Battery assembly method, battery and battery pack

Abstract

The present invention discloses a battery assembly method, a battery and a battery pack, the assembly method comprising: stacking the positive electrode sheet and the negative electrode sheet in sequence in a Z-shaped stacking manner through a diaphragm to form a pole core, and the starting end and the ending end of the diaphragm are both located on the side where the diaphragm covers the positive electrode sheet on one side; connecting the negative electrode cover plate to one end of the pole core and loading them together into the battery shell; connecting the positive electrode cover plate to the other end of the pole core; connecting the positive electrode cover plate and the negative electrode cover plate to the shell. The battery assembly method of the present invention, after assembling the pole core by the assembly method, when the pole core is heated, the positive electrode sheet will not cut the diaphragm, thereby ensuring the structural safety of the diaphragm, improving the pressure resistance of the battery, improving the reliability of the battery, and not using a diaphragm surface coating, which is conducive to reducing the cost of the battery, reducing the short circuit rate, and improving the capacity and energy density of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and in particular to a battery assembly method, a battery and a battery pack. Background Art

[0002] Laminated lithium-ion batteries are widely used in the fields of power and energy storage. With the advancement of technology, the capacity and energy density of battery cells are getting higher and higher. The current industry generally adopts a high surface density with high compaction solution to reduce the proportion of inactive substances in the battery cell, reduce the thickness of the diaphragm, and increase the energy density of the battery cell. Under high surface density and high compaction, the brittleness of the positive electrode increases, the flexibility decreases, and the edge burrs after the electrode is cut and cut are difficult to control. At present, the industry generally uses PP and PE as the base film of the diaphragm. PP has high thermal stability and low price. Due to the material properties and manufacturing process, it is difficult to make a diaphragm with a thickness of less than 10μm for PP diaphragms, which will hinder the further improvement of battery capacity and energy density. PE diaphragms can be made into diaphragms less than 10μm, but PE diaphragms have poor thermal stability and are easy to shrink at high temperatures. After the battery cell is exposed to high temperatures, the short circuit rate will increase significantly, and the proportion of short circuit defects at the cutting position of the electrode is high.

[0003] In the related art, in order to control the short-circuit rate of the battery after being exposed to high temperature, the currently conventional improvement solution is to coat the diaphragm base film with glue or ceramics to improve the high-pressure resistance of the diaphragm. However, the coating with glue or ceramics will significantly increase the cost of the diaphragm, increase the weight of the diaphragm, occupy the available space of the battery active materials, and reduce the capacity and energy density of the battery; and, the coating layer needs to be processed secondary on the diaphragm base film in terms of process, which will significantly increase the cost of the diaphragm, leading to an increase in battery costs and weakening the product's market competitiveness. There is room for improvement. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a battery assembly method, which is conducive to improving the pressure resistance of the cut edge of the diaphragm and reducing the short circuit rate.

[0005] According to the assembly method of the battery of the embodiment of the present invention, the assembly method includes: stacking the positive electrode sheets and the negative electrode sheets in sequence in a Z-shaped stacking manner through a separator to form a pole core, and the starting end and the ending end of the separator are both located on the side of the separator that unilaterally covers the positive electrode sheet; connecting the negative electrode cover plate to one end of the pole core and loading them together into the battery shell; connecting the positive electrode cover plate to the other end of the pole core; connecting the positive electrode cover plate and the negative electrode cover plate to the shell.

[0006] According to the battery assembly method of the embodiment of the present invention, after the pole core is assembled by the assembly method, when the pole core is heated, the positive electrode sheet will not cut the diaphragm, thereby ensuring the structural safety of the diaphragm, improving the pressure resistance of the battery, improving the reliability of the battery, and not using the diaphragm surface coating, which is conducive to reducing the cost of the battery, reducing the short circuit rate, and improving the battery capacity and energy density.

[0007] In some embodiments, connecting the negative electrode cover plate to one end of the pole core includes: aligning the side of the negative electrode cover plate having the explosion-proof valve with the side of the pole core where the starting end and the ending end are located; and welding the negative electrode cover plate to the negative electrode tab of the pole core.

[0008] In some embodiments, the assembly method further includes: after stacking to form a pole core: heating the pole core and applying pressure to the pole core; installing a spacer and a side plate on the pole core, and welding the positive pole tab and the negative pole tab of the pole core; and cutting off excess pole tabs of the pole core.

