Battery pack

Abstract

According to the battery pack provided by the utility model, the flue gas treatment unit is integrated in the box body of the battery pack, and the flue gas treatment unit can be used for completely and thoroughly treating thermal runaway flue gas generated by the single batteries in the battery pack, so that hidden dangers generated after the thermal runaway flue gas is exhausted are avoided, and the use safety of the battery pack is improved. The battery pack comprises a box body, a battery module and a flue gas treatment unit, an inner cavity of the box body is divided into a battery bin and a flue gas treatment bin through a first partition plate. The battery module is arranged in the battery compartment; the flue gas treatment bin comprises a first treatment cavity and a second treatment cavity; the flue gas treatment unit comprises a liquid treatment medium and a solid treatment medium; the first treatment cavity is filled with the liquid treatment medium, and the liquid treatment medium is mainly used for treating electrolyte in battery thermal runaway flue gas; the second treatment cavity is filled with the solid treatment medium, and the solid treatment medium is used for completely treating residual gas treated by the liquid treatment medium.

Description

Technical Field

[0001] The utility model belongs to the field of batteries, and specifically relates to a battery pack. Background Art

[0002] With the widespread application of lithium-ion batteries, the safe use of lithium-ion batteries has also attracted attention. Due to the high concentration of multiple lithium-ion batteries in the battery pack, under the influence of factors such as overcharge, over-discharge, overheating, and mechanical collision of lithium-ion batteries, the battery diaphragm collapses and internal short circuits occur, resulting in thermal runaway, which may eventually lead to internal fire in the battery, and in severe cases, cause explosions, posing safety hazards.

[0003] When a lithium-ion battery is in complete thermal runaway, the internal temperature of the battery is as high as 500°C or above. The gas generated during the thermal runaway process causes the internal pressure of the battery to increase, causing the battery shell to expand and rupture, and the electrolyte and reaction gases that evaporate and vaporize inside the battery are ejected and released. The above-mentioned vaporized electrolyte and reaction gases form thermal runaway flue gas, which is discharged outside the battery shell and is prone to gather and cause safety hazards such as combustion. In addition, the above-mentioned thermal runaway flue gas contains toxic gases such as HF, which will also cause certain pollution to the environment. Summary of the invention

[0004] The utility model provides a battery pack, in which a smoke treatment unit is integrated in the box of the battery pack, and the smoke treatment unit can completely and thoroughly treat the thermal runaway smoke generated by each single battery in the battery pack, so that no gas is discharged when the batteries in the battery pack thermally run away, thereby avoiding the safety hazards caused by the discharge of the thermal runaway smoke in the battery pack and improving the safety of the battery pack when in use.

[0005] In order to achieve the above object, the technical solution of the utility model is:

[0006] A battery pack comprises a case, a battery module and a smoke treatment unit; the inner cavity of the case is divided into a battery compartment and a smoke treatment compartment by a first partition, and a smoke channel connecting the battery compartment and the smoke treatment compartment is provided on the first partition; the battery module is arranged in the battery compartment; the smoke treatment compartment is divided into a first treatment chamber and a second treatment chamber by a second partition; the smoke treatment unit comprises a liquid treatment medium and a solid treatment medium; the liquid treatment medium is filled in the first treatment chamber, and is mainly used to treat the electrolyte in the thermal runaway smoke; the solid treatment medium is filled in the second treatment chamber, and is used to completely treat the residual gas after being treated by the liquid treatment medium.

[0007] Furthermore, a buffer chamber is formed in the flue gas treatment chamber through a third partition, and the thermal runaway flue gas in the battery chamber enters the first treatment chamber after being buffered in the buffer chamber.

[0008] Furthermore, the third partition and the second partition are arranged in sequence from bottom to top, so that the buffer chamber, the first processing chamber and the second processing chamber are arranged in sequence from bottom to top; the third partition and the second partition are both provided with smoke holes for thermal runaway smoke to pass through, and a first one-way valve is provided on the smoke hole of the third partition, and the smoke channel is located at the bottom of the first partition and is connected to the buffer chamber.

[0009] Furthermore, a foam copper column is provided on the first one-way valve, and at least one second one-way valve is provided on the smoke hole of the second partition.

[0010] Furthermore, an isolation membrane is provided on the smoke channel, and the pressure bearing capacity of the isolation membrane is smaller than the pressure bearing capacity of the explosion relief membrane of the battery cell in the battery module.

[0011] Furthermore, the liquid treatment medium is an alkaline solution.

[0012] Furthermore, the alkaline solution is a 0.1-0.2 mol / L NaOH solution, and the solid treatment medium is activated carbon.

