Battery, battery pack and preparation method of battery

Abstract

The invention relates to the technical field of batteries, and discloses a battery, a battery pack and a preparation method of the battery, the battery comprises a pole group, a first packaging film and a second packaging film; the first packaging film is provided with a containing groove used for installing the pole group, and the pole group is arranged in the containing groove; the second packaging film is arranged opposite to the first packaging film, and a hot melting area surrounding the accommodating groove is reserved between the second packaging film and the first packaging film; the hot melting areas of the first packaging film and the second packaging film are fixed together through hot melting plastic package to form a hot melting layer so that the pole group can be packaged in the containing groove, and the width W1 of the hot melting areas and the width W2 of the hot melting layer meet the condition that W2 / W1 is larger than or equal to 0.4 and smaller than or equal to 1.2. By limiting the relation between the width of the hot melting area and the width of the hot melting layer, the width ratio of the hot melting area to the hot melting layer is kept within a proper range, the sealing effect of the hot melting layer is improved, and material waste is reduced.

Description

Technical Field

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

[0002] The battery is mainly composed of a tab, a pole group, and a packaging film. The packaging film packages the pole group and the tab and seals them by hot pressing. However, the range of the hot melt packaging process parameters of existing batteries is relatively wide. If the process parameters of the hot melt packaging are too large, it is easy to waste packaging materials. If the process parameters of the hot melt packaging are too small, it is easy to cause the battery packaging to fail. Summary of the invention

[0003] In view of this, the present invention provides a battery, a battery pack and a method for preparing a battery to solve the problem that hot-melt packaging of the battery is prone to waste materials or is prone to failure.

[0004] In a first aspect, the present invention provides a battery, comprising:

[0005] Pole group;

[0006] A first packaging film, on which a receiving groove for mounting the electrode group is provided, and the electrode group is arranged in the receiving groove;

[0007] a second packaging film, arranged opposite to the first packaging film and respectively having a hot-melt zone around the receiving groove reserved in the first packaging film;

[0008] The hot melt areas of the first packaging film and the second packaging film are fixed together by hot melt molding to form a hot melt layer to encapsulate the electrode group in the receiving groove, and the width W1 of the hot melt area and the width W2 of the hot melt layer satisfy 0.4≤W2 / W1≤1.2.

[0009] Beneficial effects: When assembling the battery of the present invention, the electrode group is first installed in the receiving groove of the first packaging film, and then the second packaging film is covered on the first packaging film, and then the outer surface of the hot melt area of ​​the first packaging film and the second packaging film is heated and pressurized by a heat sealing pressure head to form a hot melt layer at the position of the hot melt area. The first packaging film and the second packaging film are fixed by hot melting through the hot melt layer to package the electrode group in the receiving groove. By limiting the proportional relationship between the width of the hot melt area and the width of the hot melt layer, the width ratio of the hot melt layer to the hot melt area is maintained within a suitable range, which can save the material of hot melt plastic sealing, reduce the manufacturing cost of the battery, and improve the battery yield while ensuring that the battery has a good sealing effect.

[0010] In an optional implementation, the width W1 of the hot melt zone satisfies 5mm≤W1≤20mm.

[0011] Beneficial effect: By limiting the width of the hot melting zone, a working space for the heat sealing pressure head can be provided, and sufficient heating and pressure receiving area can be ensured.

[0012] In an optional implementation, the width W2 of the hot melt layer satisfies 1mm≤W2≤24mm.

[0013] Beneficial effect: By limiting the width of the hot melt layer, the contact area between the hot melt layer and the first packaging film and the second packaging film can be ensured, the stability of the hot melt layer's fixing and bonding can be improved, and the usage of the hot melt layer can be reduced, thereby reducing manufacturing costs and material waste, thereby improving production efficiency.

[0014] In an optional embodiment, the thickness T of the electrode group and the width W2 of the hot melt layer satisfy T / 5+1.5mm≤W2≤T / 5+10mm.

