High-capacity battery and manufacturing method thereof

Abstract

The invention discloses a high-capacity battery and a manufacturing method thereof, the high-capacity battery comprises a cylinder, N cover plate assemblies, N electrode assemblies, a heat transfer tube and an electrolyte, and N is greater than or equal to 2; the N electrode assemblies with the cover plate assemblies are mounted in the cylinder, and the N electrode assemblies of the high-capacity battery are positioned in the same electrolyte system, so that the battery is ensured to have relatively high capacity, and the problem that the consumption of electrolyte and lithium ions in each single battery of the existing battery module is consistent is solved. Meanwhile, the temperature of each electrode assembly can be directly transferred to an external temperature control device through a heat transfer pipe, so that the problem that the performance of the high-capacity battery is influenced by overheating of the electrode assemblies is solved; more importantly, the probability of thermal runaway is reduced by directly controlling the temperature of each electrode assembly.

Description

Technical Field

[0001] The present invention belongs to the field of batteries, and particularly relates to a large-capacity battery and a manufacturing method thereof. Background Art

[0002] In recent years, lithium-ion batteries have been increasingly widely used, mainly for energy storage systems such as hydroelectric power, thermal power, wind power, and solar power generation, as well as electric tools, electric bicycles, electric motorcycles, electric vehicles, special equipment, special aerospace, etc.

[0003] In order to meet the large-capacity usage scenarios, existing large-capacity batteries form a battery module by combining multiple finished single cells in parallel, series, or a combination of series and parallel. A battery module connected in series can increase the total voltage, while a battery module connected in parallel can increase the total capacity.

[0004] However, no matter which of the above methods, there are differences in each single cell in the existing battery module itself, resulting in differences in the consumption of electrolyte and lithium ions in each single cell after the battery module operates for a period of time, and the uniformity of each single cell is poor. Furthermore, it will directly limit the cycle life of the battery module. Therefore, how to improve the uniformity of each single cell in the battery module while ensuring large capacity has become the focus and difficulty in this field. Summary of the Invention

[0005] In order to solve the problem of poor uniformity of each single cell in the existing battery module, the present invention provides a large-capacity battery.

[0006] The large-capacity battery includes a cylinder body, N cover plate assemblies, N electrode assemblies, heat transfer tubes, and electrolyte, where N≥2; the upper end of the cylinder body is open;

[0007] They are uniformly fixed to the open end of the cylinder body along the first direction of the cylinder body, thus forming a sealed box body; each cover plate assembly includes a cover plate body and a positive electrode column and a negative electrode column that are insulated and fixed on the cover plate body;

[0008] The N electrode assemblies are uniformly arranged inside the sealed box body along the first direction of the cylinder body. Above each electrode assembly, there corresponds a cover plate assembly, and the positive electrode plate and the negative electrode plate of the electrode assembly are electrically connected to the positive electrode column and the negative electrode column on the cover plate assembly respectively; the positive electrode columns on each cover plate assembly are electrically connected to form a total positive terminal, and the negative electrode columns on each cover plate assembly are electrically connected to form a total negative terminal; the total positive terminal and the total negative terminal are in heat exchange with an external temperature control device through at least one heat transfer tube; the sealed box body is filled with electrolyte.

[0009] The large-capacity battery of the present invention places N electrode assemblies into a cylinder with an open upper end, and uses N cover assemblies to seal the open end of the cylinder. All the electrode assemblies are in one electrolyte system. Therefore, this large-capacity battery avoids the problem of differences in electrolyte and lithium-ion consumption among individual batteries in the existing battery module, ensuring the service life of the large-capacity battery. Moreover, all the electrode assemblies are under one air pressure system, which also solves the problem that the internal pressure of each individual battery will vary after running for a period of time in the existing battery module, thus affecting the performance of the battery module. At the same time, it also solves the probability of thermal runaway problems caused by excessive air pressure in a certain individual battery in the existing battery module, improving the safety of the large-capacity battery.