[0013] Furthermore, the battery module includes a plurality of single cells connected in series.

[0014] Furthermore, along the arrangement direction of the single cells in the battery module, two side walls of the battery compartment are respectively provided with T-shaped positioning blocks for positioning the single cells, and the bottom of the T-shaped positioning blocks is also provided with supporting bosses for supporting the single cells.

[0015] Furthermore, a heat insulation plate is provided between each single battery in the battery module.

[0016] Compared with the prior art, the technical solution of the utility model has the following advantages:

[0017] 1. A flue gas treatment unit is integrated in the box of the battery pack of the utility model, and the flue gas treatment unit introduces the thermal runaway flue gas generated by thermal runaway of the battery in the box into a liquid treatment medium and a solid treatment medium for treatment in sequence, and the liquid treatment medium treats the electrolyte and part of the gas carried in the thermal runaway flue gas, and the solid treatment medium treats the residual gas after the treatment with the liquid treatment medium. This method of treating the thermal runaway flue gas with a combination of a liquid treatment medium and a solid treatment medium can completely and thoroughly treat the thermal runaway flue gas generated by the single cells in the battery pack, so that when any single cell in the box of the battery pack has thermal runaway, no thermal runaway gas is discharged out of the box, thereby improving the safety of the battery pack during use.

[0018] 2. In the battery pack of the utility model, the flue gas treatment unit is integrated into the box of the battery pack. The flue gas treatment unit does not occupy additional installation space, and the whole battery pack has a high degree of integration. At the same time, this arrangement makes the whole battery pack beautiful and easy to carry.

[0019] 3. In the battery pack of the utility model, the flue gas treatment chamber also includes a buffer chamber, which is mainly used to buffer the thermal runaway flue gas to prevent the thermal runaway flue gas with a large pressure from passing through the liquid treatment medium quickly and having the defect of not being able to be fully treated, thereby improving the treatment effect of the liquid treatment medium.

[0020] 4. In the battery pack of the utility model, the flue gas treatment chamber is divided into a buffer chamber, a first treatment chamber and a second treatment chamber arranged in sequence from bottom to top. This arrangement is consistent with the upward flow characteristics of thermal runaway flue gas, so that all thermal runaway flue gas is treated by liquid treatment medium and solid treatment medium, improving the treatment effect of the flue gas treatment unit. At the same time, the flue gas channel is arranged at the bottom of the first partition, which can make the electrolyte in the battery compartment flow into the buffer chamber, avoiding the electrolyte being retained in the battery compartment and affecting the single battery that has not experienced thermal runaway.

[0021] 5. In the battery pack of the utility model, a foam copper column is also provided on the first one-way valve, which disperses and diverts the thermal runaway flue gas entering the first treatment chamber, so that the thermal runaway flue gas is fully in contact with the liquid treatment medium, thereby improving the treatment effect of the liquid treatment medium. At least one second one-way valve is provided on the second partition, and the second one-way valve can form a certain pressure in the second treatment chamber, thereby improving the treatment effect of the solid treatment medium. At the same time, the second one-way valve can also control the flow rate of the thermal runaway flue gas, so that the thermal runaway flue gas enters the second treatment chamber at a uniform flow rate, so that the solid treatment medium in the second treatment chamber can fully treat the thermal runaway flue gas.

[0022] 6. In the battery pack of the utility model, the liquid treatment medium is an alkaline solution, which can not only fully treat the electrolyte carried in the thermal runaway flue gas to prevent the vaporized electrolyte from continuing to decompose, but also treat part of the gas in the thermal runaway flue gas. Among them, the effect of the alkaline solution with a concentration of 0.1 to 0.2 mol / L NaOH solution is the most significant.

[0023] 7. In the battery pack of the utility model, the solid treatment medium is selected as activated carbon with relatively low cost and relatively good treatment effect.

[0024] 8. In the battery pack of the utility model, along the arrangement direction of each single battery, T-shaped positioning blocks for positioning and installing each single battery are respectively provided on the two side walls of the battery compartment. The T-shaped positioning blocks not only position each single battery in its arrangement direction, but also position it in a direction perpendicular to the arrangement direction, so as to achieve reliable installation of each single battery and prevent the battery module from shaking in the box and colliding with the inner wall of the box.

[0025] 9. In the battery pack of the utility model, a heat insulation board is provided between each single cell in the battery module, which can isolate the heat transfer and heat spread between each single cell, and improve the safety of the battery module during normal operation and thermal runaway. At the same time, the heat insulation board can also suppress the deformation of the shell of two adjacent single cells due to expansion, avoiding the safety hazards such as leakage, internal short circuit and thermal runaway caused by bulging deformation, and improving the safety and reliability of the entire battery module.