[0009] In some embodiments, connecting the positive electrode cover plate to the other end of the pole core includes: placing the positive electrode cover plate opposite to the other end of the pole core; and welding the positive electrode cover plate to the positive electrode tab of the pole core.

[0010] In some embodiments, connecting the positive electrode cover plate and the negative electrode cover plate to the shell includes: welding the positive electrode cover plate and the negative electrode cover plate to two ends of the shell respectively.

[0011] The invention also provides a battery.

[0012] A battery according to an embodiment of the present invention comprises: a shell; a pole core, wherein the pole core is installed in the shell, the pole core comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet and the negative electrode sheet are stacked in sequence in a Z-shaped stacking manner through the separator, and the starting end and the ending end of the separator are both located on the side of the separator that unilaterally covers the positive electrode sheet; a positive electrode cover plate and a negative electrode cover plate, wherein the positive electrode cover plate and the negative electrode cover plate are respectively connected to the two ends of the pole core.

[0013] In some embodiments, the negative electrode cover plate is provided with an explosion-proof valve, and a side of the negative electrode cover plate having the explosion-proof valve is arranged opposite to a side of the pole core where the starting end and the ending end are located.

[0014] In some embodiments, the positive electrode sheet and the negative electrode sheet are formed with a positive electrode tab and a negative electrode tab at both ends of the electrode core, the positive electrode tab is welded to the positive electrode cover plate, and the negative electrode tab is welded to the negative electrode cover plate.

[0015] In some embodiments, the positive electrode cover plate and the negative electrode cover plate are respectively connected to two ends of the shell by welding.

[0016] The invention also provides a battery pack.

[0017] A battery pack according to an embodiment of the present invention is provided with a battery described in any of the above embodiments.

[0018] The advantages of the battery pack, the battery and the battery assembly method described above compared to the prior art are the same and will not be described in detail here.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 is one of the schematic flow charts of the battery assembly method according to the present invention;

[0022] Figure 2 is one of the schematic flow charts of the battery assembly method according to the present invention;

[0023] Figure 3 is one of the schematic flow charts of the battery assembly method according to the present invention;

[0024] Figure 4 is a schematic diagram of a battery according to the present invention in which the pole core is placed horizontally;

[0025] Figure 5 is a schematic diagram of a battery according to the present invention in which the pole core is placed vertically;

[0026] Figure 6 is a schematic diagram of the connection between the pole core and the negative electrode cover of the battery according to the present invention;

[0027] Figure 7 is a schematic diagram of a battery placed horizontally according to the present invention;

[0028] Figure 8 It is a schematic diagram of a battery placed vertically according to the present invention.

[0029] Reference numerals:

[0030] Battery 100,

[0031] Electrode core 1, positive electrode sheet 11, negative electrode sheet 12, negative electrode tab 121, diaphragm 13, starting end 131, ending end 132,

[0032] Negative electrode cover plate 2, explosion-proof valve 21. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0034] Reference below Figure 1-Figure 3 An assembly method for a battery according to an embodiment of the present invention is described. Through this assembly method, the cut edges of the diaphragm are located on the same side of the pole core. Gravity and pressure can be used to ensure the stability of the cut edge position, thereby improving the pressure resistance of the cut edge of the diaphragm, reducing the short circuit rate, reducing the coating, reducing the setup cost, reducing the compaction density of the pole piece, increasing the battery capacity, and improving the battery performance.

[0035] Among them, combined with Figure 1 , describing the assembly method of the battery of the embodiment of the present invention, the assembly method comprising:

[0036] S1. The positive electrode sheet and the negative electrode sheet are stacked in sequence in a Z-shaped stacking manner through the separator to form a pole core, and the starting end and the ending end of the separator are both located on the side of the separator that covers the positive electrode sheet on one side. Figure 4 and Figure 5 As shown, both the positive electrode sheet and the negative electrode sheet are multi-layered, and the multi-layer positive electrode sheet and the multi-layer negative electrode sheet are stacked alternately. The separator can be stacked in a Z-shaped winding manner between any adjacent positive electrode sheet and negative electrode sheet, so that the separator can separate the positive electrode sheet from the negative electrode sheet.

