AB battery suitable for starting automobile and manufacturing method of AB battery

Abstract

The invention belongs to the technical field of batteries, and particularly relates to an AB battery suitable for automobile starting and a manufacturing method thereof.The AB battery comprises a battery pack, the battery pack comprises a plurality of battery modules connected in parallel, and each battery module comprises a sodium ion battery pack and a lithium ion battery pack; the sodium ion battery pack consists of a plurality of sodium ion battery cells which are connected in series, and the lithium ion battery pack consists of a plurality of lithium ion battery cells which are connected in series. The manufacturing method sequentially comprises the steps of battery module manufacturing, battery pack manufacturing and battery pack detection. Through mutual cooperation of the sodium ion battery pack and the lithium ion battery pack, the low-temperature starting capacity is high, and the cycle life is long; and the thermal runaway risk is reduced, the use safety is improved, the cost is low, and popularization of the device in middle-end and low-end vehicle models is facilitated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to an AB battery suitable for automobile starting and a manufacturing method thereof. BACKGROUND

[0002] Among automobile batteries, lead-acid starting batteries are the most widely used battery type at present, but their energy density is low (about 30-50 Wh / kg), and in order to meet the starting power demand, a larger volume and weight are often needed, which increases the vehicle load, and indirectly affects the endurance of small cars and new energy vehicles. Secondly, the low-temperature performance is poor, and in an environment below-10 DEG C, the activity of the electrolyte decreases, the capacity sharply decreases, and the situation of "cold start failure" often occurs. The cycle life is mostly 300-500 times, and frequent deep discharge (such as forgetting to turn off the car lights) easily leads to plate sulfuration and shortens the service life. Although lithium battery starting batteries (mainly lithium iron phosphate) solve some problems of lead-acid batteries, their low-temperature discharge capacity is limited, and the discharge capacity of lithium iron phosphate batteries sharply decreases below-20 DEG C, and even cannot meet the large current demand (hundreds of amperes) in the starting moment, and the applicability in severe cold regions is discounted. Moreover, the cost of lithium batteries is high, and the material (such as lithium and cobalt) and production process cost of lithium batteries are much higher than those of lead-acid batteries, and the price of lithium battery starting batteries with the same capacity is usually 2-3 times that of lead-acid batteries, which restricts the popularization of lithium battery starting batteries in medium and low-end vehicles. In addition, if lithium batteries are overcharged, short-circuited or physically impacted, heat runaway may be caused, and there is a risk of fire. Therefore, both lead-acid starting batteries and lithium batteries have great limitations and shortcomings in automobile starting, and it is very necessary to design an AB battery suitable for automobile starting and application. SUMMARY

[0003] The purpose of the application is to design an AB battery suitable for automobile starting, which comprises a battery pack, the battery pack comprises a plurality of parallel-connected battery modules, the battery module comprises a sodium ion battery group and a lithium ion battery group.

[0004] The sodium ion battery group is composed of a plurality of series-connected sodium ion battery cells, and the lithium ion battery group is composed of a plurality of series-connected lithium ion battery cells.

[0005] Preferably, the sodium ion battery group and the lithium ion battery group are both two groups.

[0006] Preferably, the sodium ion battery group is composed of four series-connected sodium ion battery cells, and the lithium ion battery group is composed of four series-connected lithium ion battery cells.

[0007] Preferably, the series-connected sodium ion battery cells are fixed by aluminum bar welding, and the series-connected lithium ion battery cells are fixed by aluminum bar welding.

[0008] Preferably, the battery pack further comprises a box body, a box cover is arranged on the box body, and a battery groove matched with the battery module is arranged in the box body.

[0009] Preferably, a protection plate is arranged in the box body, the protection plate is pasted on an epoxy plate through structural glue, and the epoxy plate is pasted on a side of the battery module close to the positive and negative electrodes.

[0010] The application also comprises a manufacturing method of the AB battery suitable for automobile starting, characterized by comprising the following steps.

[0011] Step one: manufacturing of the battery module, first, lithium ion cells and sodium ion cells are classified and marked;

[0012] Then, a plurality of sodium ion cells in the same classification file are taken to form an N1 module in series, a plurality of lithium ion cells in the same classification file are taken to form an L1 module in series, and two N1 modules and two L1 modules are connected in parallel to form a four-parallel-four series battery pack;

[0013] Finally, the positive and negative electrodes of each sodium ion cell and lithium ion cell are welded using an aluminum bar, the positive and negative electrode voltages are measured after welding, the terminal voltage V1 is equal to the average voltage of the cells multiplied by 4, and the measurement is qualified, and the manufacturing of the battery module is completed.

[0014] Step two: manufacturing of the battery pack, first, the battery module is connected to the collection line, an epoxy plate is pasted on a side of the battery module close to the positive and negative electrodes, and a protection plate is fixed on the epoxy plate;

[0015] After the collection line (silicone copper wire) is connected, the interface of the collection line is inserted into the corresponding position of the protection plate, the voltage between the positive and negative electrodes of the battery pack is measured, the voltage value is equal to V1±0.5V, and it is determined that the wiring is qualified.