[0026] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a battery pack in an embodiment;

[0029] Figure 2 A schematic diagram of the structure of a battery module in a battery pack in an embodiment;

[0030] Figure 3 A schematic diagram of the box structure of the battery pack in the embodiment;

[0031] Figure 4 A partial cross-sectional view of a battery pack in an embodiment;

[0032] Figure 5 is a schematic diagram of a smoke treatment unit of a battery pack in an embodiment;

[0033] Figure 6 Schematic diagram of the structure of the smoke treatment chamber of the battery pack in the embodiment.

[0034] Figure markings: 1-box, 2-battery module, 3-liquid treatment medium, 4-solid treatment medium, 5-foam copper column, 6-second one-way valve, 7-first one-way valve, 11-first partition, 12-battery compartment, 13-smoke treatment compartment, 14-smoke channel, 15-third partition, 16-second partition, 17-isolation membrane, 121-T-shaped positioning block, 122-support boss, 131-first treatment chamber, 132-second treatment chamber, 133-buffer chamber, 21-single battery, 22-connecting terminal, 23-battery management system, 24-heat insulation board. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary persons in the field without creative work should fall within the scope of protection of the utility model.

[0036] The "other embodiments" that appear in different places in this specification do not all refer to the same embodiment, nor are they separate or selective embodiments that are mutually exclusive with other embodiments. In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of this utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited.

[0037] In the description of this specification, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate, or the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0038] At the same time, in the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "top, bottom, inside and outside" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention 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 invention.

[0039] The existing battery pack generally includes multiple single cells, which are closely arranged in the box of the battery pack. The battery pack is prone to thermal runaway during use or when it is overcharged, over-discharged, or mechanically collided. Studies have shown that when the battery is in thermal runaway, a series of chemical reactions will occur inside, releasing a large amount of heat and gas, such as: SEI film decomposition reaction (90-120°C), negative electrode and electrolyte reaction (100-350°C), electrolyte decomposition reaction (110-300°C), diaphragm shrinkage and melting reaction (>130°C), positive electrode and electrolyte reaction (200-300°C) and binder decomposition reaction (200-300°C), etc., and a large amount of thermal runaway flue gas is generated, which contains not only hydrogen, CO, CO2, methane and other gases, but also a large amount of electrolyte vapor. The thermal runaway flue gas is discharged outside the battery casing, which is easy to gather and cause safety hazards such as combustion. In addition, the above-mentioned thermal runaway flue gas will also cause certain pollution to the environment due to the presence of toxic gases such as HF.

[0040] Based on this, the utility model integrates a flue gas treatment unit on the battery pack, and the flue gas treatment unit completely and thoroughly treats the thermal runaway flue gas generated by the thermal runaway of the battery, so that no gas is discharged when the battery is in thermal runaway. The above-mentioned flue gas treatment unit mainly includes a liquid treatment medium and a solid treatment medium; when any single cell in the battery pack has thermal runaway, the thermal runaway flue gas passes through the liquid treatment medium and the solid treatment medium in sequence, and the liquid treatment medium treats the electrolyte and part of the gas carried in the thermal runaway flue gas of the battery in a targeted manner, and prevents the vaporized electrolyte from continuing to decompose and react, and then the solid treatment medium treats all the residual gas after the treatment by the liquid treatment medium. After the thermal runaway flue gas passes through the above-mentioned liquid treatment medium and the solid treatment medium, it is completely and thoroughly treated, and there is no need to discharge it after treatment, which avoids the problems caused by the discharge of the thermal runaway flue gas and improves the safety of the battery pack during use.

[0041] In the battery pack of the utility model, the smoke treatment unit is integrated in the box of the battery pack, and the smoke treatment unit does not occupy additional installation space. The whole battery pack has a high degree of integration, which makes the whole battery pack beautiful and easy to carry. At the same time, the smoke treatment unit is arranged in the box of the battery pack. When the battery in the box has thermal runaway, the generated thermal runaway smoke passes through a shorter path to the smoke treatment unit for treatment, which reduces the accumulation time of the heat generated by the thermal runaway in the battery compartment.

[0042] like Figures 1 to 5 As shown, the battery pack provided in this embodiment includes a case 1, a battery module 2 and a flue gas treatment unit; the battery module 2 and the flue gas treatment unit are both installed in the case 1, the battery module 2 is the power supply body of the battery pack, and the flue gas treatment unit mainly treats the thermal runaway flue gas generated when the battery module 2 thermally runs away.