[0037] S2. Connect the negative electrode cover plate to one end of the pole core and install them together into the battery housing. That is, during actual installation, the negative electrode cover plate can be connected to one end of the pole core, such as Figure 6 As shown, the negative electrode cover is connected to the right end of the pole core, and after the two are connected as a whole, they are installed together in the shell, thereby simplifying the installation steps and improving the installation efficiency.

[0038] S3. Connect the positive electrode cover plate to the other end of the pole core, such as connecting the positive electrode cover plate to the left end of the pole core, so that the positive electrode cover plate and the negative electrode cover plate can protect and shield the two ends of the pole core.

[0039] S4, connecting the positive electrode cover plate and the negative electrode cover plate to the housing. That is, finally connecting the positive electrode cover plate and the negative electrode cover plate to the housing as a whole, thereby enabling the pole core to have a stable and reliable operating environment in the housing.

[0040] Thus, the battery is assembled by the above-mentioned assembly method of the present invention, and after the battery is assembled, the battery can be placed flat or sideways, especially with the starting end and the ending end of the separator both located at the top or the side. Figure 4 As shown, the electrode core is placed horizontally, the negative electrode sheet is three layers, the positive electrode sheet is two layers, and the separator wraps and winds each layer of the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are wrapped on one side, such as the positive electrode sheet is wrapped on the right side, and the negative electrode sheet is wrapped on the left side. At the same time, the starting end and the ending end of the separator are both located on the same side of the electrode core, such as Figure 4 or as Figure 5 As shown, when the electrode core is placed vertically, the positive electrode sheet is wrapped on the upper side, and the negative electrode sheet is wrapped on the lower side. At the same time, the starting end and the ending end of the diaphragm are both located on the same side of the electrode core, as shown in FIG. Figure 5 The upper side of the .

[0041] Also, during actual cutting, the starting and ending ends of the separator can be set to protrude from the negative electrode sheet, so that the separator can fit the positive electrode sheet and the negative electrode sheet to the maximum extent to ensure full coverage. It should be noted that the material hardness of the positive electrode sheet is greater than that of the negative electrode sheet, and the flexibility of the negative electrode sheet is better than that of the positive electrode sheet.

[0042] Thus, after the battery is assembled, the battery can be pressurized and heated at high temperature, and the pole core is placed vertically during heating. Figure 5 As shown in , the starting end and the ending end of the diaphragm are both located on the upper side of the electrode core, and the side of the diaphragm that unilaterally covers the positive electrode sheet is located on the upper side, and the side of the diaphragm that unilaterally covers the negative electrode sheet is located on the lower side. When heated, the diaphragm shrinks due to the heat. Due to the gravity and the extrusion of the shell on the electrode core, the diaphragm and the cut edge of the positive electrode sheet form a relative displacement. By controlling the relative position of the electrode core when it passes through high temperature, it is ensured that the diaphragm-coated positive electrode sheet is located at the top of the battery. Since the negative electrode sheet is more flexible than the positive electrode sheet, and the length of the burr on the cut edge of the negative electrode sheet is smaller than that of the positive electrode sheet, the damage to the diaphragm is small under the same gravity and shell extrusion, which can improve the pressure resistance of the battery.

[0043] According to the battery assembly method of the embodiment of the present invention, after the pole core is assembled by the assembly method, when the pole core is heated, the positive electrode sheet will not cut the diaphragm, thereby ensuring the structural safety of the diaphragm, improving the pressure resistance of the battery, improving the reliability of the battery, and not using the diaphragm surface coating, which is conducive to reducing the cost of the battery, reducing the short circuit rate, and improving the battery capacity and energy density.

[0044] In some embodiments, connecting the negative electrode cover plate to one end of the electrode core in S2 includes:

[0045] S21. Align the side of the negative electrode cover with the explosion-proof valve with the side where the starting and ending ends of the electrode core are located, as shown in Figure 6. Figure 8 As shown, the explosion-proof valve is located in the upper area of ​​the negative electrode cover plate, and the starting end and the ending end of the diaphragm are both located on the upper side of the pole core, and when the negative electrode cover plate is installed at the end of the pole core, the starting end and the ending end of the explosion-proof valve and the diaphragm are both located on the upper part of the pole core.

[0046] S22, welding the negative electrode cover plate to the negative electrode tab of the electrode core, so that the negative electrode cover plate and the electrode core are relatively fixed, and the current between the two can be conducted through the negative electrode tab.