[0010] In addition, the heat transfer tubes installed at the total positive terminal and the total negative terminal can directly transfer the temperature of each electrode assembly to an external temperature control device, reducing the problem that overheating of the electrode assembly will affect the performance of the large-capacity battery. More importantly, directly controlling the temperature of each electrode assembly reduces the probability of thermal runaway. At the same time, during the manufacturing of the large-capacity battery, the heat transfer tubes can directly heat each electrode assembly to control the water content inside the electrode assembly. Compared with the traditional vacuum baking method, there is no need for a dedicated vacuum baking oven, reducing the manufacturing cost of the large-capacity battery and improving the manufacturing efficiency of the large-capacity battery at the same time.

[0011] Furthermore, in order to ensure that the cover assembly can be reliably welded to the open end of the cylinder and ensure the sealing performance of the sealed box, and at the same time, there may be a short-circuit risk when the electrode assemblies bulge and contact each other during operation, N - 1 first partitions are arranged at intervals along the first direction on the cylinder, dividing the cylinder into placement areas for N electrode assemblies, and the N placement areas are interconnected.

[0012] Furthermore, in order to make up for the problem that the upper surface of the cover body of the cover assembly is uneven after the cover assembly is placed due to the processing of each cover body and / or the open end of each placement area, a flexible gasket is arranged in a circle near the four peripheral edges on the cover body of the cover assembly. The end face of the open end of the placement area is a stepped surface. The first surface of the stepped surface is welded to the cover body, and the second surface of the stepped surface is matched with the flexible gasket; the first surface is above the second surface.

[0013] Furthermore, the positive electrode post and the negative electrode post are both provided with grooves or through holes for clamping the heat transfer tubes.

[0014] Furthermore, in order to take into account the heat conduction efficiency of the heat transfer tubes and ensure the reliability of installation at the same time, the above heat transfer tubes are aluminum water-cooled tubes, and in order to ensure safety, insulation needs to be maintained between the aluminum water-cooled tubes and the grooves or between the aluminum water-cooled tubes and the through holes.

[0015] Further, a pressure relief part is provided on the above-mentioned sealed box body. By providing this pressure relief part, the thermal runaway flue gas can be released in time when a large-capacity battery undergoes thermal runaway, avoiding the occurrence of more serious accidents.

[0016] Further, a liquid injection and replacement interface is provided on the above-mentioned sealed box body. By providing the liquid injection and replacement interface, it not only facilitates the liquid injection in the initial stage of the battery, but also can use this interface to ensure the cycle life of the large-capacity battery by replenishing electrolyte or lithium supplement additives or replacing the electrolyte as a whole when the battery capacity decays to a certain extent, so as to improve or maintain the capacity.

[0017] Further, in order to improve the cycle life of the large-capacity battery, the large-capacity battery further includes at least one second separator and an upper cover. The second separator is vertically installed in the cylinder body. A chamber with an open upper end is formed between the second separator and the side wall of the cylinder body, and this chamber communicates with the placement area. The open upper end of the chamber is sealed by the upper cover, and the inside of the chamber is filled with electrolyte.

[0018] Further, on the side wall of the cylinder body in the first direction and the side wall in the second direction, reinforcing ribs with a hollow structure are provided. The addition of these reinforcing ribs improves the strength of the cylinder body, and at the same time, the hollow reinforcing cavity can also be used as an air-cooling channel and a liquid-cooling channel, which can improve the temperature control ability of the large-capacity battery.

