A cylindrical lithium primary battery pre-treatment method and device

Abstract

A cylindrical lithium primary battery pretreatment method and device, comprising: placing a lithium primary battery that has not been sealed after liquid injection in a vacuum environment capable of discharging, adjusting the temperature and vacuum degree of the vacuum environment, and allowing the lithium primary battery pole piece to be fully soaked with electrolyte; discharging the soaked lithium primary battery, and discharging the gas generated in the lithium primary battery by adjusting the temperature and vacuum degree of the vacuum environment; after discharging is completed, filling nitrogen or argon into the vacuum environment to restore normal pressure; repeating the above steps at least once; recycling the electrolyte overflowing from the lithium primary battery, and taking the lithium primary battery out of the vacuum environment to complete the sealing of the battery. The application prevents the gas from further reacting with the electrolyte or the electrode, reduces the internal resistance of the battery, and improves the electrical performance and storage performance of the battery.

Description

Technical Field

[0001] This invention relates to a cylindrical lithium primary battery. In particular, it relates to a pretreatment method and apparatus for cylindrical lithium primary batteries. Background Technology

[0002] Lithium primary batteries are among the chemical power sources with the highest specific energy. Lithium-manganese dioxide batteries, lithium-carbon fluoride batteries, or lithium-manganese dioxide / carbon fluoride composite batteries, generally have a cylindrical structure and are widely used in life-saving equipment, military equipment, and spacecraft. With the increasing application of electrical equipment in deep space and offshore fields, higher requirements are being placed on the storage performance of lithium primary batteries.

[0003] However, lithium primary batteries such as lithium-manganese dioxide batteries, lithium-carbon fluoride batteries, or lithium-manganese dioxide / carbon fluoride composite batteries are fully charged after electrolyte filling. At a high potential, the positive electrode of the battery is prone to partial side reactions with the electrolyte and gas production. The generated gas can degrade battery performance and even pose safety hazards. At the same time, as batteries stored in a wet state, the electrolyte will undergo side reactions at the positive electrode interface during storage, resulting in capacity loss and reducing battery storage performance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method and apparatus for pretreatment of cylindrical lithium primary batteries that can improve the battery's electrical performance and storage performance.

[0005] The technical solution adopted in this invention is: a pretreatment method for cylindrical lithium primary batteries, comprising the following steps:

[0006] 1) Place the unsealed lithium primary battery after electrolyte filling into a vacuum environment that can discharge. Adjust the temperature of the vacuum environment to 20-60℃ and the vacuum degree to 0-100kpa. Let it stand for 0.2-10h to allow the lithium primary battery electrode to be fully wetted by the electrolyte.

[0007] 2) Discharge the impregnated lithium primary battery. During the discharge process, the electrolyte and electrodes form a dense and stable solid electrolyte film. At the same time, the gas generated inside the lithium primary battery is discharged by adjusting the temperature and vacuum level of the vacuum environment. After the discharge is completed, nitrogen or argon gas is introduced into the vacuum environment to restore the normal pressure.

[0008] 3) Repeat step 2) at least once, with an interval of 1-12 hours between each repetition;

[0009] 4) After the pretreatment is completed, the electrolyte overflowing from the lithium primary battery is recovered, and the lithium primary battery is taken out from the vacuum environment to complete the battery sealing.

[0010] The lithium primary battery mentioned in step 1) is a lithium-manganese dioxide battery, a lithium-carbon fluoride battery, or a lithium-manganese dioxide / carbon fluoride composite battery.

[0011] In the discharge process described in step 2), the discharge current is 0.01C-0.2C and the discharge time is 10-180min.

[0012] Step 2) describes adjusting the temperature range to 20-60℃ and the vacuum range to 0-100kPa.

