using image software.

[0061] By limiting the area S 1 The size of can ensure the effect of the guide part 23 to alleviate the impact of the electrolyte, and on this basis, the electrolyte can be diverted and fall through the first guide hole 411 as much as possible.

[0062] Please refer to Figure 7 In some embodiments, along the third direction L, there is a minimum spacing dimension Lmm between the guide portion 23 and the injection hole 20, which satisfies: 2≤L≤5. Specifically, L can be any value among 2, 3, 4, 5 or a range value between any two values. Within this range, the space between the guide portion 23 and the injection hole 20 can satisfy that the electrolyte has a certain movement path, so that the electrolyte falls smoothly to prevent the electrolyte from overflowing. At the same time, the relative position of the guide portion 23 between the electrode body 31 and the cover body 21 can be controlled so that there is enough accommodation space between them.

[0063] The minimum spacing dimension L can be measured by a three-coordinate measuring machine. Multiple points on the guide part 23 and the injection hole 20 are selected, the measuring probe moves and records the coordinate data of the measuring points, and then the distance between the guide part 23 and the injection hole 20 is calculated based on the coordinates of the measuring points.

[0064] Please refer to Figure 7 In some embodiments, the injection hole 20 has a minimum radius R 1 mm, the first guide hole 411 has an aperture D mm, satisfying: 0.2≤D / R 1 ≤1, specific, D / R 1 It can be any value among 0.2, 0.4, 0.6, 0.8, 1, or a range between any two values. Within this range, the first flow guide holes 411 can fully weaken the influence of the surface tension of the electrolyte, so that the electrolyte can flow out from more first flow guide holes 411, so as to disperse the electrolyte as much as possible and reduce the flow rate of the electrolyte after passing through the first flow guide holes 411.

[0065] The measurement method of the diameter D of the first guide hole 411 is the same as the radius R of the middle injection hole 20 1 The measurement method is the same and will not be repeated here.

[0066] Please combine Figure 2 and Figure 7 In some embodiments, the sum of the areas enclosed by the plurality of first guide holes 411 on the surface of the spacer 4 facing the cover plate assembly 2 is S 2 mm 2 , satisfying: 1.2≤S 2 / S≤3, specific, S 2 The ratio of S / S can be any value among 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, 3 or a range between any two values. The spacing between the first flow guide holes 411 and the area of ​​each first flow guide hole 411 need to be relatively large to reduce the influence of the surface tension of the electrolyte so that the electrolyte can be diverted to each first flow guide hole 411 as much as possible. When the minimum area S of the injection hole 20 remains unchanged, S 2 A larger value of the ratio θ / S indicates a greater number of first flow-guiding holes 411 , thereby expanding the range in which the electrolyte can be diverted.

[0067] The method for measuring the area of ​​the first guide hole 411 is the same as the method for measuring the area of ​​the injection hole 20 , and will not be described in detail here.

[0068] Next, several embodiments are provided to illustrate the effect of the secondary battery of the present application. 1 The ratio of S 1 / S ratio, D / R 1 The ratio and S2 The ratio of / S can be determined by conducting electrolyte injection tests on different embodiments and comparative examples. For each embodiment, 100 secondary batteries of the same model are subjected to the injection test, and the defective rate of the secondary battery diaphragm after injection is used to determine the ratio. The defective rate of the diaphragm = (the number of diaphragm folds + the number of deformations) / the total amount of secondary batteries * 100%.

[0069]

[0070] As shown in the table above, according to Examples 1 to 4, when N / R 1 When the ratio of N / R is in the range of 0.2 to 0.8, the defect rate of the diaphragm is zero. According to Examples 17 to 18, when N / R 1 When the ratio of D / R is less than 0.2 or greater than 0.8, the diaphragm has a slight defect rate to varying degrees; according to Examples 9 to 13, when D / R 1 When the ratio is in the range of 0.2 to 1, the defect rate of the diaphragm is zero. According to Examples 19 to 20, when D / R 1 When the ratio is less than 0.2 or greater than 1, the diaphragm has a slight defect rate to varying degrees; according to Examples 5 to 8, when S 1 When the ratio of S / S is 0.2 to 0.5, the defect rate of the diaphragm is zero. According to Examples 21 to 22, when S 1 When the ratio of / S is less than 0.2 or greater than 0.5, the diaphragm has a slight defect rate to varying degrees; according to Examples 1 to 16 and Example 23, when S 2 When the ratio of / S is 1.2 to 3 (not 3), the defective rate of the diaphragm is zero. 2 When the ratio of / S is 3 or less than 1.2, the diaphragm has slight defective rates to varying degrees.