[0019] Another aspect of the present invention provides a manufacturing method for the above-mentioned large-capacity battery, including the following steps:

[0020] Prepare the battery cell unit

[0021] Connect the cover plate assembly and the electrode assembly into a battery cell unit by welding;

[0022] Install the battery cell unit and form a sealed box body

[0023] Put N battery cell units into the cylinder body from the open end of the cylinder body, and then seal and fix the cover plate assembly in each battery cell unit to the open end of the cylinder body by welding. The cylinder body and N cover plate assemblies form a sealed box body;

[0024] Install the heat transfer tube

[0025] Match at least one heat transfer tube;

[0026] Dehydration

[0027] Use the heat transfer tube to heat each electrode assembly to reduce the water content in the electrode assembly;

[0028] Assembly of the total positive terminal and the total negative terminal

[0029] Electrically connect all the positive electrode posts to form a total positive terminal, and electrically connect all the negative electrode posts to form a total negative terminal;

[0030] Inject electrolyte, form, and age.

[0031] Compared with the existing battery module manufacturing process, the manufacturing process of the large-capacity battery of the present invention has a smaller difference in maintaining the consistency of each single battery at the initial state of the battery module, and it is necessary to perform the operations of grading and sorting for each single battery. In the present invention, multiple electrode assemblies are directly installed in a sealed box body and are in a unified electrolyte system, and there is no need to perform the work of grading and sorting, which improves the capacity of the large-capacity battery and also improves the manufacturing efficiency of the battery.

[0032] In addition, the present invention can heat each electrode assembly through a heat transfer tube to control the water content of each electrode assembly, and avoid the damage to the battery caused by hydrofluoric acid generated after water contacts the electrolyte. Compared with the traditional vacuum baking method, this water removal method does not require a special vacuum baking oven, reduces the manufacturing cost of the large-capacity battery, and also improves the manufacturing efficiency of the large-capacity battery. Brief Description of the Drawings

[0033] Figure 1 Schematic diagram of the structure of the large-capacity battery in Embodiment 1 Figure 1 ;

[0034] Figure 2 Schematic diagram of the structure of the large-capacity battery after removing the cylinder body;

[0035] Figure 3 Schematic diagram of the structure of the large-capacity battery in Embodiment 1 Figure 2 ;

[0036] Figure 4 Schematic diagram of the structure of the cylinder body;

[0037] Figure 5 Schematic diagram of the structure of the cover plate assembly provided with a flexible gasket;

[0038] Figure 6 Partial structure diagram of the cylinder body.

[0039] The reference numerals are as follows:

[0040] 1 - cylinder body, 2 - cover plate assembly, 3 - electrode assembly, 4 - heat transfer tube, 5 - cover plate body, 6 - positive electrode post, 7 - negative electrode post, 8 - total positive terminal, 9 - total negative terminal, 10 - groove, 11 - through hole, 12 - first partition, 13 - placement area, 14 - explosion venting part, 15 - injection / liquid replacement interface, 16 - second partition, 17 - upper cover, 18 - chamber, 19 - flexible gasket, 20 - step surface, 21 - first surface, 22 - second surface. Detailed Description of the Embodiment

[0041] The technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are only a part of the embodiments, rather than all the embodiments. Based on the following embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] Meanwhile, it should be noted that the orientation or positional relationship indicated by terms such as "top, bottom, inner, and outer" in the text is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of simplified 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 thus cannot be construed as a limitation to the technical solution. In addition, the terms "first, second, or third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0043] Unless otherwise clearly defined and limited in the present invention, the terms "mounted, connected, and coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection: It may also be a mechanical connection, an electrical connection, or a direct connection, or may be indirectly connected through an intermediate medium, or may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0044] The basic design concept of the present invention is:

[0045] Install N electrode assemblies with cover plate assemblies in a cylinder to form a large-capacity battery. The N electrode assemblies of the large-capacity battery are in an electrolyte system, which not only ensures that the large-capacity battery has a large capacity, but also avoids the problem that the cycle life of the existing battery module is reduced due to the consistent consumption of electrolyte and lithium ions in each single battery.