[0015] Beneficial effect: The thicker the electrode group, the greater the expansion of the electrode group during the charge and discharge cycle, and the greater the pulling force of the hot melt layer. By limiting the relationship between the thickness of the electrode group and the width of the hot melt layer, the tensile sealing property of the hot melt layer can be ensured.

[0016] In an optional implementation, the thickness T of the pole group satisfies 1 mm ≤ T ≤ 50 mm.

[0017] Beneficial effect: By limiting the specific size of the thickness of the electrode group and matching the relationship between the thickness of the electrode group and the width of the hot-melt layer, a process range of the width of the hot-melt layer can be provided, thereby optimizing the production process.

[0018] In an optional embodiment, in the length direction of the battery, the circumferential side of the first packaging film and the circumferential side of the second packaging film are aligned, and the margin L1 from the hot melt layer to the circumferential side of the first packaging film or the circumferential side of the second packaging film satisfies 0.3mm≤L1≤15mm, and a spacing L2 is left between the inner side of the hot melt layer and the outer side of the electrode group, and the spacing L2 satisfies 1mm≤L2≤30mm.

[0019] Beneficial effects: By limiting the margin from the hot melt layer to the peripheral side of the first packaging film or the peripheral side of the second packaging film, it is possible to effectively avoid glue overflow during the hot melt plastic sealing process. By limiting the distance between the hot melt layer and the electrode group, it is possible to avoid hot melt damage to the battery's diaphragm, resulting in a short circuit between the positive and negative electrodes.

[0020] In an optional embodiment, a positive electrode tab and a negative electrode tab are respectively provided at opposite ends of the electrode group in the length direction, and the positive electrode tab and the negative electrode tab extend outside the first packaging film and the second packaging film.

[0021] Beneficial effects: The positive electrode ear and the negative electrode ear are installed at opposite ends of the length direction of the electrode group, which facilitates the connection and layout of the positive electrode ear and the negative electrode ear with the connecting sheet. The positive electrode ear and the negative electrode ear extend outside the first packaging film and the second packaging film, which is conducive to improving the sealing of the first packaging film and the second packaging film.

[0022] In a second aspect, the present invention further provides a battery pack, comprising: the above-mentioned battery.

[0023] Beneficial effect: Since the battery pack includes a battery, it has the same effect as the battery and will not be described in detail here.

[0024] In a third aspect, the present invention further provides a method for preparing a battery, comprising:

[0025] Making a first packaging film and a second packaging film, forming a receiving groove on the first packaging film, and reserving a hot melt area around the first packaging film and the second packaging film;

[0026] Installing the electrode group in the receiving groove of the first packaging film;

[0027] The second packaging film is covered on the first packaging film, and heat-sealing heads are respectively arranged at preset positions on opposite sides of the hot-melt zones of the first packaging film and the second packaging film, and the preset positions of the hot-melt zones are heated at a preset temperature and a preset pressure to form a hot-melt layer, wherein the width W1 of the hot-melt zone and the width W2 of the hot-melt layer satisfy 0.4≤W2 / W1≤1.2;

[0028] The first packaging film and the second packaging film are fixed together by the hot melt layer to package the electrode group in the receiving groove.

[0029] Beneficial effects: The preparation method of the battery provided by the present invention is to prepare the first packaging film and the second packaging film in advance, and reserve hot melt areas around the receiving groove in the first packaging film and the second packaging film respectively. The electrode group is installed in the receiving groove of the first packaging film, and then the second packaging film is covered on the first packaging film. The preset position of the hot melt area is heated at a preset temperature and a preset pressure to form a hot melt layer, and the first packaging film and the second packaging film are fixedly bonded by the hot melt layer to encapsulate the electrode group in the receiving groove, so that the width ratio of the hot melt layer and the hot melt area is maintained within a suitable range, which can save the material consumed by hot melt plastic sealing and reduce the manufacturing cost of the battery while ensuring that the battery has a good sealing effect. Moreover, the first packaging film and the second packaging film can be fixedly bonded only by heating the outer surface of the hot melt area of ​​the first packaging film and the second packaging film through a heat sealing head, which is simple to operate and convenient to use.

