Capacitor-supported battery cell

Abstract

Capacitor-supported bag-type battery cell (10), comprising: N negative electrodes (20), wherein N is an integer greater than one, each of the N negative electrodes (20) comprising a first current collector (42), a first particulate electrode material (46) arranged on opposite sides of the first current collector (42), and a first tab (44); P positive electrodes (26), wherein: PM positive electrodes (26) of the P positive electrodes (26) comprise a second current collector (42), a second particulate electrode material (46) consisting of lithium iron phosphate (LFP) arranged on opposite sides of the second current collector (42), and a second tab (44), M positive electrodes (26) of the P positive electrodes (26) comprise a third current collector (42), a third particulate electrode material (46) made of activated carbon (AC) arranged on opposite sides of the third current collector (42), and a third tab (44) and P = N − 1, M = 2 and P − M ≥ 1 hold true; Separators (24) arranged between the N negative electrodes (20) and the P positive electrodes (26); and a bag covering that surrounds the N negative electrodes (20), the P positive electrodes (26) and the separators (24); wherein the M positive electrodes (26) of the P positive electrodes (26) are arranged approximately equidistant from the center of the P positive electrodes (26).

Description

introduction

[0001] The present invention relates to battery systems for vehicles and, more particularly, to a capacitor-assisted battery cell (CAB) for vehicle battery systems.

[0002] For general background information, please refer to DE 10 2017 116 964 A1.

[0003] Low-voltage automotive battery systems, such as 12 V battery systems, can be used to start or crank vehicles containing an internal combustion engine (ICE) and / or to support vehicle accessory loads or other vehicle systems for these types of vehicles. Low-voltage automotive battery systems can be used to support vehicle accessory loads in electric vehicles (EVs), such as battery electric vehicles, hybrid vehicles, and / or fuel cell vehicles. In some applications, the battery systems utilize lithium-ion battery cells due to their increased pulse power density in both warm and cold temperatures and their lower weight.

[0004] During starting, the battery system supplies power to a starter motor to start the internal combustion engine. In one application, once the engine has been started, the battery system continues to supply power to various electrical systems of the vehicle. An alternator or regeneration recharges the battery system. In other applications, the low-voltage battery system can also be used to support the emergency stop operation of autonomous vehicles. Summary

[0005] In one feature, a capacitor-assisted pouch-type battery cell comprises: N negative electrodes, where N is an integer greater than one, each of the N negative electrodes comprising a first current collector, a first particulate electrode material disposed on opposite sides of the first current collector, and a first tab.a first tab; P positive electrodes, wherein PM positive electrodes of the P positive electrodes comprise a second current collector, a second particulate electrode material containing lithium iron phosphate (LFP) arranged on opposite sides of the second current collector, and a second tab; M positive electrodes of the P positive electrodes comprise a third current collector, a third particulate electrode material containing activated carbon (AC) arranged on opposite sides of the third current collector, and a third tab, and P = N-1, M = 2, and PM ≥ 1; separators arranged between the N negative electrodes and the P positive electrodes; and a pouch enclosure surrounding the N negative electrodes, the P positive electrodes, and the separators; wherein the M positive electrodes of the P positive electrodes are approximately equally spaced orarranged equidistant from the center of the P positive electrodes.

[0006] In further features, N = 28 and the M positive electrodes of the positive P-electrodes are located at the 2nd and 26th positions.

[0007] In further features, the first particulate electrode material of the N negative electrodes contains graphite.

[0008] In further features, the first particulate electrode material of the N negative electrodes also contains conductive carbon, carboxymethyl cellulose (CMC) and styrene-butadiene copolymer (SBR).

[0009] In further features, the weight percentages of graphite, conductive carbon, carboxymethylcellulose (CMC) and styrene-butadiene copolymer (SBR) are 94% to 96%, 1.5% to 2.5%, 1% to 2% and 1% to 2% (wt%).

[0010] In further features, the first particulate electrode material of the N negative electrodes has a thickness on opposite sides of the first current collector in a range of 31 µm (+ / -5µm); the first current collector includes a copper foil with a thickness in a range of 8 µm (+ / -2µm); the first current collector has a width in a range of 13 cm (+ / -5%); and the first current collector has a height in a range of 10.3 cm (+ / -5%).