[0046] Embodiment 1

[0047] As Figure 1 shown, the large-capacity battery of this embodiment includes a cylinder 1, N cover plate assemblies 2, N electrode assemblies 3, a heat transfer tube 4, and an electrolyte, where N≥2. In this embodiment, N = 10. Of course, the number of N can also be increased according to the actual situation;

[0048] The upper end of the cylinder 1 is open; the cylinder 1 can be made by casting, stamping, extrusion, or 3D printing;

[0049] The N cover plate assemblies 2 are uniformly fixed to the open end of the cylinder 1 along the first direction of the cylinder, thereby forming a sealed box;

[0050] Specifically, the sum of the widths of the N cover plate assemblies 2 should be adapted to the size of the open end of the cylinder 1 in the first direction, and the length of the cover plate assembly 2 should be adapted to the size of the open end of the cylinder 1 in the second direction, so as to ensure that the N cover plate assemblies 2 can seal the cylinder 1. The fixing method of the cover plate assembly 2 at the open end of the cylinder 1 can be a welding method, or a method of fixing with sealant combined with screws. However, compared with the latter, the method of fixing and sealing by welding is simpler in operation, and has higher sealing performance and reliability.

[0051] The so-called first direction above is the length direction of the cylinder, that is Figure 1 the X direction in Figure 1 ; the second direction is the width direction of the cylinder, that is

[0052] such as Figure 2 shown, each cover plate assembly 2 includes a cover plate body 5, a positive electrode column 6 and a negative electrode column 7 that are insulated and fixed on the cover plate body; the cover plate assembly is similar in structure to the upper cover assembly of a commercially available finished square single-cell lithium battery. The difference from the upper cover assembly of a commercially available finished square single-cell lithium battery is that a pressure relief membrane and a liquid injection part are not provided on this cover plate assembly. Of course, it is also possible to choose to customize a cover plate assembly without a pressure relief membrane and a liquid injection part from the manufacturer of the upper cover assembly finished standard parts as the cover plate assembly of the present invention. When mass-producing this cover plate assembly, the price may be lower than that of the existing upper cover assembly finished standard parts.

[0053] The N electrode assemblies 3 are uniformly arranged inside the sealed box along the first direction of the cylinder. Above each electrode assembly 3, there corresponds a cover plate assembly 2, and the positive electrode plate and the negative electrode plate of the electrode assembly 3 are electrically connected to the positive electrode column and the negative electrode column on the cover plate assembly respectively; the electrode assembly 3 is made of multiple layers of electrode plates by winding or stacking. Each layer of electrode plate includes a positive electrode plate, a separator and a negative electrode plate.

[0054] The positive electrode columns 6 on each cover plate assembly 2 are electrically connected to form a total positive terminal 8, and the negative electrode columns 7 on each cover plate assembly are electrically connected to form a total negative terminal 9; the total positive terminal 8 and the total negative terminal 9 are in heat exchange with an external temperature control device through at least one heat transfer tube 4; an electrolyte is contained in the sealed box.

[0055] Among them, the total positive terminal and the total negative terminal can be formed in the following three ways;

[0056] 1. All the positive electrode columns 6 can be electrically connected through a plurality of first cables to form a total positive terminal 8, and all the negative electrode columns 7 are electrically connected through a plurality of second cables to form a total negative terminal 9;

[0057] 2. All the positive electrode columns 6 are electrically connected through a plurality of first electric connection plates to form a total positive terminal 8, and all the negative electrode columns 7 are electrically connected through a plurality of second electric connection plates to form a total negative terminal 9;

[0058] 3. All the positive electrode posts 6 are electrically connected through a first electrical connection plate with a length equivalent to that of the cylinder to form a total positive terminal 8, and all the negative electrode posts 7 are electrically connected through a second electrical connection plate with a length equivalent to that of the cylinder to form a total negative terminal 9;

[0059] To balance conductivity and installability, the first electrical connection plate is usually made of aluminum or copper plates with relatively low prices and good flexibility.