[0030] In an optional embodiment, the heat sealing press heads are respectively arranged at preset positions on opposite sides of the hot melt zone of the first packaging film and the second packaging film, and the preset positions of the hot melt zone are heated at a preset temperature and a preset pressure to form a hot melt layer, specifically comprising:

[0031] The heat sealing heads are respectively arranged at preset positions on opposite sides of the hot melt zones of the first packaging film and the second packaging film, and the preset positions of the hot melt zones are heated at a temperature of 150° C. to 200° C. and a pressure of 0.1 MPa to 1.0 MPa to form a hot melt layer.

[0032] Beneficial effect: The width ratio of the hot melt layer and the hot melt zone is determined based on the flatness, temperature and pressure of the heat sealing head. By limiting the temperature and pressure of the heat sealing head, material waste can be further reduced and the sealing effect of the first packaging film and the second packaging film can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A schematic diagram of the structure of a battery according to an embodiment of the present invention;

[0035] Figure 2 for Figure 1 A cross-sectional view of the AA battery shown;

[0036] Figure 3 for Figure 2 A partial enlarged schematic diagram of B in the figure.

[0037] Description of reference numerals:

[0038] 1. Pole group; 101. Positive electrode ear; 102. Negative electrode ear; 2. First packaging film; 201. Receiving groove; 3. Second packaging film; 4. Hot melt area; 5. Hot melt layer; 6. Heat sealing head. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0040] Combine the following Figures 1 to 3 , describing an embodiment of the present invention.

[0041] According to an embodiment of the present invention, on one hand, a battery is provided, comprising: an electrode group 1, a first packaging film 2, and a second packaging film 3. The first packaging film 2 is provided with a receiving groove 201 for mounting the electrode group 1, and the electrode group 1 is arranged in the receiving groove 201; the second packaging film 3 is arranged opposite to the first packaging film 2 and has a hot melt zone 4 set around the receiving groove 201 reserved with the first packaging film 2. The hot melt zones 4 of the first packaging film 2 and the second packaging film 3 are fixed together by hot melt plastic sealing to form a hot melt layer 5, so as to encapsulate the electrode group 1 in the receiving groove 201, and the width W1 of the hot melt zone 4 and the width W2 of the hot melt layer 5 satisfy 0.4≤W2 / W1≤1.2.

[0042] When assembling the battery provided in the embodiment of the present invention, the electrode group 1 is first installed in the receiving groove 201 of the first packaging film 2, and then the second packaging film 3 is covered on the first packaging film 2, and then the outer surface of the hot melt area 4 of the first packaging film 2 and the second packaging film 3 is heated and pressurized by the heat sealing head 6, and a hot melt layer 5 is formed at the position of the hot melt area 4. The first packaging film 2 and the second packaging film 3 are fixed by hot melting through the hot melt layer 5 to package the electrode group 1 in the receiving groove 201. By limiting the proportional relationship between the width of the hot melt area 4 and the width of the hot melt layer 5, the width ratio of the hot melt layer 5 to the hot melt area 4 is maintained within a suitable range, which can save the material of the hot melt plastic sealing, reduce the manufacturing cost of the battery, and improve the battery yield while ensuring that the battery has a good sealing effect.

[0043] It should be noted that the width ratio of the hot melt zone 4 to the hot melt layer 5 is determined based on the flatness, temperature and pressure of the heat sealing head 6. Two heat sealing heads 6 are provided, which are respectively provided on the outer surface of the hot melt zone 4 where the first packaging film 2 and the second packaging film 3 are located. The temperature of the heat sealing head 6 is 50°C to 200°C, and the pressure is 0.1Mpa to 1.0Mpa. If the ratio of W2 / W1 is too small, the width of the first packaging film 2 and the second packaging film 3 is too large, which is easy to waste materials. If the ratio of W2 / W1 is too large, the hot melt temperature of the hot melt layer 5 is too high, which is easy to cause the hot melt layer 5 to separate from the first packaging film 2 and the second packaging film 3, resulting in sealing failure.