[0047] It should be noted that when assembling the battery, if the starting end and the ending end of the diaphragm are arranged on different sides from the explosion-proof valve, the battery is baked at 100±5°C for 600±120min, and a high-voltage test is performed at 150V after baking, and the short-circuit point is concentrated at the end of the diaphragm. However, after assembling the battery core and the negative electrode cover in the manner of S21 in the present invention, the battery is baked at 100±5°C for 600±120min, and a high-voltage test is performed at 150V after baking, and the short-circuit point is not concentrated at the end of the diaphragm.

[0048] This helps to avoid the problem of concentrated short-circuit points at the end of the battery diaphragm, thereby improving the safety of the battery.

[0049] Furthermore, the assembly method further comprises: after laminating to form the pole core:

[0050] S11. Heat the pole core and apply pressure to the pole core so that the positive electrode sheet, the separator and the negative electrode sheet of the pole core are pressed and fit tightly together, thereby shaping the overall structure of the pole core so that the pole core meets the assembly requirements.

[0051] S12. Install a spacer and a side plate on the pole core, and weld the positive pole tab and the negative pole tab of the pole core; that is, after shaping the pole core, the positive pole tab and the negative pole tab can be ultrasonically welded.

[0052] S13, cutting the excess pole ears of the pole core, that is, cutting and shaping the excess pole ears after welding, so that the pole ear structure meets the connection requirements with the positive electrode cover plate and the negative electrode cover plate.

[0053] Further, in S3, the positive electrode cover plate is connected to the other end of the electrode core, including:

[0054] Place the positive electrode cover plate opposite to the other end of the electrode core. Figure 6 As shown, the left end of the pole core is arranged opposite to the positive electrode cover plate, that is, the positive electrode cover plate and the pole core can be arranged opposite to each other in the length direction of the pole core.

[0055] The positive electrode cover plate is welded to the positive electrode ear of the electrode core. For example, the positive electrode cover plate and the positive electrode ear are welded and fixed by laser welding to ensure the connection stability between the two.

[0056] Further, in S4, the positive electrode cover plate and the negative electrode cover plate are connected to the housing, including:

[0057] The positive electrode cover plate and the negative electrode cover plate are respectively welded to the two ends of the shell, so that the various components of the battery are connected as a whole to achieve the final assembly of the battery.

[0058] After the battery is assembled, the battery can be placed in an oven for high-temperature baking, and then taken out and cooled down after baking, so that the battery can be subjected to a voltage withstand test at room temperature.

[0059] Therefore, after the battery is assembled by this assembly method, the relative position of the cut edge of the pole core diaphragm in the aluminum shell can be controlled, the pressure resistance of the diaphragm cut edge can be improved, and the short circuit rate can be reduced; and no diaphragm surface coating is used, thereby reducing the material cost of the battery; at the same time, no diaphragm surface coating is used, the internal space of the aluminum shell is increased, more active substances can be coated, and the capacity and energy density of the battery are increased; further, no diaphragm surface coating is used, and the compaction density of the pole piece can be reduced when the amount of active substance coating remains unchanged, thereby improving the battery's charge and discharge capacity and cycle life, and improving the battery's electrical performance.

[0060] The present invention also provides a battery 100 .

[0061] like Figure 4-Figure 8 As shown, the battery 100 according to the embodiment of the present invention includes: a shell, a pole core 1, a positive electrode cover plate and a negative electrode cover plate 2.

[0062] The pole core 1 is installed in the shell, and the pole core 1 includes a positive electrode sheet 11, a negative electrode sheet 12 and a separator 13. The positive electrode sheet 11 and the negative electrode sheet 12 are stacked in sequence in a Z-shaped stacking manner through the separator 13, and the starting end 131 and the ending end 132 of the separator 13 are located on the same side of the pole core 1, and the positive cover plate and the negative cover plate 2 are respectively connected to the two ends of the pole core 1.