[0060] The heat transfer tube can specifically adopt the following methods:

[0061] 1. An aluminum tube is bent into a U-shaped structure, and two parallel tube sections are respectively used to cooperate with the total positive terminal 8 and the total negative terminal 9, so as to realize the heat exchange between each electrode assembly and the external temperature control device, and the liquid inlet and outlet of the aluminum tube are located on the same side; the transmission medium in the aluminum tube can be water, insulating oil or fluorinated liquid; two aluminum tubes can also be used to cooperate with the total positive terminal and the total negative terminal respectively.

[0062] 2. Two heat pipes with cores are respectively used to cooperate with the total positive terminal 8 and the total negative terminal 9, so as to realize the heat exchange between each electrode assembly and the external temperature control device. The heat pipe with a core is an evaporation-condensation type heat exchange device, and the heat transfer is realized by the state change of the working medium in the tube.

[0063] Since the heat transfer effect of the heat pipe with a core is affected by the length of the heat pipe with a core, when the number of electrode assemblies in a large-capacity battery is large (that is, when the length of the large-capacity battery is long), the use of the heat pipe with a core will be limited. Therefore, in this embodiment, an aluminum tube is preferably selected as the heat transfer tube. If the insulation between the heat transfer tube and the electrode post can be effectively ensured, considering the heat transfer efficiency, cost, etc., water can be preferably used as the heat transfer medium flowing in the aluminum tube.

[0064] In this embodiment, the cooperation mode between the heat transfer tube 4 and the total positive terminal and the total negative terminal has the following two methods:

[0065] As Figure 3 shown, a groove 10 perpendicular to the axial direction of the electrode post is opened on both the positive electrode post 6 and the negative electrode post 7. A heat transfer tube 4 is clamped in the grooves 10 of all the positive electrode posts 6 or the grooves 10 of the negative electrode posts 7. The cross-section of the groove 10 is preferably C-shaped, and the open end of the C-shaped has a certain flexibility to tightly clamp the heat transfer tube therein;

[0066] 3. As Figure 1 shown, a through hole 11 is opened on both the positive electrode post 6 and the negative electrode post 7. The heat transfer tube 4 is inserted into the through holes 11 of all the positive electrode posts 6 or the through holes 11 of all the negative electrode posts 7 through interference fit or press fit;

[0067] In the above two methods, it is easier to install the heat transfer tube 4 in the groove 10 than in the through hole 11. In the through hole 11, the contact area between the heat transfer tube and the terminal post is larger than that in the groove 10, and the heat transfer effect is better.

[0068] Since the total positive terminal 8 and the total negative terminal 9 are charged, to ensure safety, insulation must be maintained between the heat transfer tube 4 and the total positive terminal 8, and between the heat transfer tube 4 and the total negative terminal 9. The way to maintain insulation can be to oxidize the heat transfer tube, or to set an insulating layer in the area where the heat transfer tube contacts the terminal post.

[0069] One more point to note is that as Figure 4 shown, in this embodiment, N - 1 first partition plates 12 are arranged at intervals along the first direction in the cylinder body 1. The height of the first partition plate 12 is the same as the height inside the cylinder body 1, dividing the cylinder body 1 into N placement areas 13 for electrode assemblies, and the N placement areas 13 communicate with each other. There is an electrode assembly between every two adjacent first partition plates 12.

[0070] The setting of the first partition plate 12 has the following four purposes:

[0071] Purpose one: After setting the first partition plate 12, it is convenient to weld the cover plate assembly 2 at the open end of the cylinder body 1. During specific welding, the four sides of each cover plate assembly 12 can be welded to the upper edges of the two side walls of the cylinder body 1 in the first direction, and the upper edges of two adjacent first partition plates 12 to achieve fixed sealing; in some other embodiments, the edges in the width direction of the cover plate assembly 2 can also be directly welded to the upper edges of the two side walls of the cylinder body 1 in the first direction, and then the edges in the length direction of two adjacent cover plate assemblies 2 are directly welded and sealed. However, compared with the welding and sealing method of setting the first partition plate in this embodiment, the welding tightness and reliability are higher.