[0043] The box 1 in this embodiment is mainly used to install and integrate the battery module 2 and the flue gas treatment unit, and also provides safety protection for the battery module 2 to protect the battery module 2 from impact, vibration, falling, etc. in the external environment. The box 1 is a closed box, and the shape and size of the box 1 can be designed to be convenient for placement according to the application scenario of the battery module 2, such as a cylinder, prism, cube, etc. In actual use, in order to facilitate installation and placement, the shape of the box 1 is preferably a rectangular parallelepiped. In addition, in order to avoid the risk of short circuit between the battery module 2 in the box 1 and external equipment, the box 1 is generally made of insulating material and a material with high rigidity.

[0044] The battery module 2 in this embodiment mainly includes a battery management system 23, a terminal 22 and a plurality of single cells 21. The plurality of single cells 21 are arranged in series to meet different capacity requirements. The single cells 21 can be existing single cylindrical batteries, square shell batteries, and soft-pack batteries. The battery management system 23 (BMS) mainly monitors the working status of each single cell 21. During specific installation, the battery management system 23 can be set inside the box 1 or outside the box 1. When it is set inside the box 1, the connection with the single cell is more convenient and reliable. When it is set outside the box 1, it is convenient for later maintenance and replacement.

[0045] The battery module 2 is electrically connected to an external circuit or an electrical device through a terminal block 22. The terminal block 22 can be arranged on the housing 1 and exposed to the housing 1 for easy charging and discharging. When connected, the terminal block 22 can be fixedly connected to the housing 1 and cannot be disassembled from the housing 1, or can be detachably connected to the housing 1. In this embodiment, the terminal block 22 and the battery management system 23 (BMS) are integrated on the same side outside the housing 1 and are fixedly installed.

[0046] In addition, a positioning structure may be provided on the box 1 to facilitate positioning and installing the battery module 2, while also preventing the battery module 2 from shaking significantly in the box 1. The positioning structure is as follows:

[0047] like Figure 3 As shown, along the arrangement direction of each single battery 21, a plurality of T-shaped positioning blocks 121 are respectively provided on the two side walls of the battery compartment 12, and each single battery 21 is arranged between adjacent T-shaped positioning blocks 121. The T-shaped positioning blocks 121 not only position each single battery 21 in the arrangement direction, but also position it in a direction perpendicular to the arrangement direction, so as to realize the reliable installation of each single battery 21.

[0048] In other embodiments, the box 1 further has a filling material, which is filled between the battery module 2 and the inner wall of the box 1. According to the needs of the use scenario of the battery module 2, the filling material can be a heat-insulating material to prevent heat loss; or, the filling material can also be a flexible buffer material to prevent the battery module 2 from shaking in the box 1 and colliding with the inner wall of the box 1. The flexible buffer material can be made of a soft elastic material such as foam or silicone.

[0049] like Figure 2 As shown, in this embodiment, a heat insulation board 24 may be provided between each single cell 21 in the battery module 2. The heat insulation board 24 insulates each single cell 21 to avoid heat transfer between adjacent single cells 21, and can effectively prevent heat spread. At the same time, the heat insulation board 24 can also suppress the deformation of the shells of two adjacent single cells due to expansion, reduce the safety hazards such as leakage, internal short circuit and thermal runaway caused by bulging deformation, and improve the safety and reliability of the entire battery module.

[0050] The individual cells 21 in the battery module 2 are closely arranged in the box 1. The high-density arrangement makes the safety and thermal stability of the battery pack poor, which brings certain safety hazards to the safe use of the battery pack. Based on this, on the basis of the structure of the battery pack, a flue gas treatment unit is integrated in the battery pack, which can treat the thermal runaway flue gas.

[0051] like Figure 2 and Figure 3 As shown, in order to facilitate the installation of the battery module 2 and the flue gas treatment unit, the inner cavity of the box body 1 is divided into a battery compartment 12 and a flue gas treatment compartment 13 by a first partition 11. The battery compartment 12 is filled with the battery module 2, and the flue gas treatment unit is placed in the flue gas treatment compartment 13. In the specific setting, the battery compartment 12 and the flue gas treatment compartment 13 can be arranged up and down, left and right, or front and back. In the above arrangement, the left and right arrangement or the front and back arrangement is more convenient for the installation of the battery module 2 and the flue gas treatment unit than the up and down arrangement. In addition, the first partition 11 is provided with a flue gas channel 14 connecting the battery compartment 12 and the flue gas treatment compartment 13, which is used to transport the thermal runaway flue gas in the battery compartment 12 to the flue gas treatment compartment 13.