[0011] In further features, the second particulate electrode material of the PM positive electrodes of the P positive electrodes further includes conductive carbon, carbon nanotubes, and polyvinylidene fluoride.

[0012] In other features, the weight percentages of lithium iron phosphate, conductive carbon, carbon nanotubes, and polyvinylidene fluoride are 90 to 94%, 4 to 6%, 0.1 to 0.4%, and 2 to 4% (wt%), respectively.

[0013] In further features, the second particulate electrode material of the PM positive electrodes of the P positive electrodes has a thickness on opposite sides of the third current collector in a range of 50 µm (+ / - 5µm); the second current collector has a carbon-coated aluminum foil with a thickness in a range of 12 µm (+ / - 2µm); the second current collector has a width in a range of 13 cm (+ / -5%); and the second current collector has a height in a range of 10 cm (+ / -5%).

[0014] In further features, the third particulate electrode material of the M positive electrodes of the P positive electrodes has a thickness on opposite sides of the third current collector in a range of 100 µm (+ / - 30 µm); the third current collector includes an etched aluminum foil with a thickness in a range of 20 µm (+ / - 2 µm); the third current collector has a width in a range of 13 cm (+ / - 5%); and the third current collector has a height in a range of 10 cm (+ / - 5%).

[0015] In further features, the separators comprise a first layer of a ceramic film; a second layer of a polyethylene film; and a third layer of ceramic.

[0016] In further features, the separators have a thickness in a range of 13 µm (+ / - 1µm) and the separators have a height in a range of 10 cm (+ / -5%).

[0017] Other features include an electrolyte.

[0018] In further features, the electrolyte contains 1.2M lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC).

[0019] In further features, the electrolyte further contains at least one of vinylene carbonate, lithium difluorophosphate and ethylene sulfate (DTD).

[0020] In one feature, a capacitor-assisted pouch-type battery cell comprises: N negative electrodes, where N is 28, each of the N negative electrodes comprising a first current collector having a width in the range of 13 cm (+ / -5%) and a height in the range of 10.1 cm (+ / -5%), a first, graphite-containing particulate electrode material disposed on opposite sides of the first current collector, and a first tab; P positive electrodes, wherein PM positive electrodes of the P positive electrodes comprise a second current collector having a width in the range of 13 cm (+ / -5%) and a height in the range of 10 cm (+ / -5%), a second, lithium iron phosphate (LFP)-containing particulate electrode material disposed on opposite sides of the second current collector, and a second tab;M positive electrodes of the P positive electrodes comprise a third current collector having a width in a range of 13 cm (+ / -5%) and a height in a range of 10 cm (+ / -5%), a third particulate electrode material containing activated carbon (AC) disposed on opposite sides of the third current collector, and a third tab; and P is 27 and M is 2; separators disposed between the N negative electrodes and the P positive electrodes; and a pouch envelope surrounding the N negative electrodes, the P positive electrodes, and the separators.

[0021] In further features, the M positive electrodes of the P positive electrodes are arranged at a 2nd and 26th position.

[0022] In further features, the first particulate electrode material of the N negative electrodes further contains conductive carbon, carboxymethyl cellulose (CMC), and styrene-butadiene copolymer (SBR), and weight percentages of the graphite, the conductive carbon, the carboxymethyl cellulose (CMC), and the styrene-butadiene copolymer (SBR) are 94% to 96%, 1.5% to 2.5%, 1% to 2%, and 1% to 2% (wt%), respectively; the first particulate electrode material of the N negative electrodes has a thickness on opposite sides of the first current collector in a range of 31 µm (+ / - 5 µm); and the first current collector has a copper foil with a thickness in a range of 8 µm (+ / - 1 µm).