[0072] Purpose two: The setting of the first partition plate 12 can avoid the possible short - circuit problem caused by the bulging of two electrode assemblies, with higher safety.

[0073] Purpose three: The heat of the electrode assembly can be directly transferred to the cylinder body 1 through the first partition plate 12, improving the heat dissipation effect of the electrode assembly.

[0074] Purpose four: The setting of the first partition plate 12 can improve the overall strength of the cylinder body, making the cylinder body more capable of withstanding pressure.

[0075] The first partition plate 12 can be set in the cylinder body 1 by integral molding, or fixed in the cylinder body 1 by welding. From the perspective of facilitating processing and controlling costs, this embodiment selects the integral molding method to set the first partition plate in the cylinder body.

[0076] The way that the placement areas 13 communicate with each other can be to open a channel with a relatively large diameter at the bottom of each first partition 12 to ensure that each electrode assembly is under an electrolyte system, or to open a plurality of through holes on each first partition 12 to ensure that each electrode assembly is under an electrolyte system.

[0077] In order to prevent the thermal runaway gas from being discharged from the sealed box in time when the large-capacity battery undergoes thermal runaway in extreme cases and avoid more serious dangerous accidents, a pressure relief part 14 is also provided on the sealed box of the large-capacity battery. The pressure relief part 14 can be a commercially available pressure relief valve or a pressure relief film fixedly sealed on a pipe fitting.

[0078] In this embodiment, a liquid injection / replacement interface 15 is also provided on the sealed box of the large-capacity battery. By setting the liquid injection / replacement interface 15 to cooperate with an external liquid injection / replacement device, it is not only convenient for injecting liquid in the initial stage of the battery, but also can use this interface to ensure the cycle life of the large-capacity battery by replenishing electrolyte or lithium additive or replacing the electrolyte as a whole when the battery capacity decays to a certain extent to improve or maintain the capacity. It should be noted that: this interface needs to be kept blocked during the operation of the battery to ensure the sealing performance of the large-capacity battery.

[0079] Based on the above introduction of the large-capacity battery structure, the manufacturing method of the large-capacity battery will be described in detail as follows:

[0080] Step 1: Prepare the battery cell unit

[0081] Connect the cover assembly 2 and the electrode assembly 4 into a battery cell unit by welding.

[0082] Step 2: Install the battery cell unit and form a sealed box

[0083] Put N battery cell units into the cylinder 1 from the open end of the cylinder 1, and then seal and fix the cover assembly 2 in each battery cell unit to the open end of the cylinder 1 by welding. The cylinder 1 and N cover assemblies 2 form a sealed box.

[0084] Step 3: Install the heat transfer tube

[0085] Install the two parallel pipe sections of a U-shaped heat transfer tube 4 into the grooves 10 or through holes 11 of all the positive electrode posts 6 and all the negative electrode posts 7 respectively.

[0086] Step 4: Dewater

[0087] Heat is transferred to each electrode assembly through heat transfer tubes for heating, controlling the water content in the electrode assembly to reach a safe defined value, avoiding damage to the battery caused by hydrofluoric acid generated after water contacts the electrolyte. During the water removal process, dynamic nitrogen negative pressure needs to be provided, which can immediately take away the water vapor formed by vaporization; in addition, this dynamic nitrogen negative pressure link can also remove impurities in the sealed box during the assembly process, avoiding the influence of impurities on the electrolyte environment in the box. At the same time, this negative pressure state is conducive to the smooth entry of the electrolyte into the sealed box and also facilitates the full infiltration of the electrolyte into each electrode assembly;

[0088] Step 5: Assembly of the total positive terminal and the total negative terminal

[0089] All the positive electrode posts 6 are electrically connected to form the total positive terminal 8, and all the negative electrode posts 7 are electrically connected to form the total negative terminal 9; the total positive terminal 8 is actually the positive electrode of the large-capacity battery, and the total negative terminal 9 is actually the negative electrode of the large-capacity battery;