[0071] The secondary battery provided in the embodiments of the present application is introduced in detail above, and the principles and implementation methods of the present application are explained by applying specific examples. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A secondary battery, characterized in that: include: A housing (1) is provided with a receiving chamber (10); A cover plate assembly (2), comprising a cover plate body (21), the cover plate body (21) being connected to the housing (1) and covering the accommodating cavity (10), the cover plate body (21) having a liquid injection hole (20); An electrode assembly (3) is arranged in the accommodating cavity (10), the electrode assembly (3) comprising an electrode body (31) and a pole ear (32), the pole ear (32) being connected to the electrode body (31); A spacer (4) is arranged in the accommodating cavity (10) and is located between the cover plate body (21) and the electrode body (31); the spacer (4) has a plurality of first flow guide holes (411); each of the first flow guide holes (411) penetrates the spacer (4) along the thickness direction of the spacer (4); and the plurality of first flow guide holes (411) are arranged corresponding to the injection holes (20).

2. The secondary battery according to claim 1, characterized in that: The spacer (4) further comprises a plurality of second flow guide holes (412), wherein the plurality of second flow guide holes (412) are arranged at intervals on the outer periphery of the plurality of first flow guide holes (411) and are arranged to penetrate along the thickness direction of the spacer (4); The flow area of ​​each of the first flow guide holes (411) is S a mm 2 The flow area of ​​each of the second flow guide holes (412) is S c mm 2 , satisfy: S a mm 2 <S c mm 2 .

3. The secondary battery according to claim 2, characterized in that: The secondary battery has a first direction (X), and along the first direction (X), at least one second flow guide hole (412) is respectively provided on two opposite sides of a region where a plurality of the first flow guide holes (411) are located.

4. The secondary battery according to claim 3, characterized in that: The secondary battery has a second direction (Y) intersecting with the first direction (X), and each of the second flow guide holes (412) extends along the second direction (Y).

5. The secondary battery according to claim 2, characterized in that: The spacer (4) comprises a first plate (41) and a second plate (42), the first flow guide hole (411) and the second flow guide hole (412) are both arranged on the first plate (41), the second plate (42) is connected to the first plate (41), and at least a part of the second plate (42) is located on a side of the first plate (41) close to the electrode body (31); The electrode ear (32) comprises a connecting portion (321) and a folding portion (322); the connecting portion (321) is connected to the electrode body (31) and is attached to a side of the second plate (42) facing the electrode body (31); The folded portion (322) is connected to an end of the connecting portion (321) away from the electrode body (31), and is attached to the first plate body (41).

6. The secondary battery according to claim 5, characterized in that: The folded portion (322) is attached to the first plate body (41) along a surface of the first plate body (41) facing away from the second plate body (42), and extends in the direction where the second air guide hole (412) is located, avoiding the first air guide hole (411).

7. The secondary battery according to claim 1, characterized in that: The injection hole (20) has an axis, and the cover plate assembly (2) further comprises: The guide portion (23) is arranged on a side of the cover plate body (21) facing the electrode assembly (3), and has one end connected to the cover plate body (21) and the other end extending in the direction of the axis.

8. The secondary battery according to claim 7, characterized in that: The secondary battery has a third direction (Z), and the third direction (Z) corresponds to the thickness direction of the cover plate body (21). The cover plate assembly (2) also includes an insulating portion (22), and the insulating portion (22) is connected to the cover plate body (21) and is located on a side of the cover plate body (21) close to the electrode assembly (3). The insulating portion (22) has a through hole (221), and the through hole (221) and the injection hole (20) are arranged along the third direction (Z) correspondingly. The guide portion (23) is connected to the insulating portion (22).

9. The secondary battery according to claim 8, characterized in that: There are a plurality of the guide portions (23), and the plurality of guide portions (23) are arranged at intervals along the circumferential direction of the through hole (221).

10. The secondary battery according to claim 7, characterized in that: The injection hole (20) has a minimum radius of R1 mm, and the length of the portion of the guide portion (23) corresponding to the injection hole (20) in the third direction (Z) is N mm, satisfying: 0.2≤N / R1≤0.

8.

11. The secondary battery according to claim 7, characterized in that: The guide portion (23) has a guide surface (231) disposed toward the liquid injection hole (20), and an angle α is formed between the guide surface (231) and the third direction (Z), satisfying the following relationship: 90°≤α≤110°.

12. The secondary battery according to claim 8, characterized in that: Along the third direction (Z), there is a minimum spacing dimension Lmm between the guide portion (23) and the liquid injection hole (20), satisfying: 2≤L≤5.

13. The secondary battery according to claim 9, characterized in that: The cover plate body (21) comprises a first surface (211), the first surface (211) is arranged toward the electrode assembly (3), and the area enclosed by the opening end of the injection hole (20) on the first surface (211) is S mm 2 , each of the guide portions (23) has an orthographic projection on the first surface (211) along the third direction (Z), and the sum of the areas of the orthographic projections that cross the edge of the injection hole (20) and are located inside the injection hole (20) is S1 mm 2 , satisfying: 0.2≤S1 / S≤0.

5.

14. The secondary battery according to claim 13, characterized in that: The sum of the areas enclosed by the first guide holes (411) on the surface of the spacer (4) facing the cover plate assembly (2) is S2 mm. 2 , satisfying: 1.2≤S2 / S≤3.

15. The secondary battery according to claim 1, characterized in that: The injection hole (20) has a minimum radius R1 mm, and the first guide hole (411) has a hole diameter D mm, satisfying: 0.2≤D / R1≤1.

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