[0052] like Figure 5As shown, the flue gas treatment unit in this embodiment includes a liquid treatment medium 3 and a solid treatment medium 4; the liquid treatment medium 3 and the solid treatment medium 4 are arranged in a flue gas treatment chamber 13. When specifically arranged, the flue gas treatment chamber 13 includes a first treatment chamber 131 and a second treatment chamber 132. The liquid treatment medium 3 is filled in the first treatment chamber 131, and the solid treatment medium 4 is filled in the second treatment chamber 132. The liquid treatment medium 3 performs targeted treatment on the electrolyte and part of the gas carried in the thermal runaway flue gas of the battery to prevent the vaporized electrolyte from continuing to decompose and react to produce gas. Subsequently, the solid treatment medium 4 completely treats the residual gas after being treated by the liquid treatment medium 3. After the thermal runaway flue gas passes through the above-mentioned liquid treatment medium 3 and solid treatment medium 4, it can be completely treated without the need for post-treatment discharge, thereby avoiding problems such as combustion, explosion and pollution caused by the discharge of the thermal runaway flue gas, thereby improving the safety of the battery pack during use.

[0053] Since the thermal runaway flue gas is a gas with a certain pressure, when it passes through the liquid treatment medium 3, it may pass through the liquid treatment medium 3 quickly and cannot be fully treated. Figure 5 and Figure 6 As shown, the flue gas treatment chamber 13 in this embodiment also includes a buffer chamber 133, which is mainly used to buffer the pressurized thermal runaway flue gas, increase the residence time of the thermal runaway flue gas, increase the contact time between the thermal runaway flue gas and the liquid treatment medium 3, and avoid the pressurized thermal runaway flue gas from quickly passing through the liquid treatment medium 3, which may not be fully treated, thereby improving the treatment effect of the liquid treatment medium 3.

[0054] When the buffer chamber 133, the first processing chamber 131 and the second processing chamber 132 are arranged, they can be arranged left and right, or arranged up and down. If they are arranged left and right, at this time, the buffer chamber 133, the first processing chamber 131 and the second processing chamber 132 are arranged in sequence along the arrangement direction of the battery, and the buffer chamber 133 is close to the battery compartment 12. If they are arranged up and down, the buffer chamber 133, the first processing chamber 131 and the second processing chamber 132 can be arranged in sequence from top to bottom, or from bottom to top. Since the thermal runaway flue gas has the characteristic of flowing upward, the arrangement from bottom to top is consistent with the flow characteristics of the thermal runaway flue gas, and all the thermal runaway flue gas can be made to pass through the liquid treatment medium 3 and the solid treatment medium 4 as much as possible, thereby improving the treatment effect of the flue gas treatment unit. If they are arranged in sequence from top to bottom, some of the thermal runaway flue gas may be retained at the top of the buffer chamber 133, the first processing chamber 131 or the second processing chamber 132 and cannot be treated.

[0055] like Figure 6As shown, in the specific setting, a third partition 15 and a second partition 16 are added to the above-mentioned flue gas treatment chamber 13 to divide the flue gas treatment chamber 13 into a buffer chamber 133, a first treatment chamber 131 and a second treatment chamber 132 arranged from bottom to top; the third partition 15 and the second partition 16 are both provided with flue gas holes for the thermal runaway flue gas to pass through, and a first one-way valve 7 is provided on the flue gas hole of the third partition 16. The first one-way valve 7 can not only prevent the liquid treatment medium 3 in the first treatment chamber 131 from flowing back, but also control the flow rate of the thermal runaway flue gas. The thermal runaway flue gas enters the first treatment chamber 131 at a uniform flow rate, so that the liquid treatment medium 3 in the first treatment chamber can fully treat the thermal runaway flue gas. At this time, the above-mentioned flue gas channel 14 can also be arranged at the bottom of the first partition 11. The flue gas channel 14 arranged at the bottom enables the electrolyte in the battery compartment to flow into the buffer chamber 133, so as to prevent the electrolyte from being retained in the battery compartment and affecting the battery that has not experienced thermal runaway.

[0056] like Figure 3 and Figure 4 As shown, when the above-mentioned smoke channel 14 is arranged at the bottom of the first partition 11, a supporting boss 122 for supporting each single battery can also be provided at the bottom of the above-mentioned T-shaped positioning block 121, and each single battery 21 is placed on the supporting boss 122. At this time, the T-shaped positioning block 121 forms a vertical channel for the circulation of thermal runaway smoke between the short side wall of each single battery 21 and the side wall of the battery compartment 12, and the supporting boss 122 forms a transverse channel for the circulation of thermal runaway smoke between the bottom of each single battery 21 and the bottom plate of the battery compartment 12, and the transverse channel is connected with the vertical channel so that the thermal runaway smoke can flow smoothly into the smoke treatment compartment 13.