[0013] A pretreatment apparatus for a pretreatment method of cylindrical lithium primary batteries includes a vacuum chamber. The vacuum chamber is provided with N support plates for supporting the lithium primary batteries to be pretreated. Each support plate is provided with M lithium primary battery support positions and a through hole for passing through the positive and negative electrode wires connecting the M lithium primary battery support positions. The positive and negative electrode wires connecting the lithium primary battery support positions pass through the through hole and then through the wire outlet hole on the vacuum chamber to connect to a charging and discharging device located outside the vacuum chamber.

[0014] The pretreatment method and apparatus for cylindrical lithium primary batteries of the present invention have the following advantages and positive effects:

[0015] 1. This invention reduces the open-circuit voltage of the lithium primary battery by pre-discharging after electrolyte injection, thereby reducing the positive electrode potential and minimizing side reactions between the positive electrode and the electrolyte. Compared with untreated batteries, the battery discharge capacity is significantly improved. At the same time, by optimizing parameters such as discharge current, discharge time, and discharge temperature, a dense and stable solid electrolyte film is formed on the electrode surface, effectively preventing side reactions between the electrolyte solvent and the electrode material, and significantly improving the battery storage performance.

[0016] 2. The pretreatment method and apparatus provided by the present invention perform vacuuming during the pre-discharge process. By adjusting the vacuum level, the gas generated by the reaction between the electrode and the electrolyte, and the electrolyte and trace water after the lithium primary battery is injected is discharged from the battery, thereby preventing the gas from reacting further with the electrolyte or electrode, reducing the battery's internal resistance, and improving the battery's electrical performance and storage performance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the cylindrical lithium primary battery pretreatment device of the present invention;

[0018] Figure 2 This is a side view of each support plate frame with a lithium primary battery support structure in this invention;

[0019] Figure 3 This is a front view of each support plate frame with a lithium primary battery support structure in this invention;

[0020] Figure 4 This is a comparison diagram of the battery discharge capacity of Embodiment 1 of the present invention;

[0021] Figure 5 This is a comparison diagram of the battery discharge capacity in Embodiment 3 of the present invention.

[0022] In the picture

[0023] 1: Vacuum chamber; 2: Lithium primary battery

[0024] 3: Support plate frame 4: Upper support frame

[0025] 5: Lower support frame; 6: Positive wiring terminal.

[0026] 7: Negative terminal block 8: Upper conductor

[0027] 9: Lower conductor; 10: Electrolyte collection tank

[0028] 10.1: Collection tank body 10.2: Collection tank opening door

[0029] 10.3: Clip 10.4: Through slot

[0030] 10.5: Clip hole 11: Liquid guide tube

[0031] 12: Electrolyte discharge pipe Detailed Implementation

[0032] The following detailed description of a pretreatment method and apparatus for cylindrical lithium primary batteries according to the present invention, in conjunction with embodiments and accompanying drawings, provides a clearer picture.

[0033] The present invention provides a pretreatment method for cylindrical lithium primary batteries, comprising the following steps:

[0034] 1) Place the unsealed lithium primary battery after electrolyte filling into a vacuum environment that can discharge. Adjust the temperature of the vacuum environment to 20-60℃ and the vacuum degree to 0-100kpa. Let it stand for 0.2-10h to allow the lithium primary battery electrode to be fully wetted by the electrolyte.

[0035] The lithium primary battery described in this embodiment of the invention is a lithium-manganese dioxide battery, a lithium-carbon fluoride battery, or a lithium-manganese dioxide / carbon fluoride composite battery.

[0036] 2) Discharge the impregnated lithium primary battery. During the discharge process, the electrolyte and electrodes form a dense and stable solid electrolyte film. At the same time, the gas generated inside the lithium primary battery is discharged by adjusting the temperature and vacuum level of the vacuum environment. After the discharge is completed, nitrogen or argon gas is introduced into the vacuum environment to restore the normal pressure.

[0037] In the discharge process described in this embodiment of the invention, the discharge current is 0.01C-0.2C, and the discharge time is 10-180min. The temperature range is 20-60℃, and the vacuum range is 0-100kPa.