[0090] Step 6: Liquid injection

[0091] Connect the liquid injection and replacement equipment to the liquid injection and replacement interface, and inject electrolyte into the sealed box. The amount of electrolyte injected needs to ensure that the electrode plates of each electrode assembly can be fully infiltrated with the electrolyte;

[0092] Step 7: Formation

[0093] Charge at a constant current of 0.1C until 3.4V, then switch to constant voltage charging at 3.4V until the cut-off current is 0.01C, and let it stand for 30 min;

[0094] Then discharge at a constant current of 0.1C until 2.5V and let it stand for 30 min;

[0095] Then charge at a constant current of 0.2C until 3.4V, then switch to constant voltage charging at 3.4V until the cut-off current is 0.01C, and let it stand for 30 min again. The formation process can form a complete SEI film on each electrode assembly in the large-capacity battery, making the large-capacity battery have a more stable cycle ability;

[0096] Step 8: Aging

[0097] Keep the large-capacity battery in an environment with a temperature of 40 to 50 °C for a shelf time of 24 to 72 h, thereby completing the aging treatment of the large-capacity battery and completing the production of the large-capacity battery.

[0098] Compared with the existing battery module manufacturing process, in order to maintain the consistency of each single battery in the initial state of the battery module, the large-capacity battery manufacturing process of the present invention needs to perform capacity separation and sorting operations on each single battery. In the present invention, multiple electrode assemblies are directly installed in a sealed box, and each electrolytic assembly is placed in a unified electrolyte system, without the need for capacity separation and sorting, thereby improving the capacity of large-capacity batteries and the battery manufacturing efficiency.

[0099] Example 2

[0100] The differences between the large-capacity battery structure in this embodiment and that in Embodiment 1 are as follows:

[0101] 1. If Figure 4 As shown, at least one second partition 16 and an upper cover 17 are also provided in the cylinder 1. A chamber 18 with an open upper end can be formed between the second partition 16 and the side wall of the cylinder 1. The upper cover 17 is fixed to the top of the above-mentioned chamber 18 by welding. The large-capacity battery can have more sufficient electrolyte in the chamber, and the chamber needs to be connected with each placement area. Such a design is helpful to improve the cycle life of the large-capacity battery.

[0102] It should be noted that in this embodiment, the upper cover can be integrally formed with the cover body, thereby sealing the open end of the cylinder and the top of the chamber at one time, reducing the welding process.

[0103] 2. If Figure 5 and Figure 6 As shown, in order to compensate for the problem of uneven upper surface of the cover body after the cover assembly is placed due to the open end of each cover body and / or each placement area during processing, a circle of flexible gasket 19 is arranged on the cover body 5 of the cover assembly 2 near the four sides, and the open end face of the placement area 13 is a step surface 20, the first surface 21 of the step surface 20 is welded to the cover body 5, and the second surface 22 of the step surface 20 is matched with the flexible gasket 19; the first surface 21 is located above the second surface 22.

[0104] 3. In this embodiment, the injection and replacement fluid interface can be designed as a multifunctional interface so that it can be connected to the injection and replacement fluid equipment and also to the equipment that provides dynamic nitrogen negative pressure.

[0105] 4. Since a large amount of electrolyte is stored in a large-capacity battery, in order to reduce the probability of large-scale combustion of the electrolyte in the box when thermal runaway occurs, in this embodiment, it is preferred to set the explosion venting part near the bottom of the cylinder. Once thermal runaway occurs, the electrolyte in the sealed box will first be discharged out of the sealed box, and then the thermal runaway smoke will be discharged to the outside, thereby improving the safety of the large-capacity battery.

[0106] 5. Reinforcing ribs with a hollow structure are provided on the side wall of the cylinder body 1 in the first direction and on the side wall in the second direction. The addition of the reinforcing ribs improves the strength of the cylinder body. At the same time, the hollow reinforcing cavity can also be used as an air-cooling channel and a liquid-cooling channel, which can further improve the temperature control ability of the large-capacity battery.