[0044] In one embodiment, see Figure 1 The battery can be a rectangular structure, and the first packaging film 2 and the second packaging film 3 are correspondingly square sheets. The first packaging film 2 is formed with a receiving groove 201 by stamping. The electrode group 1 is installed in the receiving groove 201, that is, the electrode group 1 is wrapped by the first packaging film 2 and the second packaging film 3. The first packaging film 2 and the second packaging film 3 are respectively provided with a polypropylene layer (PP layer) in the inner layer, and the polypropylene layer in the hot melt area 4 is heated and pressurized by the heat sealing head 6 to melt and form a hot melt layer 5.

[0045] Of course, in other alternative embodiments, the battery may also be in other shapes, such as a disc shape, an elliptical cylinder shape, etc. Correspondingly, the first packaging film 2, the second packaging film 3 and the electrode group 1 are adapted to be arranged.

[0046] It should be noted that the materials of the first packaging film 2 and the second packaging film 3 of the embodiment of the present invention can be selected according to actual conditions. For example, the first packaging film 2 and the second packaging film 3 are aluminum-plastic films.

[0047] In one embodiment, see Figure 3 , the width W1 of the hot melt zone 4 satisfies 5mm≤W1≤20mm. For example, W1 is 10mm, 15mm, 20mm, etc. By limiting the width of the hot melt zone 4, a working space for the heat sealing head 6 can be provided, and sufficient heating and pressure receiving area can be ensured.

[0048] Further, in one embodiment, see Figure 3 , the width W2 of the hot melt layer 5 satisfies 1mm≤W2≤24mm. For example, W2 is 4mm, 15mm, 24mm, etc. Further, W2 / W1 is 0.4, 1, 1.2. By limiting the width of the hot melt layer 5, the contact area between the hot melt layer 5 and the first packaging film 2 and the second packaging film 3 can be ensured, the stability of the hot melt layer 5 fixing and bonding can be improved, and the use amount of the hot melt layer 5 can be reduced, the manufacturing cost and material waste can be reduced, and the production efficiency can be improved. In addition, the product yield and quality can also be improved.

[0049] In one embodiment, see Figure 3 , the thickness T of the electrode group 1 and the width W2 of the hot melt layer 5 satisfy T / 5+1.5mm≤W2≤T / 5+10mm. The thicker the electrode group 1 is, the greater the expansion of the electrode group 1 during the charge and discharge cycle, and the greater the pulling force of the hot melt layer 5. By limiting the relationship between the thickness of the electrode group 1 and the width of the hot melt layer 5, the tensile sealing property of the hot melt layer 5 can be ensured.

[0050] Furthermore, in one embodiment, the thickness T of the electrode group 1 satisfies 1 mm ≤ T ≤ 50 mm. For example, T is 1 mm, 25 mm, 50 mm, etc. By limiting the specific size of the thickness of the electrode group 1 and the relationship between the thickness of the electrode group 1 and the width of the hot melt layer 5, a process range of the width of the hot melt layer 5 can be provided to optimize the production process.

[0051] In one embodiment, in the length direction of the battery, the periphery of the first packaging film 2 and the periphery of the second packaging film 3 are aligned, the margin L1 from the hot melt layer 5 to the periphery of the first packaging film 2 or the periphery of the second packaging film 3 satisfies 0.3mm≤L1≤15mm, and a spacing L2 is left between the inner side of the hot melt layer 5 and the outer side of the electrode group 1, and the spacing L2 satisfies 1mm≤L2≤30mm. For example, L1 is 0.3mm, 5mm, 15mm, etc., and L2 is 1mm, 15mm, 30mm, etc.