[0057] It should be noted that if the buffer chamber 133 is not provided in the flue gas treatment chamber 13, the flue gas channel 14 needs to be provided on the upper part of the first partition 11, and the thermal runaway flue gas enters the flue gas treatment chamber 13 from the top of the battery chamber 12 for treatment. At the same time, an isolation membrane 17 is provided on the flue gas channel 14, and the pressure bearing capacity of the isolation membrane 17 is less than the pressure bearing capacity of the battery cell explosion relief membrane in the battery module. The isolation membrane 17 opens when the pressure in the battery chamber 12 reaches the threshold value, and the thermal runaway flue gas in the battery chamber 12 is transported to the flue gas treatment chamber 13. The main function of the isolation membrane 17 is to isolate the battery chamber 12 and the flue gas treatment chamber 13, and reduce the possibility of the liquid treatment medium in the flue gas treatment chamber 13 entering the battery chamber 12 through the flue gas channel.

[0058] The first one-way valve 7 is also provided with a foam copper column 5, which disperses and diverts the thermal runaway flue gas entering the first processing chamber 131, so that the thermal runaway flue gas is fully in contact with the liquid processing medium, thereby improving the processing effect of the liquid processing medium.

[0059] In addition, the adsorption treatment effect of the solid treatment medium 4 is related to pressure. The higher the pressure, the faster the adsorption. When the pressure rises, the adsorption phenomenon begins to be significant. At this time, the second treatment chamber 132 can be subjected to a certain pressure holding treatment. After the pressure holding treatment, the adsorbed substance will be adsorbed on the surface of the adsorbent. Based on this, a second one-way valve 6 is arranged on the second partition plate 16. The second one-way valve 6 can form a certain pressure holding effect in the second treatment chamber 132 for the thermal runaway flue gas, thereby improving the treatment effect of the solid treatment medium 4. At the same time, the second one-way valve 6 can also control the flow rate of the thermal runaway flue gas. The thermal runaway flue gas enters the second treatment chamber 132 at a uniform flow rate, so that the solid treatment medium 4 in the second treatment chamber 132 can fully treat the thermal runaway flue gas.

[0060] Based on the above structure, the thermal runaway flue gas enters the first treatment chamber 131 after being buffered by the buffer chamber 133, and is treated by the liquid treatment medium 3. The liquid treatment medium 3 can specifically be made of the following substances:

[0061] First, the liquid treatment medium 3 can be an organic solvent. According to the principle of like dissolves like, the organic solvent can fully treat the electrolyte carried in the thermal runaway flue gas, and at the same time can prevent the vaporized electrolyte from continuing to decompose. The organic solvent is specifically an ester solvent, an alcohol solvent or an aldehyde solvent. The ester solvent can specifically be diethyl phthalate solvent, methyl salicylate solvent, ethyl acetate solvent or butyl acetate solvent, etc., the alcohol solvent can specifically be benzyl alcohol solvent, isoamyl alcohol solvent, isobutanol solvent, isopropanol solvent, isooctyl alcohol solvent, n-propanol solvent or cyclohexanol solvent, etc., and the aldehyde solvent is benzaldehyde solvent, heptaldehyde, phenylpropionaldehyde or methylnonaneacetaldehyde, etc.

[0062] Second, the liquid treatment medium 3 can be an alkaline solution, and the alkaline solution can specifically be an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous barium hydroxide solution, etc. The alkaline solution can react with carbonate substances in the electrolyte to prevent the vaporized electrolyte from continuing to produce harmful gases, and treat the thermal runaway flue gas to a certain extent at the source. At the same time, the alkaline solution can cool the thermal runaway flue gas and fully dissolve the electrolyte vapor in the thermal runaway flue gas in the alkaline solution. In addition, the alkaline solution has a good treatment effect on acidic substances such as CO2, POF3 and HF, and can achieve effective treatment of thermal runaway flue gas.

[0063] At the same time, for alkaline solutions, generally the higher the concentration, the better the treatment effect on thermal runaway flue gas. However, the applicant found that low-concentration alkaline solutions have better treatment effects than high-concentration alkaline solutions, especially 0.05-0.5 mol / L alkaline solutions. When thermal runaway flue gas passes through an alkaline solution of this concentration, the amount of gas collected is minimal, and its treatment effect is better than that of alkaline solutions with a concentration of more than 0.5 mol / L. Therefore, when using alkaline solutions to treat thermal runaway flue gas, the prejudice of the prior art is overcome, and low-concentration alkaline solutions are used to treat thermal runaway flue gas, so that the alkaline solution can achieve effective treatment of thermal runaway flue gas.