Claims

1. A large-capacity battery, characterized in that: It includes a cylinder body, N cover plate assemblies, N electrode assemblies, heat transfer tubes, and electrolyte, where N ≥ 2; The upper end of the cylinder body is open; The N cover plate assemblies are uniformly fixed to the open end of the cylinder body along the first direction of the cylinder body, thus forming a sealed box; each cover plate assembly includes a cover plate body, a positive electrode post, and a negative electrode post that are insulated and fixed on the cover plate body; The N electrode assemblies are uniformly arranged inside the sealed box along the first direction of the cylinder body. Above each electrode assembly, there corresponds a cover plate assembly, and the positive electrode plate and the negative electrode plate of the electrode assembly are electrically connected to the positive electrode post and the negative electrode post on the cover plate assembly respectively; The positive electrode posts on each cover plate assembly are electrically connected to form a total positive terminal, and the negative electrode posts on each cover plate assembly are electrically connected to form a total negative terminal; the total positive terminal and the total negative terminal are in heat exchange with an external temperature control device through at least one heat transfer tube; The sealed box is filled with electrolyte.

2. A large-capacity battery according to claim 1, characterized in that: The cylinder body is provided with N - 1 first partition plates at intervals along the first direction, thereby dividing the cylinder body into N placement areas for the electrode assemblies, and the N placement areas communicate with each other.

3. A large-capacity battery according to claim 2, characterized in that: A flexible gasket is arranged in a circle near the four peripheral edges on the cover plate body of the cover plate assembly. The open end face of the placement area is a stepped surface. The first surface of the stepped surface is welded to the cover plate body, and the second surface of the stepped surface is matched with the flexible gasket; the first surface is above the second surface.

4. A large-capacity battery according to claim 2, characterized in that: Both the positive electrode post and the negative electrode post are provided with grooves or through holes for clamping the heat transfer tubes.

5. A large-capacity battery according to claim 4, characterized in that: The heat transfer tube is an aluminum water - cooled tube, and insulation needs to be maintained between the aluminum water - cooled tube and the groove, or between the aluminum water - cooled tube and the through hole.

6. A large-capacity battery according to claim 5, characterized in that: The sealed box is provided with an explosion - relief part.

7. A large-capacity battery according to claim 6, characterized in that: The sealed box is provided with a liquid injection and replacement interface.

8. A large-capacity battery according to any one of claims 2 to 7, characterized in that: It further includes at least one second partition plate and an upper cover. The second partition plate is vertically installed inside the cylinder body. A chamber with an open upper end is formed between the second partition plate and the side wall of the cylinder body, and this chamber communicates with the placement area. The open upper end of the chamber is sealed by the upper cover, and its interior is filled with electrolyte.

9. A large-capacity battery according to claim 8, characterized in that: Reinforcing ribs with a hollow structure are arranged on the side wall of the cylinder body in the first direction and on the side wall in the second direction.

10. A method for manufacturing the large-capacity battery according to claim 1, characterized in that, It includes the following steps: Prepare the battery cell unit Connect the cover plate assembly and the electrode assembly into a battery cell unit by welding; Install the battery cell unit and form a sealed box Put N battery cell units into the cylinder body from the open end of the cylinder body, and then seal and fix the cover plate assembly in each battery cell unit to the open end of the cylinder body by welding. The cylinder body and the N cover plate assemblies form a sealed box; Install the heat transfer tubes Match at least one heat transfer tube with the total positive terminal and the total negative terminal; Dehydration Use the heat transfer tubes to heat each electrode assembly to reduce the water content in the electrode assembly; Assembly of the total positive terminal and the total negative terminal Electrically connect all the positive electrode posts to form the total positive terminal, and electrically connect all the negative electrode posts to form the total negative terminal; Inject liquid, formation, and aging.

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