[0052] By limiting the margin from the hot melt layer 5 to the peripheral side of the first packaging film 2 or the peripheral side of the second packaging film 3, it is possible to effectively avoid glue overflow during the hot melt plastic sealing process. By limiting the distance between the hot melt layer 5 and the electrode group 1, it is possible to avoid hot melt damage to the battery's diaphragm, resulting in a short circuit between the positive and negative electrodes.

[0053] For the "inside" and "outside" directions of the embodiments of the present invention, please refer to Figure 3 For the length of the battery, please refer to Figure 1 The arrow L in the figure shows the width of the battery. Figure 1 Arrow W in the figure.

[0054] In one embodiment, see Figure 1 , positive electrode ears 101 and negative electrode ears 102 are respectively provided at opposite ends of the length direction of the electrode group 1, and the positive electrode ears 101 and negative electrode ears 102 extend outside the first packaging film 2 and the second packaging film 3. The positive electrode ears 101 and the negative electrode ears 102 are installed at opposite ends of the length direction of the electrode group 1, which facilitates the connection and layout of the positive electrode ears 101 and the negative electrode ears 102 with the connecting sheet. The positive electrode ears 101 and the negative electrode ears 102 extend outside the first packaging film 2 and the second packaging film 3, which is conducive to improving the sealing of the first packaging film 2 and the second packaging film 3.

[0055] Specifically, see Figure 1 The positive electrode ear 101 and the negative electrode ear 102 may be in a rectangular sheet-like structure with a large welding area to facilitate welding and assembly of the positive electrode ear 101 and the negative electrode ear 102 .

[0056] In one embodiment, see Figure 2 and Figure 3, a gap is left between the electrode group 1 and the wall of the receiving groove 201. The gap can reserve expansion space for the electrode group 1, reduce the risk of short circuit, and ensure the safety of the battery. Under extreme conditions, such as overcharge, over discharge or short circuit, the gap can also help release gas and pressure to reduce the risk of explosion or leakage. Moreover, the gap can also reserve installation space for the electrode group 1, ensuring that the electrode group 1 can be smoothly installed in the receiving groove 201, avoiding assembly difficulties caused by dimensional tolerance of the electrode group 1.

[0057] The process parameters of the battery of the embodiment of the present invention are further described in detail below in combination with specific embodiments and related comparative examples. These examples should not be construed as limiting the scope of protection claimed by the present invention.

[0058] Embodiment 1:

[0059] The width W1 of the hot melt zone 4 is 12.5 mm, and the width W2 of the hot melt layer 5 is 5 mm, then W2 / W1=0.4, and W2 / W1 is the minimum value at this time. The thickness T of the electrode group 1 is 15 mm, T / 5+1.5 mm=4.5 mm, T / 5+10 mm=13 mm, and T / 5+1.5 mm≤W2≤T / 5+10 mm is satisfied. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 5 mm. The results of the battery production line test verification are shown in Table 1.

[0060] Embodiment 2:

[0061] The width W1 of the hot melt zone 4 is 2.5 mm, and the width W2 of the hot melt layer 5 is 3 mm, then W2 / W1=1.2, and W2 / W1 is the maximum value at this time. The thickness T of the electrode group 1 is 5 mm, T / 5+1.5 mm=2.5 mm, T / 5+10 mm=11 mm, and T / 5+1.5 mm≤W2≤T / 5+10 mm is satisfied. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 2 mm. The results of the battery production line test verification are shown in Table 1.

[0062] Embodiment 3:

[0063] The width W1 of the hot melt zone 4 is 3.33 mm, and the width W2 of the hot melt layer 5 is 2 mm, then W2 / W1=0.6. The thickness T of the electrode group 1 is 2 mm, T / 5+1.5 mm=1.9 mm, T / 5+10 mm=10.4 mm, satisfying T / 5+1.5 mm≤W2≤T / 5+10 mm. At this time, the width W2 of the hot melt layer 5 is biased towards the minimum value. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 10 mm. The results of the battery production line test verification are shown in Table 1.