[0064] Taking the alkaline solution as NaOH solution as an example, a large number of battery thermal runaway tests were carried out. After a horizontal comparison of the treatment effects of water and NaOH solutions of different concentrations on thermal runaway flue gas, it was found that the volume of gas collected after the thermal runaway flue gas was the smallest after being treated with 0.05-0.5 mol / L NaOH solution, the effect was significant after being treated with 0.1-0.2 mol / L NaOH solution, and the best effect was achieved after being treated with 0.1 mol / L NaOH solution.

[0065] When the thermal runaway flue gas is transported to the NaOH solution, the NaOH solution reacts with the electrolyte, CO2, POF3 and acidic substances such as HF in the thermal runaway flue gas. For example, the ester in the electrolyte reacts with the NaOH solution: CHOOCR+NaOH=RCOONa+CHOH; CO2 reacts with the NaOH solution: 2NaOH+CO2=Na2CO3+H2O; CO2 will also react subsequently: Na2CO3+CO2+H2O=2NaHCO3; POF3 reacts with the NaOH solution: POF3+2NaOH=NaPF2O2+NaF+H2O; HF reacts with the NaOH solution: NaOH+HF=NaF+H2O. After the above reactions, the volume of the thermal runaway flue gas is greatly reduced.

[0066] Table 1 Unprocessed full-charge 32650 battery out-of-control data

[0067]

[0068] Table 2 Treatment results of different concentrations of NaOH solution

[0069]

[0070]

[0071] According to the above test data, when the thermal runaway flue gas of the fully charged 32650 battery after thermal runaway is not treated in any way, the collected gas volume is 4L. When the thermal runaway flue gas of the fully charged 32650 battery after thermal runaway passes through a NaOH solution with a concentration of 0.5mol / L or more, the collected gas is generally greater than 2L, and the treatment effect is not ideal. After the thermal runaway flue gas of the fully charged 32650 battery after thermal runaway passes through a 0.05-0.5mol / L NaOH solution, the gas volume is small, all below 2L. After being treated with 0.1-0.2mol / L sodium hydroxide, the effect is significant. After being treated with 0.1mol / L sodium hydroxide, the collected gas volume is the smallest, only about 1L, and the effect is the best. Therefore, 0.05-0.5mol / L NaOH solution has a good treatment effect on the thermal runaway flue gas after battery thermal runaway.

[0072] From the above results, it can be seen that an alkaline solution of a certain concentration can effectively treat the thermal runaway flue gas, so that the volume of the treated thermal runaway flue gas is greatly reduced. On this basis, the solid treatment medium 4 can be used to treat the remaining gas. The solid treatment medium 4 can completely treat the remaining gas without corresponding emissions, so as to improve the safety of the battery pack.

[0073] The above-mentioned solid treatment medium 4 can specifically be activated carbon, graphene, carbon nanotubes, graphite, alumina, montmorillonite, silicate, phosphate or porous glass, etc., to adsorb excess H2, CO, methane and other gases; preferably, the above-mentioned solid treatment medium selects activated carbon with relatively low cost and relatively excellent treatment effect, generally activated carbon or modified activated carbon with a higher iodine value is selected. This type of activated carbon is easy to adsorb small molecular weight gases in thermal runaway flue gas, for example, it is easy to react with hydrogen, methane, etc.

[0074] According to the above preferred materials and structures, the battery module 2 and the flue gas treatment unit are both installed in the box body 1 with an open opening, and then the open end of the box body 1 is sealed with a cover. A pressure relief port is provided on the top of each single battery 21 in the battery compartment 12, and an explosion relief membrane is provided in the pressure relief port. When the single battery 21 has thermal runaway, the explosion relief membrane ruptures, and the thermal runaway smoke diffuses in the battery compartment 12. When the thermal runaway smoke pressure of the battery compartment 12 reaches a certain value, the isolation membrane 17 at the smoke channel 14 ruptures, and the thermal runaway smoke enters the buffer chamber 133 of the smoke treatment chamber 13. The buffer chamber 133 is used to buffer the thermal runaway smoke so that the thermal runaway smoke can smoothly enter the first treatment chamber 131 to be treated by the liquid treatment medium 3, and then enter the second treatment chamber 132 through the second one-way valve 6 on the second partition 16. The solid treatment medium 4 treats the residual gas after treatment with the liquid treatment medium 3, and the thermal runaway smoke is completely treated in the smoke treatment chamber 13, thereby improving the safety of the battery pack during use.