[0023] In further features, the second particulate electrode material of the PM positive electrodes of the P positive electrodes further contains conductive carbon, carbon nanotubes, and polyvinylidene fluoride, weight percentages of the lithium iron phosphate, the conductive carbon, the carbon nanotubes, and the polyvinylidene fluoride are 90 to 94%, 4 to 6%, 0.1% to 0.4%, and 2 to 4% (wt%), respectively, the second particulate electrode material of the PM positive electrodes of the P positive electrodes has a thickness on opposite sides of the third current collector in a range of 46 µm (+ / - 3 µm); and the second current collector includes a carbon-coated aluminum foil with a thickness in a range of 12 µm (+ / - 1 µm).

[0024] In further features, the third particulate electrode material of the M positive electrodes of the P positive electrodes has a thickness on opposite sides of the third current collector in a range of 100 µm (+ / - 5 µm) and the third current collector includes an etched aluminum foil having a thickness in a range of 20 µm (+ / - 2 µm).

[0025] Further areas of applicability of the present invention will become apparent from the detailed description, claims and drawings. Brief description of the drawings

[0026] The present invention will be more fully understood from the detailed description and the accompanying drawings, in which: Fig. 1 is a side view of an example of a pouch-type capacitor-assisted battery cell (CAB) according to the present invention; Fig. 2A is a partial side cross-sectional view of an example of a part of the bag-type CAB cell according to the present invention; Fig. 2B is a side cross-sectional view of an example of a negative electrode according to the present invention; Fig. 2C is a side cross-sectional view of an example of a capacitor positive electrode containing activated carbon according to the present invention; Fig. 2D is a side cross-sectional view of an example of a positive battery electrode containing lithium iron phosphate (LFP) according to the present invention; Fig. 3 is a side cross-sectional view of an example of a bag-type CAB cell according to the present invention; and Fig. 4A and Fig. 4B are side views of an example of a bag-type CAB cell according to the present invention.

[0027] Reference numerals may be reused in the drawings to identify similar and / or identical elements. Detailed description

[0028] The present invention relates to a capacitor-assisted battery (CAB) bag-type cell with improved performance. The CAB cell contains positive electrodes comprising LFP-containing positive battery electrodes and activated carbon positive capacitor electrodes. The CAB cell comprises graphite negative electrodes. Separators are disposed between the positive and negative electrodes. The liquid electrolyte is contained within a bag-like enclosure of the bag-type CAB cell. Further details are set forth below.

[0029] Now on Fig. Referring to Figure 1, a bag-type CAB cell 10 includes a bag-like enclosure 14. As described further below, the bag-like enclosure 14 of the bag-type CAB cell 10 encloses positive electrodes, negative electrodes, separators, and the electrolyte. Positive and negative terminals 16, 18 are connected to the tabs of the positive and negative electrodes and extend through the bag-like enclosure 14.

[0030] Now on Fig. Referring to Figures 2A-2D, a portion of the bag-type CAB cell 10 is shown. In Fig. 2A, the bag-type CAB cell 10 has negative electrodes 20-1, ..., 20-(N-1), and 20-N (collectively, negative electrodes 20) and positive electrodes 26-1, ..., 26-(P-1), and 26-P (collectively, positive electrodes 26) (where N and P are integers greater than one). The bag-type CAB cell 10 includes a plurality of separators 24 disposed between the negative electrodes 20 and the positive electrodes 26.

[0031] The negative electrodes 20 and the positive electrodes 26 include a current collector 42 and a tab 44 extending beyond the particulate electrode material 46. The tabs 44 of the negative electrodes 20 and the positive electrodes 26 are connected to the negative terminal 18 and the positive terminal 16, respectively, of the bag-type CAB cell 10. A first side and a second side of the current collector 42 are connected to particulate electrode material 46. As used herein, positive (+) and negative (-) refer to the electrical charge of the charged electrode in the cell unit (while being discharged).

[0032] In Fig. 2B-2D show examples of the particulate electrode material 46. In Fig. 2B, the particulate electrode material 46 of the negative electrodes 20 consists of graphite. In Fig. 2C, the particulate electrode material 46 of some of the positive electrodes 26-AC consists of activated carbon (AC) (which forms a positive capacitor electrode). In Fig. 2D, the particulate electrode material 46 of the remaining electrodes of the electrodes 26-LFP consists of lithium iron phosphate (LFP) (which forms a positive battery electrode).