[0064] Embodiment 4:

[0065] The width W1 of the hot melt zone 4 is 9.09 mm, and the width W2 of the hot melt layer 5 is 10 mm, then W2 / W1=1.1. The thickness T of the electrode group 1 is 10 mm, T / 5+1.5 mm=3.5 mm, T / 5+10 mm=12 mm, satisfying T / 5+1.5 mm≤W2≤T / 5+10 mm. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is L2=1 mm, at which time L2 is the minimum value. The results of the battery production line test verification are shown in Table 1.

[0066] Embodiment 5:

[0067] The width W1 of the hot melt zone 4 is 6.25 mm, and the width W2 of the hot melt layer 5 is 5 mm, then W2 / W1=0.8. The thickness T of the electrode group 1 is 3 mm, T / 5+1.5 mm=2.1 mm, T / 5+10 mm=10.6 mm, satisfying T / 5+1.5 mm≤W2≤T / 5+10 mm. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 3 mm. The results of the battery production line test verification are shown in Table 1.

[0068] Comparative Example 1:

[0069] The width W1 of the hot melt zone 4 is 7.69 mm, and the width W2 of the hot melt layer 5 is 3 mm, then W2 / W1=0.39, and W2 / W1 is less than 0.4. The thickness T of the electrode group 1 is 3 mm, T / 5+1.5 mm=2.1 mm, T / 5+10 mm=10.6 mm, satisfying T / 5+1.5 mm≤W2≤T / 5+10 mm. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 3 mm. The results of the battery production line test verification are shown in Table 1.

[0070] Comparative Example 2:

[0071] The width W1 of the hot melt zone 4 is 2.3 mm, and the width W2 of the hot melt layer 5 is 3 mm, then W2 / W1=1.3, and W2 / W1 is greater than 1.2. The thickness T of the electrode group 1 is 3 mm, T / 5+1.5 mm=2.1 mm, T / 5+10 mm=10.6 mm, satisfying T / 5+1.5 mm≤W2≤T / 5+10 mm. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 5 mm. The results of the battery production line test verification are shown in Table 1.

[0072] Comparative Example 3:

[0073] The width W1 of the hot melt zone 4 is 2.25 mm, and the width W2 of the hot melt layer 5 is 1.8 mm, so W2 / W1=0.8. The thickness T of the electrode group 1 is 2 mm, T / 5+1.5 mm=1.9 mm, T / 5+10 mm=10.4 mm, and W2 is less than T / 5+1.5 mm. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 5 mm. The results of the battery production line test verification are shown in Table 1.

[0074] Comparative Example 4:

[0075] The width W1 of the hot melt zone 4 is 5.56 mm, and the width W2 of the hot melt layer 5 is 5 mm, then W2 / W1=0.9. The thickness T of the electrode group 1 is 2 mm, T / 5+1.5 mm=1.9 mm, T / 5+10 mm=10.4 mm, satisfying T / 5+1.5 mm≤W2≤T / 5+10 mm. The spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 is 0.9 mm, and L2 is less than 1 mm. The results of the battery production line test verification are shown in Table 1.

[0076] Table 1: Test results

[0077]

[0078] As can be seen from Table 1, in Examples 1 to 5, the width W1 of the hot melt zone 4 satisfies 5mm≤W1≤20mm, the width W2 of the hot melt layer 5 satisfies 1mm≤W2≤24mm, 0.4≤W2 / W1≤1.2, and satisfies T / 5+1.5mm≤W2≤T / 5+10mm. The thickness T of the electrode group 1 satisfies 1mm≤T≤50mm, and the spacing L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 satisfies 1mm≤L2≤30mm. The width ratio of the hot melt zone 4 and the hot melt layer 5 is maintained within an appropriate range, which can save materials, reduce the manufacturing cost of the battery, and improve the yield rate of the battery while ensuring that the battery has a good sealing effect.