[0038] 3) Repeat step 2) at least once, with an interval of 1-12 hours between each repetition;

[0039] 4) After the pretreatment is completed, the electrolyte overflowing from the lithium primary battery is recovered, and the lithium primary battery is taken out from the vacuum environment to complete the battery sealing.

[0040] like Figure 1 As shown, a pretreatment device for a pretreatment method of cylindrical lithium primary batteries according to the present invention includes a vacuum chamber 1. The vacuum chamber 1 contains N support frames 3 for supporting the lithium primary batteries 2 to be pretreated. Each support frame 3 has M lithium primary battery support positions and a through hole for the positive and negative electrode wires connecting the M lithium primary battery support positions. The positive and negative electrode wires connecting the lithium primary battery support positions pass through the through hole and then through wire outlet holes on the vacuum chamber 1 to connect to a charging / discharging device located outside the vacuum chamber 1. N is an integer greater than 1, and M is an integer greater than 4. The N support frames 3 are arranged side-by-side, either front-to-back or top-to-bottom, within the vacuum chamber 1.

[0041] like Figure 1 , Figure 2 As shown, the M lithium primary battery support positions have identical structures, each including an upper support frame 4 and a lower support frame 5 fixed on the support plate frame 3. The upper support frame 4 and the lower support frame 5 are used to place the lithium primary battery 2 to be processed. The upper support frame 4 is provided with a positive terminal 6 for connecting to the positive electrode of the lithium primary battery 2. The lower support frame 5 is provided with a negative terminal 7 corresponding to the positive terminal 6 for connecting to the negative electrode of the lithium primary battery 2. The positive terminal 6 and the negative terminal 7 are respectively connected to the upper wire 8 and the lower wire 9. The upper wire 8 and the lower wire 9 pass through the through hole on the support plate frame 3 and then through the wire outlet hole on the vacuum chamber 1 to connect to the charging and discharging equipment located outside the vacuum chamber 1.

[0042] Each of the aforementioned lithium primary battery support structures is further provided with an electrolyte collection tank 10 for fixing the lithium primary battery 2 and collecting the electrolyte overflowing from the lithium primary battery 2. The electrolyte collection tank 10 is fixedly installed on the support plate frame 3 and is located on the upper part of the lithium primary battery 2. A liquid guide pipe 11 is provided at the bottom of the electrolyte collection tank 10. The liquid outlet end of the liquid guide pipe 11 corresponds to the electrolyte discharge pipe 12 located at the lower part of the support plate frame 3, and is used to guide the electrolyte collected in the electrolyte collection tank 10 into the electrolyte discharge pipe 12. The liquid outlet end of the electrolyte discharge pipe 12 extends out of the vacuum chamber 1 and is connected to an electrolyte collection device located outside the vacuum chamber 1. A drain switch is provided on the electrolyte discharge pipe 12 located outside the vacuum chamber 1.

[0043] like Figure 2 , Figure 3 As shown, the electrolyte collection tank 10 of the present invention includes a collection tank body 10.1 fixed on the support plate frame 3 and a collection tank opening door 10.2. One side of the collection tank opening door 10.2 is hinged to the collection tank body 10.1, and the other side is connected to the collection tank body 10.1 through a buckle 10.3. The upper end surface of the collection tank body 10.1 is formed with a through groove 10.4 for penetrating the positive electrode of the lithium primary battery 2. When the collection tank opening door 10.2 is fixedly connected to the collection tank body 10.1 through the buckle 10.3, a locking hole 10.5 is formed on the bottom end surface that can be locked on the groove 13 at the upper end of the lithium primary battery 2, thereby fixing the lithium primary battery 2.