[0033] Now on Fig. 3, the bag-type CAB cell 100 includes the negative electrodes 20-1, 20-2, ..., 20-N, where N = 28. In some examples, the particulate electrode material 46 of the negative electrodes 20 is made of graphite. The CAB cell 100 further includes the positive electrodes 26-1, 26-2, ..., 26-P, where P = (N - 1) = 27. The particulate electrode material 46 of two of the positive electrodes 26 is made of activated carbon (AC). The particulate electrode material of 25 of the positive electrodes 26 is made of lithium iron phosphate (LFP).

[0034] In this example, the positive electrodes 26 arranged at the 2nd and 26th positions (corresponding to the positive electrodes 26-2 and 26-26 from left to right in Fig. 3) positive capacitor electrodes made of activated carbon. As can be seen, the positive electrodes 26-2 and 26-26 are arranged approximately equidistant from a center of the bag-type CAB cell 100, as shown in Fig. 3. Although specific positions are shown and described, the positive capacitor electrodes made of activated carbon may be arranged at other, approximately equidistant positions, such as the 3rd and 25th, the 4th and 24th, the 5th and 23rd, etc.

[0035] The positive capacitor electrodes may be arranged at other, approximately equidistant positions, such as the 2nd and 22nd, 4th and 23rd, 5th and 25th positions, etc. As used herein, "approximately equidistant" means within 10% of the equidistance. This arrangement enables more uniform thermal heating and cooling characteristics. As can be seen, the separators 24, the electrolyte 40, and other details are omitted for the purpose of illustration and clarity. Fig. 3 omitted.

[0036] In some examples, the positive electrodes 26-LFP have a width in the range of 13 cm (+ / - 5%) and a height in the range of 10 cm (+ / - 5%). The particulate electrode material 46 of the positive electrodes 26-LFP has a surface area of ​​less than 10 m 2 / g, a carbon coating of 1.5% + / - 1%, and a particle size D50 = 2 + / - 1µm and D97 < 8µm. The particulate electrode material 46 of the 26-LFP positive electrodes includes lithium ion phosphate (LFP), conductive carbon Super P® (SP), carbon nanotubes (CNT), and polyvinylidene fluoride (PVDF). In some examples, the chemical formulation for LFP / SP / CNT / PVDF is 90 to 94%, 4 to 6%, 0.1 to 0.4%, and 2 to 4% (wt%) of the particulate electrode material 46, respectively. In other examples, the chemical formulation for LFP / SP / CNT / PVDF is 92%, 4.8%, 0.2%, and 3% (wt%) of the particulate electrode material, respectively. In some examples the mass loading is 8.7 + / - 2 mg / cm 2 and the capacity loading 1.1 + / - 0.5 mAh / cm 2 (one-sided).

[0037] In some examples, the positive electrodes 26-LFP have a compression density of 2.0 ±0.3 g / cm 3and a porosity of 41 ±5%. The positive electrodes 26-LFP have a layer thickness of 50 µm (+ / - 5 µm) (one side) and a total thickness of 112 µm (+ / - 10 µm). The current collector 42 consists of a carbon-coated aluminum foil with a thickness of 12 µm (+ / - 2 µm), although other materials and thicknesses can also be used.

[0038] In some examples, the positive electrodes 26-AC have a width in the range of 13 cm (+ / - 5%) and a height in the range of 10 cm (+ / - 5%). In some examples, the particulate electrode material of the positive electrodes 26-AC consists of Kuraray YP50. The positive electrodes 26-AC have a mass loading of 7±2 mg / cm 2 and a capacity loading of 0.3 ± 0.15 mAh / cm 2 The positive electrodes 26-AC have a layer thickness of 100 µm (+ / - 30 µm) (one-sided) and an electrode thickness of 220 µm (+ / - 60 µm) with a porosity of 85 ± 10%.