[0079] W2 / W1 in Comparative Example 1 is lower than the lower limit of the embodiment of the present invention, the conversion ratio between the hot melt head width and the actual melt width is too poor, the width of the hot melt zone 4 is too large, and there is a problem of material waste.

[0080] W2 / W1 in Comparative Example 2 exceeds the upper limit value of the embodiment of the present invention, and the conversion ratio between the hot melt head width and the actual melt width is too large, resulting in the separation of the hot melt layer 5 from the packaging film and the failure of the seal.

[0081] W2 in Comparative Example 3 is lower than the lower limit of the embodiment of the present invention. After the electrode group 1 expands due to cyclic gas production, cracks appear at the hot melt layer 5, resulting in sealing failure.

[0082] The distance L2 between the inner side of the hot melt layer 5 and the outer side of the electrode group 1 in comparative example 4 is lower than the lower limit value of the embodiment of the present invention. During the hot melt process, the diaphragm of the electrode group 1 is burned and damaged, resulting in the positive electrode and the negative electrode overlapping and short circuit.

[0083] According to an embodiment of the present invention, on the other hand, a battery pack is provided, including: a battery.

[0084] Since the battery pack includes batteries and has the same effects as the batteries, they will not be described in detail here.

[0085] According to an embodiment of the present invention, in another aspect, a method for preparing a battery is provided, comprising:

[0086] S100 , preparing a first packaging film 2 and a second packaging film 3 , forming a receiving groove 201 on the first packaging film 2 , and reserving a hot melt area 4 around the first packaging film 2 and the second packaging film 3 .

[0087] S200 , installing the electrode group 1 in the receiving groove 201 of the first packaging film 2 .

[0088] S300, cover the second packaging film 3 on the first packaging film 2, and respectively set the heat sealing heads 6 at preset positions on opposite sides of the hot melt zones 4 of the first packaging film 2 and the second packaging film 3, and heat the preset positions of the hot melt zones 4 at a preset temperature and a preset pressure to form a hot melt layer 5, and the width W1 of the hot melt zone 4 and the width W2 of the hot melt layer 5 satisfy 0.4≤W2 / W1≤1.2.

[0089] S400 , the first packaging film 2 and the second packaging film 3 are fixed together through the hot melt layer 5 to package the electrode group 1 in the receiving groove 201 .

[0090] The preparation method of the battery provided by the embodiment of the present invention is to prepare the first packaging film 2 and the second packaging film 3 in advance, and reserve the hot melt area 4 around the receiving groove 201 in the first packaging film 2 and the second packaging film 3 respectively. The pole group 1 is installed in the receiving groove 201 of the first packaging film 2, and then the second packaging film 3 is covered on the first packaging film 2, and the preset position of the hot melt area 4 is heated at a preset temperature and a preset pressure to form a hot melt layer 5, and the first packaging film 2 and the second packaging film 3 are fixedly bonded by the hot melt layer 5 to encapsulate the pole group 1 in the receiving groove 201, so that the width ratio of the hot melt layer 5 and the hot melt area 4 is maintained within a suitable range, which can save the material consumed by hot melt plastic sealing and reduce the manufacturing cost of the battery under the premise of ensuring that the battery has a good sealing effect. Moreover, the outer surface of the hot melt area 4 of the first packaging film 2 and the second packaging film 3 only needs to be heated by the heat sealing head 6 to fix and bond the first packaging film 2 and the second packaging film 3, which is simple to operate and convenient to use.

[0091] In one embodiment, in S300, the heat sealing heads 6 are respectively arranged at preset positions on opposite sides of the hot melt zone 4 of the first packaging film 2 and the second packaging film 3, and the preset positions of the hot melt zone 4 are heated at a preset temperature and a preset pressure to form a hot melt layer 5, specifically including:

[0092] The heat sealing heads 6 are respectively arranged at the preset positions on the opposite sides of the hot melt area 4 of the first packaging film 2 and the second packaging film 3, and the preset positions of the hot melt area 4 are heated at a temperature of 150° C. to 200° C. and a pressure of 0.1 MPa to 1.0 MPa to form a hot melt layer 5. For example, the temperature of the heat sealing head 6 is 50° C., 100° C., 200° C., etc., and the pressure is 0.1 MPa, 0.5 MPa, 1.0 MPa, etc.