[0044] The following are specific examples:

[0045] Example 1: A lithium-manganese dioxide battery, model CR18650, with a rated capacity of 3.0Ah, and manganese dioxide as the positive electrode material, was pre-treated at 25°C and 100kPa for 0.2 hours after electrolyte filling. The battery electrodes were then fully wetted. A discharge device was then used to pre-discharge the battery at a current of 640mA (0.2C) for 10 minutes. During the discharge, the pre-treatment device maintained a temperature of 25°C and a vacuum of 80kPa. After the discharge process, nitrogen gas was introduced to restore atmospheric pressure. The discharge process was repeated after 3 hours. After the discharge was completed, the battery was removed and sealed.

[0046] The battery treated with the above pretreatment method has a discharge capacity of 3.43 Ah, while the untreated battery has a discharge capacity of only 3.16 Ah. Figure 4 As shown, the thick line represents the discharge curve using the method of this embodiment, and the thin line represents the discharge curve of the untreated battery.

[0047] Example 2: A lithium-carbon fluoride battery, model BR18650, with a rated capacity of 5.5Ah, and fluoride carbon as the positive electrode material. After the battery was filled with electrolyte, the temperature in the pretreatment device was set to 60°C and the vacuum degree to 20kPa. The battery was left to stand for 4 hours to ensure the battery electrodes were fully wetted. Subsequently, a discharge device was used to pre-discharge the battery with a discharge current of 55mA (0.01C) and a discharge time of 180min. During the discharge process, the temperature in the pretreatment device was maintained at 60°C and the vacuum degree at 20kPa. After the discharge process was completed, argon gas was introduced, and the pressure was restored to normal. The discharge process was repeated after 12 hours. After the discharge was completed, the battery was removed and sealed.

[0048] The battery using the above pretreatment method retained 99.69% of its capacity after being stored at 55 degrees Celsius for one month, while the battery without pretreatment retained only 98.3 Ah of its capacity after being stored at 55 degrees Celsius for one month.

[0049] Example 3: A lithium-manganese dioxide / carbon fluoride battery, model BR118650, with a rated capacity of 4.5Ah, uses a mixture of manganese dioxide and carbon fluoride as the positive electrode material. After electrolyte filling, the pretreatment device was set to a temperature of 40°C and a vacuum of 60 kPa, and left to stand for 2 hours to ensure the battery electrodes were fully wetted. Subsequently, a discharge device was used to pre-discharge the battery with a discharge current of 450 mA (0.1C) and a discharge time of 15 minutes. During the discharge process, the pretreatment device was set to a temperature of 25°C and a vacuum of 40 kPa. After the discharge process was completed, nitrogen gas was added, and the pressure was restored to normal. The discharge process was repeated after 6 hours. After the discharge was completed, the battery was removed and sealed.

[0050] The battery treated with the above pretreatment method has a discharge capacity of 4.8 Ah, while the untreated battery has a discharge capacity of only 4.54 Ah. Figure 5 As shown, the thick line represents the discharge curve of the battery using the method of this embodiment, and the thin line represents the discharge curve of the untreated battery. The battery using the above pretreatment method retains 98.84% of its capacity after one month of storage at 55 degrees Celsius, while the untreated battery retains only 97.67 Ah of its capacity after one month of storage at 55 degrees Celsius.

Claims

1. A pretreatment method for cylindrical lithium primary batteries, characterized in that, Includes the following steps: 1) Place the unsealed lithium primary battery after electrolyte filling in a vacuum environment capable of discharge. Adjust the temperature of the vacuum environment to 20-60℃ and the vacuum degree to 0-100kPa. Let it stand for 0.2-10 hours to allow the lithium primary battery electrodes to be fully wetted by the electrolyte. The lithium primary battery is a lithium-manganese dioxide battery, a lithium-carbon fluoride battery, or a lithium-manganese dioxide / carbon fluoride composite battery. 2) Discharge the impregnated lithium primary battery. During the discharge process, the electrolyte and the electrode form a dense and stable solid electrolyte film. At the same time, the gas generated inside the lithium primary battery is discharged by adjusting the temperature and vacuum level of the vacuum environment. After the discharge is completed, nitrogen or argon gas is introduced into the vacuum environment to restore normal pressure; in the discharge process, the discharge current is 0.01C-0.2C and the discharge time is 10-180min; the temperature range is 20-60℃ and the vacuum range is 0-100kPa. 3) Repeat step 2) at least once, with an interval of 1-12 hours between each repetition; 4) After the pretreatment is completed, the electrolyte overflowing from the lithium primary battery is recovered, and the lithium primary battery is taken out from the vacuum environment to complete the battery sealing.