[0016] Then, a layer of 2mm-thick structural glue is applied to the battery groove in the box body, the fixed battery module and collection line are placed in the battery groove, and the structural glue is solidified and formed after 4 hours.

[0017] The collection line and the corresponding terminal on the box cover are fixed using an M8 screw.

[0018] Finally, the box cover and the box body are buckled, and a label is attached.

[0019] Preferably, the lithium ion cells and sodium ion cells are classified and marked according to a voltage range of ±0.01v and an internal resistance of ±0.05mΩ.

[0020] Preferably, the thickness of the aluminum bar is 0.25mm.

[0021] The working principle of the present application is that (1) by the cooperation of sodium ion battery pack and lithium ion battery pack, when in low temperature environment, the sodium ion battery in the battery pack is preferentially discharged, Na + The Stokes diameter of Na+ is smaller (0.358 nm vs 0.382 nm of Li+) and the ionic charge density is lower, resulting in a weaker coordination with solvent molecules. At low temperature, Na + is more easily dissociated from the solvation sheath, and the sodium ion still maintains a high migration rate at -40℃; in addition, the disordered graphitized structure of the negative electrode material hard carbon provides abundant interlayer space (interlayer spacing of about 0.37-0.40 nm), which is more suitable for sodium ion intercalation. This structure can effectively relieve the stress caused by ion volume expansion at low temperature. Lithium ion batteries will have a significant ion transport blocking phenomenon at the same temperature due to the strong coordination of Li+ with solvent molecules.

[0022] When the device needs high energy output, the lithium ion battery pack is mainly powered to take advantage of its high energy density;

[0023] When facing large current charging and discharging or extreme environments (such as high temperature, low temperature), the sodium ion battery pack bears the main load, taking advantage of its stability and rate performance; in low power standby state, the lithium ion battery pack maintains basic power supply to reduce the invalid cycle loss of the sodium ion battery pack. Thus, the problem of limited low temperature discharge capacity of the battery in the prior art is solved, the low temperature starting ability is strong, and the service life is prolonged.

[0024] (2) According to the thermal stability of the sodium ion cell being better than that of the lithium ion cell, the thermal runaway temperature being as high as 250-300℃, and the performance of not being easy to catch fire and explode in short circuit, a part of the lithium ion cells are replaced by sodium ion cells to reduce the risk of thermal runaway.

[0025] (3) Sodium resources are abundant (about 2.3% in the earth's crust, 400 times that of lithium), and the raw material sodium carbonate is only 1 / 10 of the price of lithium carbonate, so the material cost is 30%-50% lower than that of lithium ion batteries. In addition, the sodium ion cell is maintenance-free (no need to add electrolyte), and the self-discharge rate is low (1.5% per month vs 30% of lead-acid), which further reduces the use cost.

[0026] Compared with the prior art, the present application has the beneficial effects that: through the cooperation of the sodium ion battery pack and the lithium ion battery pack, the low temperature starting ability is strong, the cycle life is long; the risk of thermal runaway is reduced, the safety of use is improved, the cost is low, and it is conducive to the popularization of the medium and low end vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described below in conjunction with the drawings and examples.

[0028] Figure 1This is a schematic diagram of the structure of an AB battery suitable for starting a car, according to an embodiment of the present invention.

[0029] In the diagram: 1. Box body; 2. Box cover; 3. Battery slot; 4. Sodium-ion battery cell; 5. Lithium-ion battery cell; 6. Epoxy board; 7. Protection board; 8. Terminal. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] like Figure 1 As shown, this embodiment proposes an AB battery suitable for automobile starting, including a battery pack, which includes four sets of parallel battery modules, namely two sodium-ion battery packs and two lithium-ion battery packs.

[0033] The sodium-ion battery pack consists of four 32700 cylindrical sodium-ion cells 4 connected in series, and the lithium-ion battery pack consists of four 32700 cylindrical lithium-ion cells 5 connected in series. The battery modules can be assembled and supported using plastic structural brackets.

[0034] Sodium-ion battery cells connected in series are fixed together by welding aluminum busbars, and lithium-ion battery cells connected in series are fixed together by welding aluminum busbars. Laser welding equipment is used for positioning welding.

[0035] The battery pack also includes a housing 1, with a cover 2 on the housing, and a battery slot 3 inside the housing 1 that matches the battery module. The housing and cover are made of plastic material.

[0036] The housing contains a protective plate 7, which is attached to the epoxy board 6 with structural adhesive. The epoxy board 6 is attached to the side of the battery module closest to the positive and negative electrodes. The protective plate 7 has functions such as overvoltage protection, undervoltage protection, overcurrent protection, and intelligent balancing, effectively ensuring the consistency and safety of the battery during charging and discharging.

[0037] Example 2

[0038] This embodiment proposes a method for manufacturing an AB battery suitable for automotive starting, characterized by the following steps:

[0039] Step 1: Battery module manufacturing. First, classify and label the lithium-ion cells 5 and sodium-ion cells 4 according to their ±0.01V voltage range and ±0.05mΩ internal resistance.