[0075] In this embodiment, the battery compartment 12 includes 15 105Ah lithium iron phosphate square shell batteries, the electrical connection method is 1P15S, the parameters after assembly are 48V / 105Ah, and the capacity is 5KWh. Since the battery module adopts a series connection, when one of the single cells 21 is in thermal runaway, the electrical connection between the single cells 21 is disconnected. At the same time, since there is a heat insulation plate 24 between each single cell, the thermal runaway single cell 21 will not affect other single cells 21 in the battery compartment 12. At this time, the flue gas treatment compartment 13 only needs to deal with the thermal runaway flue gas generated by a single thermal runaway battery. The following takes a single 105Ah lithium iron phosphate square shell battery as an example to carry out a thermal runaway test. During the test, a single 105Ah lithium iron phosphate square shell battery exploded after heating for 11 minutes, and then continued to heat for 30 minutes, and then stopped heating for 30 minutes. Its weight before thermal runaway was 2.05kg, and its weight after thermal runaway was 1.65kg.

[0076] Table 3 105A thermal runaway test records

[0077]

[0078]

[0079] According to the above test data, it was found that the 105A battery was subjected to multiple thermal runaway tests. The thermal runaway flue gas was not treated in the first three tests, and the volume of the collected gas was about 96L to 100L. Subsequently, different volumes of alkaline solution were used to treat the thermal runaway flue gas after the thermal runaway of the 105A battery. After treatment, the volume of the thermal runaway flue gas was greatly reduced, but there was residual gas discharged, and the residual gas was flammable. Subsequently, different volumes of alkaline solution and different weights of activated carbon were used to treat the thermal runaway flue gas of the thermal runaway of the 105A battery. When a certain volume of alkaline solution and a certain weight of activated carbon were used, the thermal runaway flue gas could be completely treated without gas discharge. It can be seen from this that this method of treating the thermal runaway flue gas with a combination of liquid treatment medium and solid treatment medium can completely and thoroughly treat the thermal runaway flue gas generated by the single cell in the battery pack, so that when any single cell in the box of the battery pack has thermal runaway, no thermal runaway gas is discharged from the box, which improves the safety of the battery pack during use.

Claims

1. A battery pack, characterized in that: It includes a box body, a battery module and a flue gas treatment unit; The inner cavity of the box body is divided into a battery compartment and a smoke treatment compartment by a first partition, and a smoke passage connecting the battery compartment and the smoke treatment compartment is provided on the first partition; The battery module is arranged in the battery compartment; The flue gas treatment chamber is divided into a first treatment chamber and a second treatment chamber by a second partition; The flue gas treatment unit includes a liquid treatment medium and a solid treatment medium; the liquid treatment medium is filled in the first treatment chamber and is mainly used to treat the electrolyte in the thermal runaway flue gas; The solid treatment medium is filled in the second treatment chamber to completely treat the residual gas after being treated by the liquid treatment medium.

2. The battery pack according to claim 1, characterized in that: A buffer chamber is formed in the flue gas treatment chamber through the third partition plate, and the thermal runaway flue gas in the battery chamber enters the first treatment chamber after being buffered in the buffer chamber.

3. The battery pack according to claim 2, characterized in that: The third partition and the second partition are arranged in sequence from bottom to top, so that the buffer chamber, the first processing chamber and the second processing chamber are arranged in sequence from bottom to top; the third partition and the second partition are both provided with smoke holes for the thermal runaway smoke to pass through, and the smoke hole of the third partition is provided with a first one-way valve, and the smoke channel is located at the bottom of the first partition and is connected to the buffer chamber.

4. The battery pack according to claim 3, characterized in that: A foam copper column is also provided on the first one-way valve, and at least one second one-way valve is provided on the smoke hole of the second partition.

5. The battery pack according to claim 1, characterized in that: An isolation membrane is arranged on the smoke channel, and the pressure bearing capacity of the isolation membrane is smaller than the pressure bearing capacity of the explosion relief membrane of the battery cell in the battery module.

6. The battery pack according to claim 1, characterized in that: The liquid treatment medium is an alkaline solution.

7. The battery pack according to claim 6, characterized in that: The alkaline solution is a 0.1-0.2 mol / L NaOH solution, and the solid treatment medium is activated carbon.

8. The battery pack according to any one of claims 1 to 7, characterized in that: The battery module includes a plurality of single batteries connected in series.

9. The battery pack according to claim 8, characterized in that: Along the arrangement direction of the single cells in the battery module, two side walls of the battery compartment are respectively provided with T-shaped positioning blocks for positioning the single cells, and the bottom of the T-shaped positioning blocks is also provided with supporting bosses for supporting the single cells.

10. The battery pack according to claim 8, characterized in that: A heat insulation plate is arranged between each single battery in the battery module.

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