2. A pretreatment apparatus for the pretreatment method of cylindrical lithium primary batteries according to claim 1, comprising a vacuum chamber (1), characterized in that, The vacuum chamber (1) is provided with N support plates (3) for supporting lithium primary batteries (2) that need to be pretreated. Each support plate (3) is provided with M lithium primary battery support positions and a through hole for passing through the positive and negative electrode lines on the M lithium primary battery support positions. The positive and negative electrode lines on each lithium primary battery support position pass through the through hole and then through the wire outlet hole on the vacuum chamber (1) to connect to the charging and discharging equipment located outside the vacuum chamber (1). The M lithium primary battery support positions described herein have identical structures, each including an upper support frame (4) and a lower support frame (5) fixed on the support plate frame (3). The upper support frame (4) and the lower support frame (5) are used to place the lithium primary battery (2) to be processed. The upper support frame (4) is provided with a positive terminal (6) for connecting to the positive electrode of the lithium primary battery (2). The lower support frame (5) is provided with a negative terminal (7) corresponding to the positive terminal (6) for connecting to the negative electrode of the lithium primary battery (2). The positive terminal (6) and the negative terminal (7) are respectively connected to the upper wire (8) and the lower wire (9). The upper wire (8) and the lower wire (9) pass through the through hole on the support plate frame (3) and then through the wire outlet hole on the vacuum chamber (1) to connect to the charging and discharging equipment located outside the vacuum chamber (1). Each of the lithium primary battery support structures is also provided with an electrolyte collection tank (10) for fixing the lithium primary battery (2) and collecting the electrolyte overflowing from the lithium primary battery (2). The electrolyte collection tank (10) is fixedly installed on the support plate frame (3) and located in the upper part of the lithium primary battery (2). A liquid guide pipe (11) is provided at the bottom of the electrolyte collection tank (10). The liquid outlet end of the liquid guide pipe (11) corresponds to the electrolyte discharge pipe (12) provided in the lower part of the support plate frame (3) for guiding the electrolyte collected in the electrolyte collection tank (10) into the electrolyte discharge pipe (12). The liquid outlet end of the electrolyte discharge pipe (12) extends out of the vacuum box (1) and is connected to the electrolyte collection device provided outside the vacuum box (1). A drain switch is provided on the electrolyte discharge pipe (12) located outside the vacuum box (1). The electrolyte collection tank (10) includes a collection tank body (10.1) and a collection tank opening door (10.2) fixed on the support plate frame (3). One side of the collection tank opening door (10.2) is hinged to the collection tank body (10.1), and the other side is connected to the collection tank body (10.1) by a buckle (10.3). The upper end surface of the collection tank body (10.1) is formed with a through groove (10.4) for penetrating the positive electrode of the lithium primary battery (2). When the collection tank opening door (10.2) is fixedly connected to the collection tank body (10.1) by the buckle (10.3), a card hole (10.5) is formed on the bottom end surface that can be locked on the groove at the upper end of the lithium primary battery (2).

3. The pretreatment apparatus according to claim 2, characterized in that, N is an integer greater than 1, and M is an integer greater than 4.

4. The pretreatment apparatus according to claim 2, characterized in that, The N support plates (3) are arranged side by side in front and behind or side by side in top and bottom within the vacuum chamber (1).

Images