[0093] The width ratio of the hot melt layer 5 and the hot melt zone 4 in the embodiment of the present invention is determined based on the flatness, temperature and pressure of the heat sealing head 6. By limiting the temperature and pressure of the heat sealing head 6, material waste can be further reduced and the sealing effect of the first packaging film 2 and the second packaging film 3 can be guaranteed.

[0094] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: include: Pole group; A first packaging film, on which a receiving groove for mounting the electrode group is provided, and the electrode group is arranged in the receiving groove; a second packaging film, arranged opposite to the first packaging film and respectively having a hot-melt zone around the receiving groove reserved in the first packaging film; The hot melt areas of the first packaging film and the second packaging film are fixed together by hot melt molding to form a hot melt layer to encapsulate the electrode group in the receiving groove, and the width W1 of the hot melt area and the width W2 of the hot melt layer satisfy 0.4≤W2 / W1≤1.

2.

2. The battery according to claim 1, characterized in that The width W1 of the hot melt zone satisfies 5mm≤W1≤20mm.

3. The battery according to claim 2, characterized in that The width W2 of the hot melt layer satisfies 1mm≤W2≤24mm.

4. The battery according to claim 3, characterized in that The thickness T of the electrode group and the width W2 of the hot melt layer satisfy T / 5+1.5mm≤W2≤T / 5+10mm.

5. The battery according to claim 4, characterized in that The thickness T of the electrode group satisfies 1mm≤T≤50mm.

6. The battery according to any one of claims 1 to 5, characterized in that In the length direction of the battery, the circumferential side of the first packaging film and the circumferential side of the second packaging film are aligned, and the margin L1 from the hot melt layer to the circumferential side of the first packaging film or the circumferential side of the second packaging film satisfies 0.3mm≤L1≤15mm. A spacing L2 is left between the inner side of the hot melt layer and the outer side of the electrode group, and the spacing L2 satisfies 1mm≤L2≤30mm.

7. The battery according to any one of claims 1 to 5, characterized in that A positive electrode tab and a negative electrode tab are respectively disposed at opposite ends of the electrode group in the length direction, and the positive electrode tab and the negative electrode tab extend outside the first packaging film and the second packaging film.

8. A battery pack, characterized in that: include: The battery according to any one of claims 1 to 7.

9. A method for preparing a battery, characterized in that: include: Prepare a first packaging film and a second packaging film, form a receiving groove on the first packaging film, and reserve a hot melt area around the first packaging film and the second packaging film; Installing the electrode group in the receiving groove of the first packaging film; The second packaging film is covered on the first packaging film, and heat-sealing heads are respectively arranged at preset positions on opposite sides of the hot-melt zones of the first packaging film and the second packaging film, and the preset positions of the hot-melt zones are heated at a preset temperature and a preset pressure to form a hot-melt layer, wherein the width W1 of the hot-melt zone and the width W2 of the hot-melt layer satisfy 0.4≤W2 / W1≤1.2; The first packaging film and the second packaging film are fixed together by the hot melt layer to package the electrode group in the receiving groove.

10. The method for preparing a battery according to claim 9, characterized in that: The step of respectively arranging the heat sealing heads at the preset positions on opposite sides of the hot melt zone of the first packaging film and the second packaging film, and heating the preset positions of the hot melt zone at a preset temperature and a preset pressure to form a hot melt layer specifically includes: The heat sealing heads are respectively arranged at preset positions on opposite sides of the hot melt zones of the first packaging film and the second packaging film, and the preset positions of the hot melt zones are heated at a temperature of 150° C. to 200° C. and a pressure of 0.1 MPa to 1.0 MPa to form a hot melt layer.

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