[0039] In some examples, the positive electrodes 26-AC are manufactured using a dry process based on polytetrafluoroethylene (PTFE). The current collector of the positive electrodes 26-AC consists of an etched aluminum foil with a thickness of 20 µm (+ / - 2 µm), although other materials and thicknesses can be used. In other examples, the positive electrodes 26-AC are manufactured using a PVDF-based wet process. The current collector of the positive electrodes 26-AC consists of a carbon-coated aluminum foil with a thickness of 20 µm (+ / - 5 µm), although other materials and thicknesses can be used.

[0040] In some examples, the negative electrodes 20 have a width in the range of 13.2 cm (+ / - 5%) and a height in the range of 10.3 cm (+ / - 5%). In some examples, the particulate electrode material 46 of the negative electrodes 20 includes graphite with a surface area of ​​2+5 / - 0.5 m2 / g and a particle size D50 of 7+5 / - 3 µm. In some examples, the particulate electrode material 46 comprises graphite, conductive carbon Super P® (SP), carboxymethylcellulose (CMC), and styrene-butadiene copolymer (SBR). In some examples, the chemical formulation for graphite / SP / CMC / SBR is 94% to 96%, 1.5% to 2.5%, 1% to 2%, and 1% to 2% (wt%), respectively, of the particulate electrode material 46. In some examples, the chemical formulation for graphite / SP / CMC / SBR is 95%, 2%, 1.2%, and 1.8% (wt%), respectively, of the particulate electrode material 46. In some examples, the electrode mass loading is 4 mg / cm 2 and the capacity loading 1.3±0.5 mAh / cm 2 (one-sided).

[0041] In some examples, the pressing density of the graphite electrodes is 1.4 ±0.3 g / cm 3and the porosity is 47.0±5%. The negative electrodes have a layer thickness of 31 µm (+ / - 5 µm) (single-sided) and an electrode thickness of 70 µm (+ / - 10 µm). The current collector consists of a Cu foil with a thickness of 8 µm (+ / - 2 µm), although other materials and thicknesses can also be used.

[0042] In some examples, the separators 24 have a height in the range of 10.7 cm (+ / - 5%). The separators 24 consist of outer ceramic layers and a polyethylene (PE) layer sandwiched between them. In some examples, the separators 24 have a thickness of 13 µm (+ / - 1 µm) and include a 2 µm ceramic layer, a 9 µm PE film, and a 2 µm ceramic layer. In some examples, the separators 24 have a thickness of 12 µm (+ / - 1 µm) and include a 3 µm ceramic layer and a 9 µm PE film. In some examples, the separators 24 have a porosity of 40±5%.

[0043] In some examples, the electrolyte 40 has the formula 1.2M lithium hexafluorophosphate (LiPF6) in a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) (4:4:2 by volume), with additional additions of 1~5% vinylene carbonate (VC), 1~3% lithium difluorophosphate (LiPF2O2), and 1~10% ethylene sulfate (DTD). In some examples, the amount of electrolyte 40 per cell is 6±2g / Ah.

[0044] Now on Fig. 4A and Fig.Referring to Figure 4B, examples of the dimensions of the pouch-type battery cell are shown in more detail. A width W1 of an edge of the positive terminal 16 is within a range of 25 mm (±3%). A width W2 of the positive terminal 16 and the negative terminal 18 is within a range of 32 (+ / -3 mm). A height H1 of the positive terminal 16 and the negative terminal 18 is within a range of 40 (+ / -5 mm). A height H2 of the pouch-like enclosure 14 is within a range of 120 mm (+ / - 5%). A width W4 of the pouch-like enclosure 14 is within a range of 133 mm (+ / - 5%). A width W6 of the connecting tab is within a range of 40 (+ / - 5 mm). A width W7 between the centers of the positive terminal 16 and the negative terminal 18 is in a range of 46 (+ / - 5 mm).

[0045] The CAB cell according to the present disclosure exhibits excellent capability for pulsed and continuous power at both warm and cold temperatures and excellent durability at high temperatures. In some examples, the 6.3Ah CAB cell according to the present invention provides reserve operating power for 3 minutes at 100W continuous power during an emergency stop of an autonomous vehicle. The CAB cell according to the present invention also provides high cranking current.