[0063] The electrode core 1 can be placed horizontally or vertically, and the number of positive electrode sheets 11 and negative electrode sheets 12 can be flexibly set according to actual needs. Figure 4 As shown, the pole core 1 can be placed horizontally, the negative electrode sheet 12 is three layers, the positive electrode sheet 11 is two layers, and the separator 13 is wrapped around each layer of the positive electrode sheet 11 and the negative electrode sheet 12, and the positive electrode sheet 11 and the negative electrode sheet 12 are both wrapped on one side, such as the positive electrode sheet 11 is wrapped on the right side, and the negative electrode sheet 12 is wrapped on the left side. At the same time, the starting end 131 and the ending end 132 of the separator 13 are both located on the same side of the pole core 1, as shown in FIG. Figure 4 or as Figure 5As shown, the pole core 1 can be placed vertically, such as the positive pole sheet 11 is wrapped on the lower side, and the negative pole sheet 12 is wrapped on the upper side. At the same time, the starting end 131 and the ending end 132 of the separator 13 are both located on the same side of the pole core 1, such as Figure 5 The upper side of the .

[0064] Therefore, when heating, the pole core 1 is placed vertically, and Figure 5 As shown in , the starting end 131 and the ending end 132 of the diaphragm 13 are both located on the upper side of the electrode core 1, and the side of the diaphragm 13 that unilaterally covers the positive electrode sheet 11 is located on the upper side, and the side of the diaphragm 13 that unilaterally covers the negative electrode sheet 12 is located on the lower side. When heated, the diaphragm 13 shrinks due to heat. Due to the gravity and the extrusion of the shell on the electrode core 1, the diaphragm 13 and the cut edge of the positive electrode sheet 11 form a relative displacement. By controlling the relative position of the electrode core 1 when it is subjected to high temperature, it is ensured that the diaphragm 13 covering the positive electrode sheet 11 is located at the top of the battery 100. Since the negative electrode sheet 12 is more flexible than the positive electrode sheet 11, and the length of the burr on the cut edge of the negative electrode sheet 12 is less than that of the positive electrode sheet 11, the damage to the diaphragm 13 is small under the same gravity and shell extrusion, which can improve the pressure resistance of the battery 100.

[0065] In some embodiments, the negative electrode cover plate 2 is provided with an explosion-proof valve 21, and the side of the negative electrode cover plate 2 having the explosion-proof valve 21 is arranged opposite to the side of the electrode core 1 where the starting end 131 and the ending end 132 are located. Figure 6-Figure 8 As shown, the explosion-proof valve 21 is located in the upper area of ​​the negative electrode cover plate 2, and the starting end 131 and the ending end 132 of the diaphragm 13 are both located on the upper side of the pole core 1, and when the negative electrode cover plate 2 is installed at the end of the pole core 1, the explosion-proof valve 21 and the starting end 131 and the ending end 132 of the diaphragm 13 are both located on the upper part of the pole core 1.

[0066] Among them, through the above settings, the battery 100 is baked at 100±5℃ for 600±120min, and after baking, a high voltage test is performed using a voltage of 150V. The short-circuit point is not concentrated at the end 132 of the diaphragm 13, thereby improving the safety of the battery 100. Specifically, during baking, if Figure 6 and Figure 8 As shown, the battery 100 can be placed vertically so that the explosion-proof valve 21 is located in the upper area of ​​the battery 100, or Figure 7 As shown in FIG. 1 , the battery 100 is placed horizontally, and the battery 100 is placed horizontally. Figure 7 When placed horizontally as shown in the figure, it can be turned over and baked even after being turned over.

[0067] In some embodiments, the positive electrode sheet 11 and the negative electrode sheet 12 are formed with a positive electrode tab and a negative electrode tab 121 at both ends of the electrode core 1, and the positive electrode tab is welded to the positive electrode cover plate, such as the positive electrode cover plate and the positive electrode tab are welded and fixed by laser welding to ensure the connection stability between the two. The negative electrode tab 121 is welded to the negative electrode cover plate 2, such as the negative electrode cover plate 2 and the negative electrode tab 121 are welded and fixed by laser welding to ensure the connection stability between the two.

[0068] In some embodiments, the positive electrode cover plate and the negative electrode cover plate 2 are respectively welded to the two ends of the housing, so that the various components of the battery 100 are connected as a whole, and the final assembly of the battery 100 is realized. Therefore, after the battery 100 is assembled, the battery 100 can be placed in an oven for high-temperature baking, and then taken out for cooling after baking, so that the battery 100 can be subjected to a withstand voltage test at room temperature.

[0069] The invention also provides a battery pack.