[0040] Subsequently, four 32700 sodium ion cells 4 in the same classification file are taken to form an N1 module in series, and 8 32700 cylindrical lithium ion cells 5 in the same file are taken to form an L1 module in 2 parallel 4 series, and then 2 N1 modules and L1 modules are connected in parallel to form a 4 parallel 4 series battery pack;

[0041] Finally, the positive and negative electrodes of each sodium ion cell and lithium ion cell are welded using an aluminum bar with a thickness of 0.25 mm, and the positive and negative terminal voltages are measured after welding, the terminal voltage V1 is equal to the average voltage of the cell multiplied by 4, and the measurement is qualified, and the battery module is completed.

[0042] Step two: battery pack production, first, connect the battery module collection line, and paste an epoxy plate on the side of the battery module close to the positive and negative electrodes, and fix the protection plate on the epoxy plate;

[0043] After connecting the collection line (silicone copper wire), insert the interface of the collection line into the corresponding position of the protection plate, measure the voltage between the positive and negative electrodes of the battery pack, and the voltage value is equal to V1±0.5V, and determine that the wiring is qualified;

[0044] Finally, coat the battery tank in the box with a layer of 2mm thick structural adhesive, and place the fixed battery module and collection line into the battery tank, and wait for 4 hours for the structural adhesive to solidify and form;

[0045] The collection line and the corresponding terminal 8 on the box cover are fixed using M8 screws;

[0046] Finally, tighten the box cover and the box, and then paste the label.

[0047] During the specific production process, the battery pack needs to be detected, and the battery pack is charged with a 0.5C current constant current, and the charging stops when the battery pack voltage is not more than 15.2V;

[0048] After charging, the battery pack is discharged with a 0.5C current constant current, and the discharge is terminated when the battery pack terminal voltage is less than or equal to 7.6V, and the capacity is greater than or equal to 22.5AH, and the determination is qualified, otherwise it is unqualified.

[0049] The technical scheme of the present application is not limited to the above specific embodiments, and any technical modification made according to the technical scheme of the present application falls within the protection scope of the present application.

Claims

1. An AB battery suitable for starting of an automobile, comprising a battery pack, characterized in that, The battery pack comprises a plurality of parallel battery modules, the battery modules comprising sodium ion battery groups and lithium ion battery groups; The sodium ion battery group is composed of a plurality of series-connected sodium ion battery cells, and the lithium ion battery group is composed of a plurality of series-connected lithium ion battery cells.

2. The AB battery suitable for starting of an automobile according to claim 1, characterized in that: The sodium ion battery group and the lithium ion battery group are both two groups.

3. The AB battery suitable for starting an automobile according to claim 2, wherein: The sodium ion battery group is composed of four series-connected sodium ion battery cells, and the lithium ion battery group is composed of four series-connected lithium ion battery cells.

4. The AB battery of claim 1, wherein: the AB battery is adapted for use in starting an automobile. The series-connected sodium ion battery cells are fixed by aluminum bar welding, and the series-connected lithium ion battery cells are fixed by aluminum bar welding.

5. The AB battery of claim 1, wherein: the AB battery is suitable for use in starting an automobile. The battery pack further comprises a box body, the box body is provided with a box cover, and the box body is provided with a battery groove matched with the battery module.

6. An AB battery suitable for starting an automobile according to claim 5, characterized in that: The box body is provided with a protection plate, the protection plate is pasted on an epoxy plate by structural adhesive, and the epoxy plate is pasted on one side of the battery module close to the positive and negative electrodes.

7. The method according to any one of claims 1 to 6, wherein the method is used for manufacturing the AB battery for starting the automobile. The method comprises the following steps, Step one: battery module manufacturing, first, classify and identify the lithium ion battery cells and sodium ion battery cells; Then, a plurality of sodium ion battery cells in the same classification file are taken to form N1 module in series, and a plurality of lithium ion battery cells in the same classification file are taken to form L1 module in series, and then two N1 modules and two L1 modules are connected in parallel to form a battery pack; Finally, the positive and negative electrodes of each sodium ion battery cell and lithium ion battery cell are welded by using aluminum bar, and the manufacturing of the battery module is completed; Step two: battery pack manufacturing, first, connect the collection line of the battery module, paste the epoxy plate on one side of the battery module close to the positive and negative electrodes, and fix the protection plate on the epoxy plate; After connecting the collection line, insert the interface of the collection line into the corresponding position of the protection plate, measure the voltage between the positive and negative electrodes of the battery pack, and the voltage value is equal to V1±0.5V, which is determined to be qualified; Then, apply structural adhesive to the battery groove in the box body, put the fixed battery module and collection line into the battery groove, and wait for the structural adhesive to solidify and form; Use screws to fix the collection line and the corresponding terminal on the box cover; Finally, tighten the box cover and the box body, and then paste the label.

8. The method of claim 7, wherein the AB battery is used for starting an automobile. The lithium ion battery cells and sodium ion battery cells are classified and identified according to the voltage range of ±0.01V and the internal resistance of ±0.05mΩ.

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