Claims

[1] A capacitor-assisted bag-type battery cell (10) comprising: N negative electrodes (20), where N is an integer greater than one, each of the N negative electrodes (20) comprising a first current collector (42), a first particulate electrode material (46) disposed on opposite sides of the first current collector (42), and a first tab (44); P positive electrodes (26), where: PM positive electrodes (26) of the P positive electrodes (26) comprise a second current collector (42), a second particulate electrode material (46) consisting of lithium iron phosphate (LFP) arranged on opposite sides of the second current collector (42), and a second tab (44), M positive electrodes (26) of the P positive electrodes (26) comprise a third current collector (42), a third particulate electrode material (46) consisting of activated carbon (AC) arranged on opposite sides of the third current collector (42), and a third tab (44) and P=N−1, M=2 and P−M≥1 hold; separators (24) arranged between the N negative electrodes (20) and the P positive electrodes (26); and a bag envelope surrounding the N negative electrodes (20), the P positive electrodes (26) and the separators (24); wherein the M positive electrodes (26) of the P positive electrodes (26) are arranged approximately equidistant from the center of the P positive electrodes (26). [2] A capacitor-assisted bag-type battery cell (10) according to claim 1, wherein N = 28 and wherein the M positive electrodes (26) of the P positive electrodes (26) are arranged at the 2nd and 26th positions. [3] The bag-type capacitor-assisted battery cell (10) of claim 1, wherein the first particulate electrode material (46) of the N negative electrodes (20) is made of graphite. [4] The pouch-type capacitor-assisted battery cell (10) of claim 3, wherein the first particulate electrode material (46) of the N negative electrodes (20) further consists of conductive carbon, carboxymethyl cellulose (CMC), and styrene-butadiene copolymer (SBR). [5] The capacitor-supported bag-type battery cell (10) according to claim 4, wherein weight percentages of the graphite, the conductive carbon, the carboxymethyl cellulose (CMC) and the styrene-butadiene copolymer (SBR) are 94% to 96%, 1.5% to 2.5%, 1% to 2% and 1% to 2% (wt%). [6] A capacitor-assisted bag-type battery cell (10) according to claim 1, wherein: the first particulate electrode material (46) of the N negative electrodes (20) on opposite sides of the first current collector (42) has a thickness in a range of 31 µm (+ / -5 µm); the first current collector (42) consists of a copper foil with a thickness in a range of 8 µm (+ / - 2 µm); the first current collector (42) has a width in a range of 13 cm (+ / -5%); and the first current collector (42) has a height in the range of 10.3 cm (+ / -5%). [7] The capacitor-assisted bag-type battery cell (10) of claim 1, wherein the second particulate electrode material (46) of the PM positive electrodes (26) of the P positive electrodes (26) further consists of conductive carbon, carbon nanotubes, and polyvinylidene fluoride. [8] The capacitor-assisted bag-type battery cell (10) according to claim 7, wherein weight percentages of the lithium iron phosphate, the conductive carbon, the carbon nanotubes and the polyvinylidene fluoride are 90 to 94%, 4 to 6%, 0.1 to 0.4% and 2 to 4% (wt%), respectively. [9] A capacitor-assisted bag-type battery cell (10) according to claim 1, wherein: the second particulate electrode material (46) of the PM positive electrodes (26) of the P positive electrodes (26) has a thickness on opposite sides of the third current collector (42) in a range of 50 µm (+ / - 5 µm); the second current collector (42) consists of a carbon-coated aluminum foil with a thickness in a range of 12 µm (+ / - 2 µm); the second current collector (42) has a width in a range of 13 cm (+ / -5%); and the second current collector (42) has a height in the range of 10 cm (+ / -5%). [10] A capacitor-assisted bag-type battery cell (10) according to claim 1, wherein: the third particulate electrode material (46) of the M positive electrodes (26) of the P positive electrodes (26) has a thickness on opposite sides of the third current collector (42) in a range of 100 µm (+ / - 30 µm); the third current collector (42) consists of an etched aluminum foil with a thickness in a range of 20 µm (+ / - 2 µm); the third current collector (42) has a width in a range of 13 cm (+ / -5%); and the third current collector (42) has a height in the range of 10 cm (+ / -5%).

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