[0070] According to the battery pack of the embodiment of the present invention, a battery 100 of any of the above-mentioned embodiments is provided. After the pole core 1 is assembled by the assembly method, when the pole core 1 is heated, the positive electrode sheet 11 will not cut the diaphragm 13, thereby ensuring the structural safety of the diaphragm 13, improving the pressure resistance of the battery 100, improving the reliability of the battery 100, and not using the surface coating of the diaphragm 13, which is conducive to reducing the cost of the battery 100, reducing the short circuit rate, and improving the capacity and energy density of the battery 100.

[0071] 1. In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying 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 operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0072] 2. In the description of the present invention, "first feature" and "second feature" may include one or more of these features.

[0073] 3. In the description of the present invention, "plurality" means two or more.

[0074] 4. In the description of the present invention, a first feature “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact via another feature therebetween.

[0075] 5. In the description of the present invention, “above”, “above” and “on” a first feature of a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0077] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery assembly method, characterized in that: The assembly method comprises: The positive electrode sheet and the negative electrode sheet are stacked in sequence in a Z-shaped stacking manner through a separator to form a pole core, and the starting end and the ending end of the separator are both located on the side where the separator covers the single side of the positive electrode sheet; Connecting the negative electrode cover plate to one end of the electrode core and installing them together into a battery housing; Connecting the positive electrode cover plate to the other end of the pole core; Connecting the positive electrode cover plate and the negative electrode cover plate to the housing; The assembly method further comprises: after laminating to form the pole core: The pole core is heated and pressure is applied to the pole core, and the pole core is placed vertically during heating; the starting end and the ending end of the diaphragm are both located on the upper side of the pole core, and the side of the diaphragm covering the positive electrode sheet is located on the upper side, and the side of the diaphragm covering the negative electrode sheet is located on the lower side; Installing a spacer ring and a side plate on the pole core, and welding the positive pole tab and the negative pole tab of the pole core; The redundant pole ears of the pole core are cut off.

2. The battery assembly method according to claim 1, characterized in that: The step of connecting the negative electrode cover plate to one end of the electrode core comprises: Align the side of the negative electrode cover plate having the explosion-proof valve with the side of the electrode core where the starting end and the ending end are located; The negative electrode cover plate is welded to the negative electrode tab of the electrode core.

3. The battery assembly method according to claim 1, characterized in that: The step of connecting the positive electrode cover plate to the other end of the electrode core comprises: Placing the positive electrode cover plate opposite to the other end of the electrode core; The positive electrode cover plate is welded to the positive electrode tab of the electrode core.

4. The battery assembly method according to claim 1, characterized in that: The step of connecting the positive electrode cover plate and the negative electrode cover plate to the housing comprises: The positive electrode cover plate and the negative electrode cover plate are respectively connected to the two ends of the shell by welding.

5. A battery, characterized in that: include: case; A pole core, the pole core is installed in the shell, the pole core comprises a positive pole sheet, a negative pole sheet and a separator, the positive pole sheet and the negative pole sheet are sequentially stacked in a Z-shaped stacking manner through the separator, and the starting end and the ending end of the separator are both located on the side of the separator covering the positive pole sheet on one side; and the side of the separator covering the positive pole sheet on one side is located on the upper side, and the side of the separator covering the negative pole sheet on one side is located on the lower side; A positive electrode cover plate and a negative electrode cover plate, wherein the positive electrode cover plate and the negative electrode cover plate are respectively connected to two ends of the electrode core; The pole core is heated and pressure is applied to the pole core, and the pole core is placed vertically during heating.

6. The battery according to claim 5, characterized in that The negative electrode cover plate is provided with an explosion-proof valve, and one side of the negative electrode cover plate having the explosion-proof valve is arranged opposite to the side of the pole core where the starting end and the ending end are located.

7. The battery according to claim 5, characterized in that The positive electrode sheet and the negative electrode sheet are formed with a positive electrode tab and a negative electrode tab at both ends of the electrode core. The positive electrode tab is welded to the positive electrode cover plate, and the negative electrode tab is welded to the negative electrode cover plate.

8. The battery according to claim 5, characterized in that The positive electrode cover plate and the negative electrode cover plate are respectively connected to two ends of the shell by welding.

9. A battery pack, characterized in that: A battery according to any one of claims 5 to 8 is provided.

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